Energy shortage – what energy shortage? In just ten minutes, the Earth receives as much radiant energy from the sun as its entire population uses in a year. Yet at the same time we are struggling with a chronic energy crisis, with constantly increasing use of fossil fuels and increasing emissions of greenhouse gases. We are not far off Peak Oil – i.e. the point of maximum production of crude oil, after which production will start to fall off, causing energy prices to increase dramatically unless something is done.
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The energy that we do use must be used more efficiently, and we must make greater use of new sources of energy. This is where solar energy comes into the picture. Today, it meets only 0,2 % of the world’s energy requirements for heating and cooling: a proportion that must be increased if we are to overcome the global energy crisis. Scientists point out that there is a potential for solar energy to be supplying half the world’s energy requirements in 50 years’ time. However, it’s important that we should start now, making increasing direct use of the sun as an energy source. If we can raise today’s percentage of 0,2 % of our energy supplied by solar energy to 5 %, we shall save 1 500 000 000 tonnes of CO2 emissions every year.
In Sweden, the solar energy sector has suggested a planning target of 8 TWh of solar energy by 2020 to the Government. 4 TWh of solar electricity is sufficient to supply
800 000 detached houses with their domestic electricity requirements. A further 4 TWh can be provided in the form of solar heating, equivalent to the heat demand of a town the size of Göteborg.
There are two solar energy areas that are particularly interesting. The first is that of solar cells for electricity production. Althoug the technology is already available on the market today, it is hardly commercially viable as a source of large scale electricity production. However, extensive research is in progress, and we can expect higher efficiencies and lower production costs in the years to come.
The second area, which is already commercially viable, is that of thermal solar energy, i.e. for the production of heating and cooling by means of solar collectors. Thermal solar energy systems deliver far more energy than do electricity producing solar cells.
The future energy cost of thermal solar energy is forecast as about 30–70 öre/kWh, which means that is already a viable investment. In addition, solar energy produces the least CO2 emissions of any form of energy technology during its life cycle.
Thermal solar energy systems are robust, proven and work perfectly well even in Nordic conditions. Provided that those dealing with them know what they are doing, design, calculations and installation are essentially simple. If a solar energy system is to operate properly, it is vital that it has been correctly designed, that it has an appropriate capacity and that it is installed as intended. Unfortunately, there are at present too many consultants and installation contractors who are unaware of all the aspects, leading to the installation of poor quality systems and dissatisfied customers. This is one of the reasons why thermal solar energy has not properly taken off as a real and efficient form of energy for heating and cooling.
However, there are also countless examples of professionally designed and installed systems that perform excellently and which have delivered ‘free energy’ for over 30 years without problems. These are systems that have been designed and installed correctly from the start, and it is from them that we have collected knowledge, experience and advice that are published in this guide to thermal solar energy, with support from the country’s leading solar energy experts. Its target group of readers are professional users such as town planners, property owners, architects, technical facilities managers, consultants and installation contractors.
We see this guide as contributing to practical knowledge to provide real support for the use of thermal solar energy as the basic energy supply of the future.
Stockholm, February 2010
Klas Ståhl, Managing Director, S Solar
Robert Sundqvist, Research and Development Manager, S Solar
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