Environmental Sciences Essay 代写:Uses Benefits And Negatives Of Renewable Energy

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It is used to describe a source of power or energy that has the strength to reload itself over and over again. As it relies on energy that is in infinite supply, the renewable energy can sometimes be called infinite energy.

Finite energy sources are identified as non-renewable energy sources, as they mainly rely on supplies and reserves of which there is a fixed quantity. However because of its advantages, as it does not produce such toxins that are harmful for the environment it is also considered as the clean energy.

Solar Energy is the most basic and direct form of renewable energy because it will exist for as long as the sun, which should be over 4 billion years. As once the sun burns out, we will have much larger problems than energy. Depending on the type of platform used, sunlight is converted directly into electricity or heat. If we see the from the world analysis in 2006, around 18% of global final energy came from renewable while the 13% came from the traditional biomass for example the wood burning. Hydroelectricity is also one of the largest renewable sources. It is providing 3% following solar hot water & heating contributing 1.3%.However the present technologies like the wind power, ocean energy, solar power etc together provide around 0.8% of final energy consumption.

Wind energy is another type of solar power. The wind is created when the sun heats up different areas of the surface of the earth at different rates. It has the direct relationship with the heat as when heat raises so does the air. Air above a hot surface will rise and colder air from surrounding areas will rush into to fill the annulled. This procedure induced temperature movement creates wind in its most basic form.

Some renewable energy technologies are being criticized for being intermittent or unsightly still the market is growing for many forms of renewable energy. The increasing government support with Climate change concerns coupled with high oil prices, peak oil are driving increasing renewable energy legislation, incentives and commercialization

Types of Renewable Energy

The following are the main types of renewable energy resources.


Hydropower energy is the largest source of renewable energy.  It is a renewable, nonpolluting, and reliable energy source which comes from the natural flow of water. This source of energy can provide almost 10% of the nation's electricity.  The power is usually harnessed by taking advantage of the gravity as when the water falls from one level to another and this falling water is converted into the mechanical energy. Converting flowing water into usable energy produces hydropower as per refer to figure1 (a). As mentioned before this hydropower does not release pollution but it do possesses some pros and cons like it can harm fishes, displace people from the quality of water that is produced. One disadvantage of small hydropower generators is their reliance on rain and melting snow to fill the reservoirs however which might be high for some countries where the temperature usually remains high all the time. The other concerns include the high cost of construction

However the steps are being taken for the improvement of this. And it is improving considerably.

Wind Energy

Wind turbines can be used as stand-alone applications, or they can be connected to a utility power grid or even combined with a photovoltaic (solar cell) system. Wind energy alone can produce about 2,500 megawatts of energy, and thus can generate merely 0.1% of our electricity.  The wind rotates blades around a hub; it acts much like an airplane wing. The blade is connected to the main shaft, which spins a generator.  The amount of energy needed is usually determined by the size of turbine. Winds with small turbines are usually appropriate for farms ranches and homes. The other ways to use wind energy, includes the pumping of water and grinding grain.

Wind energy also possesses some disadvantages. Firstly again the technology is very expensive beside this it creates noise and as it is dependent on natural wind which might not be present certain times, even not throughout the year.

Biomass Energy

Biomass is also one type of renewable energy source, the energy it contains comes directly from the sun. It has the same process as in the process of photosynthesis, in which the chlorophyll in plants captures the sun's energy through the conversion of carbon dioxide from the air and water by the ground into carbohydrates. The complex compounds are composed of carbon, hydrogen, and oxygen. As shown in the figure 3(a).

However when these carbohydrates are burned, they are turned back into the carbon dioxide and water, releasing the sun's energy they contain. In this way, biomass functions as a sort of natural battery for storing solar energy. This procedure can also be applied in battery and cells etc. in them through this procedure as long as biomass is produced sustainably the energy it will consume can last in the battery indefinitely.

With the development of new technology more efficient and cleaner ways are being developed to use biomass. Through the advances of recent years it can also be converted into liquid fuels for example there are certain crops like switch grass and willow trees are especially suited as energy crops (figure 3(b)).

Geothermal Energy

Geothermal renewable energy is the heat from the earth. It is the type of energy that uses the natural power contained in the Earth so that to provide useful energy when converted to electricity for people. It's clean and sustainable.

Geothermal energy resources ranges from the low ground to hot water and the hot rock that are found few miles beneath the earth's surface, and even lower/deeper of molten rock where the temperature is really high, basically known as magma.

A geothermal heat pump system consists of a heat pump, an air delivery system and a heat exchanger a system of pipes buried in the shallow ground near the building. In the winter, the heat pump removes heat from the heat exchanger and pumps it into the indoor air delivery system. However in the summer, the process is reversed. In it the heat pump moves heat from the indoor air into the heat exchanger. Its pumps can tap into this resource in order to heat and cool buildings. The heat removed from the indoor air during the summer can also be used to provide a free source of hot water.

Solar energy

It is the energy from the sun. It uses the sun's energy and light to provide heat, hot water and electricity. Often provides cooling service for homes, businesses, and industry. There are a variety of technologies that have been developed to take advantage of solar energy such as:

Passive solar: this type of energy involves designing and orientating buildings for light and heat to use the energy of the sun as efficiently as possible.

Solar water heating: It involves growing solar water heating panels, usually on the roof that actually absorb the sun's heat. It typically provides around 50 to70% of domestic hot water which is needed over a year.

Photovoltaic solar energy: this type of solar energy contains the conversion of the sun energy into electricity through the use of photovoltaic cells.

Ocean Energy

The ocean produces two types of energy:

thermal energy from the sun's heat and

Mechanical energy from the tides and waves.

As everyone knows oceans cover more than 70% of Earth's surface, making the world's largest solar collectors. The heat coming from the sun's the surface water more than the deep ocean water, and temperature creates thermal energy.

Ocean thermal energy is used for many applications such as electricity generation. The three main types of electricity conversion systems are closed-cycle, open-cycle, and hybrid. Closed-cycle systems use the ocean's warm surface water to evaporate a working fluid which has a low-boiling point which then expands and turns to a turbine. The turbine then activates a generator to produce electricity. The open-cycle systems boil the seawater at low pressures. This produces steam that passes through a turbine generally the generator. The hybrid system is the combination of both the closed-cycle and open-cycle systems.

On the other hand the ocean mechanical energy is different from ocean thermal energy. The tides are driven primarily by the gravitational pull of the moon and waves are driven primarily by the winds.

Green Power

It is electricity consumed from the resources such as wind, biomass, and geothermal, solar and low-impact hydro facilities. As much as the availability of green power will increase, it will enable electricity customers to accelerate installation of renewable energy technologies. The development of green power sources displacing conventional generation will impacts the overall environmental associated with electricity generation that will be significantly reduced. Conventional electricity generation, based on the combustion of fossil fuels, is the nation's single largest industrial source of air pollution.

Comparison of Old Houses with New Houses

Old House

If we compare the options we have in new house as compare to old house. Solar Hot water collector on South Facing roofs will supply an amount of hot water or at a temperature say about 22°C will reduce the amount of carbon produced.

According to my opinion the householder should sign up to companies which generate electricity using large scale wind generation exactly about 90m Wind Turbines. The energy which is generated is at the coast and is sold to electricity companies. The house holds using green generated energy are given certificates. Yet the cost will be the same for electricity but it is from a renewable source. Small scale wind generation does not work and causes more problems than it solves.

Taking the budget in mind, it is possible to fit a ground source heat pump but still it is not cheap. We should check the budget whichever suits us best as a renewable energy and can choose that.

It should be pointed out to the householder that they need to insulate the loft about to 600mm in depth, keeping the full fill cavity wall insulation in mind. These will both improve the air tightness of the building and will reduce the need for energy generation which in itself is sustainable. Suggest they fit double or triple glazing if possible.

But, Photovoltaic (PV) Cells on the South Facing roofs to provide electricity to be fed into the electricity grid this will give the house owner some revenue back from the electricity supplier.

New House

Same as for the Old house, the PV panels can now look like roof tiles and can cover the entire roof.

Keeping the design of the house in mind, the sun can be used to heat up the building by warming the slab which is made up from a black material. It absorbs heat and releases the heat through the night when it naturally cools. This procedure is known as Thermal Mass Heating.

A ground source heat pump can be recommended which can be either vertical or horizontal in the garden, if the garden is big enough. This will give the householder 11 to 15°C for heating purposes. Air Source Heat pumps can also be recommended, which are almost the same but the air to generate and ambient temperature can also be used to differentiate.

The overall formatting can also with the size of windows. Such as windows which are on the north and East Elevations of side should be small and non opening and the ones which are on the west and south elevations should be bigger to let the sun light in.

All of these options are useful for the client to choose for the new house.

Comparison of the Houses

The comparisons of old house with new house have clearly mentioned the differences. However much of it is the same but as illustrated above the renewable energies which are needed to install in old houses are quite expensive. Similarly in old house the installation things are more which will increase the owner cost but will give more benefit at the end of the day.

The new house has more options as we can build anything according to our perception. Taking example of the old house it is on inclined position from the backyard which will result in fewer options to install renewable energies over there. Yet to fix that up more cost can be applied but on the other hand the new house is free from these charges. No charges will be needed to fix it up, we can build in way we want and can also install any type of renewable energies which can suit us best, which would also be economical.

Taking the appliance's costs and payback period in mind because if does not result in a manner we want and gives a late pay back there is no use of spending such a big amount. To be on a save side it is better to calculate every possible solution for its payback because anything we use whatever we do should be in great depth so that to keep the costs low and payback periods should be thoroughly examined. As in last it will be for our benefit.

Before installing any renewable energy appliance or system, we should first look at the structure of the house as per solid wall installation and loft installation is required. This will help the heat being lost around the house and help prevent condensation on the wall and ceilings. It is one of a way to reduce the heating bills and to reduce the carbon dioxide emission.

As the working life for wind turbines are approximately around nineteen to twenty one year's, it can be used in multiple ways to a building. The batteries can also been used, as it has the life of almost 7 to 8 years usually depends on the environment conditions of the country. It is good of taking the suggestion of the installer when installing the appliances.

Taking the planning permission is a part of installation of the appliances. As in UK there are some legal technicalities that do not have the right to cover some of the new renewable systems. But, people still are trying to negotiate to get the approval of those appliances as per to make their life f house much easier