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

Renewable Electricity Futures

M. Maureen Hand, Ph. D.

Utility Variable-Generation Integration Group Fall 

Technical Workshop

October 24, 2012 • Omaha, Nebraska

NREL/PR-6A20-56834 

Renewable Electricity Futures Study (2012). Hand, M.M.; Baldwin, S.; DeMeo, E.; Reilly, J.M.; Mai, T.; Arent, 

D.; Porro, G.; Meshek, M.; Sandor, D., editors. Lead authors include Mai, T.; Sandor, D.; Wiser, R.; Heath, G.; 

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

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

A U.S. DOE-sponsored collaboration among more than 110 individuals from 35 organizations.
WWW.NREL.GOV/RE_FUTURES 2

• RE Futures is a low carbon, low air pollutant, low fuel use, 

low water use, domestic, and sustainable electricity source. 

• To what extent can renewable energy technologies 

commercially available today meet the U.S. electricity 

demand over the next several decades?

Renewable Electricity Futures Motivation

RE Capacity Growth 2000-2010

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

RE Futures is a U.S. DOE-sponsored collaboration with more than 110 

contributors from 35 organizations including national laboratories, 

industry, universities, and non-governmental organizations.

Volume 1 Exploration of High-Penetration Renewable Electricity Futures

Volume 2 Renewable Electricity Generation and Storage Technologies

Volume 3 End-Use Electricity Demand

Volume 4 Bulk Electric Power Systems: Operations and Transmission Planning
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Renewable Electricity Futures Introduction

RE Futures does.... RE Futures does not...

Identify 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 operating 

procedures, evolved business models, or 

market rules that could facilitate high levels

of RE generation.

Identify electric sector characteristics 

associated with high levels of RE generation.

Fully evaluate power system reliability.

Explore a variety of high renewable 

electricity generation scenarios. 

Forecast or predict the evolution of the 

electric sector.

Estimate the associated U.S. electric sector 

carbon emissions reductions.

Assess optimal pathways to achieve a lowcarbon electricity system.

Explore a select number of economic, 

environmental and social impacts.

Conduct a comprehensive cost-benefit 

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 their 

implications.

Provide a definitive assessment of high RE 

generation, but does identify areas for

deeper investigation.
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• Unprecedented geographic and time resolution for the 

contiguous United States 

• More than two dozen scenarios of U.S. electric sector focused on 

2050.

State of the Art Electric System Models
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Biopower ~100 GW

Solar CSP ~37,000 GW

Geothermal ~36 GW

Hydropower ~200 GW

Solar PV ~80,000 GW

(rooftop PV ~700 GW)

Wind ~10,000 GW

•Stand-alone

•Cofired with coal 

•Trough

•Tower

•Hydrothermal

•Run-of-river

•Residential

•Commercial

•Utility-scale

•Onshore

•Offshore fixed-bottom

With thermal

storage

Geographic location, technical resource potential, and output 

characteristics are unique to each RE generation technology.

Abundant Renewable Energy Resources

Darker Colors = Higher Resource
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A Transformation of the U.S. Electricity System

RE generation from technologies that are commercially available 

today, in combination with a more flexible electric system, is 

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

generation in 2050—while meeting electricity demand on an 

hourly basis in every region of the country.
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The capacity of RE generation technologies “built” in 2050 depends on: 

• Future RE technology cost and performance 

• Electricity demand growth

• Presence of constraints that limit new transmission infrastructure, grid 

flexibility, or the accessibility of renewable resources.

Multiple Technology Pathways to 80% RE
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RE Resource Supply from 30% - 90% Electricity

Additional variability challenges system operations, but can be 

addressed through increased use of supply- and demand-side 

flexibility options and new transmission.
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Installed capacity is sufficient to meet summer 

afternoon peak demand from diverse reserves 

supplying firm capacity.

Supply and Demand Balanced Every Hour of the Year
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Especially during low-demand periods in 

the spring months, flexibility options 

include flexible generators, flexible load, 

new transmission, and wide area 

coordination.

Flexible Electricity System Manages Variability
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Significant Long-Term RE Industry Growth

No insurmountable long-term constraints to RE technology 

manufacturing capacity, materials supply, or labor availability 

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

• ~ 80% reduction in GHG emissions (combustion-only and 

full life-cycle)

• ~ 50% reduction in electric sector water use (withdrawals 

and consumption).

High RE Reduces Emissions and Water Use
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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 and location

o Wildlife and habitat disturbance concerns

o Public engagement for generation and transmission

* USDA 2010, ** Denholm & Margolis 2008

80% RE scenarios

Gross Land Use Comparisons 

(000 km2)

Biomass 44-88

All Other RE 52-81

All Other RE (disrupted) 4-10

Transmission & Storage 3-19

Total Contiguous U.S. 7,700

2009 Corn Production* 350

Major Roads** 50

Golf Courses ** 10
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• The incremental cost of high RE scenarios is comparable to published 

cost estimates of other clean energy scenarios.

• Improvement in the cost and performance of renewable technologies 

is the most impactful lever for reducing this incremental cost.

RE Futures Cost Comparisons
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Key Results

• Renewable electricity generation from technologies that are commercially 

available today, in combination with a more flexible electric system, is more than 

adequate to supply 80% of total U.S. electricity generation in 2050–while 

meeting electricity demand on an hourly basis in every region of the country.

• Increased electric system flexibility, needed to enable electricity supply-demand 

balance with high levels of renewable generation, can come from a portfolio of 

supply- and demand-side options, including flexible conventional generation, grid 

storage, new transmission, more responsive loads, and changes in power system 

operations.

• The abundance and diversity of U.S. renewable energy resources can support 

multiple combinations of renewable technologies that result in deep reductions 

in electric sector greenhouse gas emissions and water use.

• The direct incremental cost associated with high renewable generation is 

comparable to published cost estimates of other clean energy scenarios. 

Improvement in the cost and performance of renewable technologies is the most 

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

renewable sources is possible, and further work is warranted to 

investigate this clean generation pathway.

www.nrel.gov/RE_Futures