Earth Day 2012 is less than a week away, and in honor we would like to recognize some of our favorite clean energies. Clean, green, or renewable energy is finally getting the look (and some of the investment) it deserves. Over the past few decades, technology has increased the availability, efficiency and affordability of many energy sources that were once widely untapped. Although cost of implementation will always cause concerns, clean energy sources like these are sustainable and offer ample opportunities for expansion.
Solar power: The concept and practice of harvesting the sun's energy is an age-old tradition, but modern technologies and policies can push solar power to a new level of impact. The grasp of solar power is immense; the amount of solar energy absorbed by the Earth in one hour is more energy than the entire world uses in a calendar year. And even better, this sun is an inexhaustible source (in the foreseeable future).
According to a 2011 report by the International Energy Agency (IEA), "if effective support policies are put in place in a wide number of countries this decade, solar energy in its various forms can make considerable contributions to solving some of the most urgent problems the world faces: climate change, energy security, and universal access to modern energy services."
Solar energy is versatile, and is well-suited for a variety of applications. Some popular uses include solar lighting, heating, water heating, water treatment, and cooking. Even solar vehicles are being developed, and as technology advances, a owning a solar-powered car may not be too far-fetched. For the big picture, experts at the IEA estimate that if we follow, embrace, and implement a global solar-power regimen, in 50 years it is possible that 1/3 of all global energy can be supplied by the sun.
Wind energy: Like solar power, harnessing the wind's energy is not a new practice. Windmills have long been used as water pumps and grinding stations, and in the late 1800's, the first electricity-producing windmill was created. Today, clusters of modern windmills, generally called wind turbines, constitute wind energy sites, or wind farms.
Global wind usage for electricity is still relatively low, currently providing approximately 3% of Earth's electricity demands. However, the rapid growth of wind farms has already made a significant difference in many countries. For example, in Denmark, nearly 1/3 of all power is wind-generated, and nearly 1/5 of Portugal's electricity is wind generated.
One main problem with wind energy is the aesthetic value. Since windy areas are generally raised or elevated, the wind turbines are usually visible to people in the surrounding areas. Although considered eyesores, wind turbines cause no emissions or fuel consumption, and are compatible with other land uses such as agriculture. If all goes well in the next decade, by 2020 hopefully 10% of Earth's power can be wind-generated.