It is often underestimated the amount energy which can be harnessed from the sun’s radiation. In the UK, we receive a vast amount of solar energy. In an average year we receive as much as 60% of the solar energy which is received on the equator. In other words, this can be compared to the yearly output of 1,000 power stations. It is often argued that solar technologies can only be used within the summer months, this is untrue. In fact, the UK has a large number of clear spring, autumn and winter days, where the Sun’s radiation can be harnessed, meaning that solar technologies can contribute to energy consumption for the whole year.
Figure 1 shows the total average solar irradiation falling on a one square metre surface on the horizontal, measured in kilo-watt hours (kwh). This shows that the sun’s rays falling on the ground range from > 1200 kwh m2 in the far south west of the UK, to < 900 kwh m2 in central and northern Scotland.
By tilting a surface to an angle the amount of solar radiation falling on it will be greater than that falling on a flat surface, in this country. Fortunately, the average tilt of a UK house roof is about the optimum for receiving solar energy.
By using the Sun’s abundant energy, we can reduce our consumption of conventional fuels thus reducing our emission of harmful greenhouse gases, as well as gaining enhanced fuel and energy security and making cost effective savings.
Today there is a range of high quality products, which enable us to use the Sun’s energy very effectively in the UK.
There are three broad technology categories for harnessing the Sun’s energy:
The UK, and the members of the Solar Trade Association, have a large expertise and a range of high quality products in each of these technology areas. The choice of which technology to use depends on the application. Passive solar design is only feasible on newly built properties, where all three of these technologies can be integrated to reduce carbon emissions. When deciding between using PV and active solar heating on existing properties, it is dependant on the type of application and what is wanted to be achieved. For example to provide a contribution to heat and hot water in an existing home, Active Solar Heating is usually the most practical and cost effective solution, however if the outcome is to reduce electricity demand from the grid, then PV is the best solution.
House builders are increasingly using integrated Solar Thermal and PV products such as solar tiles and collectors as building materials in their own right. For new housing developments, both Solar Thermal and PV are practical and cost-effective low carbon renewable energy solutions. PV can be used cost-effectively for commercial cladding and office building facades where it displaces conventional prestige products and is becoming increasingly popular in domestic properties. Solar Thermal systems are also increasingly being used in commercial and industrial situations as well as the traditional domestic market.