Role of CSP in Reducing CO2

EPA Region 9 Briefing 

May 7, 2015

Frank (Tex) Wilkins

Executive Director

CSP Alliance

Concentrating Solar Power Alliance

Abengoa BrightSource Cone Drive Lointek Wilson Solarpower
Agenda

• CSP Overview

• CSP: a Keystone to Success for CAA 111(d) Regulation 

• DOE Technical Assistance: modeling 111(d) portfolios

• Summary of CSPA Comments to EPA on 

Potential 111(d) Guidelines

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Overview

CSP Provides: 

• Flexible, Dispatchable Renewable Power

• Large Quantities of Carbon-Free Power

• Ability to Integrate High Levels of Renewables 

• Solutions for Any CAA 111(d) Approach Whether Through:

• Stand-alone Facilities or 

• Hybridized Fossil-Fired Power Plants

• Proven, Commercially-Deployed Technology 

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CSP - A Different Kind of Solar

Concentrating Solar Power (or “Solar Thermal Electric”):

• Sun’s Energy is “Fuel” for Conventional Turbines

• Mirrors Concentrate Sunlight to Create Heat

• Heat Boils Water to Make Steam

• Steam Spins Turbine Blades, Creating Grid-Friendly Power

• Cost-Effectively Integrates Thermal Energy Storage 

• Proven Technology 

• Invented Over 100 Years Ago, 

• In Worldwide Commercial Use

• Two Primary Technologies: Trough & Tower

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Parabolic Trough Technology

• Parabolic trough technology uses long moveable parabolic mirrors, with an absorber tube

located along the center at the focal point. Sunlight is reflected by the mirror and concentrated

on the absorber tube.

• Heat transfer fluid, comprised of oil or molten salts, flows through the tube to absorb the

concentrated sunlight. The heat transfer fluid is then used to heat steam in a turbine/generator.

• Trough systems are sensitive to economies of scale and estimated to be most cost effective at

100 MW or greater.

• Solar concentration: 75 suns | Operating temp: 730°F

• Commercially proven, able to integrate thermal energy storage with molten salt

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• Power towers use an array of flat, moveable mirrors, called heliostats, to focus the sun's rays

onto a receiver at the top of a central tower. The energy in the receiver is transferred to a

heat transfer fluid (salt or steam) which is used to heat steam in a turbine/generator.

• Molten salt allows solar energy from daylight hours to be stored to generate steam

throughout the evening. The high operating temperature enables less expensive storage.

• Due to power block requirements, power towers are sensitive to economies of scale and are

typically most economical at 100 MW or more.

• Solar concentration: 800 suns | Operating temperature: 1040°F

• Commercially proven, able to integrate thermal energy storage with molten salts

Power Tower Technology

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U.S. CSP Plants Through 2012 

(almost all in Region 9)

Name or location Utility State Size Technology Began 

operation Company

SEGS SCE California 354 MW Parabolic trough 1985 - 1991 NextEra Energy

Saguaro APS Arizona 1 MW Parabolic trough 2006 Acciona

Nevada Solar One NVEnergy Nevada 64 MW Parabolic trough 2007 Acciona

Kimberlina PG&E California 5 MW Linear Fresnel 2008 Ausra/AREVA

Sierra Sun tower SCE California 5 MW Power tower 2009 eSolar

Keahole Solar demo HELCO Hawaii 7 MW Parabolic trough 2009/2011 Sopogy

Maricopa Solar demo SRP Arizona 1 MW Dish/engine 2010 SES / Tessera Solar

Cameo hybrid Xcel Colorado 2 MW Trough add-on to coal 2010 Abengoa

Martin Solar Energy Ctr. FPL Florida 75 MW Trough add-on to 

Combined Cycle 2010 NextEra Energy

Total in

Operation -- 514 MW

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New U.S. CSP Plants 

(all in Region 9)

Solana Ivanpah Genesis Crescent 

Dunes

Mojave

Technology Trough w/

6 hrs storage

Towers

(Steam)

Trough Tower (Salt) 

w/ 10 hrs

storage

Trough

Capacity 

(MW, gross)

280 392 280 110 280

Location Arizona California California Nevada California

DOE Loan 

Guarantee

$1.45B $1.6B $0.85B $0.74B $1.2B

Completion 2013 2014 2014 2015 2014

Developer Abengoa BrightSource NextEra Solar Reserve Abengoa

Total New CSP Capacity Deployed = over 1,300 MW 

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CSP: Large Quantities of Carbon-free Power 

The US Southwest provides the excellent solar resource ideal for 

CSP plants - some of the best solar resource in the world

Potential: DOE estimates CSP could provide 28 GW of power by 2030 

and 83 GW by 2050*

* SunShot Vision Study, energy.gov/sites/prod/files/SunShot%20Vision%20Study.pdf, February 2011

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EPA Region 9 includes the 

southwestern states with the 

best solar resource (California, 

Nevada, and Arizona). Hawaii 

has a very good solar 

resource.
Keystone to Success for CAA 111(d)

CSP Uniquely Achieves 2 Critical Objectives:

• Increasing Renewable Energy Without Increasing CO2 & Criteria 

Pollutant Emissions from “Peaker” Plants

• Intermittent renewables, like PV and wind, require backup and “ramping” 

power that must be dispatched as needed to maintain reliability

• By displacing peaker plants otherwise needed for reliability, CSP avoids 

the high carbon and criteria pollutant emissions these plants produce 

• Maintaining Reliability Without Added Emissions

• CSP uses conventional turbines, providing reliability services the grid 

depends on from “rotating mass”- again displacing conventional power

• Provide dependable capacity, due to presence of thermal energy storage, 

to meet critical peak and ramping needs

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CSP and CO2 Reduction – Enabling Renewables

Enabling Higher Renewable Portfolio Standards

• High penetration of intermittent wind and solar requires flexible power to respond

• Reduced coincidence of the solar resource and demand – as PV power increases, 

peak demand shifts to the evening, creating steep “ramps” requiring flexible power 

to respond

• Conventional flexible power emits carbon and criteria pollutants, and can be 

expensive and highly inefficient 

74000

76000

78000

80000

82000

84000

86000

88000

90000

92000

12 14 16 18 20 22

Hour (Ending)

Net Load

Normal Load

2%

5%

10%

15%

Source: NREL Source: CAISO

PV

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Very low curtailment 

at 30% solar 

penetration

Higher penetration 

of solar AND greater 

penetration of PV 

due to additional 

flexibility provided 

by CSP 

CSP and CO2 Reduction - Enabling Renewables

Source: NREL

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Flexible Answer for Any CAA 111(d) Approach

CSP advances CAA 111(d) objectives:

• Reducing system-wide emissions through new, stand-alone 

power plants w/o storage 

• Reducing system-wide emissions through new, stand-alone 

power plants with storage providing all grid services

• Reducing existing fossil fuel power plant emissions through 

hybridization 

CSP is providing these emission reductions today, with 

proven, commercially-deployed technology

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Proven Technology Providing CO2 Reductions:

Stand-alone Plants 

• BrightSource Energy’s 392 MW Ivanpah tower project generates 

enough electricity to serve more than 140,000 California homes.

• Reduces CO2 emissions by more than 400,000 tons per year.

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• Abengoa’s 280 MW Solana project generates enough electricity to 

serve more than 70,000 homes in Arizona. 

• It reduces CO2 emissions by more than 475,000 tons per year.

• Solana includes 6 hours of energy 

storage, the first of its kind in the U.S. 

• Storage enables dispatch of power 

whenever most needed, day or night.

• Includes all the capabilities of a 

natural gas (e.g. reactive power, 

ancillary services) 

Potential: using DOE’s estimate of 28 GW 

by 2030, CO2 reduction could be as much 

as 47.5 million tons per year Abengoa

Proven Technology with Storage Providing CO2 

Reduction and Other Grid Services

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• At the 75 MW Martin Plant, 

in Indiantown, FL, 

CSP provides heat to the 

power block of a combined 

cycle gas plant, displacing 

natural gas use and 

offsetting over 90,000 tons 

of CO2 each year

• CSP hybridization can be 

applied to existing or new 

natural gas or coal-fired 

power plants

Source: NextEra

Potential: Fossil fueled plants in 16 states could be hybridized 

to avoid 30 million tons of CO2 each year* 

Proven Technology Providing CO2 Reduction: 

Hybridization of Fossil Plants 

* Solar Augmented Potential of US Fossil-Fired Power Plants, Turchi, Libby, et al, NREL/TP-5500-50597, February 2011

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DOE Technical Assistance – Modeling 111(d) 

Portfolios

• Most states are unable how to determine the “best” portfolio of 

energy resources to achieve their 111(d) goal

• Very few computer models are able to accurately represent 

CSP’s ability to dispatch power when it’s needed most

• CSP can be designed as a baseload, intermediate, or peaker

power plant

• DOE has national laboratories (e.g. NREL) that have models of 

the western electric grid and can accurately represent CSP

• DOE cannot ask the states if they need modeling assistance, the 

states must ask them for assistance 

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CSP Alliance Comments on EPA’s proposed 

Clean Power Plan (CPP)

• BSER evaluation should incorporate CSP wherever sufficient sun exists, including

• Stand-alone facilities or 

• Hybridized with new or existing fossil-fueled plants

• States should be properly credited when they incorporate CSP in 111(d) plans 

• To date, the greatest energy sector CO2 reductions result from renewable energy requirements 

• Existing programs may have sub-optimal effects on emissions, reliability and ratepayer costs as 

renewable power penetration increases

• States should be encouraged to design renewable energy and /or CO2 reduction requirements that 

appropriately balance carbon reductions, reliability and cost, and receive appropriate credit for doing so

• CPP should require planning and procurement for grid integration needs

• System-wide planning that properly considers reliability would allow the best emissions, cost and 

reliability outcomes– each of which are necessary for success

• CSP mitigates the intermittency impacts of wind and solar PV, enable greater penetrations of variable 

resources, and lower system emissions and costs overall

• CAA 111(d) and state goals can be achieved more efficiently with interstate 

cooperation than if compliance measures are constrained to state boundaries

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Summary

CSP Provides: 

• Proven, Commercially-Deployed Technology – Operating 

Worldwide Today

• Flexible, Dispatchable Renewable Power

• Provides Large Quantities of Carbon-Free Power

• Ability to Integrate High Levels of Renewables without HighEmission/Low Efficiency Peaker Plants

• Solutions for Any CAA 111(d) Approach

• Reduces System-wide CO2 – Stand-alone Facilities with or w/o 

storage

• CSP Hybridization Reduces Existing or New Fossil-Fired Power Plant 

CO2 Emissions 

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Joe Desmond, BrightSource Energy

Michele Boyd, Abengoa Solar

Tandy McMannes, Abengoa Solar

Arthur Haubenstock, Morgan Lewis LLC

Frank “Tex” Wilkins, CSP Alliance

Phone: (410) 960-4126

tex.wilkins@gmail.com

Thank You

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