There are two primary methods for capturing and using sunlight today: direct conversion of sunlight to electricity using photovoltaic (PV) solar panels, or focusing sunlight onto a fluid that is used to drive a steam turbine in concentrated solar power (CSP) systems. Storing hot fluid in CSP systems is a less expensive way to generate electricity when the sun is not shining compared to storing electrical energy from PV in batteries. However, PV uses just part of the solar spectrum at high efficiency, while CSP systems use the entire solar spectrum but at low efficiency. Combining the best elements of these two technologies could provide a means to get the most out of the full solar spectrum, generating both electricity and storable heat (for later use) within the same system. Developing hybrid solar energy systems that perform both functions at the same time could provide electricity at cost comparable to traditional sources, whether the sun is shining or not.
Project Innovation + Advantages:
Tulane University and its partners are developing a hybrid solar energy system capable of capturing, storing, and dispatching solar energy. The system will collect sunlight using a dual-axis tracker with concentrator dish that focuses sunlight onto a hybrid solar energy receiver. Ultraviolet and visible light is collected in very high efficiency solar cells with approximately half of this part of the spectrum converted to electricity. The infrared part of the spectrum passes through the cells and is captured by a thermal receiver that converts this part of the spectrum into heat with nearly 95% efficiency. The heat is captured by a fluid that is heated to a temperature between 100 - 590°C. This heat energy can be immediately for a variety of commercial and industrial applications that require thermal energy or the heat may be stored in a small-scale thermal energy storage bank that stores energy for conversion to electricity by a heat engine when needed most. Tulane University’s system will enable efficient use of the full solar spectrum while storing a large component of sunlight as heat for industrial processes or conversion into electricity at any time of day.
If successful, Tulane’s hybrid solar energy system will combine the best attributes of both PV and CSP systems, which would allow efficient conversion of the full solar spectrum and store solar energy for use at any time of day as heat or electricity.
Developing new systems that generate both heat and electricity at the same time could provide clean, domestically-sourced solar power at costs comparable to traditional sources, such as burning natural gas, whether or not the sun is shining.
Replacing energy systems powered by fossil fuels would provide an immediate decrease in greenhouse gas emissions from both electricity and thermal energy generation.
Cost-effective, dispatchable solar energy alternatives would stabilize electricity rates for consumers as the penetration of renewable energy increases in the coming years.