• Renewable energy is energy that comes from sources that replenish themselves over short periods of time. For the most part, renewable energy sources also provide clean energy, or energy that emits few greenhouse gases or pollutants. For this reason, many policy experts and scientists advocate renewable energy sources over traditional fossil fuels. The difficulty is achieving the technology, infrastructure, and political support to make this transition.

    The five renewable energy sources highlighted in this map series are the five largest worldwide. Hydroelectric energy is by far the most prevalent, accounting for 83% of the world's electricity generation from renewable sources. This is most likely because the requisite technology to generate electricity by harnessing the flow of water has been around the longest, dating back to the early 20th century. Wind energy is the next largest, at just over 7% of the electricity generated from renewable sources, followed by biowaste and biomass energy (7%), geothermal energy (2%), and solar, tidal, and wave energy (less than 1%).

    This map series shows electricity generation from renewable energy sources in billion kilowatt-hours. The first map shows each country's total electricity generation from all renewable energy sources averaged over the years 2006-2010. The following maps show the same figure broken down by renewable energy type. The data come from the United States Energy Information Administration.

    1. Take a look at the countries that generate the most electricity overall from renewable energy sources (the darkest color). What common features do you see?

      Each of these countries—China, the United States, Brazil, Canada, and Russia—have a vast expanse of land. These five countries are the largest in the world based on area; this larger land area means they also have a large natural resource base, giving them the potential to harness different renewable energy sources. For each of them, hydroelectricity is their main renewable energy source.

    2. Where might you expect to find the most electricity generated from hydroelectric energy? Is this reflected on the map?

      Countries with dense river systems and the infrastructure to build large dams have the most potential to generate electricity from hydroelectric sources. Hydroelectricity is the biggest source of renewable energy for each of the top five renewable energy-producing countries. China has one of the largest hydroelectric dams in the world, the Three Gorges Dam on the Yangtze River. Brazil shares another—Itaipú Dam—with Paraguay. Canada is second in the world in hydroelectric production, while Russia is second in terms of hydroelectric potential. The United States leads the world in total biomass, wind, and geothermal production in addition to getting 65% of its renewable energy from hydroelectricity.

    3. Which region of the world generates the most electricity from wind power? Why might this be?

      Although the United States leads the world in wind production, Europe overall generates the most electricity from wind. This is due largely to European Union policies that subsidize wind farm development. Germany and Spain are second and third in production behind the United States, and Denmark generates 26% of its electricity from wind alone. Since 1995, wind energy in the EU has had an average annual market growth of 15.6% and polls show that over 80% of EU citizens are in support of wind energy.

    4. Why might energy from biomass and biowaste be a particularly attractive alternative to traditional fossil fuels?

      In addition to being a renewable energy source and reducing overall greenhouse gas emissions, biomass is an energy source that is readily available everywhere. Different biofuel crops can thrive in different soil and climate conditions. In addition, certain types of municipal solid waste can also be converted to biomass energy, meaning it also can act as a waste management system. The latest hot topic in biomass research is algae biofuel—which could grow to be a $1.3 billion market by 2020.

    5. Why do you think so few countries produce electricity from geothermal energy?

      Geothermal energy is essentially heat from the Earth. In order to efficiently produce electricity using geothermal energy, the underground temperature must be very high. The places on Earth with the highest underground temperatures are regions with active volcanoes. In El Salvador, Iceland, and the Philippines, all of which have multiple active volcanoes, geothermal energy generates over 25% of the country's electricity.

    6. Why do you think solar, tidal, and wave energy are included in the same category?

      Solar, tidal, and wave energy harness two of the most powerful and widespread resources known to man—the ocean and the sun. However, less than 1% of all renewable energy comes from these three sources combined. The technology needed to efficiently and cost-effectively generate electricity from these resources is only just becoming available. In the coming years we may see significant growth in each of these sectors: Improved technology and a heightened desire to cut greenhouse gas emissions is driving the demand for solar energy in particular, says the International Energy Agency.

    • Between 2006 and 2009, China nearly doubled its electricity generation from renewable energy sources. In 2006, it generated 437 billion kilowatt hours, and in 2010 it generated 770 billion kilowatt hours, the most of any single country in the world and about 5% of its total electricity generation. 93% of China's renewable energy comes from hydroelectric power, and it produces the most hydroelectricity of any country in the world. China's hydroelectric power alone could power the United Kingdom for two years.
    • Antarctica—the windiest place on Earth—produces much of the electricity that powers its various research bases from wind farms. The southernmost one, built in 2010, is located on Ross Island at New Zealand's Scott Base. There, wind turbines are set to reduce carbon dioxide emissions by 1,227 metric tons (1,242 tons) per year.
    • Germany produces the most electricity from solar, tidal, and wave energy of any country in the world, and is producing more every day. Between 2006 and 2010, it increased its production by over 300%, and has continued to increase its capacity since. Germany is especially invested in solar energy. Despite leading the world in solar capacity, Germany only got 2% of its overall electricity from solar in 2010.
    • While the United States leads the world in overall geothermal energy production, the Philippines produces about twice as much per capita. The country has seven geothermal power plants on four different islands, which together account for 17% of the country's electricity generation. Its position in the Pacific "Ring of Fire" makes it an ideal setting for harnessing geothermal energy and many more sites are currently in development.
    • The United States is the worlds largest producer of biofuels. Biomass was the country's second largest source of renewable energy (after hydroelectric) until 2008, when it was surpassed by wind. In 2010, biomass made up about 7% of the country's electricity generation from renewable energy. Because biomass energy comes from any usable organic matter, it is available almost anywhere. In the United States, biomass energy most often comes from wood, wood waste, crops like corn, and from municipal solid waste.
  • Term Part of Speech Definition Encyclopedic Entry
    advocate Verb

    to argue in favor of something.

    Antarctica Noun

    Earth's fifth-largest continental landmass.

    Encyclopedic Entry: Antarctica
    biofuel Noun

    energy source derived directly from organic matter, such as plants.

    biomass energy Noun

    renewable energy derived from living or recently living organisms, mostly plants.

    clean energy Noun

    electrical energy that does not pollute the atmosphere, water, or earth.

    fossil fuel Noun

    coal, oil, or natural gas. Fossil fuels formed from the remains of ancient plants and animals.

    geothermal energy Noun

    heat energy generated within the Earth.

    Encyclopedic Entry: geothermal energy
    greenhouse gas Noun

    gas in the atmosphere, such as carbon dioxide, methane, water vapor, and ozone, that absorbs solar heat reflected by the surface of the Earth, warming the atmosphere.

    hydroelectric energy Noun

    energy generated by moving water converted to electricity. Also known as hydroelectricity.

    Encyclopedic Entry: hydroelectric energy
    infrastructure Noun

    structures and facilities necessary for the functioning of a society, such as roads.

    kilowatt-hour Noun

    (kWh) unit of energy equal to 1,000 watt hours.

    pollutant Noun

    chemical or other substance that harms a natural resource.

    power plant Noun

    industrial facility for the generation of electric energy.

    renewable energy Noun

    energy obtained from sources that are virtually inexhaustible and replenish naturally over small time scales relative to the human life span.

    resource base Noun

    the available supply of goods, materials, or services in a specific place at a specific time.

    Ring of Fire Noun

    horseshoe-shaped string of volcanoes and earthquake sites around edges of the Pacific Ocean.

    Encyclopedic Entry: Plate Tectonics and the Ring of Fire
    solar power Noun

    rate of producing, transferring, or using solar energy.

    switchgrass Noun

    tall grass native to North America.

    tidal energy Noun

    energy produced as ocean waters surge in and out with tides.

    Encyclopedic Entry: tidal energy
    wave energy Noun

    energy produced by ocean waves.

    wind energy Noun

    kinetic energy produced by the movement of air, able to be converted to mechanical power.

    wind farm Noun

    area with a large group of wind turbines, used to generate electric power.