Chapter 14 - Renewable Energy

Abstract

Renewable energy is regenerated at the same rate as it is used. Renewable energy technologies (RETs) can provide electricity, fuels for transport, heat and light for buildings, and power and process heat for industry. These technologies generally have little or no emissions of greenhouse gases, air pollutants, or other environmental impacts. RETs can also offset imports of foreign oil and offer important direct economic benefits. Renewable energy resources include biomass, geothermal energy, hydro power, ocean energy, solar energy, and wind energy. Renewable energy resources often vary in their availability. Many RETs involve collecting natural flows of energy. The chapter discusses the basic RETs — biomass, geothermal, hydro power, ocean solar, and wind energy. Biomass includes the full range of organic plant materials, such as trees, grasses, and even aquatic plants. It can be burned to produce heat or converted into liquid or gaseous fuels. The heat may be used to produce electricity. Geothermal energy is the accessible thermal energy or heat content of the earth's crust. It can be used to produce electricity, process heat, or to heat/cool buildings. Geothermal resources can be utilized locally. Hydro power is the energy drawn from water falling or flowing downhill. Ocean energy resources include energy conversion processes utilizing the temperature difference between surface and deep waters, recovery of potential energy from the rise and fall of the tides, and the recovery of kinetic energy from wave motion. Solar energy or sunlight is used to generate electricity directly using photo voltaic cells or to produce heat that can then be used directly or converted into electricity in a thermal power plant. Wind energy is used to turn a wind turbine to generate electricity. It is also used directly to power equipment such as water pumps.