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Residential energy efficient device adoption in South Africa
Sustainable Energy Technologies and Assessments 1 (2013) 13–27
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Orginal Research Article
Residential energy efficient device adoption in South Africa Kevin C. van Blommestein, Tugrul U. Daim ⇑ Engineering and Technology Management Department, Portland State University, P.O. Box 751, Portland, OR 97207, United States
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Article history: Recived 24 July 2012 Revised 20 November 2012 Accepted 4 December 2012
Keywords: Energy efficiency Hierarchical decision model Technology assessment Energy technology innovation South Africa
a b s t r a c t In recent years there has been a major drive for the adoption of energy efficient devices in the residential sector of South Africa. The public utility company has introduced incentives for solar and heat pump water heaters, and has begun a residential mass rollout program, in order to encourage this adoption. In this paper we attempt to evaluate a consumer’s decision when purchasing energy efficient devices in order to determine whether current incentives are focused towards the technologies that consumers are seeking. Since the adoption of energy efficient devices is a purchasing decision by the consumer, we created a Hierarchical Decision Model (HDM) in order to understand this decision. We created two scenarios in order to analyze the model, one without incentives from the utility, and one with incentives. We established that the addition of incentives for heat pump water heaters and solar water heaters shifted the preference of these technologies above the other technologies, possibly justifying the large investments in the 2010/2011 financial period. This model could be used to give insight into the incentive structure for a utility company introducing new technologies to the market. Additionally, if a company wants to encourage the adoption of a specific energy efficient technology, it could use the model to determine how it is positioned against other technologies and adjust pricing, incentives, and investments into the research and development of the device. Ó 2012 Elsevier Ltd. All rights reserved.
Introduction The power shortages experienced in late 2007 ignited the requirement for the adoption of energy efficient technologies and the reduction in electricity usage by consumers in South Africa [1]. South Africa experienced widespread blackouts due to demand for power outstripping supply [2]. The National Energy Efficiency Strategy of South Africa was reviewed in 2008 to encourage sustainable development in the energy sector by means of energy efficient practices [3]. The target final energy demand reduction by 2015 was specified as 12%, with a reduction in the residential sector of 10%. The South African electricity public utility company established an Integrated Demand Management (IDM) division in response to the energy challenges facing South Africa [4]. The purpose of IDM was to coordinate initiatives aimed at optimizing energy usage by the consumer and the promotion of energy-efficient technologies, processes and behavior among consumers.IDM implemented two methods in the residential sector, offering incentives for the purchase of solar water heater and heat pump water heaters, and offering compact fluorescent lighting, LED lighting, domestic water heater controllers, and low-flow showerheads free of charge by means of the residential mass rollout program. However, as ⇑ Corresponding author. E-mail address: [email protected] (T.U. Daim). 2213-1388/$ - see front matter Ó 2012 Elsevier Ltd. All rights reserved. http://dx.doi.org/10.1016/j.seta.2012.12.001
specified in the National Energy Efficiency Strategy of South Africa, it was difficult to justify subsidies for energy efficiency when there were so many other pressing needs nationwide. The focus of investments into the correct energy efficient technologies is therefore a priority that should be further studied. In order to achieve this, the decisions that a consumer takes into account when purchasing these energy efficient technologies should be evaluated. The commonly adopted Hierarchical Decision Model (HDM) is used for breaking down a decision into criteria, factors (sub criteria) and alternatives. These criteria and factors are used to determine the priorities for a consumer’s decision. This paper attempts to evaluate the consumer’s decision using HDM in order to determine whether current incentives are focused towards the technologies that consumers are seeking. Additionally, the weights of the criteria and factors can give a better understanding of what the consumer is looking for and what changes can be made to the energy efficient devices to accommodate these preferences. Literature review Electricity in South Africa Fig. 1 illustrates the electricity market share for South Africa together with the residential electricity consumption. One of the focuses of the Integrated Demand Management (IDM) division of
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Residential Electricity Consumption (South Africa)
Electricity Market Share (South Africa)
Cold Storage 5% Residental 18%
Industrial 48%
Other 12%
Agriculture 4%
Space Heating 16%
Pool Pump 11%
Transport 2%
Laundry 3% Other Cooking 1%
Commerical 10%
Stove and Oven 7% Lights 6%
Water Heating (Geyser) 39%
Mining 18%
Fig. 1. Electricity market share and residential electricity consumption [5,6].
Expenditure 2010/2011 Financial Year Heat pumps 7%
Residential Lighting 9%
4000 3500 Capacity (MW)
3000
Solar Water Heating
2500
Shower Heads
2000
Process Optimization
1500
New Initiatives
1000
Lighting HVAC Heat Pumps
500
Compressed Air Systems 2019
Fig. 3. Cumulative committed demand side management programs [8].
Multi perspective technology assessment Technology assessment is considered to be a method covering multiple perspectives ranging from social to political to technical [9]. Benson et al. [10] demonstrated the practical application of multiple perspectives with micro-electromechanical systems. Tran and Daim [11] reviewed and classified technology assessment methods. One of the interesting conclusions was that the private sector tended to use different methods for technology assessment when compared to government. Multi perspective models seemed to be used in both cases [12,13]. Hierarchical decision models (HDM) or analytical hierarchy process (AHP) are the names used for such assessments. HDM or AHP is a method used for breaking down various aspects of a problem into smaller sub-problems [14]. The model is generally represented as a tree diagram, consisting of a goal, criteria, sub criteria, and alternatives. A method called pairwise comparison is used to Evening Peak Demand Savings Achieved2010/2011
Water heating Load Mgt. 5%
Process Optimisatio n 21%
Solar Water Heating 2%
Heat pumps 0%
Compressed. Air System 18% Solar Water Heating 41% Ind. Lighting & HVAC 7%
Compressed Air Systems 12% Process Optimisation 13%
2020
2018
2016
2017
2015
2014
2012
2013
2011
0 2010
the utility company in South Africa was to encourage the adoption of energy efficient technologies in the residential sector. The focus of this paper is only on the residential sector, which makes up 18% of the market share. Of the residential electricity consumption, water heating (geyser) makes up the largest section (39%), followed by space heating (16%). Fig. 2 illustrates the evening peak demand savings achieved in 2010/2011 financial year for alternative Demand Side Management (DSM) programs, as a percentage of the total savings of 354.1MW [7]. This is above the target set by the utility company of 301MW. Additionally, the 2010/2011 expenditure for each of these programs is illustrated as a percentage of the total expenditure of R545 million [7]. It can be seen that the highest evening peak demand savings was achieved by residential lighting, even with one of the lowest investments. This may be due to the low pricing of CFL lighting that was distributed in the residential mass rollout program. It is also interesting to note that the high investment in solar water heating resulted in a relatively low evening peak demand savings. Fig. 3 illustrates the cumulative committed Demand Side Management (DSM) programs by the utility company for all sectors, as mentioned in the Integrated Resource Plan for Electricity in 2010 (IRP2010) [8]. The primary objective of the IRP2010 was to determine the long-term electricity demand and to specify how this demand would be met by generating capacity, type, cost and time of introduction. The majority of the committed DSM programs were focused toward expanding Solar Water Heating and Heat Pump Water Heating adoption. However, this was only a section of the potential total market for Energy Efficient Demand Side Management (EEDSM), which was estimated by the utility company to be 12933MW.The increase in committed DSM programs is required to deal with the increase in forecasted demand, which cannot be completely dealt with by only increasing the supply.
Water heating Load Mgt 9%
Fig. 2. Demand side management expenditure and savings [7].
Residential Lighting 56%
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evaluate the importance among criteria to the goal by comparing one criterion against another for all criteria. This is repeated for the sub criteria under each criterion to establish its importance to the criterion. The outcome of the model is a ranking among alternatives to the goal. In this project the goal is the selection of an energy efficient device by the consumer. The criteria are aspects that the consumer takes into account when selecting the energy efficient device, and the sub criteria are factors under each of the criterion. The alternatives are the different energy efficient technologies. HDM or AHP based models are common in assessing energy technologies [15]. They were used for evaluating power plants [16–22]; energy storage [23]; natural gas resources [16]; energy source and water desalination combination [24]; diffusion of renewable energy [25]; wind turbine design [26]; energy systems [27,28]; energy alternatives [29–31]; alternative fuels [32]; energy project selection [33]; energy efficiency [34]; building material [35] and wind turbine evaluation [36]. Methodology In this paper we try to establish whether the incentives introduced by the utility company are focused toward the appropriate energy efficient technologies, by examining the purchasing decisions of consumers. We used a HDM in order to structure the purchasing decision of a consumer into an objective, criteria, factors (sub criteria), and alternatives. The weights of each of these criteria and factors could be evaluated to understand their importance in the purchasing decision. The following methodology was therefore followed: (1) establish a HDM with criteria, factors, and alternatives (energy efficient devices) for the selection of an energy efficient device by the consumer (objective); (2) create a survey with pairwise comparisons and distribute to consumers in South Africa; (3) use the Pairwise Comparison (PCM) software [37]to determine the weights for criteria and factors from the survey responses; (4) evaluate the weights of the criteria and factors to determine their importance in the purchasing decision by the consumer. The criteria and factors with the highest weights are seen as the most important to the consumer. Additionally to determine how the factors affect the purchasing decision directly, the criteria weights and factor weights are multiplied and evaluated; (5) by using the weights from the criteria and factors, the alternative energy efficient devices are ranked against one another to determine which device would be preferred by the consumer. Two different scenarios are evaluated, one with incentives from the utility company and one without incentives; (6) introduce suggestions on the adoption of these technologies and assess whether the incentives are focused on the correct technologies. Determine possible alternative technologies for investment. Hierarchical decision model (HDM)
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account, the model was created to focus on the most common criteria and factors. The criteria chosen for the HDM model were performance, environmental, economic, service and support, and convenience. The description of each of these criteria and factors are described below. Performance [38,39] (1) Operating lifetime – this is the life expectancy of the energy efficient device, after which it should be replaced. (2) Upgradability – this is how simple and how expensive it is to upgrade the energy efficient device. The 5-point scale for this factor is described in Appendix D. (3) Reliability – this is the possibility of failure of part of the energy efficient device. The 5-point scale for this factor is described in Appendix D. (4) Effectiveness – this specifies whether the energy efficient device affects everyday life. As an example, a domestic water heater controller will turn off the water heater during some hours of the day; therefore, hot water will not always be available. This will therefore have a low effectiveness. The 5-point scale for this factor is described in Appendix D. Environmental [40] (1) Environmental performance – this is the reduced impact that the energy efficient device will have on the environment [42], which is related to the kWh savings and the purchase and installation cost of the device. This is looking at the performance per amount spent on the device. (2) Social environmental conformity – the purpose of this factor was to establish whether a consumer’s environmental awareness and concern was based on the social norm rather than on the actual reduced environmental impact achieved by energy efficient devices. Therefore, a constant value was given to all technologies for this factor since it is purely to evaluate the consumer and not to differentiate the technologies. Economic [38–41] (1) Purchase and installation cost – this is the fixed installation and purchase cost for the energy efficient device as specified on the utility and manufacturers website. (2) Maintenance cost – this is the cost associated with each maintenance interval for the energy efficient device as a percentage of the purchase cost. The 5-point scale for this factor is described in Appendix D. (3) Utility incentive/rebate – this represents the incentives offered by the utility when purchasing the energy efficient device (i.e. a certain percentage of the purchase and installation cost is reimbursed). (4) Payback period – this is the expected payback period of the initial purchase and installation cost, recuperated from the savings per month. (5) Savings per month – this is the monetary savings obtained per month after installing the energy efficient device, due to reduced electricity and water consumption. Service and support [38,39]
Criteria and factors The criteria and factors were chosen based on previous literature [38–41] and discussions with consumers in South Africa to determine what affects their purchasing decision. Although there are many criteria and factors that consumers may take into
(1) Length of warranty – this is the length of the warranty from the supplier in years from the date of purchase. (2) Type of warranty – this is the warranty coverage for the energy efficient device, which could be none, limited, or full coverage.
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(3) Maintenance intervals – this is the expected duration in months between routine maintenance activities on the energy efficient device. Convenience [41] (1) Operational simplicity – this is how easy the energy efficient device is to operate by the consumer. Some devices require no interaction and are seen as the simplest to operate. The 5-point scale for this factor is described in Appendix D. (2) Space Usage – this is how much valuable space the energy efficient device utilizes, based on the size and position of the device. The 5-point scale for this factor is described in Appendix D. (3) Visual impact - This is whether the energy efficient device changes the aesthetics of a building. As an example, a solar panel installed on the roof or on the side of the building could affect purchasing decisions. The 5-point scale for this factor is described in Appendix D. (4) Accessibility – this is how easy it is to obtain access to the energy efficient devices, which would be crucial for maintenance inspections, repairs, etc. The 5-point scale for this factor is described in Appendix D. Available technologies The energy efficient technologies that were chosen for the model can be separated into three groups. In group one are technologies that the utility company is currently pursuing, group two are technologies mentioned by the utility company as future options, and in group three are suggested technology options. The 10 technologies areas follow: Group 1: pursued technologies (1) Solar water heater: this technology can save up to 70% of the electricity used for water heating (39%) [43]. There is a current rebate for this technology that ranges between 20% and 30% of the purchase and installation cost. For the HDM it was assumed that a 200-L (53-gallon) electric water heater (geyser) was currently installed and would be retrofitted with new solar water heating equipment [44]. (2) Heat pump water heater: this technology can save up to 67% of the electricity used for water heating (39%) [42]. There is a current rebate from the utility for the purchase of this technology that ranges between 20% and 30% of the purchase and installation cost. For the HDM it was assumed that a 200 L (53 gallon) electric water heater (geyser) was currently installed and would be retrofitted with a new heat pump [45]. (3) Low-flow showerhead: this technology reduces the flow (liters per minute) from the showerhead, thereby reducing the amount of water used during showering and the amount of electricity required to heat more water. It was calculated that this technology could save up to 20% of the electricity used for water heating (39%) [46]. It was assumed that a household had two showerheads that would be replaced with the new low-flow showerheads. The technology is supplied free of charge as part of the Residential Mass Rollout program [47,48]. (4) Domestic water heater controller: this technology is used to turn the water heater off during certain times of the day. It was calculated that this technology can save up to 10% of the electricity consumption [46]. The technology is supplied free of charge as part of the residential mass rollout program [47,48].
(5) LED lighting: it was assumed that a household currently has twenty incandescent light bulbs that could be replaced with LED light bulbs. The savings for this technology is said to be up to 90% of the lighting consumption (6%) [48]. The technology is supplied free of charge as part of the residential mass rollout program [47,48], however with a small installation cost. Group 2: possible technologies (1) Energy efficient pool pump: this is a variable speed pool pump that reduces power consumption by running at lower speeds. It is mentioned that the technology can save up to 70% of the pool pump consumption (11%) [49]. There is no current incentive for this technology. (2) Gas stove hob: this is the replacement of the current electric stove with a gas stove, therefore requiring LP Gas instead of electricity. It is calculated that the use of LP Gas will cost 15% more than electricity to perform the same function [50]. There is no current incentive for this technology. (3) Energy efficient appliances: this is the replacement of the current clothes washer and dryer, fridge, and dishwasher with Energy Star qualified appliances [51–53]. There are no current incentives for these technologies and the purchasing costs are generally high. Group 3: suggested technologies (1) Occupancy sensors: this technology is used to turn the lights on or off when someone enters or leaves a room. It is mentioned that this technology can save up to 70% of the lighting consumption (6%) [54]. It was assumed that there are ten rooms per household that would require occupancy sensors. There is no current incentive for this technology. (2) Customer engagement platform: this is a method of engaging the customer in becoming more energy efficient by distributing electricity savings reports, methods of saving electricity, etc. The savings for this technology can be up to 3.5% of the total monthly consumption, based on savings illustrated on the OPower website [55]. Technology assumptions In order to determine the savings per month and payback period for each technology the following assumptions were made: (1) the average monthly electricity bill was R1200 per month [42] and the 2012/2013 tariff was R1.20 per kWh [56], (2) optimal savings per technology, as previously specified, was achieved, (3) the average distribution of Electricity Consumption, as shown in Fig. 1, was followed, (4) the price of Liquid Petroleum Gas (LPG) was R22.08 per kg (June, 2012) [57] (used to calculate savings for the gas stove hob), and 2012/2013 water tariff for Johannesburg was R19.68 per kL [58] (used to calculate savings from appliances). Decision model Fig. 4 illustrates the HDM for the selection of an energy efficient device in the residential sector. The model is structured with the objective (residential energy efficient device selection), criteria (performance, environmental, economic, service and support, and
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Fig. 4. HDM model.
convenience), the factors associated with each criterion, and finally all the technology options. Expert responses The experts for the model are the consumers, the persons making the decision when purchasing an energy efficient device. The survey shown in Appendix A was sent out to possible consumers (home owners) in South Africa. A total of eleven complete responses were received, all in the middle to high income housing category. The respondent ages ranged from the mid-twenties to early sixties, and the majority were professionals in their respective fields. Although the pairwise comparison process is clearly stated in the beginning of the survey, some responses were not complete or were not completed correctly and were therefore disregarded. Calculating weights The survey in Appendix A was used to obtain the pairwise comparisons from the consumers in South Africa. The comparisons were manually entered into the Pairwise Comparison Method (PCM) software [37] and the respective weights for the criteria and factors were obtained. The technology rankings were then obtained using these weights and the technology values per device. Results Criteria weights Fig. 5 illustrates the weights for the five criteria together with the inconsistency value between the responses. Out of the eleven responses there were two inconsistencies above 0.1 for the criteria pairwise comparison. It can be seen that the ‘‘Performance’’ and ‘‘Economic’’ criteria have the highest weights, while the ‘‘Support and Service’’ criterion has the lowest weight.
Fig. 5. Criteria weights.
Factor weights Factor weight under criteria The weights for each factor are shown in Fig. 8 in Appendix B. There was a total of two inconsistencies above 0.1 from individual responses, out of a total of fifty-five pairwise comparisons. The inconsistencies among the eleven respondents were all below 0.1. The highest and lowest factors under each criterion are summarized in Table 1. Factor weights to objective Fig. 6 illustrates the weights for each factor to the objective. This was calculated by multiplying the weight for a criterion with the weight for a factor. As an example, ‘‘Operating Lifetime’’ was calculated by multiplying the weight for criterion ‘‘Performance’’ with the weight for factor ‘‘Operating Lifetime’’. The calculated weights give a better representation of the impact of the factors on the overall decision. It is shown that the ‘‘Environmental Performance’’ factor was the most important factor to the consumer when making the purchasing decision, while the least important factors to consumers were ‘‘Upgradability’’ and ‘‘Utility Incentive/
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Technology ranking
Table 1 Highest and lowest factors for each criterion. Criteria
Highest factor
Lowest factor
Performance Environmental
Operating lifetime, reliability Environmental performance
Economic Support and service Convenience
Purchase and installation cost Length of warranty, type of warranty Operational simplicity
Upgradability Social environmental conformity Utility incentives/rebate Maintenance intervals Space usage
Overall Weight
Rebate’’. A majority of the highest factors were under the ‘‘Performance’’ and ‘‘Environmental’’ criteria.’’Utility Incentive/Rebate’’ was possibly one of the lowest factors since consumers were more concerned about the payback period for the device rather than the incentives offered.
The rankings for ‘‘Without Incentives’’ was calculated by setting the ‘‘Utility Incentive/Rebate’’ factor value per technology close to zero. The value was changed to the current incentives offered by the utility company in order to calculate the ‘‘With Incentives’’ ranking. Technology values in Appendix C [59–61] were used for calculations. Fig. 7 illustrates the outcome of the decision model, showing the ranking among the energy efficient technologies with and without incentives. Without incentives the domestic water heater controller was ranked the highest among the technologies, while the gas stove hob and energy efficient appliances were ranked the lowest. With incentives the heat pump water heater moved ahead of the domestic water heater controller, while the gas stove hob and energy efficient appliances remained the lowest. Additionally, the solar water heater and LED lighting moved to the
0.14 0.12 0.1 0.08 0.06 0.04 0.02 0
Factors Fig. 6. Factor weights to goal.
Fig. 7. Technology rankings with and without incentives.
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same level as the domestic water heater controller. The low-flow showerhead and customer engagement platform remained in the top six ranked devices with and without incentives. Results discussion As mentioned under results, the domestic water heater controller was ranked the highest without incentives. This is because the purchase and installation cost is low with a relatively high savings per month, which also results in a high environmental performance. The outcome remains similar for the domestic water heater controller with incentives; however the solar water heater and heat pump water heater move above the controller in the rankings. This is due to the high incentives for the technologies, the high savings per month and the high environmental performance achieved. The lowest ranked technologies were the energy efficient pool pump, energy efficient appliances, and the gas stove hob with and without incentives. The pool pump and appliances both have a high purchase and installation cost with a relatively low savings per month, and therefore a low environmental performance. Since LP Gas is more expensive in South Africa than electricity for the same output [50], the gas stove hob was bound to be one of the
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lowest ranked. None of these technologies has incentives from the utility company and therefore their rankings do not change. As shown in the IRP2010, the largest growth of energy efficient devices until 2020 will be solar water heaters and heat pumps [8]. As discussed, these two technologies move up the rankings when incentives are introduced, which correlates with the intended investments in these technologies. Also shown are the benefits of the residential mass rollout program for LED lighting, however the savings per device is not as substantial as the water heating technologies. The customer engagement platform ranked relatively well with and without incentives, which could possibly be pursued as a viable option for the utility company. The expenditure into solar water heaters was substantially higher than heat pumps in 2010/2011 financial year. From this paper it can be suggested that the utility company invests more into the heat pump technology and the customer engagement platform, as opposed to the high investments into solar water heaters. As described under available technologies, the customer engagement platform can be introduced into the residential sector easier than other technologies. However the adoption of this technology in South Africa has not yet been proven. A trial introduction of this technology should be conducted before pursuing a complete implementation.
Fig. 8. Criteria and factor weights and inconsistencies.
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Conclusion
Future work
The model is an effective method of obtaining consumer expectations from multiple perspectives when selecting an energy efficient device. It confirms that the addition of incentives for heat pump water heaters and solar water heaters ranks these technologies above most of the others. The large investments into these technologies can be justified by the model; however, additional evaluations of the consumer may be required. Although the decision model introduced in this article covers most of the technologies pursued by the utility company, it is possible to use the same model for new energy efficient technologies. This will give insight for the utility company to determine how it should structure the incentives for the new technologies. Additionally, if the company wanted to encourage the adoption of a specific energy efficient technology, it could use the model to determine how it is positioned against other technologies, and adjust pricing, incentives, and investments into research and development of the device.
The decision model introduced in this article is a foundation for future research that could be extended in multiple directions. A possible improvement would be to include utility curves for each factor in order to obtain a technology value for each energy efficient device, as introduced by Gerdsri and Kocaoglu [38]. The survey could also be completed by experts in the utility company and the results compared against the consumer. This may help the utility company align themselves with the consumer in order to introduce the technologies into the market more effectively. Additionally the decision model could be used for emerging technologies in the energy efficient field. The model could also be easily implemented in other countries after obtaining new weights from consumer responses. Some factors for the technologies are subjective and may require further evaluation together with the effect of the large weighting assigned to the ‘‘Environmental Performance’’ factor.
Appendix A. Survey Residential energy efficient device survey The purpose of this survey is to establish the importance of different criteria and factors that a person takes into account when deciding to purchase Energy Saving (Efficient) Devices for their home (to reduce your electricity bill). These are devices such as solar water heaters, heat pumps for water heating, energy efficient lighting, geysers controllers, low-flow shower heads, etc. Section 1: comparisons Introduction The comparisons in this section are done by a method called pairwise comparison. This is when you have 100 points available and you assign them between two options. For example, the following is comparing Performance against Environmental: Pairwise comparison Performance
40
60
Environmental
Since I see Environmental as slightly more important than Performance I assign more points to Environmental than Performance. If I see them as equal I assign 50 to Performance and 50 to Environmental. If I see Environmental as substantially more important than Performance I assign 99 points to Environmental and 1 point to Performance. Do not assign 100 point to one option only. Also make sure that the values add up to 100 points for each comparison. Comparison 1 The first comparison is between the following criteria when purchasing an Energy Saving (Efficient) device: (1) Performance – this is the performance (reliability, lifetime) of the Energy Saving device. (2) Environmental – this is the positive effect on the environment the Energy Saving device has. (3) Economic – this is the purchase and installation cost, savings on your electricity bill, payback period, etc when purchasing the Energy Saving device. (4) Support and service – this is the length of the warranty and type of warranty for the Energy Saving device. (5) Convenience – this is how easy the Energy Saving device is to operate, whether you can access the device, etc. Please complete the comparison below: Pairwise comparison Performance Performance Performance Performance Environmental Environmental Environmental Economic Economic Support and service
Environmental Economic Support and service Convenience Economic Support and service Convenience Support and service Convenience Convenience
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Comparison 2 The second comparison is between factors under Performance, which are: (1) Operating lifetime – this is how many years the Energy Saving device is expected to operate. (2) Upgradability – this is how easy the Energy Saving device is to upgrade (e.g. when you upgrade the size of your geyser, how expensive and easy is it to upgrade the solar panel, geyser controller, etc.) (3) Reliability – this is how reliable the Energy Saving device is. (4) Effectiveness – this is how effective the Energy Saving device is at getting its task done in time (e.g. a solar water heating may take a long time to heat the water). Please complete the comparison below: Pairwise comparison (performance) Operating lifetime Operating lifetime Operating lifetime Upgradability Upgradability Reliability
Upgradability Reliability Effectiveness Reliability Effectiveness Effectiveness
Comparison 3 The third comparison is between factors under Environmental, which are: (1) Environmental performance – this is the positive impact that the Energy Saving device will have on the environment (i.e. green house gas emissions). (2) Social environmental conformity – if your neighbours, friends, or family are conscious about the environment, will this change your behaviour. Please complete the comparison below: Pairwise comparison (environmental) Environmental performance
Social environmental conformity
Comparison 4 The fourth comparison is between factors under Economic, which are: (1) (2) (3) (4)
Purchase and installation cost – this the fixed installation and purchase costs for the Energy Saving device. Maintenance cost – this the costs in maintaining the Energy Saving device. Utility incentive/rebate – this the Rebate from the utility (Eskom) for purchasing an Energy Efficient device. Payback period – this is the expected payback period (installation and purchase costs minus the savings on your electricity bill per month). (5) Savings per month – this is the savings obtained per month after installing the Energy Efficient device. Please complete the comparison below: Pairwise comparison (economic) Purchase and installation Purchase and Installation Purchase and installation Purchase and installation Maintenance cost Maintenance cost Maintenance cost Utility incentive/rebate Utility incentive/rebate Savings per month
cost cost cost cost
Maintenance cost Utility incentive/rebate Savings per month Payback period Utility incentive/rebate Savings per month Payback period Savings per month Payback period Payback period
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Comparison 5 The fifth comparison is between factors under Service and Support, which are: (1) Length of warranty – this is the length of the warranty by the supplier from the purchase date. (2) Type of warranty – this is none, limit or full warranty on the Energy Saving device. (3) Maintenance intervals – this is the expected time duration between maintaining the Energy Saving device. Please complete the comparison below: Pairwise comparison (service and support) Length of warranty Length of warranty Type of warranty
Type of warranty Maintenance interval Maintenance interval
Comparison 6 The sixth comparison is between factors under Convenience, which are: (1) Operational simplicity – this is how easy the Energy Saving device is to operate. (2) Space usage – this is how much space the device takes up. (3) Visual impact – this is the visual impact of the Energy Saving device (e.g. installed on the side of your house or on your roof). (4) Accessibility – this is how easy the device is to access. Please complete the comparison below: Pairwise comparison (convenience) Operational simplicity Operational simplicity Operational simplicity Space usage Space usage Visual impact
Thank you for your patience and time for completely this survey!!!!
Space usage Visual impact Accessibility Visual impact Accessibility Accessibility
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Appendix B. Criteria and factor weights per respondent
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Appendix C. Technology data
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Appendix D. Description of 5 point scale for factors
(continued on next page)
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Appendix D. (continued)
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Contents lists available at SciVerse ScienceDirect
Sustainable Energy Technologies and Assessments journal homepage: www.elsevier.com/locate/seta
Orginal Research Article
Residential energy efficient device adoption in South Africa Kevin C. van Blommestein, Tugrul U. Daim ⇑ Engineering and Technology Management Department, Portland State University, P.O. Box 751, Portland, OR 97207, United States
a r t i c l e
i n f o
Article history: Recived 24 July 2012 Revised 20 November 2012 Accepted 4 December 2012
Keywords: Energy efficiency Hierarchical decision model Technology assessment Energy technology innovation South Africa
a b s t r a c t In recent years there has been a major drive for the adoption of energy efficient devices in the residential sector of South Africa. The public utility company has introduced incentives for solar and heat pump water heaters, and has begun a residential mass rollout program, in order to encourage this adoption. In this paper we attempt to evaluate a consumer’s decision when purchasing energy efficient devices in order to determine whether current incentives are focused towards the technologies that consumers are seeking. Since the adoption of energy efficient devices is a purchasing decision by the consumer, we created a Hierarchical Decision Model (HDM) in order to understand this decision. We created two scenarios in order to analyze the model, one without incentives from the utility, and one with incentives. We established that the addition of incentives for heat pump water heaters and solar water heaters shifted the preference of these technologies above the other technologies, possibly justifying the large investments in the 2010/2011 financial period. This model could be used to give insight into the incentive structure for a utility company introducing new technologies to the market. Additionally, if a company wants to encourage the adoption of a specific energy efficient technology, it could use the model to determine how it is positioned against other technologies and adjust pricing, incentives, and investments into the research and development of the device. Ó 2012 Elsevier Ltd. All rights reserved.
Introduction The power shortages experienced in late 2007 ignited the requirement for the adoption of energy efficient technologies and the reduction in electricity usage by consumers in South Africa [1]. South Africa experienced widespread blackouts due to demand for power outstripping supply [2]. The National Energy Efficiency Strategy of South Africa was reviewed in 2008 to encourage sustainable development in the energy sector by means of energy efficient practices [3]. The target final energy demand reduction by 2015 was specified as 12%, with a reduction in the residential sector of 10%. The South African electricity public utility company established an Integrated Demand Management (IDM) division in response to the energy challenges facing South Africa [4]. The purpose of IDM was to coordinate initiatives aimed at optimizing energy usage by the consumer and the promotion of energy-efficient technologies, processes and behavior among consumers.IDM implemented two methods in the residential sector, offering incentives for the purchase of solar water heater and heat pump water heaters, and offering compact fluorescent lighting, LED lighting, domestic water heater controllers, and low-flow showerheads free of charge by means of the residential mass rollout program. However, as ⇑ Corresponding author. E-mail address: [email protected] (T.U. Daim). 2213-1388/$ - see front matter Ó 2012 Elsevier Ltd. All rights reserved. http://dx.doi.org/10.1016/j.seta.2012.12.001
specified in the National Energy Efficiency Strategy of South Africa, it was difficult to justify subsidies for energy efficiency when there were so many other pressing needs nationwide. The focus of investments into the correct energy efficient technologies is therefore a priority that should be further studied. In order to achieve this, the decisions that a consumer takes into account when purchasing these energy efficient technologies should be evaluated. The commonly adopted Hierarchical Decision Model (HDM) is used for breaking down a decision into criteria, factors (sub criteria) and alternatives. These criteria and factors are used to determine the priorities for a consumer’s decision. This paper attempts to evaluate the consumer’s decision using HDM in order to determine whether current incentives are focused towards the technologies that consumers are seeking. Additionally, the weights of the criteria and factors can give a better understanding of what the consumer is looking for and what changes can be made to the energy efficient devices to accommodate these preferences. Literature review Electricity in South Africa Fig. 1 illustrates the electricity market share for South Africa together with the residential electricity consumption. One of the focuses of the Integrated Demand Management (IDM) division of
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Residential Electricity Consumption (South Africa)
Electricity Market Share (South Africa)
Cold Storage 5% Residental 18%
Industrial 48%
Other 12%
Agriculture 4%
Space Heating 16%
Pool Pump 11%
Transport 2%
Laundry 3% Other Cooking 1%
Commerical 10%
Stove and Oven 7% Lights 6%
Water Heating (Geyser) 39%
Mining 18%
Fig. 1. Electricity market share and residential electricity consumption [5,6].
Expenditure 2010/2011 Financial Year Heat pumps 7%
Residential Lighting 9%
4000 3500 Capacity (MW)
3000
Solar Water Heating
2500
Shower Heads
2000
Process Optimization
1500
New Initiatives
1000
Lighting HVAC Heat Pumps
500
Compressed Air Systems 2019
Fig. 3. Cumulative committed demand side management programs [8].
Multi perspective technology assessment Technology assessment is considered to be a method covering multiple perspectives ranging from social to political to technical [9]. Benson et al. [10] demonstrated the practical application of multiple perspectives with micro-electromechanical systems. Tran and Daim [11] reviewed and classified technology assessment methods. One of the interesting conclusions was that the private sector tended to use different methods for technology assessment when compared to government. Multi perspective models seemed to be used in both cases [12,13]. Hierarchical decision models (HDM) or analytical hierarchy process (AHP) are the names used for such assessments. HDM or AHP is a method used for breaking down various aspects of a problem into smaller sub-problems [14]. The model is generally represented as a tree diagram, consisting of a goal, criteria, sub criteria, and alternatives. A method called pairwise comparison is used to Evening Peak Demand Savings Achieved2010/2011
Water heating Load Mgt. 5%
Process Optimisatio n 21%
Solar Water Heating 2%
Heat pumps 0%
Compressed. Air System 18% Solar Water Heating 41% Ind. Lighting & HVAC 7%
Compressed Air Systems 12% Process Optimisation 13%
2020
2018
2016
2017
2015
2014
2012
2013
2011
0 2010
the utility company in South Africa was to encourage the adoption of energy efficient technologies in the residential sector. The focus of this paper is only on the residential sector, which makes up 18% of the market share. Of the residential electricity consumption, water heating (geyser) makes up the largest section (39%), followed by space heating (16%). Fig. 2 illustrates the evening peak demand savings achieved in 2010/2011 financial year for alternative Demand Side Management (DSM) programs, as a percentage of the total savings of 354.1MW [7]. This is above the target set by the utility company of 301MW. Additionally, the 2010/2011 expenditure for each of these programs is illustrated as a percentage of the total expenditure of R545 million [7]. It can be seen that the highest evening peak demand savings was achieved by residential lighting, even with one of the lowest investments. This may be due to the low pricing of CFL lighting that was distributed in the residential mass rollout program. It is also interesting to note that the high investment in solar water heating resulted in a relatively low evening peak demand savings. Fig. 3 illustrates the cumulative committed Demand Side Management (DSM) programs by the utility company for all sectors, as mentioned in the Integrated Resource Plan for Electricity in 2010 (IRP2010) [8]. The primary objective of the IRP2010 was to determine the long-term electricity demand and to specify how this demand would be met by generating capacity, type, cost and time of introduction. The majority of the committed DSM programs were focused toward expanding Solar Water Heating and Heat Pump Water Heating adoption. However, this was only a section of the potential total market for Energy Efficient Demand Side Management (EEDSM), which was estimated by the utility company to be 12933MW.The increase in committed DSM programs is required to deal with the increase in forecasted demand, which cannot be completely dealt with by only increasing the supply.
Water heating Load Mgt 9%
Fig. 2. Demand side management expenditure and savings [7].
Residential Lighting 56%
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evaluate the importance among criteria to the goal by comparing one criterion against another for all criteria. This is repeated for the sub criteria under each criterion to establish its importance to the criterion. The outcome of the model is a ranking among alternatives to the goal. In this project the goal is the selection of an energy efficient device by the consumer. The criteria are aspects that the consumer takes into account when selecting the energy efficient device, and the sub criteria are factors under each of the criterion. The alternatives are the different energy efficient technologies. HDM or AHP based models are common in assessing energy technologies [15]. They were used for evaluating power plants [16–22]; energy storage [23]; natural gas resources [16]; energy source and water desalination combination [24]; diffusion of renewable energy [25]; wind turbine design [26]; energy systems [27,28]; energy alternatives [29–31]; alternative fuels [32]; energy project selection [33]; energy efficiency [34]; building material [35] and wind turbine evaluation [36]. Methodology In this paper we try to establish whether the incentives introduced by the utility company are focused toward the appropriate energy efficient technologies, by examining the purchasing decisions of consumers. We used a HDM in order to structure the purchasing decision of a consumer into an objective, criteria, factors (sub criteria), and alternatives. The weights of each of these criteria and factors could be evaluated to understand their importance in the purchasing decision. The following methodology was therefore followed: (1) establish a HDM with criteria, factors, and alternatives (energy efficient devices) for the selection of an energy efficient device by the consumer (objective); (2) create a survey with pairwise comparisons and distribute to consumers in South Africa; (3) use the Pairwise Comparison (PCM) software [37]to determine the weights for criteria and factors from the survey responses; (4) evaluate the weights of the criteria and factors to determine their importance in the purchasing decision by the consumer. The criteria and factors with the highest weights are seen as the most important to the consumer. Additionally to determine how the factors affect the purchasing decision directly, the criteria weights and factor weights are multiplied and evaluated; (5) by using the weights from the criteria and factors, the alternative energy efficient devices are ranked against one another to determine which device would be preferred by the consumer. Two different scenarios are evaluated, one with incentives from the utility company and one without incentives; (6) introduce suggestions on the adoption of these technologies and assess whether the incentives are focused on the correct technologies. Determine possible alternative technologies for investment. Hierarchical decision model (HDM)
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account, the model was created to focus on the most common criteria and factors. The criteria chosen for the HDM model were performance, environmental, economic, service and support, and convenience. The description of each of these criteria and factors are described below. Performance [38,39] (1) Operating lifetime – this is the life expectancy of the energy efficient device, after which it should be replaced. (2) Upgradability – this is how simple and how expensive it is to upgrade the energy efficient device. The 5-point scale for this factor is described in Appendix D. (3) Reliability – this is the possibility of failure of part of the energy efficient device. The 5-point scale for this factor is described in Appendix D. (4) Effectiveness – this specifies whether the energy efficient device affects everyday life. As an example, a domestic water heater controller will turn off the water heater during some hours of the day; therefore, hot water will not always be available. This will therefore have a low effectiveness. The 5-point scale for this factor is described in Appendix D. Environmental [40] (1) Environmental performance – this is the reduced impact that the energy efficient device will have on the environment [42], which is related to the kWh savings and the purchase and installation cost of the device. This is looking at the performance per amount spent on the device. (2) Social environmental conformity – the purpose of this factor was to establish whether a consumer’s environmental awareness and concern was based on the social norm rather than on the actual reduced environmental impact achieved by energy efficient devices. Therefore, a constant value was given to all technologies for this factor since it is purely to evaluate the consumer and not to differentiate the technologies. Economic [38–41] (1) Purchase and installation cost – this is the fixed installation and purchase cost for the energy efficient device as specified on the utility and manufacturers website. (2) Maintenance cost – this is the cost associated with each maintenance interval for the energy efficient device as a percentage of the purchase cost. The 5-point scale for this factor is described in Appendix D. (3) Utility incentive/rebate – this represents the incentives offered by the utility when purchasing the energy efficient device (i.e. a certain percentage of the purchase and installation cost is reimbursed). (4) Payback period – this is the expected payback period of the initial purchase and installation cost, recuperated from the savings per month. (5) Savings per month – this is the monetary savings obtained per month after installing the energy efficient device, due to reduced electricity and water consumption. Service and support [38,39]
Criteria and factors The criteria and factors were chosen based on previous literature [38–41] and discussions with consumers in South Africa to determine what affects their purchasing decision. Although there are many criteria and factors that consumers may take into
(1) Length of warranty – this is the length of the warranty from the supplier in years from the date of purchase. (2) Type of warranty – this is the warranty coverage for the energy efficient device, which could be none, limited, or full coverage.
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(3) Maintenance intervals – this is the expected duration in months between routine maintenance activities on the energy efficient device. Convenience [41] (1) Operational simplicity – this is how easy the energy efficient device is to operate by the consumer. Some devices require no interaction and are seen as the simplest to operate. The 5-point scale for this factor is described in Appendix D. (2) Space Usage – this is how much valuable space the energy efficient device utilizes, based on the size and position of the device. The 5-point scale for this factor is described in Appendix D. (3) Visual impact - This is whether the energy efficient device changes the aesthetics of a building. As an example, a solar panel installed on the roof or on the side of the building could affect purchasing decisions. The 5-point scale for this factor is described in Appendix D. (4) Accessibility – this is how easy it is to obtain access to the energy efficient devices, which would be crucial for maintenance inspections, repairs, etc. The 5-point scale for this factor is described in Appendix D. Available technologies The energy efficient technologies that were chosen for the model can be separated into three groups. In group one are technologies that the utility company is currently pursuing, group two are technologies mentioned by the utility company as future options, and in group three are suggested technology options. The 10 technologies areas follow: Group 1: pursued technologies (1) Solar water heater: this technology can save up to 70% of the electricity used for water heating (39%) [43]. There is a current rebate for this technology that ranges between 20% and 30% of the purchase and installation cost. For the HDM it was assumed that a 200-L (53-gallon) electric water heater (geyser) was currently installed and would be retrofitted with new solar water heating equipment [44]. (2) Heat pump water heater: this technology can save up to 67% of the electricity used for water heating (39%) [42]. There is a current rebate from the utility for the purchase of this technology that ranges between 20% and 30% of the purchase and installation cost. For the HDM it was assumed that a 200 L (53 gallon) electric water heater (geyser) was currently installed and would be retrofitted with a new heat pump [45]. (3) Low-flow showerhead: this technology reduces the flow (liters per minute) from the showerhead, thereby reducing the amount of water used during showering and the amount of electricity required to heat more water. It was calculated that this technology could save up to 20% of the electricity used for water heating (39%) [46]. It was assumed that a household had two showerheads that would be replaced with the new low-flow showerheads. The technology is supplied free of charge as part of the Residential Mass Rollout program [47,48]. (4) Domestic water heater controller: this technology is used to turn the water heater off during certain times of the day. It was calculated that this technology can save up to 10% of the electricity consumption [46]. The technology is supplied free of charge as part of the residential mass rollout program [47,48].
(5) LED lighting: it was assumed that a household currently has twenty incandescent light bulbs that could be replaced with LED light bulbs. The savings for this technology is said to be up to 90% of the lighting consumption (6%) [48]. The technology is supplied free of charge as part of the residential mass rollout program [47,48], however with a small installation cost. Group 2: possible technologies (1) Energy efficient pool pump: this is a variable speed pool pump that reduces power consumption by running at lower speeds. It is mentioned that the technology can save up to 70% of the pool pump consumption (11%) [49]. There is no current incentive for this technology. (2) Gas stove hob: this is the replacement of the current electric stove with a gas stove, therefore requiring LP Gas instead of electricity. It is calculated that the use of LP Gas will cost 15% more than electricity to perform the same function [50]. There is no current incentive for this technology. (3) Energy efficient appliances: this is the replacement of the current clothes washer and dryer, fridge, and dishwasher with Energy Star qualified appliances [51–53]. There are no current incentives for these technologies and the purchasing costs are generally high. Group 3: suggested technologies (1) Occupancy sensors: this technology is used to turn the lights on or off when someone enters or leaves a room. It is mentioned that this technology can save up to 70% of the lighting consumption (6%) [54]. It was assumed that there are ten rooms per household that would require occupancy sensors. There is no current incentive for this technology. (2) Customer engagement platform: this is a method of engaging the customer in becoming more energy efficient by distributing electricity savings reports, methods of saving electricity, etc. The savings for this technology can be up to 3.5% of the total monthly consumption, based on savings illustrated on the OPower website [55]. Technology assumptions In order to determine the savings per month and payback period for each technology the following assumptions were made: (1) the average monthly electricity bill was R1200 per month [42] and the 2012/2013 tariff was R1.20 per kWh [56], (2) optimal savings per technology, as previously specified, was achieved, (3) the average distribution of Electricity Consumption, as shown in Fig. 1, was followed, (4) the price of Liquid Petroleum Gas (LPG) was R22.08 per kg (June, 2012) [57] (used to calculate savings for the gas stove hob), and 2012/2013 water tariff for Johannesburg was R19.68 per kL [58] (used to calculate savings from appliances). Decision model Fig. 4 illustrates the HDM for the selection of an energy efficient device in the residential sector. The model is structured with the objective (residential energy efficient device selection), criteria (performance, environmental, economic, service and support, and
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Fig. 4. HDM model.
convenience), the factors associated with each criterion, and finally all the technology options. Expert responses The experts for the model are the consumers, the persons making the decision when purchasing an energy efficient device. The survey shown in Appendix A was sent out to possible consumers (home owners) in South Africa. A total of eleven complete responses were received, all in the middle to high income housing category. The respondent ages ranged from the mid-twenties to early sixties, and the majority were professionals in their respective fields. Although the pairwise comparison process is clearly stated in the beginning of the survey, some responses were not complete or were not completed correctly and were therefore disregarded. Calculating weights The survey in Appendix A was used to obtain the pairwise comparisons from the consumers in South Africa. The comparisons were manually entered into the Pairwise Comparison Method (PCM) software [37] and the respective weights for the criteria and factors were obtained. The technology rankings were then obtained using these weights and the technology values per device. Results Criteria weights Fig. 5 illustrates the weights for the five criteria together with the inconsistency value between the responses. Out of the eleven responses there were two inconsistencies above 0.1 for the criteria pairwise comparison. It can be seen that the ‘‘Performance’’ and ‘‘Economic’’ criteria have the highest weights, while the ‘‘Support and Service’’ criterion has the lowest weight.
Fig. 5. Criteria weights.
Factor weights Factor weight under criteria The weights for each factor are shown in Fig. 8 in Appendix B. There was a total of two inconsistencies above 0.1 from individual responses, out of a total of fifty-five pairwise comparisons. The inconsistencies among the eleven respondents were all below 0.1. The highest and lowest factors under each criterion are summarized in Table 1. Factor weights to objective Fig. 6 illustrates the weights for each factor to the objective. This was calculated by multiplying the weight for a criterion with the weight for a factor. As an example, ‘‘Operating Lifetime’’ was calculated by multiplying the weight for criterion ‘‘Performance’’ with the weight for factor ‘‘Operating Lifetime’’. The calculated weights give a better representation of the impact of the factors on the overall decision. It is shown that the ‘‘Environmental Performance’’ factor was the most important factor to the consumer when making the purchasing decision, while the least important factors to consumers were ‘‘Upgradability’’ and ‘‘Utility Incentive/
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Technology ranking
Table 1 Highest and lowest factors for each criterion. Criteria
Highest factor
Lowest factor
Performance Environmental
Operating lifetime, reliability Environmental performance
Economic Support and service Convenience
Purchase and installation cost Length of warranty, type of warranty Operational simplicity
Upgradability Social environmental conformity Utility incentives/rebate Maintenance intervals Space usage
Overall Weight
Rebate’’. A majority of the highest factors were under the ‘‘Performance’’ and ‘‘Environmental’’ criteria.’’Utility Incentive/Rebate’’ was possibly one of the lowest factors since consumers were more concerned about the payback period for the device rather than the incentives offered.
The rankings for ‘‘Without Incentives’’ was calculated by setting the ‘‘Utility Incentive/Rebate’’ factor value per technology close to zero. The value was changed to the current incentives offered by the utility company in order to calculate the ‘‘With Incentives’’ ranking. Technology values in Appendix C [59–61] were used for calculations. Fig. 7 illustrates the outcome of the decision model, showing the ranking among the energy efficient technologies with and without incentives. Without incentives the domestic water heater controller was ranked the highest among the technologies, while the gas stove hob and energy efficient appliances were ranked the lowest. With incentives the heat pump water heater moved ahead of the domestic water heater controller, while the gas stove hob and energy efficient appliances remained the lowest. Additionally, the solar water heater and LED lighting moved to the
0.14 0.12 0.1 0.08 0.06 0.04 0.02 0
Factors Fig. 6. Factor weights to goal.
Fig. 7. Technology rankings with and without incentives.
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same level as the domestic water heater controller. The low-flow showerhead and customer engagement platform remained in the top six ranked devices with and without incentives. Results discussion As mentioned under results, the domestic water heater controller was ranked the highest without incentives. This is because the purchase and installation cost is low with a relatively high savings per month, which also results in a high environmental performance. The outcome remains similar for the domestic water heater controller with incentives; however the solar water heater and heat pump water heater move above the controller in the rankings. This is due to the high incentives for the technologies, the high savings per month and the high environmental performance achieved. The lowest ranked technologies were the energy efficient pool pump, energy efficient appliances, and the gas stove hob with and without incentives. The pool pump and appliances both have a high purchase and installation cost with a relatively low savings per month, and therefore a low environmental performance. Since LP Gas is more expensive in South Africa than electricity for the same output [50], the gas stove hob was bound to be one of the
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lowest ranked. None of these technologies has incentives from the utility company and therefore their rankings do not change. As shown in the IRP2010, the largest growth of energy efficient devices until 2020 will be solar water heaters and heat pumps [8]. As discussed, these two technologies move up the rankings when incentives are introduced, which correlates with the intended investments in these technologies. Also shown are the benefits of the residential mass rollout program for LED lighting, however the savings per device is not as substantial as the water heating technologies. The customer engagement platform ranked relatively well with and without incentives, which could possibly be pursued as a viable option for the utility company. The expenditure into solar water heaters was substantially higher than heat pumps in 2010/2011 financial year. From this paper it can be suggested that the utility company invests more into the heat pump technology and the customer engagement platform, as opposed to the high investments into solar water heaters. As described under available technologies, the customer engagement platform can be introduced into the residential sector easier than other technologies. However the adoption of this technology in South Africa has not yet been proven. A trial introduction of this technology should be conducted before pursuing a complete implementation.
Fig. 8. Criteria and factor weights and inconsistencies.
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Conclusion
Future work
The model is an effective method of obtaining consumer expectations from multiple perspectives when selecting an energy efficient device. It confirms that the addition of incentives for heat pump water heaters and solar water heaters ranks these technologies above most of the others. The large investments into these technologies can be justified by the model; however, additional evaluations of the consumer may be required. Although the decision model introduced in this article covers most of the technologies pursued by the utility company, it is possible to use the same model for new energy efficient technologies. This will give insight for the utility company to determine how it should structure the incentives for the new technologies. Additionally, if the company wanted to encourage the adoption of a specific energy efficient technology, it could use the model to determine how it is positioned against other technologies, and adjust pricing, incentives, and investments into research and development of the device.
The decision model introduced in this article is a foundation for future research that could be extended in multiple directions. A possible improvement would be to include utility curves for each factor in order to obtain a technology value for each energy efficient device, as introduced by Gerdsri and Kocaoglu [38]. The survey could also be completed by experts in the utility company and the results compared against the consumer. This may help the utility company align themselves with the consumer in order to introduce the technologies into the market more effectively. Additionally the decision model could be used for emerging technologies in the energy efficient field. The model could also be easily implemented in other countries after obtaining new weights from consumer responses. Some factors for the technologies are subjective and may require further evaluation together with the effect of the large weighting assigned to the ‘‘Environmental Performance’’ factor.
Appendix A. Survey Residential energy efficient device survey The purpose of this survey is to establish the importance of different criteria and factors that a person takes into account when deciding to purchase Energy Saving (Efficient) Devices for their home (to reduce your electricity bill). These are devices such as solar water heaters, heat pumps for water heating, energy efficient lighting, geysers controllers, low-flow shower heads, etc. Section 1: comparisons Introduction The comparisons in this section are done by a method called pairwise comparison. This is when you have 100 points available and you assign them between two options. For example, the following is comparing Performance against Environmental: Pairwise comparison Performance
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60
Environmental
Since I see Environmental as slightly more important than Performance I assign more points to Environmental than Performance. If I see them as equal I assign 50 to Performance and 50 to Environmental. If I see Environmental as substantially more important than Performance I assign 99 points to Environmental and 1 point to Performance. Do not assign 100 point to one option only. Also make sure that the values add up to 100 points for each comparison. Comparison 1 The first comparison is between the following criteria when purchasing an Energy Saving (Efficient) device: (1) Performance – this is the performance (reliability, lifetime) of the Energy Saving device. (2) Environmental – this is the positive effect on the environment the Energy Saving device has. (3) Economic – this is the purchase and installation cost, savings on your electricity bill, payback period, etc when purchasing the Energy Saving device. (4) Support and service – this is the length of the warranty and type of warranty for the Energy Saving device. (5) Convenience – this is how easy the Energy Saving device is to operate, whether you can access the device, etc. Please complete the comparison below: Pairwise comparison Performance Performance Performance Performance Environmental Environmental Environmental Economic Economic Support and service
Environmental Economic Support and service Convenience Economic Support and service Convenience Support and service Convenience Convenience
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Comparison 2 The second comparison is between factors under Performance, which are: (1) Operating lifetime – this is how many years the Energy Saving device is expected to operate. (2) Upgradability – this is how easy the Energy Saving device is to upgrade (e.g. when you upgrade the size of your geyser, how expensive and easy is it to upgrade the solar panel, geyser controller, etc.) (3) Reliability – this is how reliable the Energy Saving device is. (4) Effectiveness – this is how effective the Energy Saving device is at getting its task done in time (e.g. a solar water heating may take a long time to heat the water). Please complete the comparison below: Pairwise comparison (performance) Operating lifetime Operating lifetime Operating lifetime Upgradability Upgradability Reliability
Upgradability Reliability Effectiveness Reliability Effectiveness Effectiveness
Comparison 3 The third comparison is between factors under Environmental, which are: (1) Environmental performance – this is the positive impact that the Energy Saving device will have on the environment (i.e. green house gas emissions). (2) Social environmental conformity – if your neighbours, friends, or family are conscious about the environment, will this change your behaviour. Please complete the comparison below: Pairwise comparison (environmental) Environmental performance
Social environmental conformity
Comparison 4 The fourth comparison is between factors under Economic, which are: (1) (2) (3) (4)
Purchase and installation cost – this the fixed installation and purchase costs for the Energy Saving device. Maintenance cost – this the costs in maintaining the Energy Saving device. Utility incentive/rebate – this the Rebate from the utility (Eskom) for purchasing an Energy Efficient device. Payback period – this is the expected payback period (installation and purchase costs minus the savings on your electricity bill per month). (5) Savings per month – this is the savings obtained per month after installing the Energy Efficient device. Please complete the comparison below: Pairwise comparison (economic) Purchase and installation Purchase and Installation Purchase and installation Purchase and installation Maintenance cost Maintenance cost Maintenance cost Utility incentive/rebate Utility incentive/rebate Savings per month
cost cost cost cost
Maintenance cost Utility incentive/rebate Savings per month Payback period Utility incentive/rebate Savings per month Payback period Savings per month Payback period Payback period
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Comparison 5 The fifth comparison is between factors under Service and Support, which are: (1) Length of warranty – this is the length of the warranty by the supplier from the purchase date. (2) Type of warranty – this is none, limit or full warranty on the Energy Saving device. (3) Maintenance intervals – this is the expected time duration between maintaining the Energy Saving device. Please complete the comparison below: Pairwise comparison (service and support) Length of warranty Length of warranty Type of warranty
Type of warranty Maintenance interval Maintenance interval
Comparison 6 The sixth comparison is between factors under Convenience, which are: (1) Operational simplicity – this is how easy the Energy Saving device is to operate. (2) Space usage – this is how much space the device takes up. (3) Visual impact – this is the visual impact of the Energy Saving device (e.g. installed on the side of your house or on your roof). (4) Accessibility – this is how easy the device is to access. Please complete the comparison below: Pairwise comparison (convenience) Operational simplicity Operational simplicity Operational simplicity Space usage Space usage Visual impact
Thank you for your patience and time for completely this survey!!!!
Space usage Visual impact Accessibility Visual impact Accessibility Accessibility
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Appendix B. Criteria and factor weights per respondent
.
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Appendix C. Technology data
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Appendix D. Description of 5 point scale for factors
(continued on next page)
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Appendix D. (continued)
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