There are a number of advantages combined with use of a building surface for production of electricity by photovoltaic modules (PV), which can be supplied to the electricity supply network that is already installed in the building. Then the produced solar electricity is first used directly in the building and a possible excess of electricity can be supplied to the electricity supply system. In Denmark it has as a support to PV been agreed to accept netmetering so one can use an electricity meter, which can go both ways so the electricity consumer will get the maximum benefit of using PV-modules.

In connection with new building and rehabilitation projects considerable savings can be obtained, both as regards materials and installation, by integration of PV-modules in the ordinary fašade or roof surfaces on a building. If a standard building integrated PV-system is installed it can in some case be possible to obtain a lower price of installed PV-modules than the price of only the PV-modules, as the possible savings of fašade or roof surfaces can be considerable.

By using building integrated PV-modules it is also easier to utilise a combined production of electricity and heat from the PV-modules, which can increase the total utilisation of the incident solar energy to building integrated PV-modules. The electricity production from the PV-modules can in several cases be increased because they are cooled, e.g. by preheating of ventilation air in connection with a solar wall or solar roof with built-in PV-modules.

PV-modules can on a long view also operate together with natural gas fired local combined heat and power systems on a beneficial way for the society. The heat demand during the summer is not very large and it sets a limit for a combined heat and power production in this period. Electricity production by PV-modules increases the local electricity production, without producing heat that one cannot utilise. Electricity from PV-modules does not compete with utilisation of solar heating for hot water in the summer.

As to use of building integrated PV-modules, the experiences from completed projects have both shown examples of very expensive solutions and in some cases solutions that did not cost extra because they are building integrated. It will here be the aim to develop PV solutions at a much lower price than the present and thus it is a great challenge to develop integration designs of PV-modules for roofs and facades on buildings, which result in very small additional expenses.

It is therefore an obvious possibility to stake on a close cooperation between producers of PV-modules, PV specialists and producers of building elements. This is also one of the aims of the Danish Energy Agency's demonstration and research programme for building integrated PV-modules. At the same time it is necessary to focus much on the hybrid use of PV-modules to secure that a market for building integrated PV-modules is created as soon as possible on a normal economic basis.

As an example, the following describes experiences from the Danish companies Cenergia and SolarVent as regards use of PV-modules for preheating of ventilation air and use of PV-modules for direct operation of ventilation systems. But e.g. also use of PV-modules for direct operation of lighting systems or PV-modules as part of daylight solutions or sunlight protection designs are interesting to work with.