What a 1.5°C target means for UK buildings
Reports about Climate Change usually give global or national targets that are difficult to apply in practice: 80% reduction, global warming below 1.5°C, halve energy use of new buildings by 2030. We work to translate these large-scale targets into something that we can use, and that our clients can apply at a local level. It’s difficult!
The cases that we have looked at consistently show that to get close to the targets we need all the available measures. This includes better energy efficiency for new buildings and retrofit of the old ones, low carbon heat, space for building mounted renewables, dynamic demand management and energy storage. There is little room for trade-off between policy areas, and it is sobering. You can play with this at a national level using the DECC 2050 calculator.
Bespoke carbon pathway for a local authority
We have started to unpick what local effect targets will have. In this example we took population growth and building stock statistics from a London local authority and estimated carbon emissions from buildings over the next 30 years, a carbon pathway. It’s our version of the analysis carried out nationally by the Committee on Climate Change (CCC) and is useful to show whether local policy matches sustainability aims.
The key policy areas are energy efficiency of new buildings, retrofit of existing buildings, and low carbon heat. Their contribution to carbon reductions over time is shown on the graph below, along with the background reductions already given by decarbonisation of the electricity grid.
The pathway is for an invented very good case scenario, look at the assumptions needed in the righthand column. With this level of commitment it shows that a 90% emission reduction from the estimated 1990 level is possible, but real net zero operational carbon is potentially beyond reach. We need full commitment from the construction industry and improvements in technology to achieve the reductions. And we also need to find solutions to the rest. We think local policy needs to be very ambitious to get to what has been committed to by national government, so are continuing to unpick what this means for individual local authorities and landowners.
Buildings will shoulder the brunt of emission reductions
Some things will still unavoidably be emitting greenhouse gases in 2050 and beyond, for example aircraft and industrial processes. Policy makers see buildings as an easier opportunity, and heating buildings in particular is the area where large savings are technically possible, with a positive impact on the economy too. We need buildings to make up for emissions reductions that other sectors cannot achieve, hence net zero carbon, or 90% reductions.
In practice progress is very slow. Nationally the total carbon emissions from the UK are reducing, however most of this is from closing coal power stations and building large wind farms. Reductions in emissions from the electricity grid are hiding a shameful lack of progress in the building sector.
On top of this it is not clear whether the theoretical savings used in high level policy are actually achievable in practice, or what that will mean for our building stock. It is up to us to find this out, and to find an engineering solution for the maximum reductions possible.
 Kuramochi et al., 2017 show that 1.5C-consistent pathways require building emissions to be reduced by 80–90% by 2050, new construction to be fossil-free and near-zero energy by 2020, and an increased rate of energy refurbishment of existing buildings to 5% per annum in OECD countries.
 Committee on Climate change: Meeting carbon budgets – 2017 progress report to Parliament: Closing the policy gap (2017)