Solar Thermal Energy
Solar Thermal Energy is specifically the heat that can be gathered and collected from solar power - and not by the use of photoelectric cells. Solar Thermal Energy is energy that can be transferred into water and stored in insulated containers and kept heated constantly by the sun, and retain energy overnight (which makes them great for night operation of sterling engines - which run off of heat differentials). They are also used to heat water and heat homes, and find various applications throughout the United States and world. Some thermal energy is used to superheat water in massive solar power plants that use steam based turbines to generate electric power, and are very environment friendly with no emissions. The collection of this energy is usually done through a panel, or a series of panel which has water pumped through it - the panel could have a head conducting liquid in it to increase efficency of heat transfer to the water while that chemical liquid is not mixed with it. Panels are usually black to absorb as much head as possible in one area, and may include mirrors to focus in on specific points within the panel. These panels are commonly seen in home hot water systems that can cut consumption of energy used for heating water greater than half.
In power plants that use super-heated steam it is usually a mirror based system that reflects light from many different points on to one location to collect and create a super-heated point, which then superheats water into steam to force a steam turbine to spin through pressure(it is a combination of turning heat into steam power, which is used in many power plants [indeed most] today - coal plants heat boilers, nuclear plants heat water, and oil or natural gas plants also heat boilers which force steam through pipes into turbines, spinning them and using the energy created by the heat to generate electricity). Finally there are the panels used for sterling engine transfer of energies through heat differentials. How this works is that one of the pistons in the sterling engine is cooler than the other, creating motion without combustion. A highly efficient sterling can run off of very little heat, and increasing the heat increases the speed it will run at. Usually collection of thermal energy is done with water, thus being able to keep differentials at night time too, using more than one sterling will generate enough power to do most tasks. All of this is by using solar thermal energy.