Transcript Concentrating Solar Power - Thoughts of a Lapsed Physicist

Concentrating Solar Power: The Emerging
Solar Energy Technology
Presentation to
Electric Power 2010
Session 4B:
Solar Power and Photovoltaic
Dr. Allan R. Hoffman
U.S. Department of Energy
19 May 2010
Outline of Presentation

Why the renewed interest?

The four “flavors” of concentrating solar power (CSP)

CSP history

Advantages and disadvantages

Thermal storage

Current status

Concluding remarks
2
Why the Renewed Interest in CSP?

traditional CSP (trough, tower, dish) is not new – long history
dating back to 1980’s

key advantage: close resemblance to existing plants



Increasing utility interest in deployment of CSP plants to meet
requirements of state renewable portfolio standards


use many of the same technologies and equipment
substitutes concentrated high-temperature solar heat for combustion
of fossil fuels or heat from nuclear reactors
huge solar resource in Southwest U.S.
federal government encouraging development of CSP plants
through 30% investment tax credit


good through FY 2016
alternative 30% Treasury grant good through FY 2010
3
4
State Renewable Portfolio Standards
 States with RPS
http://www.epa.gov/chp/state-policy/renewable_fs.html
 States with RPS goal
5
Four CSP technologies

CSP technology systems use reflective surfaces to gather
and concentrate unscattered solar radiation to create heat

The requirement for unscattered (“direct normal”) radiation
limits CSP plants to certain locations, primarily desert
regions with limited cloud cover

Three of the four CSP technologies use the collected heat to
power conventional Rankine steam cycles, similar to those
used for coal and nuclear plants


parabolic trough, linear Fresnel, power tower
Dish-engine systems use the concentrated sunlight to
power a small heat engine at the dish’s focal point
6
Parabolic Trough
Kramer Junction, CA
7
Power Tower
Barstow, CA
8
Dish-Engine
9
Compact Linear Fresnel
10
CSP History - Luz and SEGS

nine trough systems, SEGS I-IX, built by Luz International
between 1984 and 1990 (354 MWe total)
 SEGS I: 13.8MWe
 SEGS II-VII: 30MWe each
 SEGS VIII, IX: 80 MWe each

regulatory and policy obstacles forced Luz bankruptcy in 1991
 plans to construct SEGS X, XI and XII canceled (240 MWe)

nine original SEGS plants still operating, feeding power into
Southern CA Edison power grid (but under new ownership)
 largest solar power station complex in operation

original Luz owner now head of Bright Source Energy Inc.
 Luz II technology uses distributed power towers (DPT)
11
Advantages

resemble traditional power plants





can be built in small sizes and added to as needed
can achieve high steam operating temperatures,
allowing more efficient power generation
capable of combined heat and power generation



generation based on steam and is large scale
use standard equipment for power generation
steam for absorption chillers, industrial process heat,
desalination
Non-carbon emitting power generation
incorporates storage





storage not major part of generation cost
size of steam power plant that lacks storage does not have
to be increased when storage added
added storage cost effective if energy sold at peak hours
allows generation to match utility load profile
can be hybridized with intermittent renewables
12
Disadvantages

high upfront capital costs for concentrators and storage

require unscattered “direct normal” solar radiation, thus
limiting where CSP plants can be located


require cooling, as with any steam power plant, creating a
requirement for water or air cooling


desert areas are best (but also arid)
water limitations may necessitate air cooling in many locations,
with penalty in capital cost, generating efficiency and energy cost
require large surface areas for placement of concentrators
13
Thermal Storage



SEGS-I storage method used an organic heat transfer fluid (HTF)
 organic HTFs can only be used below 800F
 troughs can operate at just over 1000F, thus use
of HTF limits plant efficiency by >12%
power towers can reach very high temperatures (>2000F) but
have only been used to date with molten salt storage
 Salt melts at 430F (must be kept heated)
 maximum storage temperature: 950F
Modern trough plants:
 either use no storage
 more profitable under current U.S. incentives
to build without storage, or
 use HTF and molten salt storage
14
Can We Do Better?

Modern high efficiency power plants can be designed
to use steam at 1300-1400F

ideal storage temperature: 1500-1700F

desired top temperature for gas turbines is > 1700F

a heat transfer fluid and storage method that operate at
temperatures above those of HTFs and molten salt would
lead to significant energy cost reductions (>30%)

Such a heat transfer and storage system has been invented
by Dr. Reuel Shinnar (City University of New York)
(patent # 20090178409/Apparatus and Method for Storing Heat Energy,
16 July 2009)
15
The Shinnar Thermal Storage System

combines two proven concepts with a special adaptation



uses pressurized CO2 as the heat transfer fluid flowing in a closed loop
through the solar collectors and either through the power plant or the
heat storage system
 compressed CO2 is one of the most effective gaseous high
temperature heat transfer fluids used in industry
The heat storage system uses commercially available vessels
(cylindrical metal pipe) filled with a ceramic solid filler
 can be designed to operate at temperatures up to 3000F
special feature: uses a cyclic counter-current pebble bed



pebble-bed heat exhanger based on theory developed in 1920s
has been used reliably for many industrial processes
heat propagates as a sharp front: one end of storage remains cold, the
other end hot at constant temperature
 allows recovery of heat at same top temperature it was stored
16
Current Status


after a long hiatus, deployed CSP capacity has expanded from 354 MWe to
more than 820 MWe today
many new projects are in the pipeline in many countries
 when those under construction are completed, capacity will approach
3,000 MWe
 an even greater number of projects are in development
 > 10,000MWe in the U.S. alone
 CSP plants deployed or under development in
 USA
 Spain
 Italy
 Morocco
 Algeria
 Egypt
 Jordan
 Tunisia
17
SolarPACES (Solar Power And Chemical Energy Systems)

collaborative RD&D program (Implementing Agreement) under
umbrella of International Energy Agency that focuses on
development and marketing of CSP systems

Currently has 16 member countries
 Australia, Austria, Algeria, Egypt, EC, France, Germany, Israel,
Italy, Mexico, S. Korea, S. Africa, Spain, Switzerland, UAE, USA
 membership open to all countries

compiles data on CSP projects around the world that have plants
that are operational, under construction, or under development
 can browse project files by country, project name, technology
and status
 http://www.solarpaces.org/News/Projects/projects.htm
18
CSP Projects in the U.S.

California
 Abengoa Mojave Solar Project
 Alpine Sun Tower
 Blythe Solar Power Project
 Calico-Solar one
 Genesis Solar Energy Project
 Imperial Valley-Solar Two
 Ivanpah Solar Electric Generating Station
 Kimberlina Solar Electric Generating Station
 Palen Solar Power Project
 Rice Solar Energy Project
 Ridgecrest Solar Power Project
 Sierra SunTower
 SEGS I-IX
19
CSP Projects in the U.S. (continued)

Nevada
 Crescent Dunes Solar Electric Project (Tonopah)
 Nevada Solar One (NSO)

Arizona
 Maricopa Solar Project
 Saquaro Power Plant
 Solana

Florida
 Martin Next Generation Solar Energy Center MNGSEC)

New Mexico
 New Mexico SunTower
20
DESERTEC

Derives from the TREC concept which has been around for
many years:
 generate CSP electricity in N. Africa, ship electricity to
Europe, use revenues to stimulate African development

DESERTEC Foundation created in 2008 to advance
DESERTEC Concept worldwide

DESERTEC Industrial Initiative (DII) established in 2009
under German law to create the conditions for accelerated
implementation of the DESERTEC Concept in EUMENA
(Europe, Middle East, North Africa)


HVDC transmission to southern Europe (loss 3% per 103 km)
less seasonal variation in solar insolation MENA vs. S. Europe
21
Concluding Remarks

CSP has the potential to supply a significant share of U.S.
and global electricity demand

ability to load follow, firm up intermittent generation,
incorporate storage, and provide heat and electricity
are major advantages

cooling requirements present a water and cost challenge
(as do requirements of other steam power plants)

costs still high but should come down significantly as more
and more systems are manufactured and deployed
22
Thank You
Contact information:
E-mail:
[email protected]
Telephone:
202-586-8302
23
Additional Material on Shinnar TS System
“I now believe that CSP technology which follows the
guidelines outlined in our report could be designed at
approximately half the cost of CSP plants today despite the
fact that storage and air cooling have been added.”
(letter from Dr. Shinnar to Thomas Rueckert, CSP
program manager, U.S. DOE, 21 April 2010)
24