What are the different kinds of renewable energy?

What are the different kinds of renewable energy?

Renewable energy is energy that cannot run out – we get it from wind, the sun, water (hydro power), from biomass and from the earth. Wind, solar, hydro is all regarded as clean energy because no water or air pollution is generated during the process of creating energy.

WindEvery year, wind energy produces enough electricity to serve one million households. This is only a small amount of the electricity used and produced.

One reason wind plants don’t produce more electricity is that they can only run when the wind is blowing 22.5 km/h or more.

In most places with wind farms, the wind is only right for producing electricity about three-fourths of the time. That means most windmills run 18 hours out of 24.

Wind machines have some advantages over conventional power plants.

First, wind machines are clean. They don’t cause air or water pollution because no fuel is burned.

Second, we may run out of fossil fuels some day, but we won’t run out of wind.
On the economic front, there is a lot of good news for wind energy.

First, a wind plant is far less expensive to construct than a conventional energy plant. Wind plants can simply add wind machines as electricity demand increases.

Second, the cost of producing electricity from the wind has dropped dramatically in the last two decades. Electricity generated by the wind cost 30 cents per kWh in 1975, but now costs about four cents per kWh. New turbines are lowering the cost even more.

Solar energySolar energy is free and clean. There is enough for everyone, and we will never run out of it. Solar energy is obviously renewable. The sun will keep making energy for millions of years.

South Africa has one of the world's highest levels of solar radiation because we have so many days of sunlight.

In Europe, solar radiation averages at 910kWh/m2 per year.

In some areas of South Africa, solar radiation is more than double this amount at 1950 kWh/m2 per year. The lowest areas at 1450 kWh/m2 per year are still way above the European average.

In Europe, solar radiation is mostly used to heat water in households.So why don’t we use the sun for all our energy needs? We don’t know how to yet. The hard part is capturing the sunlight.

It shines all over the earth and only a little bit reaches any one place. On a cloudy day, most of the light never reaches the ground at all.

Today, solar energy provides only a tiny bit of the electricity we use. In the future, it could be a major source of energy. Scientists are looking for new ways to capture and use solar energy.

Western Cape government leads in renewable energy

Engineering News of July 25-31 2008 reports that the Western Cape provincial government has committed itself to source 15% of its energy from renewable sources by 2014.

It will install 1000 solar water heaters in Hassequa municipality near Riversdale and train 60 people to maintain them and is negotiating with national government to provide a further 100 000 solar water heaters across the province.

It is also considering introducing laws that will force developers to use renewable energy sources in future housing developments.Meanwhile a factory in Paarl is being converted to manufacture solar panels.

HydroThe water on earth will always be there. We won’t run out of it. So hydropower is a renewable energy source.

And hydropower is a clean source of energy as no fuel is burned. And moving water can be used to make electricity.

First, a dam is built across a river. This stops the water and makes a big lake behind the dam. This lake is called a reservoir. When the gates of the dam are opened, the water rushes out. Gravity pulls it.

The water flows down big tubes called penstocks and turns giant wheels, called turbines. The spinning turbines make electricity.The amount of electricity we get from hydropower depends on the amount of rainfall during the year.

Globally, hydropower is a significant energy source, producing about 25% of the world’s electricity. Hydropower is the cheapest way to generate electricity today.

No other energy source, renewable or non-renewable, can match it. Today, it costs about one cent per kWh to produce electricity at a typical hydro plant. In comparison, it costs coal plants about four cents per kWh and nuclear plants about two cents per kWh to generate electricity.

Producing electricity from hydropower is cheap because, once a dam has been built and the equipment installed, the energy source, flowing water, is free.

Tidal energy, wave energy and, in the future, ocean thermal energy conversion (the utilisation of the difference of temperature between the surface water and the deep water), also are sources of hydropower.

Bethlehem to get its own hydro power station

Hydro power will come to Bethlehem at Christmas says Engineering News of July 24 2008. NuPlanet, an energy development company, is building the power station at a cost of R77 million.

The project has received financing from the Dutch government together with a loan from the Development Bank of South Africa.

The project will use water from the Lesotho Highlands Water Project on the As River to drive two power stations and will then sell the electricity to the Dihlabeng Municipality.

These two power stations will "cut back the emission of 33 000 tons of carbon dioxide a year by displacing coal-fired electricity".

The project will receive about R1,8m each year for the sale of these 'carbon credits' to a European buyer. NuPlanet is also looking at building another three hydro power stations along the same river.

BiomassBiomass is anything that is alive. It is also anything that was alive a short time ago. Trees, crops, garbage and animal waste are all biomass. Most of the biomass we use for energy today is wood.

We burn wood to make heat. Biomass also can be used to make electricity. Many towns burn their garbage in waste-to-energy plants. Instead of putting the garbage in landfills, they burn it to make electricity.
It also can be used to make an energy-rich gas called biogas. Biogas is like the natural gas we use in stoves and furnaces. Last but not least, biomass can be turned into a fuel like gasoline.

The waste from producing sugar, maize and wheat can all be made into ethanol. Ethanol is a fuel a lot like gasoline. Ethanol is renewable and cleaner than gasoline. In many places, gasoline and ethanol are mixed together to make a fuel that any vehicle can use.

Geothermal energyGeothermal energy is heat inside the earth. The inside of the earth is very hot. Sometimes, this heat comes near the surface and we can use it to warm our houses or make electricity. It also heats the water underground and we can next use this heated water.

The hot water we use will be replaced by rain and the heat inside the earth will warm it. Consequently, geothermal energy is a renewable energy source.

It’s also a clean energy as no fuel is burned and the steam is turned into water and put back into the earth.Unfortunately South Africa has no geothermal energy it can use.

Renewable energy a job creator

According to research done by Agama Energy in 2003:* if South Africa generates just 15% of its total electricity in 2020 using renewable energy technology, it will create 36 400 new direct jobs, without taking any new jobs away from coal-based electricity.*

Over 1.2 million direct and indirect jobs would be generated if a portion of South Africa’s total energy needs, including fuels, used renewable energy technologies.

Another advantage with these jobs is that they will not necessarily be in the major cities (like the example of the hydro electric scheme in Bethlehem) nor will they all require specialist skills like nuclear power stations need.

For example less skilled workers can be employed to manufacture or to install solar panels, especially in rural areas where poverty and unemployment is very high.

Further research, they say, shows that if 1% of South Africa's needs "were met by wind energy within the next 10 years, that this would be a high enough target to stimulate 100% local production of inputs into the wind industry.

"However experience from other countries, especially Europe, shows that for renewable energy to be a success, government intervention is needed.

The benefits that government will reap are less carbon emissions, more employment and less overall cost to the economy.

Thanks to Earthlife Africa for supplying the article "What are the different kinds of renewable energy?" www.earthlife.org.za Find the complete article by Agama Energy on the Earthlife website.


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