Hybrid Photovoltaic/Thermal Solar Plus Storage Cogeneration

M. Anderson, E. Gonzalez
Icarus RT, Inc.,
United States

Keywords: energy storage, solar plus storage, thermal energy storage


Hybrid photovoltaic/thermal (PV/T) solar plus storage cogeneration systems have been explored for many years with little success due to practical cost barriers. New materials, technologies and design and manufacturing techniques enable hybrid applications to be highly cost competitive today for commercial and utility scale applications. Hybrid system typically cool PV panels by extracting waste heat, collecting and storing thermal energy, and converting thermal energy into hot water and/or additional power on demand (i.e., after sunset or during peak demand time of use rates). Current PV technology is inefficient, converting only about 21% of solar energy into usable power typically rated at the ideal temperature of 25 °C. Panels often reach temperatures of 65–75 °C significantly reducing production. The mismatch between daily solar energy output and utility peak energy demand periods compounds the problem. The California “Duck” Curve illustrates this concept – solar energy production decreases in the afternoon as demand increases, straining energy resources and the grid. Despite technology and economic advances, high battery cost plus panel inefficiencies deters commercial business owners from purchasing solar plus storage systems. Still, commercial and industrial PV plus storage is expected to grow from $8.6 billion in 2020 to $30.1 billion in 2030. Many have tried and failed to develop hybrid PV/T technologies. Icarus offers an effective alternative that overcomes the shortcomings of previous attempts of PV/T systems with a solar plus storage system that improves panel efficiency and provides affordable and environmentally safe thermal energy storage. A primary factor for the cost reduction is that systems today boost PV array daytime output while charging the thermal battery without consuming PV production. Traditional battery systems consume PV output to charge, reducing the power available during the day. Overall, hybrid systems can provide improved panel efficiency, increased power output, energy storage for power and/or hot water, and continuous grid reliability at a lower cost without the environmental downsides of Li-ion batteries. A case study of the Icarus RT, Inc. Quartet system will be explored, compared to similar technologies and evaluated.