The oil price shocks of the 1970s and 1980s spurred a national movement to develop other kinds of energy and decrease our dependence on petroleum. In this period, Texas oil and gas production peaked and the industry began to play a diminishing yet still important role in the state’s economy. As energy prices fell, however, interest in renewable energy sources waned. Recent events, including dramatically higher oil prices and environmental concerns, again have led to heightened interest in renewable sources of energy, such as solar and wind energy, biomass, hydropower and geothermal power, which are virtually inexhaustible and relatively clean.
In a sense, at the beginning of the 21st century, Texas has come full circle. Windmills that pumped water for farms and ranches in the late 1800s now stand in the shadow of giant wind turbines that generate electricity. Native Americans and settlers once gathered buffalo chips for fuel to build fires on the High Plains; soon cattle feedlots near Hereford will provide manure to fuel ethanol plants. Settlers once burned wood in East Texas to heat their cabins and cook their food – and a proposed plant near Nacogdoches may burn forest products to produce electricity.
By definition, renewable energy is abundant and constantly replenished. It includes energy from the sun, earth and wind. Most renewable energy comes either directly or indirectly from the sun, which itself is a fusion nuclear reactor 93 million miles from earth. The sun projects a reliable, continuous spectrum of radiation. Sunlight intercepted by the earth provides renewable solar energy that can be used to generate electricity, provide heat and light and drive photosynthesis – the essential life-giving process by which the energy of sunlight creates food for green plants.
The sun’s heat also drives the earth’s winds. The earth’s rotation and topography combine to produce predictable wind patterns that can be used by large wind turbines to generate electricity. The motive power of wind (and moving water) has historically played a valuable role in turning milling wheels, driving pumps and sending ships across the sea. Today, wind power accounts for a growing part of Texas’ energy portfolio.
Biomass is defined as any plant or animal matter used to produce electricity, heat or transportation fuels. Sources of biomass include wood products, food crops, grasses, agricultural residues, manure, municipal solid waste and landfill gas. The stored hydrocarbons in biomass provide the same chemical building blocks as coal, oil and natural gas, which are simply ancient forms of biomass gathered and transformed by nature. While most renewable sources of energy are used to produce electricity, some biomass sources are well-suited, through appropriate technology, for conversion into transportation fuels or boiler fuels.
Hydropower relies on capturing the energy in flowing water, which is linked to the sun through the hydrological cycle – water evaporation from the oceans turns into clouds and later condenses, falling as rain. The ocean itself can produce energy from the action of the waves (driven by the sun’s heat and winds) and tides, based on the gravitational pull of the sun and moon.
Geothermal energy uses the internal heat of the earth to generate electricity, as well as more direct uses such as spas and greenhouses. The ground itself, due to its more constant temperatures, provides a form of geothermal energy that is used for climate control of buildings (as with ground-source heat pumps). The heat of geothermal resources generally increases in intensity with depth. In the richest geothermal zones, heat from deep underground penetrates the earth’s surface as geysers and volcanically active areas.