Solar energy is projected by many one of the most promising sectors of renewable energy. Compared with other types of electricity production from renewable sources, solar energy has the greatest potential for long-term growth.
Although wind has been harnessed for centuries, it has only recently emerged as a modern energy solution. Prior to the 21st century, wind power was often used to pump water from wells and to grind grain. Over the last twenty years, technology advances have reduced the cost of wind energy by more than 80 percent, making wind the most affordable form of renewable energy.