Barriers to Low and Zero carbon homes
The following section highlights some of the key barriers to the diffusion of LZC new build and retrofit in the UK. Although many of the issues are fairly consistent between both new build and retrofit, where innovation and adoption faces similar barriers, there are a number of areas where the challenges diverge. These barriers are associated with concerns over the economic benefits, technical challenges and shortfalls and the cultural and behaviour attitudes that may inhibit the transition to a predominantly low energy building regime.
The following section will provide a brief summary of some of the key barriers and challenges that are associated with the diffusion and adoption of new low and zero carbon housing, with reference to the current policy landscape. Whilst many of the methods and technological solutions adopted are similar in both the new build and retrofit contexts, some of the modes and methods of delivery along with the associated incentive schemes and government interventions differ considerably.
A key concern at the launch of the Zero Carbon standard for 2016, was the perceived costs associated with delivering the standard. Niche technological solutions that were available in 2006, were thought to add around £36,000 to build costs (Osmani and O’Reilly, 2009). Projects such as the Lighthouse by Potton . demonstrated a large range of the technological solutions that were available, however many remained very high cost, when used in combination. Osmani and O’Reilly (2009) noted in a number of detailed surveys with industry that; ‘developers are reluctant to instigate innovation and achieve high sustainability standards due to the prohibitively perceived or real elevated costs associated’ with their implementation.
Nevertheless the incremental increases in the energy and CO2 performance requirements of new buildings, via Par L; as shown, and local authority requirements (section 2.2), have been a key driver in the adoption and diffusion of energy saving measures. This has largely been delivered through increased thermal performance via insulation measures, improvements in air permeability detailing, relating to the (FEES) and the adoption of condensing boilers (Heffernan et al., 2015). Some local authority standards have also driven increasing use of low carbon energy systems, as described.
It is widely acknowledged that the 2016 standards would have also necessitated the inclusion of one or more onsite renewable energy systems, as the delivery of the standard without these measures would require levels of fabric performance at or beyond the Passivhaus standard (ZCH 2014).
However it can be argued that the mix of UK regulatory ‘push’ interventions in the form of Part L and demand ‘pull’ policies such as the FIT, have contributed to driving down the cost of both types of measures through economies of scale and technological learning. It is important to note that there has been an observable shift towards a simplified approach to the delivery of zero carbon homes, via fewer individual LZC technologies and an increased focus on fabric measures and energy conservation ,(McLeod et al., 2012, ZCH, 2009).
This process of refinement, combined with significant cost reductions in the development of PV technology in the last 10 years, has significantly reduced the associated costs of delivering buildings to the zero carbon standard. PV panels are often specified in preference of other forms of renewable technology, such as biomass boilers or heat pumps, in large schemes delivering to London plan targets (personal experience). Indeed the ZCH describe; ‘in the seven years since the zero carbon policy was first announced by the Government we have seen costs fall by tens of thousands of pounds’ (ZCH, 2014)
Estimates on the marginal additional cost of achieving the Zero Carbon standard now indicate these costs to be from 2016-2020, including allowable solutions payments;
detached house £5,700-6,300 per home,
semi-detached and mid-terraced homes £2,900-3,600 per home.
low-rise apartments £1,900-2,000 per home.
However other scholarly publications point to the limited voluntary penetration of zero carbon homes thus far, as systematic of a lack of financial incentives (Heffernan et al., 2015). Given in part to the fact that energy savings and subsidy revenues cannot be captured by developers, and homebuyers may be poorly informed as to the financial benefits associated with low and zero carbon buildings.
In addition a comprehensive cost study on the ZC standard in 2014, has indicated that extreme fabric standards such as the Passivhaus approach, introduce greater costs than a more balanced approach that incorporates renewable micro generation (ZCH, 2013). However proponents of the standard, point to how the Passivhaus approach introduces fewer performance gap issues. Given the comprehensive and thorough nature of the Passivhaus design process, modelled savings may be more representative in the buildings real operation (McLeod et al., 2012).
In terms of the diffusion of more niche technologies associated with the Passivhaus approach, it can be seen from the data gathered in this report, that the penetration of this standard has been extremely limited. Indeed the higher capital cost associated with some of the design features, i.e. triple glazing, reduction of thermal bridges etc. are likely to be continuing barriers to the adoption of this standard among private developers. This may also be true of other high capital cost innovations such as vacuum and aerogel insulation. This is to some extent contrasted when considering the growing popularity of the Passivhaus standard, among self-builders and housing associations, where these groups stand to receive more of the financial benefits associated with the reduced energy use. However as shown in this report these activities remain confined to a niche minority (Heffernan et al., 2015, Osmani and O’Reilly, 2009)
It seems clear that these issues of split financial incentives are a key remaining barrier to the voluntary adoption of zero carbon buildings; even where positive cost payback periods exist. Notwithstanding these issues, there are a number of important structural and social barriers to innovation and diffusion associated zero carbon buildings, which extend beyond pure economic concerns.
HEFFERNAN, E., PAN, W., LIANG, X. & DE WILDE, P. 2015. Zero carbon homes: Perceptions from the UK construction industry. Energy Policy, 79, 23-36.
MCLEOD, R. S., HOPFE, C. J. & REZGUI, Y. 2012. An investigation into recent proposals for a revised definition of zero carbon homes in the UK. Energy Policy, 46, 25-35.
OSMANI, M. & O’REILLY, A. 2009. Feasibility of zero carbon homes in England by 2016: A house builder’s perspective. Building and Environment, 44, 1917-1924.
ZCH 2009. Defining A Fabric Energy Efficiency Standard – Task Group Recommendations. London: Zero Carbon Hub.
ZCH 2013. Closing the gap between design and as-built performance, New Homes, Interim Progress Report. London: Zero Carbn Hub.
ZCH 2014. Cost Analysis – Meeting the Zero Carbon Standard. Zero Carbon Hub.