Transcript Energy

Energy
Sustainable World
summarized by Stanka Samokovska
Non-renewable energy sources
• We use energy every day; from powering our vehicles and
factories to heating and lighting our homes, schools and offices.
These needs are met mainly by stores of energy, such as coal
and oil, which were built up over millions of years.
• Today we are using these stores very rapidly, much
faster than they can be replaced or renewed. These sources of
energy are also very polluting and are known to contribute to
climate changes. They are non-renewable energy sources,
becoming harder to find and more expensive to use.
Alternative ways
• There are alternative ways to provide energy, without further
harming the environment.
• These alternatives are known as sustainable energy, or
renewable sources, and their use is growing rapidly as people
become aware of the dangers of ignoring the energy problem.
• These sources include wind, water, sunshine, biomass energy.
The power of water
• As water falls it releases energy that can be captured and used to
generate electricity. This is known as hydro electric power and is a
clean and renewable form of energy.
• It normally involves the construction of large dams across river
valleys and the creation of an artificial reservoir behind them. The
water is then released through turbines that spin to generate
electricity.
Kyoto’s Protocol
• In 1992, world leaders met in Rio de Janeiro, Brazil, for the
Earth Summit. Climate change was high on their agenda and 160
nations signed an agreement to tackle the issue.
• At a follow-up meeting in Kyoto, Japan, in 1997, targets were
set to reduce emissions of greenhouse gases by 5.2 per cent
below their 1990 levels by 2012.
• Attention since Kyoto has focused on CO2 emissions from the
burning of fossil fuels and many countries are now following a
new direction towards a future built on sustainable energy.
Wind energy
• The winds that circulate around the world are an inexhaustible
supply of energy. Wind energy is captured using turbines that
stand alone, or are arranged in clusters known as wind farms.
• Wind energy is a clean and renewable form of energy and many
countries are now actively placing wind at the centre of their
sustainable energy policies.
• Denmark, Germany, France and the UK are among the European
countries currently developing offshore wind farms.
Solar energy I
• Solar energy is still a relatively expensive form of energy, but as
solar technology improves and demand for sustainable energy
increases it is becoming cheaper. Between 1980 and 2000 the
price of photovoltaic cells fell by 83 per cent.
• The production of solar PV cells also increased over six-fold
between 1990 and 2000. PV cells convert solar energy into
electricity and are used in a wide variety of ways.
• Small PV cells are used to power wristwatches or calculators.
• PV cells are a particularly useful form of sustainable energy as
they can be installed wherever there is sunlight.
• This means they are often the cheapest form of electricity for
areas that are not connected to an electrical grid.
Solar energy II
• PV cells also work in more cloudy countries – they do not need
direct sunlight. In Norway, PV systems provide electricity for
over 50,000 rural homes and their use is growing annually.
• In 1998 Germany announced a scheme to promote solar energy
by installing PV systems on 100,000 rooftops.
• A similar scheme in Japan proved a great success following its
introduction in 1997. By 2000, almost 52,000 Japanese homes
had had PV systems installed.
Geothermal Energy
• It is found in regions with volcanic activity. It is a clean and
sustainable source. This energy is due to the intense heat at
the center of the earth (over 4, 900°C) which is found much
closer to the surface.
• The heat rises through vents in the earth. This water can be
extracted to provide “geothermal” energy.
• The geothermal energy can be used to provide direct heat by
piping the heated water around homes, offices and factories.
E.g. Iceland, Reykjavik-giant district heating system. It meets
the needs of almost 150,000 people. Others: the USA, New
Zealand, etc.
• The superheated water, steam can be used to drive generators
and produce electricity.
Biomass Energy + Biogas
• 1/3 of the world’s population burn the biomass directly to obtain
heat and some light. It is sustainable but on the other hand
produces limited amounts of energy, it’s collection is timeconsuming.
• Biomass consists of wood, agricultural waste, waste from paper
production, waste (bagasse) from sugar mills.
• Biomass also generates electricity. It furnaces heat water and
produce steam for turning electricity generators.
• By burning biomass in a chamber starved of oxygen, it can be
turned into biogas.
• As biogas it can be used like natural gas for heating or
generating electricity.
Making sustainable energy work
• Awareness of the consequences of continued dependence on
fossil fuels.
• Information about the sustainable energy options.
• Is the cost of the sustainable energy too expensive?
• In Europe, electricity produced from coal costs around € 0.034
per kilowatt hour.
• Electricity from wind energy costs € 0.071 per kWh.
• Electricity from solar energy costs € 0.66 per kWh.
• In calculating the real price of energy we should include the
external costs that using an energy source has on the
environment, human health, the economy.
Making sustainable energy work II
• In the UK, for example, an average wind farm will repay the
energy used in its construction within five month.
• Over its lifetime, each wind turbine will produce around 30 times
more energy than was used to make it.
• Coal and nuclear power stations produce only a 1/3 of the energy
used to build and run them.
Subsidies for sustainability
• The Japanese government has been subsidizing the installation
of PV systems since 1994. It pays around 1/3 of the cost of
installation.
• The German government provides a 10 year interest free loan to
those who install solar systems.
• In the USA, a reduction in the amount of tax credit on the
production of wind energy was responsible for the rapid growth
of US wind power in the late 1990s.
• In India various subsidies have helped its sustainable energy
programme become one of the biggest in the world.
References
• Bowden, Rob Sustainable World: Energy, Hodder Wayland, 2004
• www.waylinks.co.uk/series/susworld/energy