Industry insight: Zero carbon buildings could be the answer to climate change and the housing crisis
Recent developments on the UK climate policy front have given environmentalists some good reasons to be cheerful. Last September, the subsidised cost of wind energy plummeted to a record low and, the following month, the UK Government outlined its Clean Growth Strategy, at the heart of which is a pledge to make buildings less carbon intensive. So far so good, but are all these important steps enough to take on climate change? And, talking about buildings specifically, are the green construction technologies that are currently available being used to their full potential?
Perhaps not everyone remembers that, until recently, the UK had a bold plan in place, one that could have triggered a radical transformation in the way homes, offices and factories are built. This strategy, launched in 2006, would have forced all housebuilders to build ‘zero carbon’ homes from 2016. While addressing the climate threat, it may also have offered an effective solution to address the UK’s housing crisis, helping produce more – and more affordable – homes.
Whereas the plan was scrapped two years ago, zero carbon technology has not stopped developing and continues to offer an unprecedented opportunity to move towards a low-carbon economy and more affordable buildings. But what does ‘zero carbon’ actually mean? And why should we care so much about buildings when it comes to environmental policies?
Zero carbon and why it matters
The buildings where we live, work, shop and dine are responsible for 40% of the world’s energy use and, in the UK alone, they account for 37% of greenhouse emissions. With these figures in mind, it is not difficult to understand why any serious effort to tackle the climate should start from buildings, which is where zero-carbon technology comes in.
What sets a zero-carbon building – also known as net zero energy building (NZEB) - apart is its ability to meet its energy demand without virtually producing any greenhouse gas emissions. Whereas the building may still need to import some energy from the grid during the colder months, this would be matched or even exceeded by the electricity surplus that is generated on site over the rest of the year.
This is made possible by enhanced insulation combined with on-site renewable energy systems such as photo-voltaic (PV) panels, wind turbines or solar thermal energy facilities that generate as much energy as the building consumes to power, heat, lighting and ventilate itself.
Zero carbon technology is not a thing of the future
3D printing and advanced materials combined with renewable energy have opened up unprecedented opportunities to boost zero-carbon buildings. For example, 3D-printed ‘solar sprays’ can give glass and other surfaces photovoltaic capability, while super insulating materials such as In’flector, originally developed by NASA, can be used as window blinds that control heat in different seasons. It is even possible to manufacture ceiling tiles using phase change material (PCM) that melts when it absorbs heat and then reforms to expel the heat back into the room when the weather gets cooler.
Armed with these and other zero-carbon technologies and building techniques, it is possible to design buildings that are not only able to meet their energy demand, but even to export excess power to the grid. For example, Cardiff University has built a house with insulated render on the outside as well as glazed PV panels and battery storage to run both the combined heating, ventilation and hot water system and the electrical power system, which includes appliances, LED lighting and a heat pump.
As they generate zero-bills and can potentially offer an additional source of income with excess power generation, zero-carbon buildings like this can clearly offer a more affordable and sustainable way of boosting the UK’s housing and commercial building market.
Killing two birds with one stone: climate change and the housing crisis
The clear advantage of adopting the zero-carbon approach is that it can also offer an opportunity to tackle the housing crisis and build the social and affordable housing stock that the country desperately needs.
The use of a modular approach means that buildings can be erected quickly, easily and, perhaps more importantly, at a low cost. Cardiff University’s house, for example, took just 16 weeks to construct and cost £1,000 per sq m, which is within the range for social housing of £800 to £1,000 per sq m.
Other building companies such as ZEDfactory, led by architect Bill Dunster, have designed modular, zero-carbon pop-up buildings – also known as ‘pods’ – that can be factory-produced and assembled on site in a matter of days. Sitting on elevated platforms, the pods are designed to be erected in existing urban settings such as car parks, without impacting the green belt and allowing Local Authorities to build affordable homes without the need for land or capital expenditure. They can also make urban mobility smarter, as homes can be built right next to jobs or public transport.
Retrofitting is a reality
So far so good, but what about the millions of existing – and often high-carbon - buildings dotted around the UK? The development of technology such as solar roofs now makes it possible to retrofit existing structures and bring them to low-carbon standards.
Composed of large interlocking tiles that are fully interchangeable allowing different combinations of PV, SHW and rooflights, solar roofs are able to cover up to 100% of the electricity demand of existing structures while also turning existing cityscapes into more pleasant and liveable public spaces.
The future: becoming a world leader in decarbonisation
The UK is emerging as one the world’s leaders in decarbonisation, reducing its carbon intensity faster than any other major economy. Zero-carbon buildings now present the country with a unique opportunity to embark on a more radical transition to a truly ‘low-carbon’ economy while also giving its citizens more affordable buildings to live in and do business.
Marco Giudici, PR Senior Account Manager, Technical Associates Group