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Renewable energy

Introduction:

As the exhaustion of fossil fuels and the environmental damage cause by the

pollutants produced, Some of energy sources are becoming popular: solar, wind,

hydroelectric, biomass and geothermal energy.

CATEGORIES OF ENERGY SOURCES: The energy sources have been split into

three categories: fossil fuels, renewable sources, and nuclear sources. The fossil

fuels covered here are coal, petroleum, and natural gas. The renewable energy

sources are solar, wind, hydroelectric, biomass, and geothermal power. Thenuclear-powered sources are fission and fusion.

Petroleum is the most commonly used energy source, supplying about 40%of the planet's energy. Petroleum is used to produce fuels, such as gasoline(petrol), diesel, and numerous fuels for heating. This rich energy source is

found in crude oil.

Coal is the next largest energy source used today. It is used mostly to createthe steam in boilers, so as to generate electricity or drive large machinery.

In many countries coal is still used as a source of heat. Even though coal isused widely across the globe, it does have a sizeable drawback, pollution.

Natural gas makes up about 21% of the total energy used world wide. Used inhouseholds and commercial buildings for cooking and heating, natural gasis extracted from the earth (like petroleum). Natural gas is the cleanestburning fossil fuel, as it is refined naturally during its formation within the

earth.

The supply of fossil fuels is being depleted at quite an alarming rate. Soon itmay be necessary to extract the oil from bituminous sands and oil shale.Bituminous sands are sands that have been covered with oil producing

substances. Rocks that can be processed to make crude oil, known as oil shale, mayalso be a substitution for other types of energy even if it may be more costly.

Hydro Power creates about 7% of the total energy used today.Hydropower, or water power, is the process of capturing the energy of 

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water that falls from a higher point to a lower point. The water turns large turbineswhich then create electrical energy. Hydropower creates no pollution of any kindand is the cleanest energy source we possess. The only major shortcoming of 

hydropower is the need for large and very expensive dams. 

Nuclear energy provides about 6% of today's energy used commercially.Nuclear fission is the process of splitting atomic nuclei of elements such as

plutonium and uranium. The advantage of nuclear fission, is that it produceshuge amounts of energy from small quantities of fuel. Today it powersmany naval vessels and other large ships. Nuclear energy also has some

quite formidable disadvantages. Nuclear fission produces many radioactive

wastes that stay harmful for many hundreds of years. Since nuclear power fuelsources are so unstable, any sort of accident would release toxic radiation into theenvironment. This tragedy was seen at the nuclear power plant in Chernobyl. 

Solar Energy is used widely across the globe. Unfortunately, as currently utilized,this source of energy fails to produce enough power with which to run towns or

buildings. It is used mainly on a household level. The sun's rays arecollected with flat-plate collectors mounted in an area with good directsunlight. The collectors convert that solar energy into heat energy.

Electricity is produced by solar, or photovoltaic cells, typically providing heatfor both living spaces and water. Solar power produces clean and virtuallyunlimited power, but it is not yet economically suitable as a major source of electricity for large scale energy needs. Solar power generation is limited by the

amount of sunlight available. Since it is adversely affected by bad weather anddarkness, it is most suited to regions with many long cloud-free days.

Wind power is another clean power source and is more widely used thansolar power. Electricity is generated by the wind turning the largepropellers of windmills. Wind power is a very efficient source of energy in

areas that are invariably windy.

Tidal energy is produced by water as it flows from high tide to low tide. As thewater rises, a dam closes in the bay. Then when the tide falls, the water isreleased and flows through a turbine generating energy. The onlydisadvantage with this system is that energy is only being produced when

water in the tide is falling.

Geothermal power is another clean alternative to fossil fuels. Steam power isproduced whenever water is channeled onto the incredibly hot rocks that lie

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beneath the surface of the earth. Power companies drill deep into the earth andgenerate energy with the steam that is given off. Geothermal energy is alreadybeing produced in some European and Asian countries, as well as in the UnitedStates.

Hydrogen will probably be a replacement for many fuels in the future. Itproduces large amounts of energy, and the only byproduct is water.Hydrogen at low temperatures can be stored in tanks, and is extremelylightweight. The Hydrogen atoms are removed from water by hydrolysis.

Unfortunately hydrolysis is a costly process, but perhaps with continued research itmay be realistic alternative to existing energy sources.

Magnetohydrodynamic (MHD) generators are a futuristic answer to the

energy crisis. MHDs convert fuel directly into electricity by burning a fuel athigh temperatures, producing ionized gasses. These gasses can be pushedthrough a magnetic field creating electricity. These generators still have to berefined before they can be widely accepted.

biomass (wood, wastes, dry crop wastes and aquatic plants) contribute about10%..Biomass is simply the conversion of stored energy in plants into energy thatwe can use. Thus, burning wood is a method of producing biomass energy.

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Renewable statistics 2010

Hydro installed power GW

1-china 200(23%)

2-canada 90(62%)

3-brazil 70(85%)

4-usa 80(6%)

5-russia 45(18%)

6-norway 30(98%)

Wind-2010 total = 195 GW (it doubles every 3 years)

1-china 45

2-usa 40

3-germany 28 production 2

4-spain 21 15-india 13

6-uk 5 3

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Levelised energy cost (LEC, also commonly abbreviated as LCOE) is the price atwhich electricity must be generated from a specific source to break even. It is aneconomic assessment of the cost of the energy-generating system including all thecosts over its lifetime: initial investment, operations and maintenance, cost of fuel,cost of capital, and is very useful in calculating the costs of generation fromdifferent sources.

It can be defined in a single formula as:

where

  LEC = Average lifetime levelised electricity generation cost   I t  = Investment expenditures in the year t   M t  = Operations and maintenance expenditures in the year t  F t  = Fuel expenditures in the year t   E t  = Electricity generation in the year t  r = Discount rate  n = Life of the system

Typically LECs are calculated over 20 to 40 year lifetimes, and are given in the

units of currency per kilowatt-hour, for example EUR/kWh or per megawatt-hour, for example usd/MWh

System boundaries

When comparing LECs for alternative systems, it is very important to define theboundaries of the system and the costs that are included in it. For example, shouldtransmissions lines and distribution systems be included in the cost? tax, andenvironmental impact studies? the costs of impacts on public health andenvironmental damage? the costs of government subsidies?

Discount rate

Another key issue is the decision about the value of the discount rate r . The valuethat is chosen for r can often 'weigh' the decision towards one option or another.The discount rate depends on the cost of capital, including the balance betweendebt-financing and equity-financing, and an assessment of the financial risk. 

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US Department of Energy estimates

The tables below list the estimated cost of electricity by source for plants enteringservice in 2016. The tables are from a December 16, 2010 report of the EnergyInformation Administration (EIA) of the U.S. Department of Energy (DOE) called"Levelized Cost of New Generation Resources in the Annual Energy Outlook 2011"

  Total System Levelized Cost (the rightmost column) gives the dollar costper megawatt-hour that must be charged over time in order to pay for thetotal cost. Divide by 1000 to get the cost per kilowatt-hour (move thedecimal point 3 places to the left).

These calculations reflect an adjustment to account for the high level of carbon

dioxide produced by coal plants. From the EIA report:

a 3-percentage point increase in the cost of capital is added when evaluating

investments in greenhouse gas (GHG) intensive technologies like coal-fired

power and coal-to-liquids (CTL) plants without carbon control and

sequestration (CCS). While the 3-percentage point adjustment is somewhat

arbitrary, in levelized cost terms its impact is similar to that of a $15 per

metric ton of carbon dioxide (CO2) emissions fee. As a result, the levelized

capital costs of coal-fired plants without CCS are higher than would

otherwise be expected."

No tax credits or incentives are incorporated in the tables. From the EIA report(emphasis added):

"Levelized cost represents the present value of the total cost of building and

operating a generating plant over an assumed financial life and duty cycle,

converted to equal annual payments and expressed in terms of real dollars to

remove the impact of inflation. Levelized cost reflects overnight capital

cost, fuel cost, fixed and variable O&M cost, financing costs, and anassumed utilization rate for each plant type. The availability of various

incentives including state or federal tax credits can also impact the

calculation of levelized cost. The values shown in the tables below do not

incorporate any such incentives. 

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