In these days of increasing environmental concern, governments and the scientific community work to maximise the use of renewable energy resources. There is growing recognition of the valuable role solar power can play in reducing pollution - particularly in the battle to stabilise carbon dioxide levels. The technology is now available for the industrial, commercial and residential consumer.

As the only renewable energy source that can be widely deployed in towns and cities, Building Integrated Photovoltaics can make a unique contribution towards a better environment. Grid-connected PV systems offer the opportunity to generate significant quantities of high-grade energy near the consumption point, avoiding transmission and distribution losses. These systems operate in parallel with existing electricity grids, allowing exchange of electricity to and from the grid.

Building integration adds some advantages to grid connected PV systems. The most important is the cost displacement gained by integrating PV materials into the fabric of buildings, especially into commercial buildings with expensive cladding. It could as well give some extra-economical motivations to people to invest in this new technology. Building integrated systems are expected to be the first cost effective application of Grid Connected PV in the developed world and will become a small, but important source of electricity generation in the next century. The world market for grid-connected photovoltaic systems is growing rapidly. Two main applications are evolving:

RPV: Residential PV for the domestic sector (1-5 kWp).

BIPV: Building Integrated PV for the commercial and industrial sector (10-250 kWp).

Much work has been done all over the world in the last decades to identify and solve the potential problems associated with these dispersed power generation systems. In the last years, several European countries as well as the USA, Japan and developing countries, are making an important effort to explore and exploit the possibilities of Photovoltaics in the electricity supply network. However, the UK has not been very actively involved in these activities and lacks experience in the area. Research on building integration is still in a very early stage, the PV Industry does not have experience in grid connected applications, and the utilities are not prepared, neither regulations are.

Our first objective has been to carry out a general analysis of the economics and the environmental impact of such systems in the UK. In a second stage, we have tried to find ways to optimise Grid Connected PV systems for the UK, and look at problems that could arise for grid connection. We have done an extensive review of the experience in other countries and tried to carry out some specific analysis for the UK.

We have found there is scope for improvement and system optimisation in the UK, and the most important problems arise when grid connection has to be undertaken. Lack of experience, regulation and standardisation make things difficult for developers and utilities. This is one of the first issues that have to be properly addressed in order to make grid connected applications possible. Research specific for the UK in areas like system design optimisation, building integration and power quality are necessary as well, but can not be experimentally developed if the regulatory framework is not clearly established.