As of 2015, there are two types of solar energy collection in common use. The first type of solar power uses photovoltaic cells to create energy by collecting light from the sun. The second type of solar energy focuses the light from a large area onto one point to boil a liquid.
Photovoltaic cells use specially treated semiconductor wafers that have positive and negative sides. The light hitting the wafer knocks electrons loose from the semiconductor. Conductors that have been hooked up to the cell transmit the electric current to an end point, such as a battery or a light. The amount of current produced by each cell depends on the amount of light that strikes the cell. These photovoltaic cells produce only a small amount of electricity, but they can be wired together to form modules. Modules can then be wired together to form arrays.
Concentrated solar energy involves the use of mirrors to gather sunlight and refocus the light from a wide area onto a small point. The focus point may be for each individual mirror or for the entire array. Both curved and flat mirrors are used in this application. The sunlight is focused to boil liquids, which turns a steam-powered turbine that produces electricity.Learn More
Threats to savannas include mining, hunting and poaching. Wind-farm development is another major threat to the savannas as it destroys natural resources.Full Answer >
Scrap paper prices in the United States in 2014 varied from $30 to $110 per megaton, according to Scrapmonster. The amount of money a person receives from recycling paper varies depending on the quantity, the type of paper and the market. These factors can determine how much paper is worth.Full Answer >
According to the Natural Resources Defense Council, renewable energy comes from either sources that cannot be depleted or from sources that can replenish themselves on a human time scale. The former category includes wind, solar, geothermal and hydroelectric power, and an example of the latter is biofuel.Full Answer >
Solutions to prevent depletion of the ozone layer involve banning the use of chemicals that cause ozone depletion, such as chlorofluorocarbons and hydrofluorocarbons. National laws and international treaties help accelerate the control of ozone-depleting substances.Full Answer >