Last edited 11 Nov 2015

Zero carbon homes


[edit] Background

The Climate Change Act was introduced in the UK in 2008, setting a target of reducing carbon emissions by 80% compared to 1990 levels by 2050, with a reduction of at least 34% by 2020. A strategy for how this was to be achieved was set out in The Carbon Plan published in December 2011.

In December 2006, the Labour government committed that from 2016 all new homes would be ‘zero carbon’ and introduced the Code for Sustainable Homes, a code against which the sustainability of new homes could be rated. This commitment was affirmed in the Building a Greener Future: Policy Statement in 2007 which proposed progressive tightening of the building regulations to achieve the 2016 goal, first by 25% in 2010 and then by 44% in 2013.

The Labour budget in 2008 announced a further intention that all new non-domestic buildings should also be zero carbon from 2019.

[edit] Definition

Whilst these were seen as bold commitments, there was scepticism about whether such ambitious targets could be met, as well as some confusion about what ‘zero carbon’ meant.

The first definition of a zero carbon home was a home achieving Level 6 of the Code for Sustainable Homes. This included emissions of both regulated energy (space heating, hot water, lighting and ventilation) as well as unregulated energy (such as appliances and cooking).

In the 2011 budget, the coalition government confirmed the commitment that from 2016 all new homes would be zero carbon, however it excluded unregulated energy use from the definition.

In England, the definition of a zero carbon home became one where CO2 emissions from regulated energy use were limited or mitigated by a combination of three factors (the first two of which are known as ‘carbon compliance’ standards):

1. Achieving minimum Fabric Energy Efficiency Standards (FEES) based on space heating and cooling:

  • 39 kWh/m^2/year for apartments and mid-terraced houses.
  • 46 kWh/m^2/year for end of terrace, semi-detached and detached houses.

2. Using low and zero carbon technologies and connected heat networks to limit on-site built emissions:

  • 10 kg CO2(eq)/m^2/year for detached houses.
  • 11 kg CO2(eq)/m^2/year for attached houses.
  • 14 kg CO2(eq)/m^2/year for low-rise apartments.

3. Where it is not possible to reduce the regulated CO2 emissions to zero using these on-site measures, the remaining carbon emissions could be mitigated through allowable off-site solutions.

So in effect, developers would have to avoid or mitigate all regulated emissions using a combination of on-site energy efficiency measures (such as insulation and low energy heating systems), on-site zero carbon technologies (such as solar panels) and off-site measures to deal with any remaining emissions.

'Allowable solutions’ were expected to include the developer being able to make payments to an ‘allowable solutions provider' who could be a local authority provider or a private provider. There was also the possibility of creating a national carbon abatement fund, with payments made by means of an agreed fee per kg CO2 to offset emissions over a 30 year period. See CLG: Open consultation: Next steps to zero carbon homes: allowable solutions.

On 8 July 2014, the government published a response to the summary of responses to its consultation on allowable solutions. This confirmed the four approaches to allowable solutions for house builders; abatement on site, their own abatement off site, third party off-site abatement, or to payment into a price-capped fund. It also confirmed that a national design framework would be established for the scheme.

In England, the requirement for zero carbon homes was to be set out and enforced in the 2016 building regulations, specifically parts L (Conservation of Fuel and Power), F (Ventilation) and J (Heat Producing Appliances) and their approved documents.

[edit] Criticism

A number of concerns were raised about these proposals:

  • Typically, every year, new homes account for just 1% of the total housing stock, and at present it is considerably lower than this. This means that the proposed measures would take a long time to have a significant impact on total emissions from the UK building stock.
  • Developers might find it easier to adopt ‘allowable solutions’ rather than meet the carbon compliance standards.
  • The standards might not really achieve 'zero carbon', focussing on operating emissions rather than capital emissions (ie they did not take account of carbon emissions resulting from actually constructing a new home).
  • It was not clear how long-term maintenance or future alterations to new buildings would be regulated.
  • There was concern about the impact these measures would have on the pressing need for more new homes as the UK population increases.
  • Questions remained about measures to deal with the difference between the predicted and actual energy performance of buildings which can be significant.
  • Whether the time-frame for change was realistic.

[edit] Infrastructure Bill

The Infrastructure Bill published by the Department for Transport on 6 June 2014 proposed re-setting the zero-carbon home standard at Level 5 of the Code for Sustainable Homes, but permitting developers to build to Level 4 by using allowable solutions to achieve Level 5.

However, controversially and unexpectedly it also proposed exempting small sites from allowable solutions requirements. There was no definition of what constituted ‘small sites’, although on 17 July 2014, DLCG minister Lord Ahmad suggested it might be similar to the 10-homes exemption already proposed for Section 106 agreements (ref Today's House of Lords debates - Thursday 17 July 2014). This was seen by some to introduce a significant loophole.

A consultation on the proposed exemption was launched on 18 November 2014. Ref DCLG Next steps to zero carbon homes: small sites exemption. On 27 March 2015, the government published its response to the consultation, confirming that sites of 10 units or fewer or a maximum size of 1000 square metres of floor space would be exempt from the allowable-solutions element of the zero-carbon homes standard.

[edit] Fixing the foundations

On 10 July 2015, the government published ‘Fixing the foundations: creating a more prosperous nation’ a plan for increasing Britain’s productivity.

Amongst a great number of wide-ranging changes, the report states, 'The government does not intend to proceed with the zero carbon Allowable Solutions carbon offsetting scheme, or the proposed 2016 increase in on-site energy efficiency standards, but will keep energy efficiency standards under review, recognising that existing measures to increase energy efficiency of new buildings should be allowed time to become established.'

This announcement was made with no consultation and came as a surprise to much of the industry.

Julie Hirigoyen, chief executive of the UK Green Building Council, said "It is short-sighted, unnecessary, retrograde and damaging to the house building industry, which has invested heavily in delivering energy-efficient homes".

Paul King, managing director of LendLease Europe, said, “...after almost 10 years of commitment and progress, UK house builders and developers have come a very long way. It is therefore extremely disappointing that the government has today removed a world-leading ambition for all new homes to be zero carbon from 2016.”

BSRIA Chief Executive Julia Evans said, "BSRIA is disappointed with the government’s recent announcement of the end of the UK’s zero carbon buildings policy, but the industry remains ambitious that all new homes are built to the best standard, and they adopt the most energy efficient standards possible.”

Following the announcement, the UK Green Building Council (UKGBC) organised 200 signatories to publish an open letter to the Chancellor calling on him to rethink the decision. The letter said "For the best part of a decade, in response to a long-established Government target, the construction and property sector has been gearing up to deliver zero carbon homes and buildings. Last Friday, we were extremely disappointed to learn that this policy is being arbitrarily scrapped, despite the fact that the necessary primary legislation only acquired Royal Assent in February this year.... Since the policy was first launched eight years ago, business has invested heavily in preparing for future standards. This sudden U-turn has undermined industry confidence in Government and will now curtail investment in British innovation and manufacturing in low carbon products and services..." Ref UKGBC 20 July 2015.

However, CIBSE technical director Hywel Davies said the decision was not a huge surprise, and the move was welcomed by the Home Builders Federation who suggested that zero-carbon standards would have cost purchasers in the order of £2,500 per home.

The announcement did not specifically mention proposals for zero carbon non-domestic buildings, but it has been widely interpreted by the industry as signalling that these have also been scrapped.

It is not clear where this leaves the UK in fulfilling its requirements under the Energy Performance of Buildings Directive to move towards nearly zero energy buildings.

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