Hiba NaffaaUnder the direction of Prof. Michael Driscoll

and Doctor Koroush ShirvanMIT, Department of Nuclear Engineering

Advanced Solar Power Tower Coupled to a

SupercriticalCO₂ Turbine Cycle

Objectives

• Evaluate the use of the supercritical CO₂ cycle (S-CO₂) in solar power tower plant designs• Generate 100 MW of solar power• Generate electricity for Lebanon• Heat-to-electricity efficiency on the order of 50%• Improved compatibility with the use of dry cooling tower• More compact and cheaper equipment

Power Tower Flow Diagram

Types of the heliostats New receiver

Name Country Peakelectric power

Operated Characteristics

Ivanpah UnitedStates

392MW

On February 13,2014

Three solar thermal power plants. 347,000 heliostats. Boilers are on centralized solar power towers. Uses steam turbines

Solar One UnitedStates

10 MW From 1982 to 1988

Water/steam as the heat-transfer fluid in the receiver

Solar Two UnitedStates

10 MW From 1996 to 1999

Molten salt storage and a tur-bine/generator

Fort Irwin SolarProject

UnitedStates

500MW

By 2022 Occupies 14,000 acres. Will produce 1,250 gigawatt hours of renewable energy per year at Fort Irwin facilities

DhirubhaiAmbaniSolar Park

India 40 MW Commissionedon March 31, 2012

Covers an area of 350 acres (140ha)

PlantaSolar 10(PS10)

Spain 11 MW In 2007 624 heliostats. The receiver and a steam turbine are on top of a 115 meter high tower. The turbine drives a generator, producing electricity

PlantaSolar 20(PS20)

Spain 20 MW In 2009 1,255 heliostats. Receiver is on the top of a 165 m high tower and a turbine generator

Current State

Name Country Peak electric power

Operated Characteristics

Palen UnitedStates

500 MW Expected to be complete and producing electricity in 2016

Two-unit power system 250-MW each. Will cover approx. 3,800 acres. 170,000 heliostats. Receiver is on a top a 750-foot tall power tower

BrightSourcePPA5,6,7

UnitedStates

200 MWeach

AFC Not YetFiled

solar power tower

Rice SolarEnergyProject

UnitedStates

150 MW Approved in January 2013 Molten salt thermal storage system. About 17,000 heliostats. Central receiver tower with a height of 199 m

Suntower UnitedStates

92 MW In 2010, it was under construc-tion

456,960 heliostats and wet cooling towers

eSolar 1,2 UnitedStates

84 MW,66 MW re-spectively

AFC Not YetFiled

solar power tower

Alcazar Spain 50 MW Construction began in 2010 Molten salt and a dry-cooled design

AlmadenPlant

Spain 20 MW Announced inSpain in 2007

1,255 heliostats. A 155 meter tower

Ordos China 2GW=2000MW

Began in 1 June 2010 to be completed by 2020

Includes 4 phases: Phase 1 (30 MW), Phases 2, 3 and 4 (100 MW, 870 MW and 1000 MW)respectively

MashaveiSadde

Israel 60 MW Announced Solar thermal power station

Name Country Peak electric power Operated Characteristics

Cerro Dominador Chile 110 MW Expected to start in the second half of 2014

Heliostats, molten salt receiver, tower salt storage

Crossroads UnitedStates

150 MW Expected to operate in 2016 Heliostats, a central receiver, liquid salt to collect the energy, a storage tank, to heat exchangers and a conventional steam turbine cycle

Ashalim 1 Israel 121MW

Under construction. Expected completion:2017

Combine 3 kinds of energy. Solar thermal energy composes 220 MW. 121 MW by this CSP and another will be built

CrescentDunes

UnitedStates

110MW

Construction finished at the end of 2013

17,500 heliostats and molten salt flowing through a 160m tall solar power tower and a storage tank

Khi Solar One(KSO)

SouthAfrica

50 MW Under construction. Expected completion:2014

Covers 140 hectares (346 acres). More than 4,000 heliostats. Boiler is on top a centralized 205 m high tower, a superheated steam cycle, a saturated accumulator steam and a dry cooling system

Gemasolar Spain 19.9MW

Since May2011. Its official launch was held in October 2011

Molten salt heat storage system. A 140m high tower receiver, a power island and 2650 heliostats

Efficiency Plot: Comparison Chart

Flow Chart

Power Cycle Efficiency

Theoretical maximum: Carnot Cycle

The real efficient is given by: npc = nL.n

Where• W is the work done by the system, • QH is the heat put into the system,• TC is the absolute temperature of the cold reservoir,• TH is the absolute temperature of the hot reservoir, and• n is the maximum efficiency.

Power Cycle Efficiency

In our plant:

• Tcold = 30◦C = 303◦K where ◦K = ◦C + 273

• Thot = 700◦C = 973◦K

then n = 0.688

An actual cycle is less efficient eg Engineering experience suggests nL = 0.7Thus npc = 0.7 (0.688) = 0.48 = 48%

Installed Capacity in the Middle East

Conclusion

• An advanced form of power tower conversion using S-CO2 has advantages • Move on to tests of physical systems• Julich, the best option to test

Acknowledgement

• Professor Michael Driscoll• Doctor Koroush Shirvan • Marie Herring• Jessica Shi and Raj Vatsa• The entire staff of RSI• Research Science Institute• Center for Excellence in Education• Massachusetts Institute of Technology• Mr. Rafic A. Bizri• Mrs. Bahia Hariri• David Thompson