While at the Solar Power Finance and Investment Summit, I got to sit down and chat with Hank Price, CTO from Abengoa Solar, about solar thermal. Solar Thermal Electric (STE) uses concentrated solar energy to generate high temperature thermal energy (1050°F) that can either be stored for later use or used to generate electricity in a conventional type power plant. A key aspect of solar thermal is storing the energy for when the sun isn’t shining or during peak hours when generation can’t meet the demand.
Abengoa leverages molten salt, also known as Solar Salt, which is a mix of sodium nitrate (40%) and potassium nitrate (60%). It has a very high melting point and retains heat well. This is used as their primary storage medium. Hank explained that this is a very efficient way to store energy, and it can be stored for multiple days. Abengoa focuses on large scale deployments in the form of power plants, like one down in Chile that is designed to operate at 100 MegaWatts, 24 hours per day.
While this application is a great technology for energy generation and storage, it isn’t as cost effective as photovoltaic (PV) solar panels, for residential deployments. This may change over time, but PV solar panels have a higher demand and production, which keeps the cost down.
As far as the future of solar goes, Hank stressed that we need to keep our focus on the bigger goal at hand, which is to reduce the Carbon output generated from Electricity Plants. Leveraging a technology, like Solar Thermal, will offer an alternative source of energy that has the ability to scale and meet demands even when the sun isn’t shining. Deploying STE requires about 3-5 years to finish a project that can be leveraged by utilities.