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Vladimirskiy State University named after the Stoletov brothers

Renewable energy sources

Kaloyanov A.S., prof. Fedulenkova T.N.

Vladimir, Russia

As part of the implementation of energy conservation and energy efficiency policies, the introduction and use of renewable energy resources in the housing and communal services sector is one of the promising areas.

Renewable energy is energy that is collected from renewable resources, which are naturally replenished on a human timescale, such as sunlight, wind, rain, tides, waves, and geothermal heat. Renewable energy often provides energy in four important areas: electricity generation, air and water heating/cooling, transportation, and rural (off-grid) energy services.

Renewables contributed 19.2% to humans' global energy consumption and 23.7% to their generation of electricity in 2014 and 2015, respectively.

Wind energy. This is one of the energy sources that have been in use for a very long time and for centuries. It was used in powering sailing ships, which made it possible for explorers to sail around their trade routes in distant lands. A single windmill can power the crop irrigation, and the family energy needs, water pumping and electric lights. It does not cause any air pollution and have created several jobs in last few decades. Advancement in technologies has brought down the cost of setting up wind power plant. Wind energy can only be used in areas which experience high winds which mean that it cannot be used as a source to extract energy anywhere on earth. They sometimes create noise disturbances and cannot be used near residential areas. These disadvantages have made the use of wind energy to particular regions only.

Solar energy. Solar is the first energy source in the world. It was in use much earlier before humans even learn how to light a fire. Many living things are dependent on solar energy from plants, aquatic life and the animals. The solar is mostly used in generating light and heat. Solar energy is one the alternative energy source that is used most widely across the globe. About 70% of the sunlight gets reflected back into the space and we have only 30% of sunlight to meet up our energy demands. While solar energy is used for producing solar energy, it is also used for drying clothes, used by plants during the process of photosynthesis.

Solar energy can be extracted either by Solar Thermal or using Photovoltaic (PV) Cells. This method converts the sun's energy into electricity. Photovoltaic cells are most popular form of converting solar energy into electricity. These cells are silicon based pieces of materials that absorb the sun's light. When the sunlight enters the cells, it causes the electrons to move. These electrons move in a certain direction which is known as current. This electricity is in the form of direct current.

PV module anatomy is shown in Figure 1.

Figure 1- PV module anatomy

Solar energy is available throughout the world and in many parts of the world it is possible to capture that energy and use it to meet up our growing demands. The main benefit of solar energy is that it doesn't cause any or little pollution, is a free energy source and is available in abundant quantity.

Geothermal energy. `Geo' means Earth and `thermal' means energy. Geothermal energy means energy drawn or harnessed from beneath the earth. It is completely clean and renewable. Geothermal energy has been in used since last several years. The earth contains a molten rock called magma. Heat is continuously produced from there. The temperature increases about 3 degrees Celsius, for every 100 meters you go below ground. Below, 10,000 meters the temperature is so high, that it can be used to boil water. Water makes its way deep inside the earth and hot rock boils that water. The boiling water then produces steam which is captured by geothermal heat pumps. The steam turns the turbines which in turn activates generators. Geothermal heat pumps structure is shown in Figure 2.

Figure 2- Geothermal heat pumps structure

Geothermal energy can be found anywhere on the earth. Most countries tap this energy to generate electricity, using thermal mass flowmeters, and power millions of homes. The areas which have high underground temperatures are the ones which are the ones which are prone to earthquakes and volcanoes. Geothermal energy produces no pollution, reduces our alliance on fossil fuels. It also results in significant cost savings as no fuel is required to harness energy from beneath the earth. These advantages make geothermal energy as one the best alternative energy source. But, geothermal has its downsides too. It is suitable to particular region and cannot be harnessed everywhere.

Hydroelectric energy. Solar energy is produced by sun and wind energy is produced by moving of winds. The heat caused by sun drives the wind. The movement of winds is then captured by wind turbines. Both wind and sun cause water to evaporate. The water vapor then turns into rain or snow and flows down to sea or oceans through rivers or streams. The energy of the moving water can then be captured and called as hydroelectric power.

Hydroelectric power stations capture the kinetic energy of moving water and give mechanical energy to turbines. The moving turbines then convert mechanical energy into electrical energy through generators. Dams around the world have been built for this purpose only. Hydropower is the largest producer of alternative energy in the world. There are different types of hydropower plants. The selection of hydropower plant depends on many volume and flow of water. Hydropower is renewable, constant, predictable and controllable source of energy.

Biomass energy. This is the process by which an alternative energy is generated through conversion of biological materials and wastes into forms that can be used as energy sources for heating, power generation and transportation. Those carbon based substances or materials converted over a long period of time to fossil fuels are not regarded as biomass. However, in their original state they are regarded as biomass. This is because of the separation of the carbon they previously contained from the carbon cycle. This makes them figure differently affecting carbon dioxide levels in air.

Biomass energy has been around since ancient times when people use to burn wood or coal to heat their homes or prepare food. Wood still remains the most common source to produce biomass energy. Apart from wood, the other products that are used to create biomass energy include crops, plants, landfills, municipal and industrial waste, trees and agricultural waste. It does not create any greenhouse gases and is can be easily extracted through the process of combustion. Another advantage of biomass is that it helps to reduce landfills. But biomass is comparatively ineffective as compared to fossil fuels. They release methane gases which can be harmful to the environment.

Ocean energy. Due to massive size of oceans, this energy can be used on much wider scale than other alternative sources of energy. The waves produced by the ocean and tides that hit the sea shore has enormous potential in them. If they are harnessed with full capacity they can go a long way in reducing world's energy problems. There are 3 ways i.e. Tidal energy, Wave energy and Ocean thermal energy conversion (OTEC) via which ocean energy can be harnessed.

Tidal power basically involves using kinetic energy from the incoming and outgoing tides. The difference in high tides and low tides are also important in this respect. There is a lot of energy that can be harnessed from waves for use. It is another form of hydropower. The rise and fall of ocean tides are captured by tidal energy generators which turn turbines. The movement of turbines is responsible for producing electricity. energy renewable communal efficiency

These are some of the alternative energy sources that can be taken into consideration when planning your energy production and usage. You can harness any of these and you will satisfy your power needs.

References

1. Robin Tennant-Wood, Following the Sun, - ANU E Press,2012

2. Robert Ferry, Elizabeth Monoian, A Field Guide to Renewable Energy Technologies, - Society for Cultural Exchange, 2012

3. S. M. Muyeen, Wind Power, - InTech, 2010

4. B Viswanathan, An Introduction to Energy Sources, - Indian Institute of Technology, 2006

5. Ralph Nansen, Sun Power: The Global Solution for the Coming Energy Crisis, - Ocean Press, 1995

6. https://www.conserve-energy-future.com/alternativeenergysources.php

7. Gary L. Johnson, Wind Energy Systems, - Kansas State University, 2006

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