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Does “100% renewable” trump concern for spatial impacts?
Energy Policy 130 (2019) 304–310
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Does “100% renewable” trump concern for spatial impacts?
T
Robert Herendeen Rubenstein School of Environment and Natural Resources, Gund Institute for Environment, University of Vermont, Burlington, VT, USA
A R T I C LE I N FO
A B S T R A C T
Keywords: Renewable energy Spatial impact Net-zero energy Sustainability Efficiency Carrying capacity
I live in Burlington (pop. 43,600), state of Vermont (pop. 624,000), USA (pop. 326,000,000). We are the first U.S. city to become 100% renewable in electricity. We get hydro electricity from as far away as 700 km. (in Quebec, Canada) and as close as 1 km. Our wind electricity comes from sources 25–250 km distant. Our 50 MWe biomass plant burns forestry residues harvested within 160 km. Burlington now plans to become a “net-zero energy” city by 1. providing this renewable electricity (more) locally, and 2. extending coverage to present uses of fuel oil, petrol, and natural gas, with the notable exception of airplane fuel. This spatial reach has historically been de-emphasized in waves of enthusiasm for energy efficiency, sustainability (often loosely defined), and now renewability-especially in confronting greenhouse gas (GHG) emissions. I briefly review this history, and then present quantitative spatial impacts of Burlington's plans.
1. Introduction “Renewable” is an “in” term in energy, to the fairly systematic deemphasis of spatial impacts, though these lead to piecemeal local battles over wind and solar electricity generation in my home state of Vermont. This is the current stage in a historical pattern in which several concepts have sequentially dominated the discussion. Thus, starting around 1970, accelerating after the 1973 oil embargo, and carrying through to today's global warming consciousness, the broad pattern has been: (carrying capacity) – > (efficiency) – > (sustainability) – > (renewability). In this article I illustrate this progression by personal anecdotes over my almost five decades in energy analysis and environmental bookkeeping. I then visit examples of areal impact of supplying electricity to Burlington, Vermont, USA. (See Table 1 for population and area data.) Burlington's supply is 100% renewable, but comes mostly from distant sources. My examples are somewhat anecdotal and are not comprehensive. Defining renewability is complicated, changing over time, and even political. For example, while small hydroelectric generators have always been declared renewable in Vermont, large hydro (peak power ≥ 200 MW) was declared non-renewable for ca. 20 years. Then in 2010 the Vermont legislature reversed, declaring it renewable. There are clear biophysical differences based on size, but dominant contributing factors in the switch include the rights of First Nations peoples in Canada, the desire to stimulate in-Vermont renewable energy development, and the anticipated closing of the Vermont Yankee nuclear
plant, which occurred in 2014. In all the discussions, “renewable” is seldom defined carefully, with an explicit time scale. The examples illustrate that Burlington's pursuit of renewability in electricity, and ultimately all energy, will lead to land use of different size and location depending on energy type. With the possible exception of solar photovoltaic (PV), it will require a significant extension beyond the city limits, and a significant impact on the State and region. Electricity from Canada will likely increase. 2. Illustrative historical anecdotes 2.1. A thought on 22 April 2018, Earth Day #49 On Earth Day #1, 22 April 1970, I shook an electric toothbrush at an elementary school class in Ithaca, New York, USA. I claimed that gadgets like this were the problem! I drove there, but the obvious contradiction didn't complicate my thinking. That was especially ironic, because as a new physics Ph.D. I routinely did back-of-the-envelope calculations to check the feasibility of experiments and the believability of results. But then I naively viewed the environmental problem to be about someone else's pipes spewing pollution-having little to do with me, and certainly not meriting a calculation of the relative impacts of driving and brushing teeth. I was righteous: I lived in a cabin with a woodstove and an outhouse and drove a Volkswagen. Now 48 years later, I do environmental calculations, mostly about energy, all the time-in fact, for a living. I know about indirect pathways, development, ecological footprint, the power (and frustrations) of compounding trends. I know about the pressures for economic growth
E-mail address: [email protected]. https://doi.org/10.1016/j.enpol.2019.04.002 Received 9 April 2018; Received in revised form 2 April 2019; Accepted 2 April 2019 0301-4215/ © 2019 Elsevier Ltd. All rights reserved.
Energy Policy 130 (2019) 304–310
R. Herendeen
Table 1 Population and area of Burlington, Chittenden County, Vermont, and USA. (WIKI, 2018).
Population Area (sq. km.) Avge. population density (people/sq. km.)
Burlington
Chittenden County
State of Vermont
USA
43,600 26.7 1630
162,000 1391 116
624,000 23,870 26
326 million 9.15 million 36
learned and internalized that the desired product was energy service (say refrigerated space, travel from A to B, or dancing electrons) and that with consciously designed technology, we could get much more energy service from a unit of energy. We are now familiar with the resulting success story: in 2017 as compared with 2000 we Americans used 1.1% less energy (EIA, 2018) while the real GDP increased 37% (BEA, 2018). Locally, Burlington's electricity use in 2017 was actually less than in 1989 thanks to Burlington's activist efficiency programs in a time of significant economic growth (BED, 2017). Among my near and far colleagues were the innovative, persuasive analysts and proponents of efficiency. These pioneers established academic programs at universities (Berkeley, Princeton, Michigan, Copenhagen, and elsewhere), and spearheaded the establishment of, e.g., the American Council for an Energy Efficient Economy. Even then, however, I felt uneasy: improved efficiency was often emphasized as the goal itself, not the means to hold environmental impact to boundaries based on total ecological/social/economic system capacity at the local, regional, national, and planetary level (Steffen et al., 2015). Indeed, even no-growth at today's consumption level does not guarantee that. Certainly many voices cautioned against oversimplification, but the buzz from the field was to tacitly equate more efficiency with complete success. 2.4. 1980s forward: It's sustainable! The Brundtland Report (World Commission, 1987) coined sustainability and defined it thus:
Fig. 1. Burlington, Vermont's energy supply BED Portfolio, 2015. Total consumption = 354,000 MWh. Individual percentages vary year to year. Source: BED Portfolio (2015). Note: NextEra hydro (out of state) was replaced by instate hydro (but 160 km distant) on 1 January 2018.
“ … development that meets the needs of the present without compromising the ability of future generations to meet their own needs.” This is inspirational but extremely vague. Scientists continue to argue about what it means in biophysical terms, while business interests, politicians, and the other usual suspects continue to cast it in their own favorite tropes. So “sustainable development” has quickly morphed into “sustainable growth”, sustainable meals, sustainable construction projects, and so on. Of the many uses of “sustainable”, almost none incorporate the quantitative thinking and breadth of concern that started it all and that are still needed. As with efficiency, the means tended to become the end. The consequence was that the energy analysis world and the larger society tended to equate sustainability with efficiency.
(from the top and the bottom) and the energy cost of living, about lags in all systems, about denial, about the perennial hope and trust in new technical innovations, and citizen and specialist burnout. I know toothbrushes are a drop in the bucket. 2.2. From Earth Day #1: carrying capacity The dictionary definition of carrying capacity is “the maximum population (as of deer) that an area will support without undergoing deterioration”. In the 1960s and 70s we emphasized reducing perhectare impacts. Frequently impacts could be considered, and analyzed fruitfully, as a compounding of several factors. For example, the simple but powerful equation I=P*A*T (Ehrlich et al., 1972) expressed the compounding total impact of population(P), per-capita consumption (A), and impact per unit of consumption (T). Implicitly we understood that spreading impact over a larger area would likely reduce deterioration. In 1972 “The Limits to Growth” (Meadows et al., 1972) was published. Its major message was about positive feedback/exponential growth/dynamics and lags, but always in a context of limits. Its models were for the entire world, so it was concerned with global limits.
2.5. 2000 forward, particularly in Vermont, especially in Burlington: does renewability say it all? The dramatic cost reduction of solar and wind energy in the 21st century (IRENA, 2017) makes an eventual transition away from fossil fuels almost inevitable instead of its doubtful status in the 20th. Certainly there are difficult issues about timing, inertia, and equity, along with resistant people, corporations, institutions, and governments, but it's a wave that has arrived. For example, Burlington Electric Dept. (BED), our local utility, is now 100% renewable (a mix of hydro, wind, biomass, and solar) (BED Portfolio, 2015; see Fig. 1). Of course even that claim to renewability can be challenged. Are forestry-based wood chips, which feed our 50 MWe McNeil Power Plant, truly renewable over many harvests? Does Hydro Quebec's (HQ's) flooding, rerouting,
2.3. 1973 forward: enter efficiency Following the Mideast oil embargo in 1973, U.S. consciousness was jolted by realizations and resolutions about energy-use efficiency. We 305
0.33
1.10
30
220
100
100
32
15
% of Burlington's area
0.58
0.0064
4.1
0.61
% of Chittenden County's area
0.034
0.00038
0.24
0.036
% of Vermont's area
BED (2017), p. 22.
ECOS (2018), p. 30.
Source
Based on predicted performance; came on line 1 January 2018. Cap. factor calculated from data = 0.18. 0.036 sq. km. per peak MW.
Cap. factor calculated from data = 0.14. 0.19 sq. km. per peak MW.
Comments
306
Biomass thermal electricity, estimate #1 McNeil biomass electric station. This analysis based on information from Burlington Electric Dept's chief forester. 50MWe, producing 269,000 MWh/yr, of which half goes to Burlington. Area refers to forests from which logging residue fuel is obtained. Above, extrapolated to 100% Burlington coverage Biomass thermal electricity, estimate #2 McNeil biomass electric station. This analysis based on outside research on regional forest productivity. In 2017 McNeil purchased 367,000 tonnes of wood for its full output. Buchholz et al., estimated that Vermont forests can supply 845,000 to 1,030,000 tonnes/yr of biomass on a sustainable basis. This corresponds to a maximum of approx. 2.5 McNeils in all of Vermont. Above, extrapolated to 100% Burlington coverage 3030
7970 17,800
47,000
100 38
100
% of Burlington's area
38
% of Burlington's electric energy
890
340
150
58
% of Chittenden County's area
53
20
8.9
3.4
% of Vermont's area
Buchholz et al. (2011)
Lesnikoski (2018)
Source
There is controversy over the sustainability of harvesting programs, especially about dynamic vs. steady state and dependence on the forests' initial condition.
To provide Burlington's electricity share requires approx. 809 sq. km., based on 40.4 sq. km./yr*reentry time of 20 years. This removal rate averages ca.1 tonne/0.4 ha-yr. (in American units, 1 ton/acre-yr.)
Comments
Table 3 Two estimates of the area required to satisfy part or all of Burlington's electricity by burning forest biomass. Based on Burlington's (jointly-owned) McNeil biomass-burning electric plant (50MWe). Burlington receives 50% of output. The total land impacted is the area harvested in one year multiplied by the number of years between harvests (“reentry time’).
Above, extrapolated to 100% Burlington coverage
Solar PV, estimate # 1 Rooftops, parking lots, etc., distributed. 43 MW, producing 52,500 MWh/yr. Area = 8.55 sq. km. Above, extrapolated to 100% Burlington coverage Solar PV, estimate #2 Solar farm, unobstructed fixed panels, 2.5 MW, producing 3900 MWh/yr. Area = 0.089 sq. km.
% of Burlington's electric energy
Table 2 Two estimates of the area required to satisfy part or all of Burlington's electricity use with solar PV. Capacity factor = (annual average power)/(peak power). Nominal value for cap. factor in practice is 0.14 (Renewable Energy Atlas, 2018). Note that Tables 2 and 4 apply to overlapping areas and therefore cannot be added.
R. Herendeen
Energy Policy 130 (2019) 304–310
Energy Policy 130 (2019) 304–310
R. Herendeen
Fig. 2. The squares represent the size of areas in renewable forestry needed to produce Burlington's share of electricity from the McNeil biomass plant. Red is for current share, 38%. Yellow is for 100%. Refer to Table 3, example #1. (For interpretation of the references to colour in this figure legend, the reader is referred to the Web version of this article.)
Make Burlington a “net zero energy city” across electric, thermal, and ground transportation sectors by managing demand, realizing efficiency gains, and expanding local renewable generation, while increasing system resilience. o BED defines “net zero” as Burlington sourcing at least as much renewable energy as it consumes in energy for electric, thermal, and transportation purposes. o We source energy from New England and adjoining states and territories with a strong preference for generation closest to Burlington. o For thermal and electric, we will work toward net zero with Burlington residential, commercial, and industrial customers. o For transportation, our goal is to make in-city travel net zero, and lower the impact of intercity travel. Air travel is not included at this time.
and regulating of watersheds covering ca. one fifth the Province's area qualify? Does Burlington Electric Dept.’s selling and buying renewable energy credits to keep our per-kWh cost low jibe with a fair definition? (The process is illustrated in BED Portfolio (2015), where three distinct pie charts depict the fraction of renewable sources at various stages of this trading.) My concern here is that renewability is the newly touted substitute for, or equivalent of, sustainability-itself usually scarcely defined. 2.6. Being renewable and local returns us to the space question To put it baldly, do we now say uncritically that if it's renewable, more is better? Will there be a land-use crunch? After all, critics of solar electricity rightly point out that sunlight is diffuse relative to coal, oil, or natural gas, or even nuclear-and they have a point. This areal impact question appears implicitly in a new vision of Burlington Electric Dept., encapsulated in the recent strategic plan (BED Strategic, 2018):
Let us acclaim this bold and exciting extension of BED's purview to fossil fuels, beyond just electricity. (This will eventually mean electrifying almost all of space conditioning and transportation.) And let us
2030 Vision 307
3.1. Solar The solar PV energy fraction was 0.9% in 2017. The addition of a 2.5 MW solar field within city limits should raise this to 2.0% for 2018 (BED, 2017, p. 22). Table 2 lists two estimates (and data used) of Burlington's solar PV potential. For Burlington to provide all electricity this way, 30–220% of the city's area would be needed. The larger figure is based on installations on rooftops, parking lots, etc., which produce much less MWh/yr. per sq. km. than an unobstructed solar farm, for which the smaller figure applies. 3.2. Biomass Burlington Electric Dept. owns a 50% share in the McNeil 50MWe biomass electric power plant, which is located inside the city limits. Burlington's share provides approx. 38% of its electricity. Unsurprisingly, the area needed for a sustainable supply of forestry residues (wood chips) far exceeds Burlington's area. A more relevant metric is the fraction of the entire state. Table 3 shows two estimates. The first, based on data from Burlington Electric Dept. staff (Lesnikoski, 308
ECOS (2018), p. 31
Source % of Chittenden County's area
0.84 [0.058]
% of Burlington's area
44 [3.0]
% of Vermont's area Approx. 1.3 Approx. 12.6
0.050 [0.0034]
Comments
Cap. factors calculated from data. Ridge line potential assumed = 9 MW/km. Ridgeline in Vermont = approx. 1000 km (both from Blittersdorf, 2015)
Comments Source
BED Portfolio (2015). Approx. 0.24 Approx. 2.4
Wind electricity, estimate # 1 (ridgeline location) Georgia Mountain, 10 MW, 33145 MWh/yr, cap. 19.3 factor = 0.38. Sheffield Wind, 16 MW, 35006 MWh/yr, cap. factor = 0.25. (BED, 2015) Above, extrapolated to 100% Burlington 100 coverage % of Burlington's electric energy Wind electricity, estimate #2 (local location) 103 Within Burlington: [6.9] Total: 119 MW, producing 364,000 MWh/ yr. Area = 12.0 sq. km. Of which: [“Prime”: 8 MW, producing 24,500 MWh/yr. Area = 0.81 sq. km. ]
Burlington's electric energy use is ca. 354,000 MWh/yr, 100% renewable but often from distant sources. Details are shown in Fig. 1. The question is to what degree more local sourcing is feasible. The data sources and methods are of varying quality and rigor; results are only illustrative. Additionally, I assume that we develop lossless storage for electric energy to solve the intermittency problem. Admittedly this is a big assumption, but addressing it is beyond the scope of this article.
% of Vermont's ridgelines
3. Burlington’s electricity spatial impact today and looking forward
km. ridge line required
acknowledge that BED is already 100%* renewable, the “*” indicating several persistent arguable components mentioned above. Instead, let's concentrate on the land area required for renewable energy: how “local” can Burlington be? As we become more local we will pull the distant sources closer and make them more visible. These land demands will compete with many other uses. How that area compares with Burlington's and Vermont's area is a critical issue. Given that spatial impact and carrying capacity are closely (but inversely) related, this represents almost a full circle from Earth Day #1, 48 years ago.
% of Burlington's electric energy
Table 4 Two estimates of land required for present and potential wind electricity for Burlington. Nominal value for cap. factor in practice is 0.35 (Renewable Energy Atlas, 2018). “Prime” means more distant from housing and therefore potentially less controversial. Note that Tables 2 and 4 apply to overlapping areas and therefore cannot be added.
Fig. 3. Georgia Mountain Wind, 25 km northeast of Burlington. Four 2.5 MW turbines along 1 km of ridge line. All energy is sold to Burlington Electric Dept.
Cap. factor = 0.35; calculated from given data.
Energy Policy 130 (2019) 304–310
R. Herendeen
Energy Policy 130 (2019) 304–310
R. Herendeen
3.4. Hydroelectric energy Hydroelectricity comprises ca. 29% of Burlington's total. It comes from far away-from Niagara Falls in western New York State (400 km), and from Hydro Quebec, which has a network of major river diversions, reservoirs, and power stations reaching 700 km north. Fig. 4 is an attempt to show our HQ dependence; see caption for explanation. But hydro is also local; the Winooski 1 plant, which we own (7 MW run-ofriver, producing approx. 7% of Burlington's electricity), is within 100 m of city limits. As of 1 January 2018, hydro from Maine (12%) has been replaced by hydro from the Connecticut River, 160 km away on Vermont's east side. There is no more hydro available inside Burlington. There is some additional potential (as much as 35% of Vermont's developed potential (Barg, 2007),), but this is a mix of small sources with various complicating issues such as fish impacts. The beckoning source for all of New England plus New York State, which includes the megacities of Boston and New York, is Hydro Quebec. Almost daily battles are fought over siting the new transmission lines for it; proposals include underwater cables running the length (ca. 160 km) of Lake Champlain. Except for transmission problems, HQ energy represents an ideal combination of NIMBY (not in my back yard) and politically declared renewability. Much of the claim to renewability, and to actual GHG reduction, of programs in Vermont and farther south, can be based on using this source. Vermont's Comprehensive Energy Plan (CEP, 2016) calls for 90% of Vermont's energy to be from renewable sources by the year 2050. I do not discuss that plan here, but it is clear that implementation will increase pressure for HQ electricity.
Fig. 4. One attempt at showing the areal reach of hydroelectricity for Burlington, which is located at the green star. Most of the shaded area is the watersheds that Hydro Quebec exploits. Some of the shading at lower left is for New York State Power Authority energy. The large lakes shown in yellow are either enlarged or totally human-made. This includes the remarkable ringshaped impact crater dammed as the Manicouagan Reservoir. The tiny red pixel is intended to show Burlington's share from Hydro Quebec proportionally, but it is still too large because of graphics resolution. (For interpretation of the references to colour in this figure legend, the reader is referred to the Web version of this article.)
2018), indicates 3.4% of all of Vermont at Burlington's current use and 8.9% if enough identical biomass plants were available to provide 100%. Fig. 2 depicts this area in relation to Vermont's. Another research project has more pessimistically indicated that Vermont's forests could support only ca. 2.5 McNeils plants (Buchholz et al., 2011), in which case the resulting areal requirements would be 20 and 53%, respectively. These are dauntingly large fractions of Vermont's area. Further, since the State's electricity use is ca. 15 times larger, Vermont electricity could not be fueled with wood from Vermont.
4. Upshot: How far, and hard, should we reach? Alternatively, how earnestly should we attempt to foster local energy supply? This question is now central to Burlington Electric Dept., to the Chittenden County Regional Planning Commission, and to the Vermont Energy Plan. In broad terms the numbers above show that, with the possible exception of solar PV, Burlington must continue to reach beyond its borders to maintain 100% renewability for electricity. In terms of required area, biomass is most demanding. Hydro requires the most geographical reach. One can also ask if Vermont could achieve 100% renewable electricity in-state. This is possible for solar PV or wind, with wind likely encountering more popular resistance. (I again emphasize that these conclusions assume lossless storage of electricity to deal with intermittency.) For biomass and hydro, Vermont would have to look beyond its borders. My basic concern is that renewable energy still has environmental costs. This is not new, but in the rush to renewability, it tends not to be news. E. O. Wilson (2016) proposes that half of the earth should be set aside for nature. The reasons span spiritual/religious, scientific, economic, and social issues. In the empty world into which modern humans radiated ca. 60 thousand years ago, the question of when “enough becomes plenty” (or perhaps better, when “plenty is enough”) was moot; we i had no discernable effect. We know that is no longer true. Worldwide, humanity's ecological footprint (which is expressed in units of area) (Wackernagel et al., 2018) exceeds earth's productive area. As calculated today, ca. half of that footprint is attributed to the impact of fossil fuel burning, using a necessarily crude and arguable estimate of afforestation needed to absorb anthropogenic CO2. As our energy supply turns to renewable sources which produce much less CO2, it is likely that the ecological footprint will decrease. This welcome news will hopefully be tempered by recommitting to comprehensive analysis of the impacts of areal conversion and disturbance-of what we still have.
3.3. Wind Wind is highly controversial in Vermont because the preferred stronger wind locations are at higher elevations (ca. 500–1000 m) along the forested ridge lines which comprise Vermont's wildest land, and which are often the background for iconically beautiful vistas (see Fig. 3). In contrast, Burlington is in the Champlain Valley and only 35–60 m above sea level. Additionally, there are local aesthetic and proximity issues (e.g., noise) that elicit strong reactions, including claims about human health. Table 4 includes two estimates. The first accepts the strong likelihood that only ridge lines will be used. Detailed identification of (physically) suitable sites can be found in Wind (2018). An estimate of the potential is provided by Blittersdorf (2015). The second, from the Chittenden County Regional Planning Association (ECOS, 2018), assumes that significant in-city wind capacity is possible. Given the need for height for higher wind speeds and for isolation from people, this option seems extremely unlikely. Table 4 shows that Burlington could produce today's electric energy from wind on 43% of the City's area, which is impossible because of conflicting use and occupancy. If relatively non-conflicted land (called “prime”) is used, only 7% of the City's electricity could be produced. All these sites are less than 100 m above sea level. Burlington already accesses some distant wind energy. In-state sources typically are on ridge lines above 400 m. For example, Georgia Mountain Wind, ca. 25 km away, provides 19% of the City's electricity from four 2.5 MW turbines on 2.4 km of ridge, which is 0.24% of the State's ridgeline total. Extrapolating to 100% coverage yields 12.6 km (1.3%).
Acknowledgements Thank you to the Gund Institute for Environment, University of 309
Energy Policy 130 (2019) 304–310
R. Herendeen
Commoner's book “the closing circle”, and response by B. Commoner. Environ. 14 (No. 3 (April)), 24–52. EIA, 2018. U.S. Energy Consumption. pp. 1950–2017. https://www.eia.gov/totalenergy/ data/monthly/pdf/sec1_7.pdf, Accessed date: 27 July 2018. IRENA, 2017. Electricity Storage and Renewables: Costs and Markets to 2030. International Renewable Energy Agency, Abu Dhabi. http://www.irena.org/-/ media/Files/IRENA/Agency/Publication/2017/Oct/IRENA_Electricity_Storage_ Costs_2017.pdf, Accessed date: 27 July 2018. Lesnikoski, 2018. Personal Communication with Betsy Lesnikoski. Burlington Electric Dept. , Accessed date: 22 March 2018. Meadows, Donella, Meadows, Dennis, Randers, Joergen, Behrens III, William, 1972. The Limits to Growth: A Report for the Club of Rome's Project on the Predicament of Mankind. Potomac Associates. Renewable Energy Atlas, 2018. http://www.nvda.net/files/Sheffield%20Energy %20Profile(1).pdf, Accessed date: 26 July 2018. Steffen, W., Richardson, K., Rockström, J., Cornell, S.E., Fetzer, I., Bennett, E.M., Biggs, R., Carpenter, S.R., de Vries, W., de Wit, C.A., Folke, C., Gerten, D., Heinke, J., Mace, G.M., Persson, L.M., Ramanathan, V., Reyers, B., Sorlin, S., 2015. Planetary boundaries: guiding human development on a changing planet. Science 347 (6223), 1259855-1-10. Wackernagel, M., Galli, A., Hanscom, L., Lin, D., Mailhes, L., Drummond, T., 2018. Ecological footprint accounts: principles. In: Bell, Simon, Morse, Stephen (Eds.), Routledge Handbook of Sustainability Indicators, pp. 244–264. WIKI, 2018. http://en.wikipedia.org/wiki/List_of_U.S._states_and_territories_by_area, Accessed date: 28 March 2018. Wilson, E.O., 2016. Half-Earth: Our Planet's Fight for Life. Liveright Publishing Corporation. Wind, 2018. http://windexchange.energy.gov/maps-data/130, Accessed date: 4 April 2018. http://www.vtenergydashboard.org/energy-atlas. World Commission, 1987. Our Common Future. World Commission on Environment and Development. Oxford University Press.
Vermont, for travel support. References Barg, L., 2007. The Undeveloped Hydro Potential of Vermont. Community Hydro, vol. 113 Bartlett Rd, Plainfield, VT 05667. BEA, 2018. GDP Data from U.S. Bureau of Economic Analysis. http://www.bea.gov/ national/#gdp, Accessed date: 27 July 2018. BED Portfolio, 2015. Energy Sources Are Quantified. http://www.burlingtonelectric. com/our-energy-portfolio, Accessed date: 31 March 2018. BED, 2017. Performance Measures Report, vol. 2017 Burlington Electric Dept, Burlington, VT 05401. BED Strategic, 2018. Strategic Plan Statement. http://www.burlingtonelectric.com/ 2017-2018-strategic-direction, Accessed date: 24 July 2018. Blittersdorf, 2015. Interview with David Blittersdorf, developer of the Georgia Mountain wind facility. “(To reach) 3,000 megawatts, you can put about 15 megawatts per mile – so that's 200 miles of ridges. In Vermont we have about 600-plus miles of ridge lines. ...”. https://www.wind-watch.org/news/2015/07/24/green-energy-ceovermonters-must-abandon-the-car-embrace-renewable-energy-future/, Accessed date: 26 July 2018. Buchholz, T., Canham, C.D., Hamburg, S.P., 2011. Forest Biomass and Bioenergy: Opportunities and Constraints in the Northeastern United States. Report. Cary Institute of Ecosystem Studies, Millbrook, NY. CEP, 2016. Vermont Comprehensive Energy Plan 2016. http://outside.vermont.gov/sov/ webservices/Shared%20Documents/2016CEP_Final.pdf. ECOS, 2018. Chittenden County ECOS Plan, Supplement 6–Energy Analysis, Targets, & Methodology. Chittenden County Regional Planning Commission, Winnooski, Vermont Adopted 6/20/2018. http://www.ecosproject.com/wp/wp-content/ uploads/2017/09/ECOSPlan_ProcessSupplement6_EnergyData_Methodology_ Final20180615.pdf, Accessed date: 26 July 2018. Ehrlich, P., Holdren, J., Commoner, B., 1972. Review by Ehrlich and Holdren of B.
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Does “100% renewable” trump concern for spatial impacts?
T
Robert Herendeen Rubenstein School of Environment and Natural Resources, Gund Institute for Environment, University of Vermont, Burlington, VT, USA
A R T I C LE I N FO
A B S T R A C T
Keywords: Renewable energy Spatial impact Net-zero energy Sustainability Efficiency Carrying capacity
I live in Burlington (pop. 43,600), state of Vermont (pop. 624,000), USA (pop. 326,000,000). We are the first U.S. city to become 100% renewable in electricity. We get hydro electricity from as far away as 700 km. (in Quebec, Canada) and as close as 1 km. Our wind electricity comes from sources 25–250 km distant. Our 50 MWe biomass plant burns forestry residues harvested within 160 km. Burlington now plans to become a “net-zero energy” city by 1. providing this renewable electricity (more) locally, and 2. extending coverage to present uses of fuel oil, petrol, and natural gas, with the notable exception of airplane fuel. This spatial reach has historically been de-emphasized in waves of enthusiasm for energy efficiency, sustainability (often loosely defined), and now renewability-especially in confronting greenhouse gas (GHG) emissions. I briefly review this history, and then present quantitative spatial impacts of Burlington's plans.
1. Introduction “Renewable” is an “in” term in energy, to the fairly systematic deemphasis of spatial impacts, though these lead to piecemeal local battles over wind and solar electricity generation in my home state of Vermont. This is the current stage in a historical pattern in which several concepts have sequentially dominated the discussion. Thus, starting around 1970, accelerating after the 1973 oil embargo, and carrying through to today's global warming consciousness, the broad pattern has been: (carrying capacity) – > (efficiency) – > (sustainability) – > (renewability). In this article I illustrate this progression by personal anecdotes over my almost five decades in energy analysis and environmental bookkeeping. I then visit examples of areal impact of supplying electricity to Burlington, Vermont, USA. (See Table 1 for population and area data.) Burlington's supply is 100% renewable, but comes mostly from distant sources. My examples are somewhat anecdotal and are not comprehensive. Defining renewability is complicated, changing over time, and even political. For example, while small hydroelectric generators have always been declared renewable in Vermont, large hydro (peak power ≥ 200 MW) was declared non-renewable for ca. 20 years. Then in 2010 the Vermont legislature reversed, declaring it renewable. There are clear biophysical differences based on size, but dominant contributing factors in the switch include the rights of First Nations peoples in Canada, the desire to stimulate in-Vermont renewable energy development, and the anticipated closing of the Vermont Yankee nuclear
plant, which occurred in 2014. In all the discussions, “renewable” is seldom defined carefully, with an explicit time scale. The examples illustrate that Burlington's pursuit of renewability in electricity, and ultimately all energy, will lead to land use of different size and location depending on energy type. With the possible exception of solar photovoltaic (PV), it will require a significant extension beyond the city limits, and a significant impact on the State and region. Electricity from Canada will likely increase. 2. Illustrative historical anecdotes 2.1. A thought on 22 April 2018, Earth Day #49 On Earth Day #1, 22 April 1970, I shook an electric toothbrush at an elementary school class in Ithaca, New York, USA. I claimed that gadgets like this were the problem! I drove there, but the obvious contradiction didn't complicate my thinking. That was especially ironic, because as a new physics Ph.D. I routinely did back-of-the-envelope calculations to check the feasibility of experiments and the believability of results. But then I naively viewed the environmental problem to be about someone else's pipes spewing pollution-having little to do with me, and certainly not meriting a calculation of the relative impacts of driving and brushing teeth. I was righteous: I lived in a cabin with a woodstove and an outhouse and drove a Volkswagen. Now 48 years later, I do environmental calculations, mostly about energy, all the time-in fact, for a living. I know about indirect pathways, development, ecological footprint, the power (and frustrations) of compounding trends. I know about the pressures for economic growth
E-mail address: [email protected]. https://doi.org/10.1016/j.enpol.2019.04.002 Received 9 April 2018; Received in revised form 2 April 2019; Accepted 2 April 2019 0301-4215/ © 2019 Elsevier Ltd. All rights reserved.
Energy Policy 130 (2019) 304–310
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Table 1 Population and area of Burlington, Chittenden County, Vermont, and USA. (WIKI, 2018).
Population Area (sq. km.) Avge. population density (people/sq. km.)
Burlington
Chittenden County
State of Vermont
USA
43,600 26.7 1630
162,000 1391 116
624,000 23,870 26
326 million 9.15 million 36
learned and internalized that the desired product was energy service (say refrigerated space, travel from A to B, or dancing electrons) and that with consciously designed technology, we could get much more energy service from a unit of energy. We are now familiar with the resulting success story: in 2017 as compared with 2000 we Americans used 1.1% less energy (EIA, 2018) while the real GDP increased 37% (BEA, 2018). Locally, Burlington's electricity use in 2017 was actually less than in 1989 thanks to Burlington's activist efficiency programs in a time of significant economic growth (BED, 2017). Among my near and far colleagues were the innovative, persuasive analysts and proponents of efficiency. These pioneers established academic programs at universities (Berkeley, Princeton, Michigan, Copenhagen, and elsewhere), and spearheaded the establishment of, e.g., the American Council for an Energy Efficient Economy. Even then, however, I felt uneasy: improved efficiency was often emphasized as the goal itself, not the means to hold environmental impact to boundaries based on total ecological/social/economic system capacity at the local, regional, national, and planetary level (Steffen et al., 2015). Indeed, even no-growth at today's consumption level does not guarantee that. Certainly many voices cautioned against oversimplification, but the buzz from the field was to tacitly equate more efficiency with complete success. 2.4. 1980s forward: It's sustainable! The Brundtland Report (World Commission, 1987) coined sustainability and defined it thus:
Fig. 1. Burlington, Vermont's energy supply BED Portfolio, 2015. Total consumption = 354,000 MWh. Individual percentages vary year to year. Source: BED Portfolio (2015). Note: NextEra hydro (out of state) was replaced by instate hydro (but 160 km distant) on 1 January 2018.
“ … development that meets the needs of the present without compromising the ability of future generations to meet their own needs.” This is inspirational but extremely vague. Scientists continue to argue about what it means in biophysical terms, while business interests, politicians, and the other usual suspects continue to cast it in their own favorite tropes. So “sustainable development” has quickly morphed into “sustainable growth”, sustainable meals, sustainable construction projects, and so on. Of the many uses of “sustainable”, almost none incorporate the quantitative thinking and breadth of concern that started it all and that are still needed. As with efficiency, the means tended to become the end. The consequence was that the energy analysis world and the larger society tended to equate sustainability with efficiency.
(from the top and the bottom) and the energy cost of living, about lags in all systems, about denial, about the perennial hope and trust in new technical innovations, and citizen and specialist burnout. I know toothbrushes are a drop in the bucket. 2.2. From Earth Day #1: carrying capacity The dictionary definition of carrying capacity is “the maximum population (as of deer) that an area will support without undergoing deterioration”. In the 1960s and 70s we emphasized reducing perhectare impacts. Frequently impacts could be considered, and analyzed fruitfully, as a compounding of several factors. For example, the simple but powerful equation I=P*A*T (Ehrlich et al., 1972) expressed the compounding total impact of population(P), per-capita consumption (A), and impact per unit of consumption (T). Implicitly we understood that spreading impact over a larger area would likely reduce deterioration. In 1972 “The Limits to Growth” (Meadows et al., 1972) was published. Its major message was about positive feedback/exponential growth/dynamics and lags, but always in a context of limits. Its models were for the entire world, so it was concerned with global limits.
2.5. 2000 forward, particularly in Vermont, especially in Burlington: does renewability say it all? The dramatic cost reduction of solar and wind energy in the 21st century (IRENA, 2017) makes an eventual transition away from fossil fuels almost inevitable instead of its doubtful status in the 20th. Certainly there are difficult issues about timing, inertia, and equity, along with resistant people, corporations, institutions, and governments, but it's a wave that has arrived. For example, Burlington Electric Dept. (BED), our local utility, is now 100% renewable (a mix of hydro, wind, biomass, and solar) (BED Portfolio, 2015; see Fig. 1). Of course even that claim to renewability can be challenged. Are forestry-based wood chips, which feed our 50 MWe McNeil Power Plant, truly renewable over many harvests? Does Hydro Quebec's (HQ's) flooding, rerouting,
2.3. 1973 forward: enter efficiency Following the Mideast oil embargo in 1973, U.S. consciousness was jolted by realizations and resolutions about energy-use efficiency. We 305
0.33
1.10
30
220
100
100
32
15
% of Burlington's area
0.58
0.0064
4.1
0.61
% of Chittenden County's area
0.034
0.00038
0.24
0.036
% of Vermont's area
BED (2017), p. 22.
ECOS (2018), p. 30.
Source
Based on predicted performance; came on line 1 January 2018. Cap. factor calculated from data = 0.18. 0.036 sq. km. per peak MW.
Cap. factor calculated from data = 0.14. 0.19 sq. km. per peak MW.
Comments
306
Biomass thermal electricity, estimate #1 McNeil biomass electric station. This analysis based on information from Burlington Electric Dept's chief forester. 50MWe, producing 269,000 MWh/yr, of which half goes to Burlington. Area refers to forests from which logging residue fuel is obtained. Above, extrapolated to 100% Burlington coverage Biomass thermal electricity, estimate #2 McNeil biomass electric station. This analysis based on outside research on regional forest productivity. In 2017 McNeil purchased 367,000 tonnes of wood for its full output. Buchholz et al., estimated that Vermont forests can supply 845,000 to 1,030,000 tonnes/yr of biomass on a sustainable basis. This corresponds to a maximum of approx. 2.5 McNeils in all of Vermont. Above, extrapolated to 100% Burlington coverage 3030
7970 17,800
47,000
100 38
100
% of Burlington's area
38
% of Burlington's electric energy
890
340
150
58
% of Chittenden County's area
53
20
8.9
3.4
% of Vermont's area
Buchholz et al. (2011)
Lesnikoski (2018)
Source
There is controversy over the sustainability of harvesting programs, especially about dynamic vs. steady state and dependence on the forests' initial condition.
To provide Burlington's electricity share requires approx. 809 sq. km., based on 40.4 sq. km./yr*reentry time of 20 years. This removal rate averages ca.1 tonne/0.4 ha-yr. (in American units, 1 ton/acre-yr.)
Comments
Table 3 Two estimates of the area required to satisfy part or all of Burlington's electricity by burning forest biomass. Based on Burlington's (jointly-owned) McNeil biomass-burning electric plant (50MWe). Burlington receives 50% of output. The total land impacted is the area harvested in one year multiplied by the number of years between harvests (“reentry time’).
Above, extrapolated to 100% Burlington coverage
Solar PV, estimate # 1 Rooftops, parking lots, etc., distributed. 43 MW, producing 52,500 MWh/yr. Area = 8.55 sq. km. Above, extrapolated to 100% Burlington coverage Solar PV, estimate #2 Solar farm, unobstructed fixed panels, 2.5 MW, producing 3900 MWh/yr. Area = 0.089 sq. km.
% of Burlington's electric energy
Table 2 Two estimates of the area required to satisfy part or all of Burlington's electricity use with solar PV. Capacity factor = (annual average power)/(peak power). Nominal value for cap. factor in practice is 0.14 (Renewable Energy Atlas, 2018). Note that Tables 2 and 4 apply to overlapping areas and therefore cannot be added.
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Energy Policy 130 (2019) 304–310
Energy Policy 130 (2019) 304–310
R. Herendeen
Fig. 2. The squares represent the size of areas in renewable forestry needed to produce Burlington's share of electricity from the McNeil biomass plant. Red is for current share, 38%. Yellow is for 100%. Refer to Table 3, example #1. (For interpretation of the references to colour in this figure legend, the reader is referred to the Web version of this article.)
Make Burlington a “net zero energy city” across electric, thermal, and ground transportation sectors by managing demand, realizing efficiency gains, and expanding local renewable generation, while increasing system resilience. o BED defines “net zero” as Burlington sourcing at least as much renewable energy as it consumes in energy for electric, thermal, and transportation purposes. o We source energy from New England and adjoining states and territories with a strong preference for generation closest to Burlington. o For thermal and electric, we will work toward net zero with Burlington residential, commercial, and industrial customers. o For transportation, our goal is to make in-city travel net zero, and lower the impact of intercity travel. Air travel is not included at this time.
and regulating of watersheds covering ca. one fifth the Province's area qualify? Does Burlington Electric Dept.’s selling and buying renewable energy credits to keep our per-kWh cost low jibe with a fair definition? (The process is illustrated in BED Portfolio (2015), where three distinct pie charts depict the fraction of renewable sources at various stages of this trading.) My concern here is that renewability is the newly touted substitute for, or equivalent of, sustainability-itself usually scarcely defined. 2.6. Being renewable and local returns us to the space question To put it baldly, do we now say uncritically that if it's renewable, more is better? Will there be a land-use crunch? After all, critics of solar electricity rightly point out that sunlight is diffuse relative to coal, oil, or natural gas, or even nuclear-and they have a point. This areal impact question appears implicitly in a new vision of Burlington Electric Dept., encapsulated in the recent strategic plan (BED Strategic, 2018):
Let us acclaim this bold and exciting extension of BED's purview to fossil fuels, beyond just electricity. (This will eventually mean electrifying almost all of space conditioning and transportation.) And let us
2030 Vision 307
3.1. Solar The solar PV energy fraction was 0.9% in 2017. The addition of a 2.5 MW solar field within city limits should raise this to 2.0% for 2018 (BED, 2017, p. 22). Table 2 lists two estimates (and data used) of Burlington's solar PV potential. For Burlington to provide all electricity this way, 30–220% of the city's area would be needed. The larger figure is based on installations on rooftops, parking lots, etc., which produce much less MWh/yr. per sq. km. than an unobstructed solar farm, for which the smaller figure applies. 3.2. Biomass Burlington Electric Dept. owns a 50% share in the McNeil 50MWe biomass electric power plant, which is located inside the city limits. Burlington's share provides approx. 38% of its electricity. Unsurprisingly, the area needed for a sustainable supply of forestry residues (wood chips) far exceeds Burlington's area. A more relevant metric is the fraction of the entire state. Table 3 shows two estimates. The first, based on data from Burlington Electric Dept. staff (Lesnikoski, 308
ECOS (2018), p. 31
Source % of Chittenden County's area
0.84 [0.058]
% of Burlington's area
44 [3.0]
% of Vermont's area Approx. 1.3 Approx. 12.6
0.050 [0.0034]
Comments
Cap. factors calculated from data. Ridge line potential assumed = 9 MW/km. Ridgeline in Vermont = approx. 1000 km (both from Blittersdorf, 2015)
Comments Source
BED Portfolio (2015). Approx. 0.24 Approx. 2.4
Wind electricity, estimate # 1 (ridgeline location) Georgia Mountain, 10 MW, 33145 MWh/yr, cap. 19.3 factor = 0.38. Sheffield Wind, 16 MW, 35006 MWh/yr, cap. factor = 0.25. (BED, 2015) Above, extrapolated to 100% Burlington 100 coverage % of Burlington's electric energy Wind electricity, estimate #2 (local location) 103 Within Burlington: [6.9] Total: 119 MW, producing 364,000 MWh/ yr. Area = 12.0 sq. km. Of which: [“Prime”: 8 MW, producing 24,500 MWh/yr. Area = 0.81 sq. km. ]
Burlington's electric energy use is ca. 354,000 MWh/yr, 100% renewable but often from distant sources. Details are shown in Fig. 1. The question is to what degree more local sourcing is feasible. The data sources and methods are of varying quality and rigor; results are only illustrative. Additionally, I assume that we develop lossless storage for electric energy to solve the intermittency problem. Admittedly this is a big assumption, but addressing it is beyond the scope of this article.
% of Vermont's ridgelines
3. Burlington’s electricity spatial impact today and looking forward
km. ridge line required
acknowledge that BED is already 100%* renewable, the “*” indicating several persistent arguable components mentioned above. Instead, let's concentrate on the land area required for renewable energy: how “local” can Burlington be? As we become more local we will pull the distant sources closer and make them more visible. These land demands will compete with many other uses. How that area compares with Burlington's and Vermont's area is a critical issue. Given that spatial impact and carrying capacity are closely (but inversely) related, this represents almost a full circle from Earth Day #1, 48 years ago.
% of Burlington's electric energy
Table 4 Two estimates of land required for present and potential wind electricity for Burlington. Nominal value for cap. factor in practice is 0.35 (Renewable Energy Atlas, 2018). “Prime” means more distant from housing and therefore potentially less controversial. Note that Tables 2 and 4 apply to overlapping areas and therefore cannot be added.
Fig. 3. Georgia Mountain Wind, 25 km northeast of Burlington. Four 2.5 MW turbines along 1 km of ridge line. All energy is sold to Burlington Electric Dept.
Cap. factor = 0.35; calculated from given data.
Energy Policy 130 (2019) 304–310
R. Herendeen
Energy Policy 130 (2019) 304–310
R. Herendeen
3.4. Hydroelectric energy Hydroelectricity comprises ca. 29% of Burlington's total. It comes from far away-from Niagara Falls in western New York State (400 km), and from Hydro Quebec, which has a network of major river diversions, reservoirs, and power stations reaching 700 km north. Fig. 4 is an attempt to show our HQ dependence; see caption for explanation. But hydro is also local; the Winooski 1 plant, which we own (7 MW run-ofriver, producing approx. 7% of Burlington's electricity), is within 100 m of city limits. As of 1 January 2018, hydro from Maine (12%) has been replaced by hydro from the Connecticut River, 160 km away on Vermont's east side. There is no more hydro available inside Burlington. There is some additional potential (as much as 35% of Vermont's developed potential (Barg, 2007),), but this is a mix of small sources with various complicating issues such as fish impacts. The beckoning source for all of New England plus New York State, which includes the megacities of Boston and New York, is Hydro Quebec. Almost daily battles are fought over siting the new transmission lines for it; proposals include underwater cables running the length (ca. 160 km) of Lake Champlain. Except for transmission problems, HQ energy represents an ideal combination of NIMBY (not in my back yard) and politically declared renewability. Much of the claim to renewability, and to actual GHG reduction, of programs in Vermont and farther south, can be based on using this source. Vermont's Comprehensive Energy Plan (CEP, 2016) calls for 90% of Vermont's energy to be from renewable sources by the year 2050. I do not discuss that plan here, but it is clear that implementation will increase pressure for HQ electricity.
Fig. 4. One attempt at showing the areal reach of hydroelectricity for Burlington, which is located at the green star. Most of the shaded area is the watersheds that Hydro Quebec exploits. Some of the shading at lower left is for New York State Power Authority energy. The large lakes shown in yellow are either enlarged or totally human-made. This includes the remarkable ringshaped impact crater dammed as the Manicouagan Reservoir. The tiny red pixel is intended to show Burlington's share from Hydro Quebec proportionally, but it is still too large because of graphics resolution. (For interpretation of the references to colour in this figure legend, the reader is referred to the Web version of this article.)
2018), indicates 3.4% of all of Vermont at Burlington's current use and 8.9% if enough identical biomass plants were available to provide 100%. Fig. 2 depicts this area in relation to Vermont's. Another research project has more pessimistically indicated that Vermont's forests could support only ca. 2.5 McNeils plants (Buchholz et al., 2011), in which case the resulting areal requirements would be 20 and 53%, respectively. These are dauntingly large fractions of Vermont's area. Further, since the State's electricity use is ca. 15 times larger, Vermont electricity could not be fueled with wood from Vermont.
4. Upshot: How far, and hard, should we reach? Alternatively, how earnestly should we attempt to foster local energy supply? This question is now central to Burlington Electric Dept., to the Chittenden County Regional Planning Commission, and to the Vermont Energy Plan. In broad terms the numbers above show that, with the possible exception of solar PV, Burlington must continue to reach beyond its borders to maintain 100% renewability for electricity. In terms of required area, biomass is most demanding. Hydro requires the most geographical reach. One can also ask if Vermont could achieve 100% renewable electricity in-state. This is possible for solar PV or wind, with wind likely encountering more popular resistance. (I again emphasize that these conclusions assume lossless storage of electricity to deal with intermittency.) For biomass and hydro, Vermont would have to look beyond its borders. My basic concern is that renewable energy still has environmental costs. This is not new, but in the rush to renewability, it tends not to be news. E. O. Wilson (2016) proposes that half of the earth should be set aside for nature. The reasons span spiritual/religious, scientific, economic, and social issues. In the empty world into which modern humans radiated ca. 60 thousand years ago, the question of when “enough becomes plenty” (or perhaps better, when “plenty is enough”) was moot; we i had no discernable effect. We know that is no longer true. Worldwide, humanity's ecological footprint (which is expressed in units of area) (Wackernagel et al., 2018) exceeds earth's productive area. As calculated today, ca. half of that footprint is attributed to the impact of fossil fuel burning, using a necessarily crude and arguable estimate of afforestation needed to absorb anthropogenic CO2. As our energy supply turns to renewable sources which produce much less CO2, it is likely that the ecological footprint will decrease. This welcome news will hopefully be tempered by recommitting to comprehensive analysis of the impacts of areal conversion and disturbance-of what we still have.
3.3. Wind Wind is highly controversial in Vermont because the preferred stronger wind locations are at higher elevations (ca. 500–1000 m) along the forested ridge lines which comprise Vermont's wildest land, and which are often the background for iconically beautiful vistas (see Fig. 3). In contrast, Burlington is in the Champlain Valley and only 35–60 m above sea level. Additionally, there are local aesthetic and proximity issues (e.g., noise) that elicit strong reactions, including claims about human health. Table 4 includes two estimates. The first accepts the strong likelihood that only ridge lines will be used. Detailed identification of (physically) suitable sites can be found in Wind (2018). An estimate of the potential is provided by Blittersdorf (2015). The second, from the Chittenden County Regional Planning Association (ECOS, 2018), assumes that significant in-city wind capacity is possible. Given the need for height for higher wind speeds and for isolation from people, this option seems extremely unlikely. Table 4 shows that Burlington could produce today's electric energy from wind on 43% of the City's area, which is impossible because of conflicting use and occupancy. If relatively non-conflicted land (called “prime”) is used, only 7% of the City's electricity could be produced. All these sites are less than 100 m above sea level. Burlington already accesses some distant wind energy. In-state sources typically are on ridge lines above 400 m. For example, Georgia Mountain Wind, ca. 25 km away, provides 19% of the City's electricity from four 2.5 MW turbines on 2.4 km of ridge, which is 0.24% of the State's ridgeline total. Extrapolating to 100% coverage yields 12.6 km (1.3%).
Acknowledgements Thank you to the Gund Institute for Environment, University of 309
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Commoner's book “the closing circle”, and response by B. Commoner. Environ. 14 (No. 3 (April)), 24–52. EIA, 2018. U.S. Energy Consumption. pp. 1950–2017. https://www.eia.gov/totalenergy/ data/monthly/pdf/sec1_7.pdf, Accessed date: 27 July 2018. IRENA, 2017. Electricity Storage and Renewables: Costs and Markets to 2030. International Renewable Energy Agency, Abu Dhabi. http://www.irena.org/-/ media/Files/IRENA/Agency/Publication/2017/Oct/IRENA_Electricity_Storage_ Costs_2017.pdf, Accessed date: 27 July 2018. Lesnikoski, 2018. Personal Communication with Betsy Lesnikoski. Burlington Electric Dept. , Accessed date: 22 March 2018. Meadows, Donella, Meadows, Dennis, Randers, Joergen, Behrens III, William, 1972. The Limits to Growth: A Report for the Club of Rome's Project on the Predicament of Mankind. Potomac Associates. Renewable Energy Atlas, 2018. http://www.nvda.net/files/Sheffield%20Energy %20Profile(1).pdf, Accessed date: 26 July 2018. Steffen, W., Richardson, K., Rockström, J., Cornell, S.E., Fetzer, I., Bennett, E.M., Biggs, R., Carpenter, S.R., de Vries, W., de Wit, C.A., Folke, C., Gerten, D., Heinke, J., Mace, G.M., Persson, L.M., Ramanathan, V., Reyers, B., Sorlin, S., 2015. Planetary boundaries: guiding human development on a changing planet. Science 347 (6223), 1259855-1-10. Wackernagel, M., Galli, A., Hanscom, L., Lin, D., Mailhes, L., Drummond, T., 2018. Ecological footprint accounts: principles. In: Bell, Simon, Morse, Stephen (Eds.), Routledge Handbook of Sustainability Indicators, pp. 244–264. WIKI, 2018. http://en.wikipedia.org/wiki/List_of_U.S._states_and_territories_by_area, Accessed date: 28 March 2018. Wilson, E.O., 2016. Half-Earth: Our Planet's Fight for Life. Liveright Publishing Corporation. Wind, 2018. http://windexchange.energy.gov/maps-data/130, Accessed date: 4 April 2018. http://www.vtenergydashboard.org/energy-atlas. World Commission, 1987. Our Common Future. World Commission on Environment and Development. Oxford University Press.
Vermont, for travel support. References Barg, L., 2007. The Undeveloped Hydro Potential of Vermont. Community Hydro, vol. 113 Bartlett Rd, Plainfield, VT 05667. BEA, 2018. GDP Data from U.S. Bureau of Economic Analysis. http://www.bea.gov/ national/#gdp, Accessed date: 27 July 2018. BED Portfolio, 2015. Energy Sources Are Quantified. http://www.burlingtonelectric. com/our-energy-portfolio, Accessed date: 31 March 2018. BED, 2017. Performance Measures Report, vol. 2017 Burlington Electric Dept, Burlington, VT 05401. BED Strategic, 2018. Strategic Plan Statement. http://www.burlingtonelectric.com/ 2017-2018-strategic-direction, Accessed date: 24 July 2018. Blittersdorf, 2015. Interview with David Blittersdorf, developer of the Georgia Mountain wind facility. “(To reach) 3,000 megawatts, you can put about 15 megawatts per mile – so that's 200 miles of ridges. In Vermont we have about 600-plus miles of ridge lines. ...”. https://www.wind-watch.org/news/2015/07/24/green-energy-ceovermonters-must-abandon-the-car-embrace-renewable-energy-future/, Accessed date: 26 July 2018. Buchholz, T., Canham, C.D., Hamburg, S.P., 2011. Forest Biomass and Bioenergy: Opportunities and Constraints in the Northeastern United States. Report. Cary Institute of Ecosystem Studies, Millbrook, NY. CEP, 2016. Vermont Comprehensive Energy Plan 2016. http://outside.vermont.gov/sov/ webservices/Shared%20Documents/2016CEP_Final.pdf. ECOS, 2018. Chittenden County ECOS Plan, Supplement 6–Energy Analysis, Targets, & Methodology. Chittenden County Regional Planning Commission, Winnooski, Vermont Adopted 6/20/2018. http://www.ecosproject.com/wp/wp-content/ uploads/2017/09/ECOSPlan_ProcessSupplement6_EnergyData_Methodology_ Final20180615.pdf, Accessed date: 26 July 2018. Ehrlich, P., Holdren, J., Commoner, B., 1972. Review by Ehrlich and Holdren of B.
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