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The potential hydro power that can be harnessed in the world is in excess of 14,000 TWh. The EU directive on promotion of electricity production from renewable energy sources and electricity certificates has meant that interest in improving existing power plants and reactivating those previously closed down has increased. Just in Sweden, Vattenfall, E.ON and Fortum plan to invest approx. SEK 2 billion annually in their hydro plants over the next ten years.
Background and technical development
Hydro power exploits the energy in falling and flowing water. Hydro power can be used directly, like mechanical power. This was common before, for example in mills that ground corn between stones that were rotated by the water. Nowadays the ordinary energy is converted to electricity, by the water driving a turbine connected to a generator.
Hydro power in the world – support and objectives
Global
The annual global hydro power electricity production amounts to approx. 715,000 MW which accounts for 19% of the total world electricity production. The potential to harness hydro power in the world exceeds 14,000 TWh. Hydro power production was developed significantly in North America and Europe until the 1980’s. Extensive development of hydro power is now taking place in Latin America and Asia. The world’s largest producers of hydro power include Canada, China and Brazil. In Europe and North America about 50% of the hydro power potential has been exploited. In South America and Asia, approx. 15% is exploited and only 4% in Africa. A large proportion of the electricity production of Norway, Sweden and Canada comes from hydro power. The exploitation is mainly limited on environmental grounds, since the construction of hydro power plants involves considerable interference with the landscape.
EU
Large and small-scale hydro power plants constituted 10% of the EU’s total electricity production during 2005. The production varies considerably however according to the weather. The capacity of small-scale hydro power plants has increased by 3.8 % on average within the EU during the past four years. The development has been limited on account of exploited potential and high administrative obstacles to securing environmental permits. Several of the new member states such as Slovenia and Poland have however displayed higher growth of up to 8% (the EU Commission).
Sweden
At present, hydro power in Sweden generates 64.5 TWh on average which corresponds to approx. 45% of the country’s total electricity production. In 2005, Sweden had 2,082 hydro power plants, 511 of which were larger than 1.5 MW. The combined capacity of Sweden’s hydro power plants amounts to 16,200 MW. The rivers that produce most energy are Luleälven, which accounts for 15.9 TWh and Ångermanälven, which accounts for 13.6 TWh.
Small-scale hydro power in Sweden is defined as hydro power plants with a capacity of not more than 1,500 kW. The definition differs between different countries. The EU Commission has set the limit at 10 MW. In Sweden there are approx. 1,500 small-scale hydro power plants that produce 1.7 TWh per year combined. There are more than 2,000 closed down power plants all over Sweden that are awaiting their renaissance. Most small hydro power plants are in Västergötland, Småland and Värmland where by tradition, there has been a lot of agriculture, small industries and mills. Most of the sites there for small-scale hydro power have also been exploited, but it is also there where the majority of the closed down plants are situated. Technically speaking, it would be possible and economically feasible to raise hydro power related electricity production by approx. 30% (24 TWh). At present it is not possible due to environmental considerations. By means of environmentally compatible development it should be possible to add approx.10 TWh of new hydro power in Sweden. According to a study of the Swedish National Energy Agency, additional production of approx. 430 GWh is planned by the year 2010. Of this, approx. 50 GWh are new small-scale plants and the reminder consists of upgrades to large-scale plants.
Wave energy
Wave energy is a relatively unexplored form of renewable energy that however has great potential. The development is advancing and certain wave power plants that are built today have a capacity of 30 MW which can generate the electricity for approx. 20,000 homes. There are many advantages associated with wave power plants. It is very easy to predict the movements of the seas waves; wave power has a long operating time and does not leave any environmental traces either.
Background and technical development
The potential of wave energy is estimated globally to amount to between 10 000 – 15 000 TWh per year which is not so far from the potential of the planet’s total hydro power. The World Energy Council estimated in 2001 that 10% of the planet’s electricity needs could be met by wave power over time.
Example of wave power techniques
The wave power techniques that exist today around the world can be divided into three categories; wave propagation, oscillating water column and overtopping. These can in turn be divided into shoreline stationed, nearshore and offshore stationed wave power plants.
A system can consist of a linear generator that hangs in a floating buoy. The movements then drive a generator. Another type of wave power plant is that developed by the Scottish company Ocean Power Delivery Ltd. Pelamis is an underwater system consisting of cylindrical sections of steel that are joined by hinges. At each intersection there is also a hydraulic pump that pumps up oil through hydraulic engines under high pressure. These engines drive generators in order to produce electricity.
There are several advantages associated with wave power plants. They are largely invisible since the construction takes place under the expanse of water. Wave power also has very long operating times as waves tend to be durable. In the longer perspective, wave power has greater potential than wind and sun energy. Wave power contains e.g. 1000 times more energy than wind power and only requires 1/200 of the land area that wind power demands.
Wave energy in the world – support and objectives
Global
The installed quantity of wave energy in the world is still limited. The UK is the country with the most developed wave energy with a capacity of 15 MW. The UK is a leader on account of its geographical position since the wind direction from the Atlantic is very favourable along the UK’s coast. Other countries with large capacities are Spain and Portugal but also Denmark, Norway, China, Japan, the US Australia and India are currently extending their wave power plants.
EU
In January 2005, a new support system was established for wave and tidal water power plants in the UK amounting to GBP 45 million. The first large-scale wave and tidal water power plants should contribute electricity to the power system within three years. The support shall benefit the UK’s position as a world leader within the wave and tidal water industry for installations of plants around the coasts. The EU Commission has partly financed three major demonstration projects (OWC) of which two are in Scotland and one is on the island Pico in the Azores.
Sweden
Wave power has been relatively limited in Sweden but certain projects are under development. The Swedish National Energy Agency is involved and is financing a project in Lysekil. The trial is being carried out in collaboration with Uppsala University and Vattenfall who are one of the main sponsors. The project has been successful and even some hours after the launch, it started to supply electricity in to the gauging station on Gullholmen. The technique used in the project is adapted in order to extract energy from relatively small wave heights in the Baltic Sea and the seas to the West of Sweden. Ten generators will now be built in the coming years which shall be situated at Islandsberg, which is located outside Lysekil and Fiskebäckskil. Each generator has a capacity of 10 kW and when fully developed the plant is estimated to generate annual electricity corresponding to the electricity needs of 20 houses on the nearby located Gullholmen.
Tidal water energy
Tidal water energy has great potential. Partly on account that the quantity of energy that can be produced via tidal water is very considerable and partly on account that it is easy to plan and forecast the extracted energy. The potential of energy that is extracted through tidal water is dependent on the force of the water, the volume of water and the acceleration that is created by the gravity of the earth.
Tide water energy in the world – support and objectives
Global
There has been a tidal water plant at La Rance in Northern France since 1966 that today has a capacity of 240 MW. Their annual electricity production amounts to approx. 640,000 MWh. The conditions for tidal water energy are best in countries such as the UK, France, Eastern Canada, the Pacific coasts of Russia, Korea, China, Mexico and Chile. Other places identified as favourable are Argentina, Western Australia and Western India.
EU
The UK has set a far-reaching goal of introducing large-scale energy production from tidal water flows in order to reduce carbon dioxide emissions. The costs for tidal water power are still high. The technology exists however and the positive results in La Rance for example pave the way for other sites to apply the technology. In the longer perspective, sites like Pentland Firth in Northern Scotland, with a potential to achieve a capacity of 16 GW, will become more and more strategically important in the development of similar tidal water plants.
Sweden
Since Sweden has very little tidal water, the conditions are not sufficiently favourable in order for energy extraction from tidal water plants to be economic.
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