Physical Science : Five Forms of Green Energy


Hi, I’m Steve Jones and I’m going to tell you about the five forms of green energy. First of all these types of energy have not all been around for the same length of time. Geothermal energy has been there since the earth began, basically it’s under ground, it’s in the hot rocks below ground. And these hot rocks may be as much as a kilometer down. These hot rocks can be fractured by exploding dynamite or something like that, we can then pump water down and pump the water back up, and when it comes back up it’s hot. So this is geothermal energy. The most important one today is biomass, biomass is plants. Plants of course get their energy from the sun using the chlorophyll, the green substance in the leaves. So biomass absorbs energy from the sun, and we can reuse that energy by turning it into biodiesel for example, and biodiesel can replace the fuel produced from oil and therefore conserve oil. Hydro. Hydro energy is energy actually also from the sun.

Because rivers are created by the sun the water evaporates due to the suns energy, it then precipitates into rain and falls into the rivers, we build dams, put it in turbines and we end up with electric power. The fourth type, wind. Wind energy we all know that near the coast due to the changing temperature of the sea and the land there is always wind formed, particularly at the coast, and those winds can drive wind turbines. These are large propellers on a tall tower and they at the top of the tower also have turbines, and turbines produce electricity. The final type is solar energy, this is a more modern type thing, it’s based on silicone technology. When we shine light onto a piece of silicone chip it actually produces a small electric current, if you put enough of them together you get a lot of energy. This is quite an expensive form of reusable energy and therefore, initially solar energy is very expensive. And it tends to be in devices which have to be carried around, like on your calculator you only need a small amount of energy.

So those are the five green forms of energy..