They’re called building-integrated photovoltaic panels and they produce more electricity and are predicted to get even better
Solar photovoltaic panels are becoming ubiquitous across the UK. Cast your eyes skywards and you’ll see the predominantly deep, blue-and-silver-veined panels winking back at you (assuming the sun’s shining) from an ever-increasing number of residential and commercial buildings’ rooftops.
The government’s feed-in-tariff has largely driven the uptake. Such has been the level of interest in the tariffs that investor-backed companies, such as WTG Commercial, offer free solar PV panels, free electricity, installation and system maintenance to businesses and residents.
Traditional solar PV panels (also known as cells) are roof-mounted. The ones most commonly seen are fixed, rigid units. As such, they are generally inflexible for use as a facade or cladding material on curved or shaped buildings. Enter the next generation of solar PV: building integrated PV (BIPV), also known as building-applied PV (BAPV).
The new panels are increasingly being used to replace conventional building materials on roofs, skylights or facades. They are progressively being incorporated into the construction of new buildings as a principal or ancillary source of electrical power. Existing buildings also may be retrofitted with such panels.
A primary advantage of the new panels over the old is that the initial cost can be offset (by reducing the amount spent on building materials and labour that would normally be used to construct the part of the building that the BIPV modules replace).
Architect Richard Hywel Evans of Studio RHE in London is excited by the creative and commercial opportunities the new panels bring. “Architects are able to skillfully integrate panels into building design – and, excitingly, we might even see a new type of ‘PV graffiti’ emerging as owners seek to minimise energy costs and maximise the available feed-in tariff.
“The PV choice now includes surfaces that can be seen to create energy or can be disguised with a coated, undetectable cladding system. The new PV panels are able to be made film thick and can be easily adhered to roofing membranes, which allows not only simple retro-fitting but also the future ability to turn almost any correctly oriented surface into a power-generating resource.”
Studio RHE has wrapped the south and western facades in solar PV “bands” in its design for Silvertree, a 24-storey residential tower in London’s Royal Docks. The effect is an angled banding that creates a constant brise soleil to the apartments, providing passive thermal benefits. The tower has planning permission and construction will commence in September 2012.
Built examples utilising the BIPV system in England are the CIS Tower in Manchester, and two buildings at the School of the Built Environment, University of Nottingham. One of the systems is installed on an educational building: it consists of a thin film PV facade appropriate for commercial or office suites.
The second University of Nottingham system is installed on a detached house, and uses crystalline PV roof slates, appropriate for domestic buildings. In the US, the APS Factory in Fairfield, California, and the Intercultural Center, Georgetown University in Washington, DC, have been constructed using BAPV.
Globally, Pike Research, a USfirm of analysts, has estimated demand for solar panels, shingles and modules will surge to almost 2.4 GW (about 7% of the overall market) by 2016. That’s approximately $4bn (£2.5bn) by 2016 – and potentially up to $6bn under ideal conditions – from a start of about $740m in 2009.
Key drivers include: the falling cost per kilowatt in real terms as well as those reductions stimulated by the feed-in tariffs; continued efficiency improvements – plus 10-20% and further incremental efficiency improvements are likely to continue until 2016; risk mitigation against price increases through self-generation; training and upskilling of labour will make installation easier and cheaper.
Not least, improved aesthetics – solar tiles and shingles that blend into rooftops and crystalline silicon (c-Si) solar panels in various shapes, sizes, colours, transparencies, and patterns that appear to blend seamlessly into a building’s structure – will play a significant role in the migration to BIPV from fixed solar PV.
In future, it seems, as you look skywards you’ll no more be able to discern at a glance if a building’s roof tiles or façade are electricity generators or not; increasingly, the likelihood is they will be – from a green, renewable source.