Concentrated solar thermalProject Development of Combined Cycle Using Solar Reformed Gas
This report details the project results and lessons learned that demonstrate that hybridisation of power generation with a solar thermochemical process is achievable, with the technical challenges addressed.
This project launched in March 2013 and ran for a 12 month period, with the final outcome being a detailed assessment of the potential for solar thermal steam reforming to be integrated into a combined cycle power station. The project is led by CSIRO, with project partners GE Global research (GE GRC) and GE Australia (GE AUS).
The project is structured into three stages, with the three stages having significant overlap and interactions:
- Stage 1 – six months design of the solar thermal reformer system (CSIRO) and combined cycle power system (GE GRC);
- Stage 2 – an overlapping six month stage where the two system designs were integrated (CSIRO/GE GRC); and
- Stage 3 – a three month economic feasibility completed (GE AUS).
The reformer was developed with a capacity of 15 MWt at peak thermal input. The design utilises a surround field and cavity receiver developed specially for this application, taking into account the expected solar flux density for the site. The system utilised combusts a mix of solar derived syngas and natural gas in the gas turbine component of the combined cycle.
The design presented a number of challengers that impacted both the final power station characteristics as well as the solar reformer design. As a result, the combustion characteristics of the fuel were investigated in significant detail. The most critical of these are the operating pressure of the turbines ranging from 25-46 bar, and the ability of a combustion system to accept varying fuel compositions, keeping the flame stable, while meeting emission limits. The final design configuration includes a GE 206B Turbine in combined cycle mode, with a solar field design point capacity of 15MWt.
The project economics presented a case where the Levelized Cost of Energy (LCOE) remains effectively unchanged, despite the addition of a solar field and reactor system, Capital cost increases were offset by improvements in thermal efficiency. The assessment highlights that the risks involved in developing such a system out-way the benefits at this point in time. A number of barriers were highlighted to take the project to the next stage.