Wood and dry crop wastes are referred to as biomass derived fuels. Plants use photosynthesis, deriving the energy from the sun. About a century ago, firewood was the most common form of fuel. Although other forms of energy are currently available, biomass is still the largest form of energy available in the US.
The cheapest source of solar electricity is the wind power. Variation of pressure between areas caused by solar energy, causes wind effects. This form of energy is used to run turbines that in turn generate electricity. In the Rocky Mountains in Southern Wyoming, the average annual wind speed is 21 miles per hour, making it ideal for electricity generation.