Renewable energy
Renewable energy is derived from natural processes that are regularly replenished. Renewable energy sources and technologies include solar power, wind power, hydropower, geothermal energy, biomass, and biofuels. Each of these has unique characteristics which influence how and where they are used.[1]
About 18% of global final energy consumption comes from renewables, with 13% from traditional biomass (which is mainly used for heating) and 3% from hydroelectric power. The share of renewables in electricity generation is around 18%, with 15% of global electricity coming from hydroelectricity and 3.4% from new renewables (small hydro, modern biomass, wind, solar, geothermal, and biofuels).[2]
According to the International Energy Agency (IEA), renewable energy technologies can play an important role in addressing the challenges of moving towards clean, reliable, secure and competitive energy supply. Many countries have made progress in promoting renewables in their energy mix, but obstacles remain and, says the IEA, greater efforts are needed.[3]
Rationale for renewables
Renewable energy technologies are essential contributors to the energy supply portfolio, as they contribute to world energy security, reduce dependency on fossil fuels, and provide opportunities for mitigating greenhouse gases. The fuels that produce the most emissions of greenhouse gas are fossil fuels and they can be replaced by non-depletable sources of energy that produce much lower emissions of greenhouse gases:
...the transition from coal,oil, and gas to wind, solar, and geothermal energy is well under way. In the old economy, energy was produced by burning something — oil, coal, or natural gas — leading to the carbon emissions that have come to define our economy. The new energy economy harnesses the energy in wind, the energy coming from the sun, and heat from within the earth itself.[4]
The International Energy Agency estimates that nearly 50% of global electricity supplies will need to come from renewable energy sources in order to halve carbon dioxide emissions by 2050.
Renewable energy development
The term renewable energy covers a number of sources and technologies at different stages of development. Renewable energy development has involved three generations of technologies dating back more than 100 years.
First-generation technologies, which are already mature and economically competitive, include biomass, hydroelectricity, geothermal power and heat. Second-generation technologies are market-ready and are being deployed at the present time; they include solar heating, photovoltaics, wind power, solar thermal power stations, and modern forms of bioenergy. Third-generation technologies require continued R&D efforts in order to make large contributions on a global scale and include advanced biomass gasification, biorefinery technologies, hot-dry-rock geothermal power, and ocean energy.[5][6]
Economic trends
All forms of energy are expensive, but as time progresses, renewable energy generally gets cheaper,[7][8] while fossil fuels generally get more expensive. Al Gore has explained that renewable energy technologies are declining in price for three main reasons:[9]
First, once the renewable infrastructure is built, the fuel is free forever. Unlike carbon-based fuels, the wind and the sun and the earth itself provide fuel that is free, in amounts that are effectively limitless.
Second, while fossil fuel technologies are more mature, renewable energy technologies are being rapidly improved. So innovation and ingenuity give us the ability to constantly increase the efficiency of renewable energy and continually reduce its cost.
Third, once the world makes a clear commitment to shifting toward renewable energy, the volume of production will itself sharply reduce the cost of each windmill and each solar panel, while adding yet more incentives for additional research and development to further speed up the innovation process.[9]
Recent growth of renewables
From the end of 2004 to the end of 2008, solar photovoltaic (PV) capacity increased sixfold to more than 16 gigawatts (GW), wind power capacity increased 250 percent to 121 GW, and total power capacity from new renewables increased 75 percent to 280 GW. During the same period, solar heating capacity doubled to 145 gigawatts-thermal (GWth), while biodiesel production increased sixfold to 12 billion liters per year and ethanol production doubled to 67 billion liters per year.[10]
| Selected global indicators | 2004 | 2005 | 2006 | 2007 | 2008 |
|---|---|---|---|---|---|
| Investment in new renewable capacity (annual) | 30 | 38 | 63 | 104 | 120 billion USD |
| Existing renewables power capacity, including large-scale hydro |
895 | 930 | 1,020 | 1,070 | 1,140 GWe |
| Existing renewables power capacity, excluding large hydro |
160 | 182 | 207 | 240 | 280 GWe |
| Wind power capacity (existing) | 48 | 59 | 74 | 94 | 121 GWe |
| Biomass heating | ~250 GWth | ||||
| Solar hot water/ Space heating | 77 | 88 | 105 | 126 | 145 GWth |
| Geothermal heating | ~50 GWth | ||||
| Ethanol production (annual) | 30.5 | 33 | 39 | 50 | 67 billion liters |
| Countries with policy targets for renewable energy use |
45 | 49 | 66 | 73 |
Annual percentage growth for 2008 was significant. Wind power grew by 29 percent and grid-connected solar PV by 70 percent. The capacity of utility-scale solar PV plants (larger than 200 kilowatts) tripled during 2008, to 3 GW. Solar hot water grew by 15 percent, and annual ethanol and biodiesel production both grew by 34 percent. Heat and power from biomass and geothermal sources continued to grow, and small hydro increased by about 8 percent.[10]
In 2008 for the first time, more renewable energy than conventional power capacity was added in both the European Union and United States, demonstrating a "fundamental transition" of the world's energy markets towards renewables, according to a report released by REN21, a global renewable energy policy network based in Paris.[12]
References
- ↑ International Energy Agency (IEA) (2003). Renewable energy... into the mainstream p. 9.
- ↑ Renewable Energy Network in the 21st Century (REN21) (2008). Renewables 2007 Global Status Report (Paris: REN21 Secretariat and Washington, DC: Worldwatch Institute).
- ↑ International Energy Agency (2008). Deploying Renewables p. 1.
- ↑ Lester R. Brown. Plan B 4.0: Mobilizing to Save Civilization, Earth Policy Institute, 2009, p. 135.
- ↑ International Energy Agency (2007). Renewables in global energy supply: An IEA facts sheet (PDF) OECD, 34 pages.
- ↑ International Council for Science (c2006). Discussion Paper by the Scientific and Technological Community for the 14th session of the United Nations Commission on Sustainable Development (CSD-14) (PDF)
- ↑ Renewable energy costs drop in '09 Reuters, November 23, 2009.
- ↑ Solar Power 50% Cheaper By Year End - Analysis Reuters, November 24, 2009.
- ↑ 9.0 9.1 Al Gore (2009). Our Choice, Bloomsbury, p. 58.
- ↑ 10.0 10.1 REN21 (2009). Renewables Global Status Report: 2009 Update p. 8.
- ↑ REN21 (2009). Renewables Global Status Report: 2009 Update p. 9.
- ↑ 12.0 12.1 Eric Martinot and Janet Sawin. Renewables Global Status Report 2009 Update, Renewable Energy World, September 9, 2009.
- ↑ REN21 (2006). Renewables Global Status Report: 2006 Update, p. 3.