Presentation on theme: "Future Energy Sun, Wind and Hydrogen Sustainable energy production."— Presentation transcript:
Future Energy Sun, Wind and Hydrogen Sustainable energy production
Fossil fuels Fossil fuels Wind power Wind power Solar power Solar power Hydrogen Fuel cells Fuel cells Wind, straw and natural gas for transport Wind, straw and natural gas for transport
The most common fossil fuels are coal, oil and natural gas. They are made of plant residues from the forests which covered Earth 100 million years ago. Dead trees were compressed in the marshes. Under constantly growing pressure and heat the plant residues - containing a lot of carbon - have gradually developed into coal. Likewise residues of plankton at the sea bottom were transformed into oil and gas. These storages are nowadays drawn from the earth as coal, oil and gas to keep modern society going. Fossil fuels
The fossil fuels have been a carbon storage for millions of years. Now when they are being used during a few centuries more CO 2, sulphur, nitrogen and heavy metals, than the environment is able to absorb, are liberated. An unbalance in the ecosystem arises. The growth of CO 2 in the atmosphere may cause large climatic and geographical changes at the end of this century.
Only limited storages of fossil fuel exist. As things are now the predictions made say that we have oil for another 30 to 40 years, natural gas for about 60 years and coal for about 200 years to go. The less resources the higher the price. Today almost all transport use oil as fuel. Oil can be changed into diesel oil and petrol. Petrol can be replaced by hydrogen or ethanol.
Wind power in Denmark In Denmark about 20% of all the electricity consumed are produced by wind turbines. No other country in the world produces so much electricity from wind turbines. In the future this production will increase. Both because of smaller turbines ashore being replaced by larger turbines and because more turbines are being set up off shore. When the wind is good the turbines today are capable of producing about 65 % of the power consumption and in the future more than 100 %. If the wind is blowing and it is cold much more power than needed will be produced.
Usually the Danish power stations produce both electricity and heat. This offers the best exploitation of the fuel used for production of electricity.As a result of this the power stations cannot stop the production of electricity when it is cold. When turbines are running at the same time, too much power is produced. This surplus of power might be exported, but that is not always a satisfactory solution of the problem. Therefore new ways of storing power have to be found. A possibility is to convert power into hydrogen or to use it for the production of ethanol and methanol. These products can replace petrol.
Solenergi The energy we use on Earth comes from the Sun. Coal, oil and natural gas are stored solar energy. Both wind power and water power originate from the solar heating of Earth. The plants are growing because of solar energy. Solar energy is applicable for the heating of water and air in a solar unit. It is also applicable for power production in a solar cell. In Denmark the influx of light from the Sun is about 1,000 kwh/m 2 per year. I.e. in principle 4 or 5 m 2 of sunlight are enough to cover the power consumption of a Danish family if all solar energy in this area can be converted into power.
Photovoltaic cells About 20 years ago solar cells started to gain a larger ground. They are especially used in places without normal electricity supply. A lot of mountain huts in Norway are equipped with solar cells. In less developed countries (LDC) without power supply solar cells often get installed in order to produce power to the pumps pumping up fresh drinking water. I Several places in Denmark have attempted to use solar cells for the electricity supply. Because of the high initial cost the power production thus got 5 to 10 times higher than the usual way.
Solar energy The solar cells available on the market today are made of silicon. Silicon is an element found in beach sand. If you melt silicon and cool it quickly can make crystals. They can be cut into thin slices either for monocrystalline (black) or for polycrystalline (bluish) solar cells. The third type is called a thin film solar cell. This type is made by steaming a thin layer of silicon on a glass plate. The thin film solar cell is the least effective but the cheapest and will probably become the most widespread.
Photovoltaic cells – discovery and invention At the end of the eighteen nineties several scientists discovered that the element selenium becomes electric, when given light to. A few years later the American Charles Fritts built the worlds first solar cell. It was made of a metal sheet covered with a thin layer of selenium. The solar cell created a sensation in both the USA and in Europe. The scientists could not, however, explain the phenomenon. In 1905 Albert Einstein advanced his theory about the photoelectric power. Einstein described light as packets of energy (photons). In the nineteen twenties, using the atomic model of Bohr, the scientists could explain how photons, using enough energy, are capable of knocking electrons out of their regular ways in materials like selenium and silicon. If small thin lines are put into these materials the released electrons will start to walk through these as an electric current.
Hydrogen Hydrogen is the most frequent element of the Universe. It is a substantial component of water – H 2 O – and a lot of other chemical compounds. Hydrogen can be produced in a non- polluting way : 1) by electrolysis - splitting up water in hydrogen and oxygen. 2) in biogenic systems where algae and bacteria can produce hydrogen. Hydrogen is applicable for heating, the industry can use it as a raw material, it can be used in internal combustion engines (cars) and it can be used in the production of electricity by means of fuel cells. Zeppeliner filled with hydrogen. In the future hydrogen may become the connection between sustainable energy and consumption of energy for electricity, heating and transport.
The Hydrogen society
The fuel cell
Two thirds of the worlds consumption of oil are used for transport, and the consumption is fast increasing. The oil reserves are limited and the use of oil produces large emissions of CO 2 at the risk of an added greenhouse effect. Therefore a stable production of fuel for transport is of great importance. In Denmark the power company, Elsam, has developed a system using power from wind turbines and straw combined to natural gas in the production of fuel. From this process you get ethanol and methanol which eventually may replace petrol. Wind, straw and natural gas for transport