Building-integrated PV: Its time has come

The use of building-integrated photovoltaic (BIPV) systems has been around for a long time (16 years since the first commercial-scale system installed in the UK). However, innovation of new products within this market has been slow to gather pace. This is set to change as the effects of increasing revenues for UK solar PV firms from the feed-in tariff passes down into the UK solar PV R&D market.

So what are building-integrated PV systems? BIPV can be considered as solar PV elements that actually replace sections of buildings, meaning they are not simply solar panels stuck on roofs (which can be described as building-applied PV, or BAPV). There is a variety of forms of BIPV, such as building facades, PV tiles, PV glazing, PV shingles and so on. Solar Century, for example, has just announced it will begin selling PV slates for buildings.

The use of BIPV instead of BAPV is certainly one that should be considered for all new-build homes, especially in regions of high solar insolation (for example, the southern parts of the UK). The use of BIPV instead of conventional building materials has a number of advantages, including the fact that it replaces the cost of the materials that otherwise would have been needed. Although the PV elements would be more expensive upfront, in the long-run, the income from the feed-in tariff would ensure that the short-term investment would be worthwhile. It also means that PV systems can be integrated in a less visible form, without disrupting the architectural aspect of buildings.

There are some disadvantages to BIPV, however. Once installed, for example, it can be difficult to access. Say a problem arises with a solar PV tile installation: taking apart your roof to fix things isn’t an easy task, especially when everything is electrically live while the sun is out.

BIPV also requires extra planning and care when installing to make sure the system is both water-tight and wired correctly.

The fact that Solar Century has launched its new C21e solar PV slate shows the UK BIPV market is now growing – mainly thanks to the introduction of the feed-in tariff last April. The high number of buildings with specific forms of roofing materials — 4 million UK homes use slate roofing, for instance — offers a great opportunity to integrate solar PV discreetly, without disturbing the aesthetics of the building.

Solar Century has already seen success with its C21e Tile system due to the simplicity of installation attracting major house builders. The same can be expected for its slate system.

There are many installations in the UK and around the world where BIPV has been used in the design of some spectacular buildings, with the PV element as an architectural highlight. In fact, with the rise of corporate social responsibility, many firms are now looking to improve their “green” image, and one of the ways to do this is by installing BIPV on their offices. This sends a clear message that the company cares about lowering carbon emissions and also helps employees feel they are working within a cleaner, greener environment.

Looking ahead, the number of buildings with both applied and integrated photovoltaics systems is set to continue rapidly increasing in the UK with the support of the feed-in tariff. The review on the FIT announced by the government is not likely to affect domestic-size installations and so it can still be regarded as a safe bet. The coming years should also see an increasing output of innovation from companies such as Solar Century and various universities and research centres, as they look to lower costs in line with the annual tariff reductions of the FIT.

The question is, can the UK be a world leader in solar PV technology, seeing as it is so far behind Germany? Maybe the answer to that is to focus on specific research elements, such as BIPV, or to focus on future technologies such as multi-bandgap thin-film solar cells. More on that possibility soon …