Energy Sources - Renewable Sources

Renewable Sources

Renewable energy is energy which comes from natural resources such as sunlight, wind, rain, tides, and geothermal heat, which are renewable (naturally replenished). Renewable energy is an alternative to fossil fuels and was commonly called alternative energy in the 1970s and 1980s. In 2009, about 16% of global final energy consumption came from renewables, with 10% coming from traditional biomass, which is mainly used for heating, and 3.4% from hydroelectricity. New renewables (small hydro, modern biomass, wind, solar, geothermal, and biofuels) accounted for another 2.8% and is growing very rapidly. The share of renewables in electricity generation was around 19.4%, with 16.1% of global electricity coming from hydroelectricity and 3.3% from new renewables.

Wind power is growing at the rate of 21% annually, with a worldwide installed capacity of 238 gigawatts (GW) in 2011, and is widely used in Europe, Asia, and the United States. At the end of 2011, cumulative global photovoltaic (PV) installations surpassed 69 GW, an increase of almost 70%, and PV power stations are commonplace in Germany, Italy, and Spain. Solar thermal power stations operate in the USA and Spain, and the largest of these is the 354 megawatt (MW) SEGS power plant in the Mojave Desert. The world's largest geothermal power installation is The Geysers in California, with a rated capacity of 750 MW. Brazil has one of the largest renewable energy programs in the world, involving production of ethanol fuel from sugar cane, and ethanol now provides 18% of the country's automotive fuel. Ethanol fuel is also widely available in the USA.

Climate change concerns, coupled with high oil prices, peak oil, and increasing government support, are driving increasing renewable energy legislation, incentives and commercialization. New government spending, regulation and policies helped the industry weather the global financial crisis better than many other sectors. Scientists have advanced a plan to power 100% of the world's energy with wind, hydroelectric, and solar power by the year 2030, recommending renewable energy subsidies and a price on carbon reflecting its cost for flood and related expenses.

While many renewable energy projects are large-scale, renewable technologies are also suited to rural and remote areas, where energy is often crucial in human development. Globally, an estimated 3 million households get power from small solar PV systems. Micro-hydro systems configured into village-scale or county-scale mini-grids serve many areas. More than 30 million rural households get lighting and cooking from biogas made in household-scale digesters. Biomass cookstoves are used by 160 million households.

Wind, water, and solar power using current technology can supply all of the world's energy by 2030, and has the advantage that consumption is reduced by 30%. Excess production would be used to produce hydrogen for use in ships and airplanes. It also has the advantage that it lasts for as long as we are on the planet, vs. less than a century for most of the non-renewable resources. Conventional production of oil peaked in 2006, and the more we use the faster it will be depleted. An investment in non-renewable resources of $8 trillion is required to maintain current levels of production for 25 years, a cost that is avoided by transitioning instead to renewables. A 2010 study estimated that Australia could transition to 100% renewables for $370 billion over a ten-year period - about $8/household/week. Driving an electric car is like buying gasoline for $0.60/gallon, although in 2012 an electric car is over $8,000 more than one powered by gasoline. If they were mass produced, this differential would be reversed. The most expensive part, the battery, is projected to be reduced from $12,000 to $1,500 by 2020. Charging an electric car from roof mounted solar panels is almost free, other than the cost of installation, which could be included in the purchase price of the home. Electric cars have almost no maintenance costs. The EV1, an advanced prototypical electric car, was brought in once every 5,000 miles just to rotate the tires and re-fill the windshield washer fluid.