by Michael Edwards W hen doing the research for a article on new green products, I was unaware of many of the different ways to convert the energy of the sun into electrical power. I have written about solar cell or photovoltaic cell systems, so let’s look at another type of solar energy system. The Stirling engine goes back to the early 1800’s, when steam was the order of the day. Steam was used to power factories, trains, and many types of work that required lots of horsepower. However,