Steam turbine producer Siemens Sweden is leading the way producing steam turbines for solar thermal power plants which generate power without emission of carbon dioxide using nearly 100% solar energy.
Lars-Göran Sjöberg, chief of the Steam Turbine’s Division of Siemens Turbomachinery, said the company’s solar turbines are sold in the US, Spain, Algeria, and Egypt, but they are looking to expand even further into Asia, Africa, and Latin America.
The integrated solar-combined cycle system (ISCCS) calls for part of the heat recovery steam generator (HRSG) to be either replaced or paralleled by equipment serviced by solar thermal energy to supplement turbine exhaust gases. This approach increases thermal energy input and produces more electrical output. The system design may be thermodynamically optimized by having the exhaust gas and/or the solar thermal energy yield its heat at points in the steam cycle where local heat transfer fluid temperatures are compatible with the local steam temperature, like all heat transfer processes take place at reasonably small temperature differences.
This design philosophy optimally integrates the solar heat source into the combined cycle HRSG. The integration maximizes operation efficiency even though solar energy intensity varies according to the weather and time of day. Peak thermal-to-electric efficiency can exceed 70% for an ISCCS plant compared to 50-55% for a conventional gas-fired combined cycle plant.
Northern Algeria used the product at its Hassi R’Mel plant and Morocco at Aïn Béni Mathar in the northeast part of the country.