Stephen Armstrong

10th May 2021

Latest Thoughts

Corde Partner Decarbonising the British Library

Timber and Carbon Sequestration

The Swan School has been recognised at the Oxford Preservation Trust Awards 2021

Are We Missing a Trick with Zero Carbon?


Targets can be a helpful way of focusing the mind – though they sometimes run the risk of being too focused, and blinkering organisations into considering only one approach to a problem. The UK government’s target to reduce all greenhouse gas emissions to net zero by 2050 is a case in point. We’ve seen the electrical grid accelerating towards zero carbon, and the National Grid has predicted that our electrical infrastructure in the UK could be carbon neutral by 2033. But are we focusing too closely on how our electricity is produced, and ignoring the way it’s consumed?

Imagine a future where the grid is indeed carbon neutral. A tin shed with no insulation, direct electric heating and tungsten lighting could be considered a “zero-carbon” building – but it would be far from zero-energy. In fact, it’s arguably impossible to achieve a zero-carbon grid without reducing the demand of buildings on that grid. Lower energy demand leads to fewer power stations, renewable or otherwise, and those savings have a huge impact on the drive towards a lower-carbon future.

It’s for this reason that we should move away from simply considering carbon reduction, and broaden our focus to reducing the energy that buildings use on a day-to-day basis – their operational energy. Corde has looked at a number of different ways to do this, working with our clients to develop bespoke strategies that work for them. For instance, we’ve agreed to adopt energy use intensity measures, and are benchmarking our success against LETI’s (the London Energy Transformation Initiative) design guides for tackling the climate emergency.

To meet our targets, it’s important to set out an energy efficiency strategy at the concept stage, and to follow this through to construction. We like to take inspiration from the new London Plan’s “Energy Hierarchy”, which structures an approach around four key points:

  • Be Lean (i.e. minimise energy use with passive and active measures)
  • Be Clean (i.e. maximise the efficiency of any MEPH [mechanical, electrical and public health] systems)
  • Be Green (i.e. use the most appropriate and effective renewable energy systems)
  • Be Seen (i.e. commit to publishing and sharing your data)

The London Plan is just one example of where local governments are leading the charge here, and introducing their own energy and carbon targets to the planning process. This proactivity has left building regulations with a good deal of work to catch up – although the Government has recognised this, setting out a two-stage approach to updating these in order to meet their 2050 target.

Stage 1 (2021–2): Uplift to Part L

The Government ended its consultation process for updated Part L of the Building Regulations – the part relating to conservation of fuel and power – in April. The key changes they’re proposing include:

  • Using primary energy as the metric for comparing energy use
  • Setting new minimum standards for thermal elements, HVAC and lighting
  • Ensuring that direct electric heating is compared with heat pump technology (avoiding the issues with the “tin shed” I mentioned earlier)
  • Introducing measures to reduce the gap between the way energy “should” perform on the drawing board, and the way it actually performs in use.

Taken as a whole, the Government is aiming to achieve a 27% improvement in CO2 emissions from these changes. However, the changes also include some important measures to ensure that fabric and primary energy are used as metrics for improving energy efficiency.

Stage 2 (2025): Future Buildings Standard

This will replace Part L, going further in terms of carbon reduction and energy efficiency. The aim of the Future Buildings Standard is to construct new buildings that can become carbon neutral over time, as the grid and heat networks decarbonise. Fossil fuel boilers would make this impossible – so they’ll be banned by future building regulations, as they already are by many local planning authorities.
To replace oil and gas boilers, it’s likely that many buildings will use heat pumps. However, certain buildings such as warehouses may require spot heating with a different technology: the consultations acknowledges this by providing a breakdown of different types of building.

Where Does This Leave Us?

The key question is: is this enough? The Government’s targets for reaching net zero by 2050 are both ambitious and entirely necessary, and with such a vast gulf between our current impact on the environment and where we need to find ourselves, it’s clear that Government standards such as this are just a small part of the picture. These standards will set a minimum that clients and designers should treat as just that: a bare minimum to rise above as we aim for ever more sustainable buildings. We expect local governments to continue to push beyond these standards, just as we will continue to aim for the very best designs to respond to the climate crisis.