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| Photovoltaic power - Sun energy |
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Sun energy in the form of solar heat and solar electricity is one of the fastest growing energy sectors. Sun energy consists both of energy from sun cells, so-called photovoltaic energy, and energy from solar heat that normally is generated via solar collectors. The global sun cell market has grown on average by 25% per year during the past ten years and by 35% per year during the past five years. Many sector analysts predict that the sun cell industry will grow by 20% per year until 2020. The market for solar heat is expected to double at least within 5-10 years according to Svensk Solenergi.
Background and technical development
Sun energy can be generated via sun cells or solar heat. A sun cell system generates electricity directly from sunlight through the use of sun cells. The method uses a process that takes place naturally in certain semiconductive material, for example, silicon. Energy from the sun releases electrons in the semiconductive material whereby an electronic current is created. Sun cell systems can be used in all from small systems such as pocket calculators, traffic signs and private housing systems to larger industrial systems.
Solar heat for heat production is a generic name for the technique that converts the radiant energy of the sun to heat. Solar heat must not be mixed up with sun cell technology for electricity production. Solar heat is normally generated using a solar collector as an energy collector. A solar heat installation can reduce energy needs for a normal house by approx. 2 000 – 6 000 kWh/year depending on the system and size of the solar collector. Solar heat is the least environmentally impacting heating alternative since in principle it does not produce any air emissions. On the other hand it must be supplemented during the winter half of the year. A solar heat installation that is combined with a bio-fuelled boiler offers a very good system from an environmental standpoint. The solar heat means that the boiler does not need to be fired during the summer, as it otherwise has a lower degree of efficiency on account of low heat consumption.
Some areas where sun energy is utilized directly in Sweden are:
• Grain drying
• Drying of wood-chips and peat
• Heating of swimming pools
• Heating of hot tap water during the summer half of the year
• Passive solar heat for heating of buildings
Sun energy in the world – support and objectives
Global
Sun electricity
The global sun cell market has grown by 25% on average per year during the past ten years and by 35% on average per year during the past five years. (Solar Energy Industries Association, SEIA). During 2004, 779 MW of new sun cell panels were installed across the world. The corresponding figure for 2005 amounted to 1,092 MW (EIA). Several sector analysts, e.g. Bank Sarasin and Solarbuzz, predict that the sector will display growth in installed sun cell panels of approx 20% per year until the year 2020 (Bank Sarasin, PV Market Development and Perspectives, 2006). According to sector analysts, the photovoltaic market will record sales of between USD 18.6 to 23.1 billion in 2010 (Bank Sarasin).
Germany, Japan and the US are the leaders within installation of sun cell systems and account for approx. 94% of the annual global installed capacity. Germany displayed growth of 315% measured in terms of annual newly installed sun cell capacity between 2003-2005. Japan experienced growth of 30% during the corresponding period while growth in the US amounted to 63%. During 2005, 1,092 MW of global sun cell capacity was installed. The total installed capacity amounted to approx. 3,697 MW at the end of 2005 (IEA).
The price of sun cell modules amounts to approx. SEK 34 per watt, which means that the total sun cell market amounted to approx. SEK 26 billion during 2004 and approx. SEK 37 billion during 2005.
Enhanced incentive structures in combination with falling costs are the principal explanations for the rapid development. The aim of the incentives is to raise production of sun cell systems in order to deliver greater efficiency and cost reductions within the sun cell industry. The price for electricity generated from sun cells has fallen by a couple of percent per year in recent years and has accordingly increased the cost efficient areas of use. A positive spiral has been created of falling costs and expanding market as a result.
The most frequent incentive systems within sun cells include:
• subsidies or deductions for investments in sun cell systems,
• ”net-metering” where the electricity meter rolls backwards for the electricity that is produced by sun cell systems,
• ”feed-in tariff ” which gives producers of renewable energy a guaranteed price for the energy they sell to the electricity grid.
• ”green certificate” where producers of renewable energy obtain certificates that consumers of other electricity must purchase.
Germany, Japan and the US which are the leading countries within installation and production of sun cell systems are also the countries that had the most ambitious incentive programmes. More initiatives are now coming from countries such as Spain, China, India, Italy, Portugal, South Korea and Thailand. Sector experts consider that the number of countries with incentive programmes will rise sharply going forward.
Solar heat
There were more than 100 million m2 of solar collectors installed globally at the end of 2002 (World Energy, Survey of Energy Resources). China accounts for approx.75% of the world market. Europe comes in second place. The market for unglazed solar collectors is largest in Australia with two million m2 in installed capacity. The US and Canada have approx. 15 million m2 in installed capacity. These markets are approx. 15-20 times larger than Europe’s market for unglazed solar collectors (World Energy, Survey of Energy Resources).
Sun electricity
In Sweden the total installed photovoltaic capacity amounted to 4.2 MW during 2005 according to IEA. The total installed Swedish capacity has increased by approx. 50% since the year 2000. The means that Sweden is one of the smaller production countries in Europe. Awareness of sun cell installations has increased however in Sweden and a number of sun cell installations have been constructed in recent years. The number of modules that were produced in Sweden is increasing. During 2005 the quantity of modules produced amounted to 38.5 MW, which constituted an increase of 50% from the previous year. The total value of the Swedish sun cell market amounted to SEK 244 million during 2005 (Swedish Energy Agency, National Survey Report of PV Power Applications in Sweden 2005).
Solar heat
Historically, solar heat has played a larger role than sun electricity in Sweden. Most Swedish solar heat systems are in small houses but compared to the rest of Europe, Sweden has relatively many large solar heat systems. The most common are planed solar collectors but vacuum valve solar collectors have also increased in smaller systems. Both types are included in the glazed solar collector class. Since solar heat subsidies were introduced in Sweden in 2000, sales of glazed solar collectors have increased in Sweden by 20% per year. The installation of glazed solar collectors has increased in Sweden from 11 MW in 2002 to 20 MW in 2006. According to Svensk Solenergi, sales are expected to increase to a corresponding degree over the coming years. At present, 50% of solar heat systems are installed with the assistance of subsidies. The solar heat subsidy remains in force during 2007 and is expected to be replaced by a similar subsidy during 2008. With an average cost for solar collectors and related equipment of SEK 6,000 per square metre of solar collector, (approx. 8,500 SEK/kWh) sales of approx. SEK 180 million were recorded in connection with solar heat installations during 2006. This figure included subsidies of approx. SEK 10 million.
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