A Greener Guide to Renewable Energy
Exploring viable, alternative power sources
13 May 2009
Everyone talks about “renewable” and “sustainable” energy but ever since we realised that
vast tracts of virgin rainforest were being cut down to feed the demand for palm oil and much needed food was being turned
into fuel, it became important to know where energy really comes from. Well first of all, it seems coal fired power stations
are just about the worst of everything, polluting, inefficient and with a worrying carbon footprint - but of course coal is
plentiful and cheap. So we need viable and realistic alternatives – but what are they? Here is our brief guide:
Energy from the sea and rivers
Tidal energy: this involves using the large movements of oceanic water to generate energy. This form of energy generation can be split into tidal flow, where turbines in barrages harness energy from the ebb and flow of water and tidal stream where turbines are mounted on the seabed to harness energy, similar to giant windmills – but underwater. Tidal flow barrages have been criticised by some conservationists because of damage to the ecology of wild plants and wildlife as they can radically change habitats. Wave power involves using the movement of waves on the surface of the sea to harness electricity using wave generators which sit on the surface of the sea, often looking like giant worms wriggling away. A new ‘sea snake’ made almost entirely from rubber tube ‘swims’ head on into waves to create power. Hydroelectricity: both on a commercial scale and on a micro scale energy can be produced by harnessing the power of rivers and falling water. With hydroelectricity turbines are used to create energy. There are issues concerning the building of dams and the destruction of environments and with fresh water being a finite resource with effects of climate change, fresh water supplies will be more precious, and some current hydroelectricity plants may find difficulties as water supplies dwindle.
Generation of electricity from the wind is now one of the fastest growing sources of renewable energy. Its not new – the wind has powered sailing boats, windmills and wind pumps for hundreds of years. Recently the EU Council of Ministers lent their support for a EU super grid in the North Sea to generate electricity. However there have been concerns about the negative impact of wind farms on the landscape, particularly in areas of outstanding natural beauty. Australia’s Bluesfest is committed to using wind power at future festivals as part of a sustainable energy programme.
Solar power converts sunlight into electricity or heat energy. Solar Photovoltaics (PV) use photovoltaic cells to convert daylight into energy - electricity. Solar thermal uses energy from the sun to create hot water to use in buildings and homes. New developments include solar heated ventilators which use the sun’s energy to circulate warmed air through buildings. Bumbershoot’s visual art exhibition was powered by solar energy and Lounge on the Farm has a solar powered cinema.
Biomass, biogas and bioliquids
These are terms for organic substances or gases derived form non-fossil animal or vegetable
matter – food and farm waste is one source. They are accepted as ‘carbon neutral’ as the carbon released
in the burning process is equal to that which is absorbed when the biomass is grown (for plants and vegetation). Waste can
be used in two ways – simply burnt to produce steam to drive turbines which generate electricity or waste can be sorted
and put into a bio-digester (anaerobic digester) which produces gas which can be used to generate electricity as well as producing
bio-diesel and fertiliser as by-products. Waste to energy is a growing business and the most common form of biomass
is wood which can be burnt in the form of logs, pellets or woodchip. At present the UK’s biogas industry is small but
estimates say that they offer a major opportunity for dealing with the millions of tonnes of organic waste produced each year
and green gas could provide an important future source of gas heating and can be used to generate electricity. Community waste
to energy project are a growth industry, not least as burning waste reduces landfill and there a growing pressure on landfill
which is currently taxed at £40 per tonne which will rise to £48 per tonne next year. A failure to meet 2013 landfill
targets could result in a £130 per tonne fine. Coupled with these landfill ‘sticks’ are the ‘carrot’
of Renewable Obligation Certificates (ROCs) which will make payments to encourage the development of new technologies and
apply to energy created fro, waste. Biofuels: Biofuels have caused a lot of soul searching and clearly the production
of biofuels has an impact on local agriculture, local food sources and the environment. At the moment all we can say is that
the only acceptable source of biofuel is “already used” cooking oils. Both Bumbershoot in the US and our own Bestival
make sure that their biofuels are sourced from waste cooking oils and grease, Live Nation sends waste oils from its Hyde Park
festivals for recycling – and Glastonbury has a fleet of bio-tractors running on used cooking oils.Ground source heat
Described as a ‘fridge in reverse’ taking heat from underground and releasing this into a building. Whilst an electric pump is needed to run the system it will provide a fourfold energy ‘return’ on the electricity used.
And remember, a starting point is often energy efficiency – and this can be done before or at the same time as looking for clean energy sources. Insulating buildings, promoting energy efficiency and reducing waste will all provide immediate financial returns and a reduction in greenhouse gas emissions.
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