Renewable Energy sources – Pros & Cons

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What Is Climate Change?

Climate change refers to long-term shifts in temperatures and weather patterns. Since the 1800s, human activities have been the main driver of climate change, primarily due to burning fossil fuels like coal, oil and gas. Burning fossil fuels generates greenhouse gas emissions that act like a blanket wrapped around the Earth, trapping the sun's heat and raising atmospheric temperatures. Greenhouse gas emissions that are causing climate change include carbon dioxide and methane. These come from using gasoline for driving a car or coal for heating a building, for example. Deforestation can also release carbon dioxide. Landfills for garbage are a major source of methane emissions. Energy, industry, transport, buildings, agriculture and land use are among the main emitters.

Renewable Energy

Climate change causes the frequent occurrence of typhoons, flooding, rising ocean waters, melting of polar ice and many more. Governments around the world are creating programs to reduce if not reverse the effects of climate change. The use of renewable energies is one of the many advocacies.

Sunlight, wind, rain, tides, and geothermal heat are renewable energy sources. These are alternative energy sources to fossil fuels and nuclear power.

Renewable Energy Sources [1]
Energy Source Description Advantages Disadvantages
Biomass, biofuels and vegetable oil Biomass is biological material derived from living, or recently living organisms[2].Vegetable oil is safer to use and store than fossil fuels. Pure vegetable oil works in diesel engines but requires pre-heating. It can also be transesterified to make biodiesel, which burns like normal diesel. 1. Biomass can be produced by burning organic agricultural by-products.
2. Biomass is abundant.
3. Biomass are clean burning and has little effect on the environment.
4. Vegetable oil run engine has no net increase in CO2 emissions.
5. Biomass with geo-sequestration of CO2 could result in a net decrease of CO2 emissions.
6. Vegetable oil is safer to handle as it has a higher flash point[3].
7. Transition to vegetable oil is relatively with minor modifications.
8. Increased growth of biodiesel infrastructures.		 1. Combustion of any carbon-based fuel has similar effect on the environment as fossil fuels.
2. Competition with food production leading to reduction of food supply and increase in food prices.
3. Land use requirement is significant.
Geothermal energy Geothermal energy harnesses the heat energy from the earth. Water injected into the ground is heated by rocks produce steam. The steam isused to drive turbines coupled to electric generators. 1. Base load power.
2. Economically feasible.
3. Low deployment costs.
4. High capacity plants.
5. A geothermal power station produced energy is practically free less operating and maintenance costs.
6. A geothermal power stations are relatively small, and have a lesser impact on the environment than tidal or hydroelectric plants.
7. Geothermal energy does not affect the environment if managed correctly.		 1. Desulphuration is required prior to feeding the turbine and re-injecting the water back into the injection well.
2. Locations must have suitable subterranean temperatures within 5 km of surface.
3. Geothermal stations can created geological instability.
Hydroelectric energy Potential energy in water can be harnessed. The gravitational flow of a river can be used to turn turbines or water wheels, which drive amechanical mill or an electric generator. 1. Hydroelectric power stations can promptly increase to full capacity to coincide with peak demand.
2. Electricity can be generated constantly with sufficient water supply.
3. Hydroelectric power produces no primary waste or pollution.
4. Hydropower is a renewable resource.
5. Hydroelectricity assists in securing a country’s access to energy supplies.		 1. Dam construction have a serious environmental impact on the surrounding areas.
2. Hydroelectricity can only be produced with sufficient and continuing supply of water.
3. Water inundation from the dam can result in anaerobic decomposition releases methane, a greenhouse gas.
4. Dams can lead to catastrophic flooding.
5. Dams may have adverse effects on earth tectonic system.
6. Hydroelectric plants require long transmission lines.
Solar power Solar power involves using solar cells to convert sunlight into electricity, using sunlight hitting solar thermal panels. 1. Imparts no fuel costs.
2. A renewable resource.
3. Releases no water or air pollution.
4. Can be used in remote locations.
5. Can be used very efficiently for heating.
6. Can be installed in a relatively short time period.
7. Equipment cost has been steadily falling.
9. Localized point-of-use photovoltaic systems.
10. Photovoltaics are much more efficient compared to biofuels.		 1. Solar electricity is more expensive than grid electricity.
2. Not available at night and dependent on weather conditions.
3. Solar cells produce DC which must be converted to AC if connected to distribution grids.
4. The energy payback time—the time is dependent primarily on location.
Tidal power generation Tidal power can be extracted from moon-gravity-powered tides by locating a water turbine in a tidal current or by building impoundmentpond dams that admit-or-release water through a turbine. 1. Free once the dam is built.
2. Very reliable because it is easy to predict when high and low tides will occur.
3. Renewable because nothing is consumed in the rising of tides.		 1. Not currently economically feasible because of high initial cost.
2. May affect other industries using the water way.
3. May affect the aquatic ecosystems surrounding it.
4. Energy production is limited.
Wind power This type of energy harnesses the power of the wind. 1. Produces no pollution.
2. Does not generate greenhouse gases.
3. Renewable source of energy.
4. Can be set up at a remote setting.
5. Land occupied by wind turbines could still be used for agriculture.
6. Grid connected wind power will have backup power.
7. Siting costs are frequently low.		 1. Wind is unpredictable thus wind power is not predictably available.
2. Wind farms may be considered an eyesore or obstruction.
3. Wind farms may negatively affect bird migration patterns.
4. Windfarms may interfere with radar creating a hole in radar coverage and.
Reference:
[1] Advanced renewable energy systems - Part – I
Author: S. C. Bhatia
ISBN: 978-93-80308-43-2
[2] http://www.biomassenergycentre.org.uk/portal/page?_pageid=76,15049&_dad=portal
[3] flashpoint lowest liquid temperature at which under certain standardzied conditions, a liquid gives off vapors in a quantity such as to be capable of forming an ignitable vapor/air mixture (IEC 60079).
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