Techno-economic analysis of hybrid PV/T systems for process heat using electricity to subsidize the cost of heat
Abstract Process heat applications make up a large potential market for renewable energy. Concentrated solar thermal (CST) systems are capable of reaching temperatures necessary for a wide variety of industrial and commercial applications but are often overlooked due to the difficulty of competing with natural gas. Novel hybrid photovoltaic/thermal systems (PV/T) are capable of simultaneously generating electricity and heat. The electricity produced is of higher value and offsets the lifetime cost of the system by producing a cost savings to the facility, ultimately making solar heat competitive with natural gas, propane, coal, and other fuels. An economic model that utilizes the electricity savings as part of the cash flow within the levelized cost of energy equation is presented here. We further determine the sensitivity of PV/T system costs to technical, financial, and geographical parameters. A dish concentrator PV/T (CPV/T) system with a transmissive CPV array is used as a reference system for sensitivity analysis. Through design choices informed by this new modeling approach, the levelized cost of heat (LCOH) is shown to be competitive with natural gas in up to 6 states within the United States and can be reduced to a minimum of −1.4 ¢/kWh th in Hawaii by factoring in the electricity savings from additional energy generated by the transmissive CPV module. Competitiveness in select global regions is also considered. Further examination of several other geometries of PV/T systems with this model, for an installation in California, shows that flat plate collectors with waste heat recovery result in the lowest LCOH of 1.23 ¢/kWh th .