NREL is a national laboratory of the U.S. Department of Energy, Office of Energy Efficiency and Renewable Energy, operated by 

Renewable Electricity 

Trieu Mai, Ph.D.American Physical Society – April Meeting 201

Session: Low Carbon ElectricityDenver, ColoradoApril 14, 2013 

Renewable Electricity Futures Study (2012). Hand, M.M.; Baldwin, S.; DeMeo, E.; 

D.; Porro, G.; Meshek, M.; Sandor, D., editors. Lead authors include Mai, T.; Sand

Augustine, C.; Bain, R.; Chapman, J.; Denholm, P.; Drury, E.; Hall, D.; Lantz, E.; Ma

Hostick, D.; Belzer, D.; Hadley, S.; Markel, T.; Marnay, C.; Milligan, M.; Ela, E.; Hein

A U.S. DOE‐sponsored collaboration among more than 110 individuals from 35 o
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• RE Futures is a low carbon, low air pollutant, lo

low water use, domestic, and sustainable electr

• To what extent can renewable energy technolo

commercially available today meet the U.S. elec

demand over the next several decades?

Renewable Electricity Futures Mo

RE Capacity Growth 2000-2010

Source: RE Data Book (DOE 2011)
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Renewable Electricity Futures Rep

RE Futures is a U.S. DOE‐sponsored collaboration with 

contributors from 35 organizations including national l

industry, universities, and non‐governmental organizat

Volume 1 Exploration of High-Penetration Renewable ElectricVolume 2 Renewable Electricity Generation and Storage TechVolume 3 End-Use Electricity DemandVolume 4 Bulk Electric Power Systems: Operations and Trans
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Renewable Electricity Futures Intro

RE Futures does.... RE Futures does nIdentify commercially available RE

generation technology combinations that

meet up to 80% or more of projected 2050

electricity demand in every hour of the year.

Consider policies, new o

procedures, evolved bus

market rules that could 

of RE generation.

Identify electric sector characteristics

associated with high levels of RE generation.

Fully evaluate power sys

Explore a variety of high renewable

electricity generation scenarios.

Forecast or predict the e

electric sector.

Estimate the associated U.S. electric sectorcarbon emissions reductions.

Assess optimal pathway

carbon electricity system

Explore a select number of economic,

environmental and social impacts.

Conduct a comprehensi

analysis.

Illustrate an RE‐specific pathway to a clean

electricity future to inform the development

of integrated portfolio scenarios that

consider all technology pathways and theirimplications.

Provide a definitive asse

generation, but does idedeeper investigation.
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• Unprecedented geographic and time resolution f

contiguous United States

• More than two dozen scenarios of U.S. electric se

2050.

State of the Art Electric System M
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Biopower ~100 GW

Solar CSP ~37,000 GW

Geothermal ~36 GW

•Stand‐alone•Cofired with coal

•Trough•Tower

•Hydrothermal

With thermalstorage

Geographic location, technical resource potential

characteristics are unique to each RE generation t

Abundant Renewable Energy Reso

Darke
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A Transformation of the U.S. Electric

RE generation from technologies that are commerc

today, in combination with a more flexible electric 

more than adequate to supply 80% of total U.S. ele

generation in 2050—while meeting electricity dem

hourly basis in every region of the country.
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The capacity of RE generation technologies “built” in 2050 • Future RE technology cost and performance

• Electricity demand growth

• Presence of constraints that limit new transmission infr

flexibility, or the accessibility of renewable resources.

Multiple Technology Pathways to 8
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RE Resource Supply from 30% ‐ 90% 

Additional variability challenges system operations

addressed through increased use of supply‐ and de

flexibility options and new transmission.
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Installed capacity is sufficient to mee

afternoon peak demand from divers

supplying firm capacity.

Supply and Demand Balanced Every Hou
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Especially during low‐demand periothe spring months, flexibility option

include flexible generators, flexible 

new transmission, and wide area

coordination.

Flexible Electricity System Manages Va
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Significant Long‐Term RE Industry G

No insurmountable long‐term constraints to RE 

manufacturing capacity, materials supply, or lab

were identified.
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80% renewable electricity in 2050 could lead to:

• ~ 80% reduction in GHG emissions (combust

full life‐cycle)

• ~ 50% reduction in electric sector water use 

and consumption).

High RE Reduces Emissions and Wa
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RE Land Use Implications

• Area requirements:

o The gross estimate for RE

Futures scenarios = < 3% of

U.S. land area.

o About half of that land area is

used for biopower.

o The majority of the remainder

is used for wind, but only

about 5% is actually disrupted.

• Other siting issues:

o Permitting processes that vary with technology ano Wildlife and habitat disturbance concernso Public engagement for generation and transmissio

* USDA 2010, ** 

80% RE scenarios

Gross Land 

(0

Biomass All Other RE All Other RE (d

Transmission & Total Contiguou

2009 Corn Prod

Major Roads** Golf Courses ** 
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• The incremental cost of high RE scenarios is comparab

cost estimates of other clean energy scenarios.

• Improvement in the cost and performance of renewa

is the most impactful lever for reducing this incremen

RE Futures Cost Comparisons
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Key Results• Renewable electricity generation from technologies that are com

available today, in combination with a more flexible electric sys

adequate to supply 80% of total U.S. electricity generation in 20

meeting electricity demand on an hourly basis in every region o

• Increased electric system flexibility, needed to enable electricity 

balance with high levels of renewable generation, can come fro

supply‐ and demand‐side options, including flexible convention

storage, new transmission, more responsive loads, and changes 

operations.

• The abundance and diversity of U.S. renewable energy resource

multiple combinations of renewable technologies that result in 

in electric sector greenhouse gas emissions and water use.

• The direct incremental cost associated with high renewable gen

comparable to published cost estimates of other clean energy s

Improvement in the cost and performance of renewable techno

impactful lever for reducing this incremental cost.
A future U.S. electricity system that is largely powe

renewable sources is possible, and further work is w

investigate this clean generation pathway.

www.nrel.gov/RE_Futures