It has been a dream for many to use solar energy for heating and hot tap water. So far, the only problem has been that it is expensive to install devices to catch solar energy. At individual buildings it is normally very expensive and therefore not yet a sustainable solution.
Fortunately, the solar heating industries and district heating companies in Denmark have developed concepts for large scale solar heating plants, which can produce hot water in a cost effective way. The larger the cheaper. Plants larger than 10.000 m2 can produce hot water up to 90 dgr. C at a price of 200 DKK/MWh. It is competitive with oil boilers without taxes and subsidies. From an energy efficiency point of view it is also interesting at it is the most efficient existing technology to catch the solar energy – even 100 times more efficient than the green plants.
In Denmark such a large scale plant can produce 500 kWh/m2/a or 5.000 MWh/a – in warmer climates it could be up to 10.000 MWh/a.
In combination with an ordinary thermal storage tank, the solar heating plant can provide the consumers with a uniform load of heat during the summer period and even contribute a bit in the winter period.
A precondition is that there is a heat demand to use all the available solar heating from such a large plant.
That could be an industry, which use process heat at temperatures below 90 dgr. C or it could be a district heating system.
In Denmark we have a district heating system in almost all urban areas. Therefore, this market is booming at the moment and we foresee that there will be installed up to 4 mio. m2 of panels in Denmark within the next 10 years. In combination with seasonal pit stoages, we may, according to prognosis from Heat Plan Denmark 2010, even expect up to 8 mio. m2 before 2030. Solar heating distributed via district heating from one end of the town to the other is probably one of the most obvious examples on the benefits of urbanisation.
In Asia and America we can see that there is a great interest from private industries, which on purely commercial conditions wants to save money and be greener.