Many enthusiasts new to renewable energy get confused about solar thermal’s use for power generation.
Broadly, solar energy can classified into two – solar photovoltaic (PV) that generates power from the sunlight, and solar thermal, where the heat of the sun is utilized to recover energy.
Let’s look at solar thermal.
When solar thermal is mentioned, most people visualise the solar water heaters. This is only for heating water.
So how do you generate electricity from solar thermal?
In order to do this, you need what can be termed as high temperature solar thermal. In solar water heaters, water gets heated to about 70 deg C. In high temperature solar thermal, water gets heated to up to 400 deg C through special machinery, mostly coming under what is called Concentrated Solar Thermal. Such high temperature steam at a high pressure then drives a turbine that is connected to a generator to generate electricity.
For those familiar with thermal power plants, you will recognise that the process is similar, except that the superheated steam here is generated from the heat of sunlight and not from heating coal or natural gas.