Green Economy: Define Types of Renewable Energy

There are many types of renewable energy available worldwide, the availability of these options depending on location, cost and stage of commercialization. This article summarizes the main types of renewable energy that are currently being developed in large scales.


This is the world’s oldest and lowest-cost renewable energy source with a global installed base of approximately 850 GWe. According to the DOE, the U.S. has nameplate capacity of approx. 100 GWe, with the potential for an additional 170 GWe. China has the largest installed base, with 145 GWe and the potential to increase to 500 GWe or more.


According to the AWEA, total U.S. capacity for wind increased to 18 GWe in 2007. A report from the DOE stated that the U.S. could provide 20% of its electricity (304 GWe) from wind by 2030, saving annual CO2 emissions of 825 million tons (“Mt”). Europe has an installed capacity of 57 GWe, of which 900 MWe is from offshore wind.

TPWind targets installed capacity of 300 GWe in Europe (50% offshore/50% onshore) with annual CO2 savings of 600 Mt.

China has an installed base of 6 GWe with plans to increase it to 10 GWe by 2010. China is also exploring offshore wind, which has an estimated potential of 750 GWe. Globally, there is an estimated installed capacity for wind turbines of 95-100 GWe, and a potential for 72 TWe on land and near the coasts.


As of 2005, the installed capacity for geothermal electric power (excluding ground source heat pumps) was approx. 9 GWe worldwide, a third of which is currently operating in the U.S.

In January 2008, GEA released survey results which identified 103 projects in the U.S. for an annual capacity of 4 GWe. The Western Governor’s Task Force projects 15 GWe of geothermal power by 2025. The U.S. Geological Survey estimates geothermal resources between 95 and 150 GWe, of which 22 GWe has been identified suitable for geothermal power generation.

According to the IGEA, geothermal has a potential between 140 GWe and 6 TWe worldwide. Geothermal is also being used for direct uses with an installed capacity of 15 GWth in the U.S. (Gupta and Roy 2007) and 100 GWth worldwide.

A 2006 report by MIT, concluded that through the use of enhanced geothermal systems (“EGS”) it

would be affordable to generate 100 GWe or more by 2050 in the U.S. alone. The MIT report calculated the world’s total extractable EGS resources to be over 200 ZJ (or 400 times the world’s current total energy demand), with the potential to increase this to over 2,000 ZJ with technology improvements.


Solar PV reached a global installed capacity of approx. 12 GWe in 2007. Annual production in 2007 was 3.9 GWe. Photon International projects annual production capacity for PV of greater than 26 GWe by 2010. There is currently an installed base of 430 MWe for CST and 12 MWe for CPV,but these technologies have significant growth potential.

There are currently 40 projects under construction or development. The Prometheus Institute and Greentech Media forecast that CSP and CPV will make up 18 GWe of installed capacity by 2020. Rooftop solar thermal collectors reached 128 GWth in 2007, led by China with over 85 GWth. The overall potential for solar power is enormous. According to SolarPaces, there are 7 TWe of CSP capacity in the southwestern U.S. on “filtered,” available land. Globally, the potential for solar power is 600 TWe.


This includes tidal, wave, and thermal power. Currently, tidal power has an installed base of approx. 271 MWe with 157 GWe under consideration, and wave power has an installed base of 2 MWe with 350 MWe under consideration. According to the Electric Power Institute, potential wave energy is approx. 30 GWe in the U.S. alone.

The global wave power potential in water depths over 100 meters has been estimated to be between 1 and 10 TWe. Ocean thermal power is still under development with less than 50 MWe currently under consideration, but with the potential for 20 GWe+ in Asia/Pacific.


Electricity produced from biomass sources is estimated to be 44 GWe with another 22O GWth used for heating, excluding the use of biomass for cooking. The future potential for biomass could reach 150 to 400 EJ per year (up to 25% of world primary energy) by 2050, using available farm, forest and urban residues and by growing perennial energy crops.


Production of ethanol exceeded 172 billion gallons of ethanol and 30 billion gallons of biodiesel in 2007, displacing over 4.5 billion barrels of oil. As alternative feedstocks are developed for ethanol (cellulosic) and biodiesel (jatropha, algae), the emissions reduction potential for biofuels will be greatly enhanced, according the World Energy Council.

Post-consumer waste is also a contributor to GHG emissions with total emissions of approx. 1.3 GtCO2-eq in 2005. The largest source is landfill methane (CH4), followed by wastewater CH4 and nitrous oxide (N2O). In addition, minor emissions of carbon dioxide (CO2) result from incineration of waste containing fossil carbon (plastics; synthetic textiles).

Aided by Kyoto mechanisms, as well as other measures to increase worldwide rates of landfill CH4 recovery, the total global economic mitigation potential for reducing landfill CH4 emissions in 2030 is estimated to be greater than 1.0 Gt CO2-eq. Most of this potential is achievable at low to negative costs: 20′” 30% of projected emissions for 2030 can be reduced at negative cost and 30′”50% at costs less than $20 per ton of CO2-eq a year.

Indeed, many brooks flow into a river. It will take many technologies flowing into solutions that “power” our future energy needs.

The efforts of all nations on the planet will be required to overcome the barriers that obstruct its flow, including: land use competition, market distortions and failures, regulatory issues, environmental concerns, infrastructure requirements and initial investment costs.

With these log jams removed, the floodgates can be further opened to allow the market to achieve economies of scale, reduce the costs of these alternative power sources, and create huge money making opportunities for investors.