Article by E Lopes
Solar Power plants, or power stations, have been around for a few decades, and unlike traditional power plants they provide an environmentally benign source of energy, producing virtually no emissions, and consuming no fuel other than sunlight.
Traditional solar power plants are concentrating solar thermal plants, but more recently multi-megawatt photovoltaic plants have been built, namely those in Portugal and Germany. These are marking a trend toward larger photovoltaic power stations in different locations on the planet.
An advantage of solar thermal power plants is that they can generally be built in a few years because they are built almost entirely with modular, readily available materials. Another advantage is that while all power plants require land and have an environmental impact, the best locations for solar power plants are deserts or other land for which there might be few other human uses.
Solar thermal plants achieve the high temperatures required through concentration of solar radiation. Parabolic troughs, the most advanced technology for doing this, are very extensive and are made of shaped mirror segments. These troughs track the sun over the course of the day and focus the resulting radiation along the caustic line of the mirrors onto specially coated, evacuated absorber tube receivers. The solar radiation heats up the thermo-oil that flows through the receivers to a temperature of 400