A pathway to nearly zero energy

The Government has announced in its recent Productivity Plan that the zero carbon buildings target in England is to be dropped. This has been widely criticised, but England and the rest of the UK are still committed to all new buildings being “nearly zero energy” from January 2021 through the EU Energy Performance of Buildings Directive. Hywel Davies, Technical Director of CIBSE, proposes a practical realisation of this target.

The coalition government was committed to zero carbon homes from 2016 and zero carbon non-domestic buildings from 2019. Those goals were described back in the early days of the coalition, and George Osborne wasted little time in announcing that the idea of ‘zero carbon’ buildings, combining energy efficiency measures and “Allowable Solutions”, is finished.

The sudden change of policy has been widely criticised for removing a long standing objective that had driven innovation in the construction sector. This undermines those in the industry who do seek to reshape construction and deliver real innovation, who will find that companies will be less willing to commit to anything related to government policy because of the risk of a sudden change of policy.

In Wales, the Assembly Government was quick to express disappointment over the Chancellor’s announcement and to confirm that Wales was committed to meeting the ‘nearly zero energy’ targets. And in Scotland the 2007 Sullivan report set out an ambitious pathway to reduce energy use and emissions from buildings, even though it had to be reviewed in 2013 in the light of the economic downturn.

Policy uncertainty discourages innovation in new projects 

Zero carbon v. Zero energy
The “zero carbon” target was set before the recast of the European Energy Performance of Buildings Directive (EPBD) came into play. That Directive requires all new buildings to be “nearly zero energy” from 1 January 2021. And the UK is committed to that target.

The EPBD defines a nearly zero energy building (nZEB) as “a building that has a very high energy performance, as determined in accordance with Annex I. The nearly zero or very low amount of energy required should be covered to a very significant extent by energy from renewable sources, including energy from renewable sources produced on-site or nearby”.

It was never clear how the government intended to align the zero carbon concept, with “allowable solutions” as an offset mechanism, with this definition of nearly zero energy based on renewables. ‘Zero carbon’ homes from 2016 relied on a combination of minimum energy efficiency standards as set out in Part L, coupled with the allowable solutions payment, with no clear requirement for renewables anywhere, let alone ‘on-site or nearby’.

Building Regulations Part L

Given that it is mid 2015 now, anyone with passing familiarity with the last three rounds of revisions to Part L will realise that ‘zero carbon’ homes in 2016 would have been based broadly on Part L 2013.This would have been most unlikely to have satisfied the nZEB definition, and so a further round of changes in regulations and associated practice would have been needed for nZEB, at further significant cost to the industry.

For homes the earliest that this revised Part L could have been delivered would have been in late 2016, for the October common commencement date for new regulations. With a six month lead in before coming into force, and a year for transitional provisions, it would have been April 2018 at the earliest before we really got to ‘zero carbon’.

And for non-domestic buildings, a target of 2019 would inevitably have been based on a revised Part L coming into force in October 2019, with a potential for a transitional period of six months or a year, taking us almost to the ‘nearly zero energy’ deadline.

A model of a heat network, designed to cut energy waste


We are now on a timetable to nearly zero energy buildings from 1st January 2021. That date is outside the control of the UK government, it is in the Directive.

1.    The EPBD sets out a clear timetable for the development of Part L, as the minimum energy efficiency standard for England. Article 4 requires Member States to set minimum standards, and these must cover new build and refurbishment. Whilst the Directive acknowledges that the standards must be cost effective, this is set over the whole life of the building, not just for build cost. And Article 4 also requires the standards to be reviewed at least every five years.

2.    The EPBD requires Member States to undertake a review of how cost optimal their standards are using an EU methodology that is set out in a Regulation. This takes a different view of some aspects of cost effectiveness to the Treasury. The first such review was published in 2013, although it was due in 2012. The delay was due to the late publication of the methodology regulation. So the next cost optimal analysis is due in 2017. If that review finds that Part L is behind the curve for cost optimal requirements, then Part L will have to be brought up to speed. And that will have to be in 2018, since the previous review was in 2013. So we now have a clear timetable set out for us, not in a Treasury document, but in the EPBD and supporting Regulation.

3.    As zero carbon was a UK policy, it came under “one in two out” (rumoured to be heading for one in three out), whereby to increase the regulatory costs of Part L twice (or three times) that regulatory cost would have had to be removed through deregulatory measures. Now that we are working to an EU Directive, “one in two out” does not apply, which makes it less of a challenge to bring Part L up to reasonable requirements in 2018.

So the net results of dropping ‘zero carbon’ are:

·         A single goal, ‘nearly zero energy’.
·         A clear timetable for upgrading Part L to support this goal.
·         No potential conflict between the ‘zero carbon’ and ‘nearly zero energy’ targets.
·         A focus on energy.

A private wind turbine generates space capacity for the national grid

Next steps
Given the announcement of the expected capacity gap, or spare capacity in the national grid this coming winter, it is a welcome development. Every megawatt of energy saved in a building is energy that does not need to be generated, thereby freeing up finance for more productive purposes.

So whilst the sudden change of tack will have damaged industry confidence, our focus must now be on how we can meet the nearly zero energy targets.

CIBSE, is the professional body which is most intimately involved in the manufacture, design, installation, commissioning, operation and maintenance of most of the energy using systems installed in a building. We are uniquely placed to take a lead in considering the way forward for Part L in a nearly zero energy, cost optimal, world. We will bring together a working group to consider how Part L 2018 might most effectively support the delivery of nearly zero energy new buildings, and cost optimal requirements for refurbishment. We would encourage all those who share that interest to come and join us on the journey to delivering nearly zero energy buildings. 


Popular posts from this blog

Embodied Carbon Award: A step towards net zero carbon

Face-to-face or remote training?

An interview with the authors of Dynamic thermal modelling of basic blinds (TM69)