How does green energy work, and what are the different types of green energy. Our blog answers these questions and more.
What is green energy?
This is fairly simple to answer, green energy is a form of energy that is generated from natural resources, such as wind, water or the sun's rays. The terms green energy and renewable energy are often used interchangeably, and they are almost the same, however there is some debate around this, for example, hydropower is energy which is generated from fast flowing water, but there is industrialisation and deforestation involved in creating these hydro dams, so can this really be called a green energy?
Fossil fuels including oil and natural gas are non-renewable sources of energy. These are formed when prehistoric animals and plants died and were over long periods of time buried beneath layers of rock. So technically these are created from natural resources but they are classed as non-renewable as they take millions of years to form, and we are using them up quicker than new ones are being generated. It is estimated that if we continued using fossil fuels at our current rate then they would be completely depleted by the year 2060. Of course, due to climate change, globally we are trying to start the switch to renewable energy much before then.
To put it simply, renewable or green energy is a form of energy that is naturally available, and we can use it repeatedly, without ever running out of it. Green energy is also much better for the environment, although some green energy does cause some emissions, the difference between that and how much fossil fuels emit is huge. The minimum emissions coming from certain renewable energy sources would not be enough to cause environmental issues, such as pollution, global warming and climate change.
How does green energy work?
There are many types of green and renewable energy, so we will take a look at a few of them and see how they work.
Wind power
Wind power comes from wind turbines, and it uses the power of the wind to create electricity. You normally see wind turbines together in a group in what are called wind farms.
The wind, even a simple breeze will make the blades turn and create kinetic energy. The rotating motion will turn a shaft in the nacelle, which is the name of a box at the top of the turbine. There is a generator inside the nacelle which will convert the kinetic energy into electrical energy. This energy will then be passed through a transformer which will ramp up the voltage so it can be transported or even used on site.
There are estimated to be nearly 11,000 wind turbines in the UK, which produce enough power to meet the annual electricity demands of around 12 million homes.
Solar Power
The amount of sunlight that hits the Earth in an hour is enough to handle the entire population's energy consumption for a whole year, so this is a very powerful and useful form of energy to harness.
Photovoltaic cells are used in solar panels and when the sun hits the panel, the energy from the sunlight is absorbed by the PV cells. This creates an electric current which is then captured by the wiring in the solar panels.
Solar panels even work on a cloudy day, as long as there is some sunlight to work with, they will do their job. Although how much electricity is generated can depend on how much sunlight they are getting, and the quality and size of the solar panel itself.
Hydro Electricity
The way this works is very similar to wind energy, except it is the flow of water that is turning a turbine rather than wind. There are a few different types hydro power;
Dams - This is the most common type of hydro power, where dams will control the flow of water to drive the turbines.
Tidal Power - This is used with the predictable movement of the tides. You can generate a lot of power twice a day doing this.
Rivers - This method is simply using the natural flow of water flowing downstream.
Geothermal Energy
Geothermal power plants use steam to create electricity. This steam comes from a few miles below the Earth’s surface in hot water reservoirs. Again the steam is used to power a turbine which then activates a generator. There are three types of geothermal energy power plants;
Flash Steam - This is the most common type of geothermal power plant. Extremely hot water flows through wells in the ground, and as it flows upwards some of the water will transform into steam. This steam is then used to power the turbines, and any excess water is put back into the ground, making this method sustainable.
Dry Steam - This uses natural underground resources of steam, using the same method. For an example of where the natural sources are, there are only two known locations in the United States where a dry steam power plant can operate, and that is The Geysers in California, and a Geyser in Yellowstone Park.
Binary Steam - This is the most modern type of geothermal power plant and it can operate with lower temperatures of water.
Biomass Energy
Biomass energy is generated from living or once-living organisms, such as plants and animals. Some of the most common biomass materials are corn, soy, wood and waste. Biomass materials can be burned and the chemical energy stored inside is released as heat, and this can be converted into electricity or fuels. The main element of biomass is photosynthesis, as plants have carbon dioxide stored in them, and some animals eat these plants and some of that energy is transferred. During the biomass production, the carbon dioxide and water is released back into the atmosphere, and this is used to grow more crops and plants so the cycle can start again. This is why biomass energy is technically renewable.