Planning policies for zero carbon homes and communities

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Planning policies for zero carbon homes and communities

Planning policies for zero carbon homes and communities

Martin Taylor 07 Apr 2020
In June 2019, the Government set a commitment in the Climate Change Act 2008 for the United Kingdom to reach ‘net zero’ greenhouse gas emissions by 2050. More than two thirds of Councils across the Country have now declared a climate emergency, many looking to accelerate meeting Government’s targets in their own areas. The focus to plan for reducing carbon emissions from our homes and communities is unprecedented.
Government has consulted on changes to England’s Building Regulations introducing a ‘Future Homes Standard’ and the Department for Transport recently published “Decarbonising Transport; setting the challenge” a first step towards publishing a full transport decarbonisation plan later in 2020.
At the local level many Councils will soon, if not already, be grappling with how they can secure carbon reduction through their plan making and decision taking activities. For example Cornwall Council is currently consulting on scoping a new Climate Change Development Plan Document, specifically to “meet our [climate change] ambitions by strengthening existing policies” and many will no doubt follow suit.
Inevitably, a sharp focus will be how to suppress greenhouse gasses from the residential sector, which is the source of 15% of the UK’s emissions, predominantly via heating and cooking.
The challenge will be reconciling how to meet climate change targets, whilst also delivering the new homes and buildings that will meet local needs. Zero carbon homes is the standard that will be targeted, but right now, it is up to Local Planning Authorities to set out how they will achieve it. How should they address this challenge in plan making?
Equally, those promoting developments are being asked by Councils how their schemes will respond to the climate crisis. But how is this best done? And what is meant by zero carbon?

Definitions are everything

The meaning of zero carbon homes has varied through previous Government consultations and commitments, as well as in general usage. Key questions include:

  • Does it apply, as per building regulations, only to ‘regulated energy’ - those fixed and integral services and fittings in the home such as the space heating, hot water, ventilation and lighting - or also to ‘unregulated energy’ including things a developer can’t as easily control such as those used through plug-in appliances and cooking?

  • Does it relate to just a home’s day-to-day operational energy use or to life-cycle carbon emissions, including that embedded in its construction?

  • Does it apply to each home individually, or development-wide (or by phase for larger schemes), whereby some homes may not need to meet the standard, if the development as a whole does?

  • Does it include or exclude potential off-setting arrangements (sometimes referred to as allowable solutions), with zero carbon homes often used as shorthand for net-zero carbon homes where the homes themselves might not be zero carbon, but offset payments have been made (for example into a fund to allow the Council to improve energy efficiency in older housing stock)?

Zero carbon might refer to all or any of these but in any one place its meaning will have implications for the form of development and its viability. The costs of implementing measures to reduce carbon are on a curve: for each additional unit of carbon reduction, the marginal cost increases. This is why ‘offsetting’ - a relatively cost-effective means of achieving net zero carbon homes - is often used as a solution over and above a given threshold.
Achieving the right balance – how far towards zero carbon can a development go in a given location? – needs to feed into plan-making and writing effective policies. The NPPF requires that plans should contain policies that are clearly written and unambiguous (i.e. they need to define and be clear what is being sought) and that policies should be aspirational but deliverable (i.e. they should not impinge upon viability). Local Planning Authorities will need to justify what standards and definitions they are seeking to implement and demonstrate they have been properly tested through the viability evidence underpinning their plan. Those engaging with Local Plan consultations should be aware that such standards could vary across different areas reflecting local circumstances and priorities; there will not be a one-size fits all approach, so attention will need to be paid to the details.
So what is happening so far? There have been at least two notable Plans that have introduced net-zero carbon home standards: the new London Plan and Reading, both with off-setting arrangements. However, there are also some select examples of individual developments progressing to higher zero carbon home standards, including “true zero carbon” homes at A2 Dominion’s North West Bicester eco-town scheme which aimed to achieve full zero carbon operation for both regulated and unregulated energy (as well as significant reductions in embedded carbon within construction processes to boot – but not carbon neutrality).

The curious case of the Reading Local Plan

The Reading Borough Local Plan was adopted in November 2019 accompanied by headlines of “Reading adopts zero carbon targets for new homes”.
Policy H5 states that “All major new-build residential development should be designed to achieve zero carbon homes” with supporting text clarifying that it requires a 35% improvement in emission rates over 2013 building regulations, plus an offsetting contribution of £1,800 per tonne for remaining emissions, to be put towards carbon offsetting within Reading.
During the Examination process, the Inspector required both further evidence on how the Plan Viability Assessment had appraised the impact of zero carbon homes, and modification of the Plan to explicitly clarify that the zero carbon homes standard being applied by policy did not require new homes themselves to be designed to be carbon neutral; definitions are important!
The viability question was critical here. The original viability evidence underpinning the Plan applied a blanket 1% cost on revenue assumption with further evidence provided to the Inspector claiming “In approaching a cost estimate for achieving zero carbon we therefore took the view there would be no effective cost premium depending on the method of construction.”
This surprising assertion was not borne out by the implementation of the offsetting arrangement or by other studies looking at this (for example research by Government’s Zero Carbon Hub, prior to its closure in 2016, put cost premiums at £2,200-£7,500 per home, whilst more recent evidence underpinning the new London Plan approach put this at £6,500 per home plus £1,853 for carbon offsetting).
Perhaps in response to this, the Inspector also required a modification to clarify that the housing standards (including zero carbon homes) were all subject to viability (e.g. as may be explored at the application stage). This avenue – of allowing the standard to flex – was open to the Inspector as the Plan was being examined against the 2012 NPPF under transitional arrangements; whether such an approach could hold-up against the 2019 NPPF with its more rigorous requirements for front-loaded viability testing at the Plan stage (as discussed in Arwel Evans’ blog here) is doubtful.

Towards effective planning policies and outcomes

Achieving effective planning policies for zero carbon homes will require clarity up front on what is being required, and if we’re serious about delivering it, that they are priced-in to plan viability assessments at the outset (as required under current national policies).
Local Planning Authorities will need to evidence and explain their policies, whilst reflecting the costs in their viability evidence for Local Plans. Housebuilders and developers will be delivering the zero carbon homes, and through Local Plan processes have a role in engaging to ensure policies are workable and effective, highlighting what the industry can do to support delivery.
After many false starts, there is every chance the declarations of climate emergency across the country will now see zero carbon homes standards embedded in 2018/19 NPPF-based Plans; but it requires an up-to-date and realistic focus on viability, so that the zero carbon standards are compatible with maintaining housing delivery, whilst recognising that the practical reality will evolve in response to changing technology and best practice.