Solar success

Materials World magazine
3 Sep 2015

Khai Trung Le speaks to Professor Phil Jones, Cardiff University, and Professor Stuart Irvine, Glyndwˆr University, about the carbon-positive home, unveiled on the eve of the abolition of the UK Government zero-carbon homes scheme.

Eco-houses are nothing exceptional. Ranging from newbuilds to retrofits across social housing to stately homesteads, development to ensure our housing is increasingly green has been an ongoing process, from hobbyists bolting solar panels to roofs to large-scale construction firms. However, Cardiff University’s carbon-positive house sounds like an implausible dream. Powered by photovoltaic (PV) cells able to provide more energy back into the grid than it consumes over the winter, it was constructed at equivalent cost to social housing using off-the-shelf technology locally sourced, and completed weeks before the Government scraped the zero-carbon homes scheme. But the house, part of the SOLCER project, a grouping of six Welsh universities investigating all aspects of the low carbon agenda, has managed to achieve this in a remarkably straightforward fashion.

Technologically unassuming, the Solcer house features two main sources of renewable energy – a PV roof and a transpired solar air collector (TSC) on the face of the house – and a modest 7kW of lithium-ion battery to provide electricity during downtime on solar charging. However, the house accommodates an array of discreet innovation.

‘I think the house has given people an understanding of what a sustainable house is. Because without seeing something tangible, it's so different to imagine the concept of zero carbon. It is not an easy one,’ said Professor Phil Jones, Chair of Architectural Science, Cardiff University and the Low Carbon Research Institute. ‘We’ve had hundreds of emails since its completion, all positive and all asking the same question – “Why can’t we have one?”’

System first

While development and affordability of renewable energy sources has progressed considerably over the last decade, Jones attributed the success of the Solcer house to a unique approach to the technology – a systems-led design that amalgamated architectural design and environmental capabilities from the beginning, rather than bolting the technology around the confines of a standard home.

‘When you bring a component into a system, it often doesn’t function as you think. It doesn’t give the best performance, often due to the user relationship. What we thought was a good plan was to bring these components together and optimise them on a systems level – technology and architecture, each optimised from the back level,’ said Jones.

One example is how heating for rooms is provided – starting with passing external air through the south-facing TSC, through to a mechanical ventilation heat recovery unit (MVHR), that is delivered into the air. Exhaust air is subsequently passed through the MVHR to an exhaust air heat pump, which heats the water store. Energy for these systems is provided via PV and the battery storage system, and SOLCER claims that the predicted energy performance enables a 1.75 grid export-to-import energy ratio. This design ethos also scales down to simpler decisions, including making the roof of the house out of PV panels, allowing the loft space to be lit with natural light and removing the cost associated with bolting solar panels onto a standard roof.

Although the Solcer house is comprised of off-the-shelf, locally sourced components, Professor Stuart Irvine, Director of the Centre for Solar Energy Research at Glyndwˆr University, hastened to emphasise the innovative technology employed. ‘Some of the technology didn’t exist five or 10 years ago. For example, what we’ve got is a new generation of batteries coming along, driven on the back of the scale and work surrounding electric vehicles. As a result, the Solcer house uses lithium-ion batteries for storage, as opposed to a few years ago when we were retrofitting houses with lead acid batteries and keeping them in a container outside.’

Allowable solutions

Unsurprisingly, reception from the public, press and academic peers has been uniformly positive, and Jones has been fielding enquiries for single-storey versions to educational institutions. But the Solcer house has thus far failed to reach out to two primary groups – housebuilders and Westminster.

On 10 July 2015, the Government announced the scrapping of the zero-carbon Allowable Solutions scheme, a plan to make all new UK homes carbon neutral from 2016. A Department for Communities and Local Government (DCLG) spokesperson said, ‘The Government is not proceeding with the zero-carbon buildings policy and instead is giving developers the time they need to build energy efficient homes as required by recent changes to building regulations brought in during the last parliament.’ DCLG has stated that continuing the scheme would ‘place a significant regulatory burden on housebuilders and developers’, and ‘allowable solutions would count as a tax on developers and has no benefit to the home buyer’.

The axing of the scheme, first announced in 2006 by then-Chancellor Gordon Brown, came just six days before the unveiling of the Solcer house, and Irvine expressed his disappointment at the noncommittal reception from the Government.

‘I was hoping that the Government would see this as technologically achievable and affordable, and therefore reason to go ahead with the zero-carbon policy. The only reason for abandoning the target is if it would impose too much cost on new house building, which the Government is keen on encouraging. They are reluctant about imposing a presumably stricter building code that would then make it more difficult to build houses, but the Solcer house has demonstrated they’re wrong on that. Frankly, I wouldn’t support such a move if we didn’t have the technological solutions.’

However, while the carbon-positive house lacks fans in the heartland of British politics, Irvine stated support from outliers of the system.

‘Interestingly enough, we’ve seen more commitment where there is devolved responsibility. Edwina Hart, Energy Minster for Wales, has endorsed targets for “nearly” zero-carbon government properties by 2018, and new houses by 2020. Whether the Welsh government maintains this position or not, who knows – there’s an election for the National Assembly in 2016 and I hope whoever takes power in Cardiff afterwards will follow through. There is government commitment, just not the Government.’

Reaching the right people

Irvine believes, ‘at the end of the day, the challenge is not persuading the Government but persuading housebuilders and I’m hoping this demonstration becomes a blueprint that could actually be rolled out.’ Yet, as with Westminster, the rapturous endorsement the Solcer house has received from the public has yet to be replicated by housebuilders.

Jones commented, ‘One large-scale builder visited the house site, and they liked it, but said it wasn’t for them. I know that they’re not keen on the building regulations changing. It’s a cultural change from the top of the organisation down to the workforce, and they would have to change the whole industry. It’s not that they couldn’t do it. It’s just that they choose not to do it. I think the old industries tend to be very conservative and resistant to change, and you need a new attitude from a housebuilder to deal with this sort of market.’

Jones did not wish to identify large-scale housebuilders Cardiff had spoken with, and several of the most prolific developers including Balfour Beatty, LCB and Ogilvie declined to comment to Materials World. However, Jones remains optimistic that the impact of the Solcer house is not lost on everyone in industry.

‘It’s the smaller builders who will rise to this challenge. I liken it a bit to IBM, who said no way will every house have a computer. And then Apple came in, and look at what they’ve done. We’re told people won’t pay more or don’t want it in the first place but, from the response we’ve had from the public, it seems that there is a demand, and I think there is a market for small builders to step in and capture it.’