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Climate Change TechnologyPaper – Option 1
due April 28, 10:00 pm
ENERGY TECHNOLOGIES OUTSIDE THE U.S. AND CANADA
In order to understand the technologies that provide energy to our lives, it has been necessary
to make certain assumptions about our society. For example, we only need to study loadfollowing capabilities of technologies if we decide that load following is necessary. Or, we only
need to understand how solar panels work if we agree that CO 2 emissions are to be reduced,
because this is a major premise that motivates the installation of large numbers of solar panels.
During this course we have mainly constrained our attention to Canada and the United States
and aimed to understand the technologies that have emerged as a response to these countries’
motivations and emission reduction goals.
Now, it is time to question the motivations that have been adopted by the United States and
Canada, and we shall do so by turning our focus internationally. Your assignment is to choose a
country or region of the world that creates and uses energy in a meaningfully different manner
from Canada and the United States and write a paper of 800 to 1200 words in length on these
questions:
1. How is energy being created and used in the country of your choice? Please make your
choice of country clear. Explains the energy systems, including main source of energy,
main ways of transportation, and how the electricity grid looks like
2. What do you think is the main reason for this energy system to be different that North
America’s system? Identify the main motivator for the choice of energy source and grid
configuration
3. What roles do you think do climate change mitigation and adaptation play in the
country of your choice? Which one do you think is more important in this country?
You are encouraged to do this assignment in groups. Do understand that working in groups
requires that the range, detail, and rigor of thought that you put into this assignment be (at least)
twice or three times as impressive as if you did this alone. All group members will receive the
same grade for their assignment.
Paper Writing Guidelines
In order to succeed on this assignment, please ensure that your paper meets the following
guidelines:
•
Use specific evidence/analysis to support all claims/assertions: Assemble strong,
specific, factual evidence to support your claims, including quoting, paraphrasing, and
summarizing background information.
•
Introduce and discuss all quotations/paraphrases in detail: Each quotation must be
introduced and discussed in detail to show the reader how it relates to your paper’s
argumentative claims and overall thesis.
•
Use coherent, single-topic paragraphs: Ensure that each paragraph contains only one
subject and its supporting evidence; add transition words between ideas and between
paragraphs to show connections between the topics you discuss.
•
Be persuasive: The purpose of answering question 2 and 3 in your paper must be
to convince/persuade the reader that your position/ opinion is a correct one, not merely
to present information or discuss something widely accepted.
•
Use correct APA in-text citations and include a correct APA References list: For each
quotation and paraphrase, you must include a correct in-text citation. These in-text
citations must correspond to entries on the References list.
•
Use concise, direct, and active sentence structure: This paper should use a formal,
academic style; however, the writing should not be verbose. Using the first person often
helps to avoid the passive voice and keep sentences concise. Therefore, please feel free
to use the pronoun “I”; however, avoid hedging statements like “I feel.”
Final Paper – Evaluation Criteria
CONTENT & ORGANIZATION
☐ Near the beginning, the paper includes a clear description of the topic being
discussed.
☐ Each question in the paper description is answered clearly with specific claims
throughout the paper
☐ Each of the paper’s claims is introduced and explained in detail.
☐ The paper includes evidence for each of its claims, including quotations, paraphrases,
and summaries of information from secondary sources.
☐ All personal opinions in the paper are supported by evidence from course readings or
another research
☐ Each quotation, paraphrase, and summary is introduced and discussed in detail.
☐ Each paraphrase is re-written completely in your own words and does not mimic the
word choice or sentence structure of the original.
☐ Each quotation/paraphrase is accompanied by a correct APA citation (i.e. author,
year, and, if applicable, page number).
☐ Transition words are used within and between paragraphs to show relationships
between ideas.
WRITING MECHANICS & CITATIONS
☐ The paper uses clear and correct sentence structure and writing mechanics.
☐ The paper includes correct in-text APA citations.
☐ The paper includes a correct APA References list.
FORMATTING
☐ The paper is 800-1200 words long.
☐ The paper is in a typed electronic format.
☐ The paper includes a header with your name and the page number on every page.
☐ The paragraphs are indented, and there is no extra space between paragraphs.
Energy xxx (2014) 1e15
Contents lists available at ScienceDirect
Energy
journal homepage: www.elsevier.com/locate/energy
A roadmap for repowering California for all purposes with wind,
water, and sunlight
Mark Z. Jacobson a, *, Mark A. Delucchi b, Anthony R. Ingraffea c, d, Robert W. Howarth e,
Guillaume Bazouin a, Brett Bridgeland a, Karl Burkart f, Martin Chang a,
Navid Chowdhury a, Roy Cook a, Giulia Escher a, Mike Galka a, Liyang Han a,
Christa Heavey a, Angelica Hernandez a, Daniel F. Jacobson g, Dionna S. Jacobson g,
Brian Miranda a, Gavin Novotny a, Marie Pellat a, Patrick Quach a, Andrea Romano a,
Daniel Stewart a, Laura Vogel a, Sherry Wang a, Hara Wang a, Lindsay Willman a,
Tim Yeskoo a
a
Atmosphere/Energy Program, Department of Civil and Environmental Engineering, Stanford University, 473 Via Ortega, Stanford, CA 94305, USA
Institute of Transportation Studies, U.C. Davis, 1605 Tilia St, Davis, CA 95616, USA
c
Department of Civil and Environmental Engineering, Cornell University, 220 Hollister Hall, Ithaca, NY 14853, USA
d
Physicians, Scientists, and Engineers for Healthy Energy, Inc., 436 14th Street, Suite 808, Oakland, CA 94612, USA
e
Department of Ecology and Evolutionary Biology, Cornell University, E145 Corson Hall, Ithaca, NY 14853, USA
f
K2B Digital, 2658 Griffith Park Blvd., Suite 612, Los Angeles, CA 90039, USA
g
H.M. Gunn Senior High School, 780 Arastradero Rd, Palo Alto, CA 94306, USA
b
a r t i c l e i n f o
a b s t r a c t
Article history:
Received 16 December 2013
Received in revised form
21 June 2014
Accepted 26 June 2014
Available online xxx
This study presents a roadmap for converting California’s all-purpose (electricity, transportation, heating/
cooling, and industry) energy infrastructure to one derived entirely from wind, water, and sunlight
(WWS) generating electricity and electrolytic hydrogen. California’s available WWS resources are first
evaluated. A mix of WWS generators is then proposed to match projected 2050 electric power demand
after all sectors have been electrified. The plan contemplates all new energy from WWS by 2020, 80e85%
of existing energy converted by 2030, and 100% by 2050. Electrification plus modest efficiency measures
may reduce California’s end-use power demand ~44% and stabilize energy prices since WWS fuel costs
are zero. Several methods discussed should help generation to match demand. A complete conversion in
California by 2050 is estimated to create ~220,000 more 40-year jobs than lost, eliminate ~12,500 (3800
e23,200) state air-pollution premature mortalities/yr, avoid $103 (31e232) billion/yr in health costs,
representing 4.9 (1.5e11.2)% of California’s 2012 gross domestic product, and reduce California’s 2050
global climate cost contribution by $48 billion/yr. The California air-pollution health plus global climate
cost benefits from eliminating California emissions could equal the $1.1 trillion installation cost of
603 GW of new power needed for a 100% all-purpose WWS system within ~7 (4e14) years.
© 2014 Elsevier Ltd. All rights reserved.
Keywords:
Renewable energy
Air pollution
Global warming
1. Introduction
This paper presents a roadmap for converting California’s energy infrastructure in all sectors to one powered by wind, water,
and sunlight (WWS). The California plan is similar in outline to one
recently developed for New York State [39], but expands, deepens,
and adapts the analysis for California in several important ways.
* Corresponding author. Tel.: þ1 650 723 6836; fax: þ1 650 723 7058.
E-mail address: jacobson@stanford.edu (M.Z. Jacobson).
The estimates of energy demand and potential supply are developed specifically for California, which has a higher population,
faster population growth, greater total energy use, and larger
transportation share of total energy, but lower energy-use per
capita, than does New York. The California analysis also includes
originally-derived (1) computer-simulated resource analyses for
both wind and solar, (2) calculations of current and future rooftop
and parking structure areas and resulting maximum photovoltaic
(PV) capacities for 2050, (3) air-pollution mortality calculations
considering three years of hourly data at all air quality monitoring
stations in the state, (4) estimates of cost reductions associated
http://dx.doi.org/10.1016/j.energy.2014.06.099
0360-5442/© 2014 Elsevier Ltd. All rights reserved.
Please cite this article in press as: Jacobson MZ, et al., A roadmap for repowering California for all purposes with wind, water, and sunlight,
Energy (2014), http://dx.doi.org/10.1016/j.energy.2014.06.099
2
M.Z. Jacobson et al. / Energy xxx (2014) 1e15
with avoided air-pollution mortality and morbidity, (5) potential
job creation versus loss numbers, (6) estimates of the future cost of
energy and of avoided global-warming costs, and (7) WWS supply
figures based on 2050 rather than 2030 energy demand along with
a more detailed discussion of energy efficiency measures. It further
provides a transition timeline and develops California-relevant
policy measures. The California plan as well as the prior New
York plan build on world and U.S. plans developed by Jacobson and
Delucchi [37,38] and Delucchi and Jacobson [12]. Neither the California plan nor the prior New York plan is an optimization study;
that is, neither attempts to find the least-cost future mix of generation technologies, demand-management strategies, transmission systems, and storage systems that satisfies reliability
constraints. However, this study does discuss results from such an
optimization analysis based on contemporary California energy
demand.
Several partial renewable-energy plans for California have been
proposed previously. For example, California has a renewable
portfolio standard (RPS) requiring 33% of its electric power to come
from renewable sources by 2020. Williams et al. [77] hypothesized
the infrastructure and technology changes need to reduce California emissions 80% by 2050. Wei et al. [76] used detailed projections
of energy demand and a high-resolution resource capacity planning model to evaluate supply and demand alternatives that could
reduce greenhouse-gas emissions in California 80% below 1990
levels by 2050. Although these efforts are insightful and important,
the plan proposed here goes farther by analyzing a long-term
sustainable energy infrastructure that supplies 100% of energy in
all sectors (electricity, transportation, heating/cooling, and industry) from wind, water, and solar power (without fossil fuels,
biofuels, or nuclear power), and hence provides the largest possible
reductions in air pollution, water pollution, and global-warming
impacts. In addition, unlike the other California studies, the present study quantifies air-pollution mortality and reduced costs due
to reduced mortality and climate damage upon a conversion, along
with job creation minus loss numbers. Further, it quantifies and
differentiates between footprint and spacing areas required for the
energy technologies and provides in-depth first-step policy measures for a conversion.
2. How the technologies were chosen?
The WWS energy technologies chosen for California are existing
technologies ranked the highest among several proposed energy
options for addressing pollution, public health, global warming,
and energy security [35]. That ranking study concluded that, for
electricity; wind, concentrated solar, geothermal, solar PV, tidal,
wave, and hydroelectric power (WWS) were the best overall options. For transportation, battery electric vehicles (BEVs) and
hydrogen fuel cell vehicles (HFCVs), where the hydrogen is produced by electrolysis from WWS electricity, were the ideal options.
Long-distance transportation would be powered by BEVs with fast
charging or battery swapping (e.g., Ref.[50]). Heavy-duty transportation would include BEV-HFCV hybrids. Heating/cooling would
be powered primarily by electric heat pumps. High-temperature
industrial processes would be powered by electricity and combusted electrolytic hydrogen. Hydrogen fuel cells would be used
only for transportation, not for electric power generation due to the
inefficiency of that application for HFCVs. Although electrolytic
hydrogen for transportation is less efficient and more costly than is
electricity for BEVs, there are some segments of transportation
where hydrogen-energy storage may be preferred over batteryenergy storage (e.g., ships, aircraft, long-distance freight). Jacobson and Delucchi [38] and Jacobson et al. [39] explain why this
energy plan does not include nuclear power, coal with carbon
capture, liquid or solid biofuels, or natural gas. However, this plan
does include energy efficiency measures.
3. Change in California power demand upon conversion to
WWS
Table 1 summarizes global, U.S., and California end-use power
demand in 2010 and 2050 upon a conversion to a 100% WWS
infrastructure (zero fossil fuel, biofuel, or nuclear energy). The table
was derived from a spreadsheet available in Ref. [40] using annually
averaged end-use power demand data and the same methodology
as in Ref. [38]. All end uses that feasibly can be electrified are
assumed to use WWS power directly, and remaining end uses are
assumed to use WWS power indirectly in the form of electrolytic
hydrogen. Some transportation would include HFCVs, and some
high-temperature industrial heating would include hydrogen
combustion. Hydrogen would not be used for electricity generation
due to its inefficiency in that capacity. In this plan, electricity requirements increase because all energy sectors are electrified, but
the use of oil and gas for transportation and heating/cooling decreases to zero. The increase in electricity use is much smaller than
the decrease in energy embodied in gas, liquid, and solid fuels
because of the high efficiency of electricity for heating and electric
motors. As a result, end-use power demand decreases significantly
in a WWS world (Table 1).
The 2010 power required to satisfy all end-use power demand
worldwide for all purposes was ~12.5 trillion watts (terawatts, TW).
Delivered electricity was ~2.2 TW of this. End-use power excludes
losses incurred during production and transmission of the power. If
the use of conventional energy, mainly fossil fuels, grows as projected in Table 1, all-purpose end-use power demand in 2050 will
increase to ~21.6 TW for the world, ~3.08 TW for the U.S., and
~280 GW for California. Conventional power demand in California
is projected to increase proportionately more in 2050 than in the
U.S. as a whole because California’s population is expected to grow
by 35.0% between 2010 and 2050, whereas the U.S. population is
expected to grow by 29.5% (Table 1).
Table 1 indicates that a complete conversion by 2050 to WWS
could reduce world, U.S., and California end-use power demand and
the power required to meet that demand by ~30%, ~38%, and 44%,
respectively. About 5e10 percentage points of these reductions (5.6
percentage points in the case of California) are due to modest
energy-conservation measures. The EIA [21] growth projections of
conventional demand between 2010 and 2050 in Table 2 account
for some end-use efficiency improvements as well, so the 5e10
percentage point reductions are on top of those. Table S6 and
Section 11 indicate that efficiency measures can reduce energy use
in non-transportation sectors by 20e30% or more, which means
that our assumption of a 5e10% demand reduction due to energy
conservation on top of EIA [21] assumed modest demand reductions in the baseline projection is likely conservative. Thus, if
the achieved demand reduction by 2050 exceeds our assumption,
then meeting California’s energy needs with 100% WWS will be
easier to implement than proposed here.
Another relatively small portion of the reductions in Table 1 is
due to the fact that conversion to WWS reduces the need for upstream coal, oil, and gas mining and processing of fuels, such as
petroleum or uranium refining. The remaining and major reason for
the reduction in end-use energy is that the use of electricity for
heating and electric motors is more efficient than is fuel combustion for the same applications [38]. Also, the use of WWS electricity
to produce hydrogen for fuel cell vehicles, while less efficient than
is the use of WWS electricity to run BEVs, is more efficient and
cleaner than is burning liquid fossil fuels for vehicles [33,38].
Combusting electrolytic hydrogen is slightly less efficient but
Please cite this article in press as: Jacobson MZ, et al., A roadmap for repowering California for all purposes with wind, water, and sunlight,
Energy (2014), http://dx.doi.org/10.1016/j.energy.2014.06.099
M.Z. Jacobson et al. / Energy xxx (2014) 1e15
3
Table 1
Contemporary (2010) and projected (2050) end-use power demand (TW of delivered power) for all purposes by sector, for the world, U.S., and California if conventional fuel use
continues as projected or if 100% conversion to WWS occurs.
Energy sector
Residential
Commercial
Industrial
Transportation
Total
Percent change
Conventional fossil fuels and
wood 2010 (TW)
Conventional fossil fuels and
wood 2050 (TW)
Replacing fossil fuels and wood with
WWS 2050 (TW)
World
U.S.
CA
World
U.S.
CA
World
U.S.
CA
1.77
0.94
6.40
3.36
12.47
0.39
0.29
0.78
0.92
2.37
0.030
0.024
0.048
0.103
0.206
3.20
2.00
11.2
5.3
21.6
0.49
0.37
1.02
1.20
3.08
0.041
0.032
0.066
0.141
0.280
2.6
1.9
8.9
1.7
15.1
(30%)
0.41
0.33
0.82
0.37
1.92
(37.6%)
0.033
0.030
0.053
0.042
0.157
(43.7)
Source: Spreadsheets to derive the table are given in Ref. [40], who used the method of Jacobson and Delucchi [38] with EIA [21] end-use demand data. U.S (CA) population was
308,745,538 (37,309,382) in 2010 and is projected to be 399,803,000 (50,365,074) in 2050 [70], giving the U.S. (California) 2010e2050 population growth as 29.5% (35.0%).
cleaner than is combusting fossil fuels for direct heating, and this is
accounted for in Table 1.
The percentage reduction in California power demand upon
conversion to WWS in Table 1 exceeds the reduction in U.S. power
demand because the transportation-energy share of the total is
greater in California than in the U.S., and efficiency gains from
electrifying transportation are greater than are those from electrifying other sectors. The power demand reduction in the U.S. exceeds that worldwide for the same reason.
4. Numbers of electric power generators needed and land-use
implications
How many WWS power plants or devices are needed to power
California for all purposes assuming end-use power requirements
in Table 1 and accounting for electrical transmission and distribution losses? Table 2 provides one of several possible future
scenarios for 2050. Upon actual implementation, the number of
each generator in this mix will likely shift e e.g., perhaps more
offshore wind, less onshore wind. Environmental and zoning
regulations will govern the siting of facilities. Development in
“low-conflict zones,” where and biological resource value is low
and energy resources are high, will be favored. Some such areas
include lands already mechanically, chemically or physically
impaired; brown fields; locations in or near urban areas; locations
in the built environment; locations near existing transmission and
roads; and locations already designated for renewable energy
development. Decisions on siting should take into account biodiversity and wildlife protection but should not inhibit the implementation of the roadmap, because such a delay would allow
fossil fuel plants to persist and cause greater damage to human
and animal life.
Solar and wind are the largest generators of electric power
under this plan because they are the only two resources sufficiently
available to power California on their own, and both are needed in
combination to ensure the reliability of the grid. Lund [47] suggests
an optimal ratio of wind-to-solar of 2:1 in the absence of load
balancing by hydroelectric or CSP with storage. The present study
includes load balancing by both, which makes it reasonable for us
to assume larger penetrations of solar (in Table 2) than in that
study. In addition, since a 100% WWS world will include more
flexible loads than today, such as BEV charging and hydrogen
production, it will be possible to shift times of load to match better
peak WWS availability. Finally, power in many U.S. states will be
dominated by wind (e.g., in Ref. [39], the proposed New York windto-solar ratio is 1.5:1 with hydroelectric used for load balancing).
California, though, has a larger accessible solar resource than most
states, and wind is more limited in terms of where it is available. In
sum, the choice of a larger ultimate penetration of solar in
California for 2050 was not based on an optimization study but on
practical considerations specific to the state, the load balancing
resources available, and the potential for large flexible loads in the
state.
Since a portion of wind and all wave and tidal power will be
offshore under the plan, some transmission will be under water and
out of sight. Transmission for new onshore wind, solar, and
geothermal power plants will be along existing pathways but with
enhanced lines to the greatest extent possible, minimizing zoning
issues as discussed in Section S4.
The footprint area shown in Table 2 is the physical area on top
of the ground needed for each energy device (thus does not
include underground structures), whereas the spacing area is the
area between some devices, such as wind, tidal, and wave power,
needed, for example, to minimize interference of the wake of one
turbine with downwind turbines. Most spacing area can be used
for open space, agriculture, grazing, etc. Table 2 indicates that the
total new land footprint required for this plan is ~0.90% of California’s land area, mostly for solar PV and CSP power plants (as
mentioned, rooftop solar does not take up new land). Additional
space is also needed between onshore wind turbines. This space
can be used for multiple purposes and can be reduced if more
offshore wind resources are used than proposed here. Fig. 1 shows
the relative footprint and spacing areas required in California.
5. WWS resources available
California has more wind, solar, geothermal, plus hydroelectric
resource than is needed to supply the state’s energy for all purposes
in 2050. Fig. 2a and b shows estimates, at relatively coarse horizontal resolution (0.6 WeE 0.5 SeN), of California’s onshore
and offshore annual wind speed and capacity factor, respectively
(assuming an RePower 5 MW, 126-m rotor turbine) at 100 m above
the topographical surface. They are derived from threedimensional computer model simulations performed as part of
this study. The deliverable power in California at 100 m in locations
with capacity factor >30%, before excluding areas where wind
cannot readily be developed, is ~220 GW (1930 TWh/yr). This
translates to ~713 GW of installed power for this turbine operating
in 7e8.5 m/s winds. Assuming two-thirds of the windy areas are
not developable gives a technical potential of ~238 GW of installed
capacity and 73.3 GW of delivered power. These resources easily
exceed the 39.4 GW (345 TWh/yr) of delivered power needed to
provide 25% of California’s 2050 all-purpose energy demand in a
WWS world (Table 2). Because of land-use exclusions in California,
which depend on local zoning decisions, it may alternatively be
useful to obtain a portion of onshore wind from Wyoming, where
wind resources are enormous and underutilized, or from Oregon or
Washington.
Please cite this article in press as: Jacobson MZ, et al., A roadmap for repowering California for all purposes with wind, water, and sunlight,
Energy (2014), http://dx.doi.org/10.1016/j.energy.2014.06.099
4
Energy technology
Rated power of
one unit (MW)
Percent of 2050
power demanda
met by technology
Technical potential
nameplate
capacity (GW)b
Onshore wind turbine
Offshore wind turbine
Wave device
Geothermal plant
Hydroelectric plant
Tidal turbine
Res. roof PV system
Com/gov roof PV system
Utility PV plant
Utility CSP plant
Total
Total new land required
5
5
0.75
100
1300
1
0.005
0.10
50
100
25
10
0.5
5
3.5
0.5
8
6
26.5
15
100
238
166
7.5
187.1
20.9
7.4
83.1
55.3
4122
2726
Assumed installed
nameplate capacity
of existing þ new
units (GW)
Percent of assumed
nameplate capacity
already installed
2013
Number of new units
needed for California
Footprint for new
units (percent of
California land area)c
Spacing for new
plants/devices
(percent of California
land area)
25,211
7809
4963
72
0d
3371
14,990,000e
533,700e
3450f
1226f
624,407
4.42
0
0
21.8
100
0
1.66
1.17
0.37
0.0
3.4
0.000078
0.000024
0.00065
0.0061
0
0.00024
0.139
0.099
0.320f
0.579
1.14
0.90g
2.77
0.859
0.031
0
0
0.0031
0
0
0
0
3.67
2.77h
131,887
39.042
3.723
9.188
11.050
3.371
76.237e
54.006e
173.261
122.642
Rated powers assume existing technologies. The percent of total demand met by each device assumes that wind and solar are the only two resources that can power California independently (Section 5) and that they should be in
approximate balance to enable load matching (Sections 6 and S3). Because of California’s extensive solar resources, solar’s total share is higher than that of wind’s. The number of devices is calculated as the California end-use
power demand in 2050 from Table 1 (0.157 TW) multiplied by the fraction of power from the source and divided by the annual power output from each device, which equals the rated power multiplied by the annual capacity
factor of the device and accounting for transmission and distribution losses. The capacity factor is determined for each device as in Ref. [40]. Onshore wind turbines are assumed to be located in mean annual wind speeds of 7.5 m/
s and offshore turbines, 8.5 m/s [17]. These mean wind speeds give capacity factors (before line losses) of 0.338 and 0.425, respectively, for the 5-MW turbines with 126-m diameter rotors assumed. Footprint and spacing areas
are similarly calculated as in Ref. [40]. Footprint is the area on the top surface of soil covered by an energy technology, thus does not include underground structures. Transmission and distribution losses for onshore wind are
assumed to range from 5 to 15%; those for offshore and all other energy sources; 5% due to the proximity of offshore to load centers.
a
Total California projected end-use power demand in 2050 is given in Table 1.
b
Onshore wind, offshore wind, tidal, and wave estimates are derived in Section 5. Rooftop residential and commercial/government PV estimates are derived in Section S2. The rest is from Ref. [46]. The “technical” potential
accounts for the availability of each resource (e.g., wind speed, solar insolation), the performance of the technology, topographic limitations, and environmental and land-use constraints on siting. The technical potential does not
consider market or economic factors. It also treats each technology in isolation, and not as part of a system, with the result that, for example, some of the technical potential for CSP and some the technical potential for utility PV
might be based on the same land. The potential for hydro in Ref. [46] was for hydro beyond existing hydro, so that was added to existing hydro here.
c
The total California land area is 404,000 km2.
d
California already produces about 90.6% (4.98 GW of delivered power in 2010) of the hydroelectric power needed under the plan (5.495 GW of delivered power in 2050). The remaining hydro can be obtained as described in
the text.
e
The average capacity factors for residential and commercial/government solar are estimated in Section S4. The nameplate capacity of installed rooftop solar PV is estimated in Section S2.
f
For utility solar PV plants, nominal “spacing” between panels is included in the plant footprint area. The capacity factor assumed for utility PV is estimated in Section S4. The capacity factor for CSP is 21.5%. These capacity
factors assume that most utility PV and CSP are in desert areas.
g
The total footprint area requiring new land is equal to the footprint area for new onshore wind and geothermal plus that for utility solar PV and CSP plants. Offshore wind, wave and tidal are in water, and so do not require
new land. Since no new hydroelectric plants are proposed here (hydro’s capacity factor is assumed to increase), hydro does not require new land. The footprint area for rooftop solar PV does not entail new land because the
rooftops already exist and are not used for other purposes (that might be displaced by rooftop PV).
h
Only onshore wind entails new land for spacing area. The other energy sources either are in water or on rooftops, or do not use additional land for spacing. Note that most of the spacing area for onshore wind can be used for
multiple purposes, such as open space, agriculture, grazing, etc.
M.Z. Jacobson et al. / Energy xxx (2014) 1e15
Please cite this article in press as: Jacobson MZ, et al., A roadmap for repowering California for all purposes with wind, water, and sunlight,
Energy (2014), http://dx.doi.org/10.1016/j.energy.2014.06.099
Table 2
Number, capacity, footprint area, and spacing area of WWS power generators needed to provide California’s total annually averaged all-purpose end-use power demand in 2050, accounting for transmission, distribution, and
array losses. Ref. [40] contains spreadsheets used to derive the table.
M.Z. Jacobson et al. / Energy xxx (2014) 1e15
5
Fig. 1. Spacing and footprint areas required, from Table 2, to repower California for all purposes in 2050. The dots do not indicate the actual location of energy farms. For wind, the
small red dot in the middle is footprint on the ground (not to scale) and the green or blue is space between turbines. For others, footprint and spacing are the same. For rooftop PV,
the dot represents the rooftop area needed. (For interpretation of the references to colour in this figure legend, the reader is referred to the web version of this article.)
Dvorak et al. [17] mapped the West Coast offshore wind resources at high resolution (Supplemental information, Fig. S1).
Their results indicate that 1.4e2.3 GW, 4.4e8.3 GW, and
52.8e64.9 GW of deliverable power (accounting for exclusions)
could be obtained from offshore wind in California in water depths
of
