Renewable energy

windfarm near Kopenhague - Danmark © Yann Arthus-Bertrand
Renewable energy made up 12.7% of global energy production in 2006. 10% came from wood and waste combustion, 2.2% from hydroelectricity and 0.5% from other sources of renewable energy.

According to Observ'ER, renewable electricity production amounted to 18.6% of total production, 89% coming from water-power and 5.7% from biomass, the rest being shared out between wind-power (3.5%), geothermal power (1.7%), and solar power (0.2%). North America is world's first producer of renewable energy with 21.8% of total production, followed by western Europe (19.3%), East and South-East Asia (19.2%) and South America (19%). In 2007, wind-powered electricity production increased from 20,000 MW to 94,000 MW. Photovoltaic production increased by 50% compared to 2006, reaching 12,400 MW.

The United States experienced the greatest increase, followed by China and Spain. Investments in renewable energy amounted to 66 billion dollars, an increase of 20 to 25% compared to 2006. However, the European Commission predicts that the percentage of renewable energy used in global consumption will decrease from 13% to 8% between 2000 and 2030, which means that global energy consumption will grow faster than the production of renewable energy.

Three Gorges Dam

The gigantic Three Gorges Dam, located on the Yangtze, in the centre of China, became operational in June 2006. At 2.3 kilometres long and 185 meters high, the structure now regulates the waters of the third largest river in the world. After the dam is filled, it will hold 4 billion m3 of water, covering an area of over 58,000 km2. In 2009, when the 26 turbines start working, the hydroelectric structure will generate 18,200 megawatts per hour, 10% of Chinese electrical consumption. This is one-third more than the Itaipu Dam, in Brazil, which had previously been the world’s largest hydro-electricity scheme.

Greenhouse gases

Renewable energy is energy from non-fossil sources such as wind, solar, geothermal, hydraulic power or biomass. Throughout the length of their production cycle, these energy sources emit various amounts of greenhouse gases, in much smaller proportions than fossil energies (from 300 to 800 g equivalent CO2/KWh depending on technologies), as shown in a study by the Global Chance association, which remarks that figures depend on “the transformation technologies, the modes of resources exploitation, and the nature and quantities of fossil energies eventually used in the process?. Emissions range from 20 to 130 grams of CO2 equivalent per kWh for the photovoltaic, from 5 to 30 for wind power, and from 4 to 20 for large hydraulic power. In terms of jobs, the photovoltaic sector creates 35 jobs per gigawatt hour (GWh), wind-energy 1, small hydraulic power 0.25, nuclear energy creating 0.15. Regarding the production price of 1 kWh of electricity, it depends on several factors such as public subsidies, the acknowledgement of impacts on the environment, economies of scale resulting from an increase of investment in renewable energies, or the price of oil.

Overview of renewable energy

- Hydro-electric: 2.2% of global energy production
Main countries of production: China (397,000 GWh), Canada (360,000 GWh), Brazil (334,000 GWh), United States (270,000 GWh), Russia (173,000 GWh), France (61,000 GWh, an increase of 8.6% compared to 2005). In Europe, hydro-electric energy makes up 13% of electric production.

- Wind energy: 0.1% of global energy production, average annual growth rate of 28.4%.
Investments: 25 billion euros invested in 2007 in the construction of new equipment.
Main countries of production (2007): Germany (22,247 MW, a decrease of 25% compared to 2006, and 7.2% of national electric consumption), Spain (13,500 MW and 8% of national electric consumption), United States (16,800 MW (2006), an increase of 20% compared to 2005, half of which was produced by Texas and California, and 1% of national electric consumption), India (8,000 MW), China (6,000 MW, an increase of 156% compared to 2006), Denmark (3,122 MW and 20% of the national electric consumption), France (2,257 MW, an increase of 129% from 2005).

Europe produces 65% of the world’s wind energy capacity, with more than 57,000 MW installed by the end of 2007, an increase of 17% compared to 2006. This wind energy generates electricity for 10 million people, avoiding the production of 24 millions tons of CO2 each year. Asia produces 26% of global wind energy.
The largest wind generator is located in Germany; it stands at a height of 126 metres and has a capacity of 5 MW.

- Solar energy: 0.5% of world energy production.
In Europe, 3,400 MWc were installed in 2006, of which 1,150 MWc in Germany, with 3 million m2 sensors, an increase of 44.3% compared to 2005.
In 2008, China became the leading producer of photovoltaic cells, followed by Germany, Japan, and the United States. The world’s largest photovoltaic plant, currently under construction in Germany, will have a capacity of 40 MW.

Solar energy is used in photovoltaic form (production of electricity) and thermal form (production of heat). The photovoltaic market is hindered by the scarcity of silicon, the main raw material of solar cells. Solar energy is particularly well-suited for the electrification of isolated sites, notably in developing countries.

- Biomass energy: 10% of global energy production.
This one results from the transformation of vegetable organic materials, issue de cultivated plants, woods, wastes, etc. It takes different forms : gaseous (biogas), liquid (biofuels) or solid (wood). They are used to produce heat, electricity, and fuels for transport, either by combustion, fermentation or distillation. Biofuels have long been used in Brazil and the United States, the leading producers of ethanol. Combustible wood, the oldest energy used by man, remains dominant in developing countries. In Europe, particularly in Germany and France, wood logs represent 46.1% of the biomass market, wood waste used in industrial and collective boilers, 20.8% and wood pellets, 1.8%.

- Geothermal: 0.35% of global energy production.
This is energy that is extracted from the heat produced by the earth. It is used to produce heat (low-energy geothermal) and electricity (high-energy geothermal). For this latter, 350 geothermal installations of high and medium energy counted in 2007 are equal to a power of 9,700 MW. The United States is the first country with an effective output of 2,687 MW (production per year of 15 TWh), followed by the Philippines (1,970 MW). For the production of heat, excluding geothermic heat pumps, the effective output is estimated at 27,000 MW, which is equal to a production greater than 70 TWh per year. In 2005, more than 70 countries declared using geothermal power to produce heat, the main ones being Japan, China, Iceland, the United-States and European countries (2,500 MW).

- With a world potential of 1400 TWh, as estimated by the World Energy Council, wave power is still limited to experimental research. Japan, India, Portugal, United-Kingdom and Norway have been trying to capture this energy for thirty years. Two first-generation wave generators have been produced since 2001, one in Azores (Pico, 0,4MW) and one in Scotland (Islay, 0,5MW), and one project is under construction in French Polynesia. New systems are being experimented: "Pelamis" of Ocean Power Delivery Ltd, which can produce up to 3MW (Great-Britain), SEAREV of the collaboration of Nantes central School and the CNRS (France).

- The kinetic energy of water masses, present in the oceanic streams and tides (tidal current power plant and tidal energy generation plant), constitutes a theoretical resource of 50 TWh/year worldwide. The United-Kingdom is the country where the researches are the most advanced, with the SeaGen project of 1MW implanted in the Strangford Lough fjord in Northern Ireland. Other projects are currently being studied, notably in France (Marénergie, Harvest, Hydrogen), in Italy (Enermar), in Norway (Hammerfest Strom), in the US (Hudson river).