Alternative Energy Sources

There is now growing awareness on the imperatives for a global energy future which marks a distinct departure from past trends and patterns of energy production and use. These imperatives emerge as much from the need to ensure energy security/ as they do from the urgency of controlling local pollution from combustion of different fuels and/ of course/ the growing challenge of climate change/ which requires reduction in emissions of greenhouse gases (GHSs)/ particularly carbon dioxide.
- Dr. R. K. Pachauri/ Chairman, Intergovernmental Panel on Climate Change

8Many important events have occurred during the history of using renewable sources even though the use of renewable energy is not new. Five generations (125 years) ago, wood supplied up to 90 percent of our energy needs. Due to the convenience and low prices of fossil fuels, wood use has fallen. Now, some biomass that would normally be taken to the dump is converted into electricity (e.g., manufacturing wastes, rice hulls, and black liquor from paper production).
Renewable energy effectively uses natural resources such as sunlight, wind, rain, tides and geothermal heat, which may be naturally replenished. Renewable energy technologies range from solar power, wind power, hydroelectricity/ micro hydro, biomass and biofuels for transportation. Renewable energy sources can be replenished in a short period of time. The five renewable sources used most often are:

• wind
• solar
• geothermal
• biomass energy
• water harvesting
In 2006, about 18 percent of global final energy consumption came from renewables, with 13% coming from traditional biomass, like wood-burning. Hydropower was the next largest renewable source, providing 3%, followed by hot water/heating which contributed 1.3%. Modern technologies, such as geothermal, wind, solar, and ocean energy together provided some 0.8% of final energy consumption. The technical potential for their use is very large, exceeding all other readily available sources.
Renewable energy technologies are sometimes criticised for being intermittent or unsightly, yet the market is growing for many forms of renewable energy. Wind power has a worldwide installed capacity of over 100 GW and is widely used in several European countries and the USA. The manufacturing output of the photovoltaics industry reached more than 2,000 MW per year in 2006, and PV power plants are particularly popular in Germany. Solar thermal power stations operate in the USA and Spain, and the largest of these is the 354 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 percent of the country's automotive fuel. Ethanol fuel is also widely available in the USA.
While there are many large-scale renewable energy projects, renewable technologies are also suited to small off-grid applications, sometimes in rural and remote areas, where energy is often crucial in human development. Kenya has the world's highest household solar ownership rate with roughly 30,000 small (20-100 watt) solar power systems sold per year.
Climate change concerns coupled with high oil prices, peak oil and increasing government support are driving increasing renewable energy legislation, incentives and commercialization. European Union leaders reached an agreement in principle in March 2007 that 20 percent of their nations' energy should be produced from renewable fuels by 2020, as part of its drive to cut emissions of carbon dioxide, blamed in part for global warming. Investment capital flowing into renewable energy climbed from $80 billion in 2005 to a record $100 billion in 2006. This level of investment combined with continuing double digit percentage increases each year has moved what once was considered alternative energy to mainstream. Wind was the first to provide 1 % of electricity, but solar is not far behind. Some very large corporations such as BP, General Electric, Sharp, and Royal Dutch Shell are investing in the renewable energy sector.

The need for renewable energy use and current global warming trends

Carbon dioxide emissions are causing the Earth's climate to change and warm, which will have catastrophic results if we do not act to reduce them. Carbon dioxide emissions in our atmosphere are at their highest levels in recorded history, spanning over 650,000 years.
The effects of climate change can be seen now. Temperatures are increasing, glaciers are receding at unprecedented speeds, storms are becoming more frequent and severe, and chunks of ice the size of Connecticut are breaking off the Antarctic ice shelf.