By Josh Tobin, Mechanical Engineer at EDC
The UK is facing a massive energy challenge, decarbonise and be net-zero carbon by 2050.
On the 27th of June 2019, the UK passed a revolutionary bill that required the UK, by law, to cut net greenhouse gas emissions by a level of 100% by 2050.
This legislation superseded The Climate Change Act passed in 2008 which required a lower target of 80% against the 1990 emissions baseline (Shepheard, 2020). The legislation was introduced to create a framework to maintain the UK’s compliance with the 2016 Paris Agreement. To achieve this, a significant increase in renewable energy feed in is to be expected over the next 30 years.
This will see over the course of the next 30 years the UK power sector potentially installing close to 6,520 wind turbines, 66 biomass facilities, 48 natural gas power stations, 6 nuclear power stations and undefined unit capacities for onshore wind, solar and energy storage (Institute, 2020).
As part of this new strategy, the CCC is heavily targeting emissions reduction in the heating sector as the current statistics from the UK Government shows “that Renewable heat accounted for 7.9 per cent of total heat consumption” (DBEIS, 2020).
This effectively means that almost 92.1% of current heat generation is from non-renewable fuel inputs at the beginning of 2020. This figure needs to drastically reduce to help the UK achieve its necessary targets by 2050.
The heating sector in the UK compromises approximately 37% of the UK’s total GHG emissions and as the carbon intensity of electricity continues to fall below gas a push towards heat network electrification will become more prevalent (Catapult Energy Systems, 2020).
What are the changes and what does this mean for future developments?
The carbon intensity of the UK electrical grid back in 2012 represented a network heavily driven by non-renewable inputs compared to present day. With the electricity carbon intensity set at 0.519 kgC02/kWh for the past 8 years, heat network designers avoided using electricity as the primary fuel input as it would have driven the carbon reduction for any development into a non-compliance zone.
This is reflected in Table 1 as the emissions factor for electricity was almost 4 times higher than the current estimate in SAP10. Fast forward to 2019 and the result is electricity from the grid is now cleaner than gas. This drop in carbon intensity is the main reason heat generation strategies are now changing from gas to electricity on developments.
Schemes on SAP12 over the last 8 to 9 years have been designed to gas being lower on carbon intensity than electricity. The strategy to achieve a significant BE CLEAN and BE GREEN carbon reduction on large residential schemes would be to offset the need for high carbon electricity imports typically through the use of combined heat and power and or photovoltaic installations.
By opting for a gas-driven system now as your primary driver you are no longer getting the benefit of carbon reduction on a scheme like you used to under SAP12. The primary drivers on larger schemes now need to utilise electricity, this is where heat pumps will be introduced.
Heat pumps going forward will be the primary load drivers on developments. These heat pumps can take the form of air source, ground source or water source. Each one of these systems are complex designs in their own right and require specialist knowledge to fully implement and coordinate.
All developments approved under planning from the 1st of January 2019 are required to be assessed under the SAP10 carbon factors if governed by the GLA in London. Outside of London local authorities may have different views until the next iteration of Part L is finally introduced. Always check with your energy assessor what the planners are expecting in terms of the energy strategy and that will detail whether right now if SAP10 applies.
Should you have any queries on how these can be incorporated into a scheme or general advice about the change please feel free to contact us.
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