Conferencia de Manuel Romero, IMDEA Energía, en el marco de la jornada sobre Pequeños sistemas modulares para centrales termoeléctricas. 1_07_2010

1. Small Solar Thermal Power
Systems/ Pequeños Sistemas
para Centrales Solares
Termoeléctricas
Jornada de difusión técnica
Madrid, 1 de julio de 2010
UNION EUROPEA
FONDO SOCIAL EUROPEO

2. IMDEA Energía
• Mission:
• To promote the development of renewable
energies.
• To promote the development of clean energy
technologies having none or minimum
environmental impact.
• Research topics:
• Solar energy (high flux/high temperature).
• Sustainable fuels: biofuels, wastes, hydrogen.
• Energy storage.
• Smart energy networks.
• Efficient end-use of energy
• CO2 valorisation
• 40 Researchers (18 PhD; 16
from foreign R&D Centers)

3. High Temperature Processes Unit
Objectives
Development of efficient and cost-effective high temperature technologies
and applications with special emphasis on Concentrating Solar Power
Systems and production of Solar Fuels and Chemicals.
R&D lines
 Modular concepts with minimum environmental
impact
 Advanced thermal fluids for high temperature
applications and energy storage
 Solar receivers and reactors
 Solar concentration optics
 High flux/high temperature characterization
techniques and simulation tools
 Efficient integration schemes into power
conversion systems
 Solar-driven high temperature production of H2
/Chemicals

5. CSP in the world
Source: Photon International (December 2009)
- Spain: 831 MW grid-connected by December 2010 and
permits assigned for 2,5 GW by 2013.
-USA: Near- to medium-term CSP pipeline over 10 GW,
with 4.5 GW to break ground by the end of 2010.

6. Concentrating Solar Power:
Cost and Availability
• Future costs depend on many things
– technology progress
– production rates and continuity
Initial SEGS Plants
– political, economic, and financial issues
– market needs and acceptance
Larger SEGS Plants
O&M Cost Reduction at SEGS Plants
Impact of 1-2¢ adder
for green power
Conventional Technology
for Peaking or Intermediate Power
(IEA market assumptions)

7. Limitations of first-generation CSP
Commercial projects use technologies of parabolic troughs with low
concentration in two dimensions and linear focus, or systems of
central tower and heliostat fields, operating with thermal fluids at
relatively modest temperatures, below 400 ºC .
The most immediate consequences of these conservative designs
are:
 the use of systems with efficiencies below 20% nominal in the
conversion of direct solar radiation to electricity,
 the tight limitation in the use of efficient energy storage Extresol 1 and 2 (ACS/Cobra)
systems,
 the high water consumption and land extension due to the
inefficiency of the integration with the power block,
 the lack of rational schemes for their integration in distributed
generation architectures and
 the limitation to reach the temperatures needed for the
generation processes following thermochemical routes of
solar fuels like hydrogen.
PS10 and PS20 (Abengoa Solar)

8. Impact of innovation on cost reduction
100
Scaling up
15%
90
80
R+D
60%
70
60
Market
50 series
25%
40
2005 2010 2015 2020 2025 Year

9. Concentrating Solar Power:
Applications and Features
Distributed Power Dispatchable Power
• distributed, on-grid (e.g., line support) • utility peak and intermediate
• stand-alone, off-grid (e.g., water • high-value, green markets
pumping, village electrification)
kW's to MW’s 10's to 100’s of MW's
Dispatchability:
l hybridization with gas or liquid hybrid gas combined l thermal storage for peaking,
fuels for extended Stirling or cycle load following, or extended
Brayton engine operation l coal, fuel oil, or gas operation
steam cycle
Manufacturing:
l Relatively conventional technology (glass, steel, gears, heat engines, etc.) allows
rapid manufacturing scale-up, low risk, conventional maintenance

10. Aprovechamiento Térmico de la Energía Solar de manera
Gestionable, Eficiente y Modular en Sistemas de Alta
Concentración

11. SOLGEMAC
TODAY
Conservative first-generation schemes
1500 ºC
SOLGEMAC • Combustibles y química
• Ciclo Brayton
Efficiency (high-temperature/high-flux) • Calentamiento aire
Dispatchability (storage/hybrid) • Ciclo Brayton
• Calentamiento aire
Modularity (small size)
Environmental impact (water) • Calentamiento aire
Receptores
cerámicos
Solar fuels Receptores Alta presión
1000 ºC
cerámicos Alta temperatura Receptores
Baja presión Partículas sólidas
Alta temperatura
Temperatura
Motores Stirling
solarizados
• Ciclo Brayton Receptores • Disco Stirling
• Precalentamiento aire metálicos aire
500 ºC
Receptores Receptores
Sodio Sales nitrosas
Receptores • Calentamiento aire
Agua/vapor • Ciclo Rankine
• Calentamiento de vapor
• Ciclo Rankine
• Calentamiento de vapor
Receptores
Aceite Actualidad
• Calentamiento de vapor
Conceptos tecnológicos ACTUALES Conceptos tecnológicos AVANZADOS

12. SOLGEMAC
(Imdea Energía Coord.)
MODULARITY EFFICIENCY DISPATCHABILITY
A.3. ENERGY STORAGE FOR DISTRIBUTED
A.2. SOLAR RECEIVERS/REACTORS FOR GENERATION CONCENTRATING SOLAR SYSTEMS.
A.1. MODULAR CONCENTRATING HIGH FLUX/HIGH TEMPERATURES.
SYSTEMS A.3.1.Hydrogen production with thermochemical cycles
A.2.1. Volumetric receivers with metallic A.3.2. Hydrogen storage with MOF-type materiales.
A.1.1. Systemas dish/Stirling absorbers A.3.3. Electrochemical storage
A.1.2. Multitower Modular Arrays A.2.2. Volumetric receivers with ceramic A.3.4. End-use of hydrogen in microturbines
A.1.3. Solarization of gas microturbines absorbers
A.2.3. Particle receivers
A.2.4. Materials
URJC (Coord.)
CIEMAT-DQ
CIEMAT-SSC (Coord.) CIEMAT-SSC
Imdea Energía (Coord.)
Imdea Energía Imdea Energía
INTA UAM
URJC
CIEMAT-SSC TORRESOL INTA
TORRESOL Hynergreen Hynergreen
A4. INTEGRATION INTA (Coord.)
INTEGRATION A.4.1. Comparison of technologies
A.4.2. Integration schemes URJC, Imdea Energía, CIEMAT-SSC, CIEMAT-DQ,
A.4.3. LCA and impact TORRESOL, Hynergreen

13. STEPS TO SCALING-UP SOLAR CSP & CSFC
1-5 kW
Solar Simulator
30-50 kW
Solar Furnace
1-100 MW 100-500 kW
Central Receiver System Mini-tower

14. Discos parabólicos
Motor solar de Augustin
Mouchot en la exposición de Discos-Stirling Eurodish en la
Paris de 1861 Paris Plataforma Solar de Almería

15. Discos Parabólicos con generador Stirling:
Estado de la Tecnología
 Varios diseños de disco y de
receptor han demostrado la alta
eficiencia necesaria para sistemas
comerciales
 La durabilidad del receptor aún
necesita mejorarse
 El coste del disco
colector/concentrador es crítico para
dar paso a las primeras
producciones comerciales.
STM
Solo
 Motores Stirling
avanzados están
mostrando altas eficiencias
y durabilidades

16. Expectations for Cost Degression
225
200
175
Investment cost in k€
150
125 Transport, Assembly
Concentrator
Drives
100 Stirlingmotor
Control
75 Turntable
Foundation
50
25
0
Prototype DISTAL 1 DISTAL 2 EuroDish 100/Year 1000/Year 3000/Year 10000/Year
Stuttgart 1991 1995 2000/2001
1989

17. Pequeños sistemas de receptor central
Pequeños campos con pequeños Configuraciones multitorre
helióstatos
Multitower arrays

18. Mini-campos con mini-helióstatos
agrupados: Recordando al Prof. Francia
• Planta construida en Italia y
montada en los EEUU en el
año 1977 en el Instituto
Tecnológico de Georgia
(Advanced Component Test
Facility)
•550 helióstatos
•Potencia térmica 400 kW.
•Campo octogonal y torre
central (22,8 m)
•Foco rectangular de 2,44
m.
•Espejos con seguimiento
polar y tracking colectivo.
ACTF de Georgia

19. Sistemas modulares multitorre
Comparison of Solar Power Technologies with respect to Integration in the Urban
Environment
P. Schramek, D.R. Mills and W. Lang

20. Advantages of the MIUS concept
• Origin: In 1972 by US HUD. Related to Total Energy Systems,
Power Islands, District Heating, Energy Cascade and Cogeneration
• Distributed Utility structure for large residential, commercial or
institutional building complexes.
• Typical size: 300-1,000 dwelling units
• Reduction of transmission and distribution costs
• Modular track of demand and spread construction costs over time
• Maximum utilization about 4,500 hours
• Use of single-cycle high efficiency gas turbines plus waste heat
applications like district heating, cooling, desalination or water
treatment
• Increment of solar share to 50 %
•Find a niche of size (a few
The keys for MWe)
•Find modular small CRS design
CRS in MIUS
•Competitive investment cost
•Perform with high efficiencies

21. INTEGRATION OF CRS INTO MIUS STRUCTURE
Water
7,965 GJ 13,280 GJ
Exhaust gases
Auxiliary boiler
Fuel Space heating
Water 2,690 GJ
14,690 GJ
Hot water
12,000 GJ
Steam Wasted
4,252 GJ Domestic hot water
22,000 GJ
Fuel Hot gases Absorption
11,023 GJ chiller
Rejected heat
5.50 GWhe 22,793 GWh
60,526 GJ
Compression
0.21 GWhe air-conditioning
Air
Domestic and auxiliary
5.29 GWhe electricity
SOLAR TOWER
Example of a 450-unit apartment complex in Spain

22. MIUS Solar Tower:
Application to a shopping center
1400
- Stable demand
- 85 % during day-time 1200
October
- High consumption at November
peak periods
Power Demand (kWe)
1000 December
- Monthly differences January
between 800-1,300 kW 800 February
March
- Demand increase
april
between June and 600 may
October.
June
- Peaks in July and 400 July
Christmas August
September
200
Operation strategy: 0
0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23
- Night-time: Grid
Solar Time (h)
- From 6:00 to 20:00 solar
hybrid turbine in power island Demand from 6 to 20 h: 4,348 MWe and
mode 18,890 MWth

23. Proposal of a small-size tower plant
 Small tower and heliostats that reduce visual impact and
achieve higher field efficiencies (up to 4% more than large
area heliostats).
 Air as heat transfer media in a pressurized volumetric
receiver (3.4 MWth outlet).
 Use of an efficient (39.5 %) small solar-gas turbine (1.36
MWe) with intercooling, heat recuperation and low working
temperature (860 ºC).
 Waste heat (670 kWth) at 198 ºC for water heating and
space cooling/heating.
 Operation in a fuel-saver mode
 As in the case of dish system parks, the small tower fields
for distributed power should target maximum unattended
operation, to minimize O&M costs.

24. MIUS solar tower technical specifications
Tower optical height (m) 26
Number heliostats 345
Heliostat surface (m2) 19.2
Receiver surface (m2) 16.5
Receiver tilt angle (º) 30
Land (m2) 38,000
Design point Power Efficiency
DNI (W/m2) 875 ----
Power onto mirrors area (MWt) 5.8 100 %
Gross power onto receiver (MWt) 4.3 74 %
Power to turbine (MWt) 3.4 80 %
Gross electric power (MWe) 1.4 39 %
Total efficiency ---- 23 %
Investment
Heliostats 995,765 $
Land 62,745 $
Tower 104,575 $
Receiver 484,750 $
Inst.&Control 107,000 $
Power block 1,146,000 $
Fixed cost 65,350 $
Direct capital cost 2.97 M$
Installed cost (including turbine set) 2,120 $/kW

25. Heron H1 Technical Specifications
Electrical power 1,407 kWe
Thermal power 1,200 kWth
Fuel consumption 3,280 kW
Heat rate 8,392 kJ/kWh
Electrical efficiency 42.9 %
Thermal efficiency 36.6 %
Total efficiency 79.5 %
NOx emission <20 g/GJ

26. Theoretical solarization based on Turbine Heron H-1 and 10
pressurized volumetric receivers
1.0 bar
1.0 bar
198 ºC 573 ºC
Intercooler
8.9 bar
151 ºC Recuperator
8.9 bar
3.0 bar 573 ºC
25 ºC 740 ºC
661 ºC 757 ºC
R1 R2 R3 R7 R8
3.0 bar
137 ºC 3.1 bar
635 ºC
R4 R5 R6 R9 R10
HPC LPC
8.9 bar 3.1 bar
860 ºC 860 ºC
C1 C2 C3 PT
PR=3.0 PR=2.7 1.36 MWe
PR=3.0
1.0 bar
15 ºC
Air filter Heatflow SOLAR R1-R6 = 1.95 MW
Heatflow SOLAR R7-R10 = 1.49 MW
1.0 bar Total = 3.44 MW
15 ºC Air inlet
m=5.15 kg/s

27. MIUS Solar Tower: Application to a shopping center
Solar electricity production = 2,456 MWh
Fossil electricity production = 1,892 MWh
Solar electricity excess = 428 MWh

28. MIUS Solar Tower: Application to a shopping center
56 % power demand supplied Few hours at loads of 20 %
by solar (683 toe) during start-ups
Typical solar working load 75 %

29. MIUS Solar Tower: Application to a shopping center
Solar is contributing to the waste heat produced with 4,374 GJ that
represents 49.5% of the heat demand.

30. CONCLUSIONS
CSP is focusing its growth still on first generation
large-fields
The solar field should be small and modular to account
for the maximum flexibility in approaching real
systems.
Up to 60% future cost reduction should come from
R&D.
Solgemac project objectives are modularity,
dispatchability and efficiency by high flux/high T.
A potential niche for the application of dish-engine
systems and small solar towers to Modular Integrated
Utility Systems has been identified.