1. Energy Sustainable World summarized by Stanka Samokovska

2. 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.

3. 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.

4. 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.

5. 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.

6. 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.

7. 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.

8. 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.

9. 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.

10. 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 time- consuming. 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.

11. 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.

12. 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.

13. 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.

14. References Bowden, Rob Sustainable World: Energy, Hodder Wayland, 2004 www.waylinks.co.uk/series/susworld/energy