CONCENTRATED SOLAR THERMAL TO ENERGY
NEC’s concentrated solar thermal (CST) power plant architecture utilizes solar radiation for utility scale electric power generation. The parabolic trough design utilizes long metallic mirrors to focus sunlight onto a receiver filled with heat transfer fluid. The hot fluid circulates through a heat exchanger, transferring thermal energy to drive a power block and generator. A typical CST project may range from 50 to 500+ megawatts of generating capacity.
Operating a CST project beyond peak sunlight hours is available with NEC’s hybrid plant design, which utilizes clean natural gas as a secondary energy source to increase the plant's availability during times of decreased insolation or darkness. The advantage of this design is that it doubles the thermal leverage of the steam cycle portion of the plant, maximizing the project's efficiency, and can supply continuous power day and night at far lower costs and carbon emissions than traditional fossil fuel fired plants.
Highlights of the NEC CST power design:
Solar radiation is collected by reflective parabolic troughs and is converted to heat when focused on a receiver pipe along the focal line of the trough.
Because of their parabolic shape, trough collectors track the sun from East to West by rotation on one axis. The high precision reflector panel system concentrates the solar radiation from the sun at 30-60 times its normal intensity on the focal line receiver.
Synthetic fluid is circulated through the receiver pipes and captures the solar heat, reaching temperatures up to 400° C. The heated oil is transferred through a heat exchanger to generate steam.
This steam is used in a Rankin cycle to produce electricity in a steam turbine-generator set. Multiple sets are aggregated for large generation capacity.
Hybrid design that utilizes natural gas to stabilize the plant's designed capacity during times of decreased insolation, utilizing the same steam cycle.
CST energy is a local energy resource, which minimizes the risks of access and economic control over remote energy sources. CST power projects provide local employment opportunities and valuable careers in the growing and globally important renewable energy and green/environmental sector. This helps build the technical abilities of local communities.
NEC’s CST power plants produce ultra-clean electric power without significant greenhouse gasses, particularly during peak daytime periods, offsetting the demand on high polluting fossil fuel power plants.
CST power plants have few environmental impacts other than land use, and have the highest potential of near zero-carbon electricity since they can be combined with natural gas, and the resulting hybrid power plants provide high-value, dispatchable power. CST power projects are scalable and can be sized from 50MW to more than 500MW of grid-connected power. These attributes, along with high solar-to-electric conversion efficiencies, make concentrating solar power an attractive renewable energy option in many regions worldwide.