Energy use in housing in the UK accounts for 27 per cent of carbon emissions. Therefore improving energy efficiency and using renewable energy in housing stock presents a great opportunity to contribute towards the 2050 target of an 80 per cent reduction of greenhouse gas emissions.
With the cost of living increasing while real wages remain stagnant, priority of expenditure is a decision many households have to make, often having to choose between food, rent, council tax, gas/electric bills and transport costs. By reducing energy bills householders will have additional funds to spend on other necessities and may be helped out of energy poverty.
By building the necessary 250,000 new homes as low or zero-carbon at an affordable cost, using replicable techniques and technologies that are easy to use and maintain, there is a potential for this type of home to become the ‘norm’ rather than a novelty. This would help to reduce carbon emissions, stimulate the economy and reduce energy bills.
What progress has been made so far?
Low-energy housing design was initiated in the UK as a response to the oil crisis of the early 1970s and has developed over time to include passive and renewable energy supply and storage technologies. Zero-carbon homes are becoming a realistic possibility for large-scale roll out in the near future as a result of significant progress in the development of affordable energy generation and storage products and technologies to reduce energy use.
A clear ambition was defined by the Zero-Carbon Homes policy set in 2006 to make all new UK homes carbon-neutral by 2016. In July 2015, however, the policy was scrapped to the dismay of many in the construction, property and energy technology industries, on the basis that it was deemed not possible to build a cost-efficient, carbon-neutral home.
The Zero-Carbon Homes policy, if left in place, would have been the ‘stick’ that would have encouraged the large-scale construction of affordable zero-carbon housing in the UK with current barriers including cost and risk associated with using unfamiliar technologies having to be overcome. However, with the removal of this policy and a reduction in financial support for the installation of low-carbon technologies, such as the reduction of the Feed In Tariff which has fallen from £13.39/kWh to £4.32/kWh for an equivalent domestic photovoltaic system, there appears to be little incentive for large-scale change.
The Solcer House, launched by the Welsh School of Architecture at Cardiff University just as the Zero-Carbon Homes Policy was scrapped, has demonstrated that it is possible to achieve a zero-carbon house at an affordable cost using off-the-shelf technologies. The Solcer House uses a systems-based approach, combining technologies that reduce energy use, generate energy and store energy. The Solcer House is highly insulated and therefore provides a comfortable internal environment. The maintenance of the house has been considered through the selection of low-carbon materials from the local supply chain wherever possible. In the past technologies such as photovoltaic panels have been ‘bolted on’ to buildings which can add costs and overcomplicate design.
At the Solcer House the technologies have been integrated into the structure of the house; for example, the photovoltaic panels are the roof, removing the expense of standard roof tiles. A battery system has been included which stores energy generated by the photovoltaic panels during the day and energy can be used in the evenings when electrical energy is required by the occupants. Over an annual period the Solcer House generates 1.75 times more energy than it uses. Costing £1,200/m2 to build, which is in the budget range for social housing, the Solcer House has the added bonus that energy bills will be very low, at around £200 per year, therefore reducing the potential for energy poverty for the householders.
Pentre Solar, a hamlet of six homes located in west Wales, focuses on energy demand reduction, rather than technologies. The design uses photovoltaic panels as a renewable energy source, and focuses on thermal efficiency of the building fabric and passive solar heating to generate a high proportion of the space heating. The houses at Pentre Solar cost £1,000 to £1,100/m² to build including the PV panels, and the running cost will be below £300 per year. Each house also produces enough energy to power an electric car.
These demonstration projects unequivocally show that, in contrast to the political reasoning of the recent past, it is possible to build affordable, low/zero-carbon housing within the cost range required by social and high volume house builders, and occupiers can benefit from reduced energy bills and improved wellbeing.
What needs to be done to ensure more progress?
The projects presented have demonstrated that it is possible to build attractive and affordable low-carbon housing using local skills and supply chains that are replicable at scale. Large scale uptake is still likely to require a clear, straightforward and consistent policy to encourage volume builders to include a proportion of low carbon housing within their portfolios. In turn, this would lead to the removal of the broader barriers that are preventing progress at scale, such as establishing supply chains that provide high quality products and services, establishing and maintaining a skills base motivated to implement the appropriate technologies, from planning through design to construction and operation, and bringing costs down further in the long term.
The Welsh government has run two phases of Arbed, a programme to stimulate the uptake of energy efficiency measures and renewables. Although together Arbed has helped to reduce emissions of over 12,000 homes in Wales and has had a positive overall impact, the time lag between the two phases resulted in an unsustainable situation for some SME technology installers who struggled to cover costs during the interim period. This was a bureaucratic limitation rather than a technological issue.
Without a clear and ambitious policy drive, potentially including quantitative targets, there remains little incentive to change current practice. This status quo would be a failure to realise the benefits that existing technologies can deliver to society, reduced carbon emissions and energy costs, improved wellbeing as well as the stimulation of market opportunities through the supply chain.
Is it possible for low-carbon housing to be economically viable in the long-term?
The examples provided illustrate that the costs to construct the houses are within the remit of social housing providers and that, if constructed at scale, costs are likely to be reduced further. A broad range of stakeholder groups including local and national government, construction services, and large-scale housing developers and providers from both the UK and internationally have expressed a keen interest, indicating the desire to change within the sector. In this respect, demonstrating through example has been a success and will provide the construction, property and low-carbon technology industries confidence to continue to make positive changes.
Overall, low/zero-carbon homes contribute to solving a number of current social issues including energy poverty, climate change and security of energy supply, for little, if any, additional cost compared to many current building practices. In the long-term, these benefits will allow low-carbon housing to be viewed as self-sustaining and will become the ‘norm’ rather than what might be seen as a ‘novelty’ project.
Appropriate policy would help technologies to be adopted earlier; however, we should be confident that in the not too distant future a vibrant low-carbon construction industry will look back and say: “Why didn’t we do that sooner?”