Accelerating net zero building retrofit
As part of the Net Zero programme series, this blog explores how Towns can work towards Net Zero when thinking about their retrofit projects. It will discuss the following areas:
How to achieve emission reduction in the building sector
Exploring various options to retrofit
Five ways to integrate Net Zero into Towns Fund retrofit projects
1. Retrofitting: a way to reach Net Zero
Reducing emissions in the building sector is a huge part of reaching Net Zero by 2050 – and retrofitting is key to this. This includes significantly improving the energy efficiency of our buildings through insulation, glazing and controls, as well as a shift from gas heating to low carbon heat supply. The UKGBC Net Zero Whole Life Carbon Roadmap suggests that meeting our national commitments will require no new boilers to be installed after 2030 and the use of heat pumps in 80% of homes by 2040.
Why is retrofit needed to meet Net Zero targets?
The UK legislative targets are to meet net zero emissions by 2050 and reduce greenhouse gas emissions by 78% by 2035 on 1990 levels.
Buildings make up 17% of UK emissions.
Homes are the most significant contributor to building emissions.
Heat pumps are widely considered as the obvious alternative to gas boilers and are available for a wide range of heat sources, including air-source, water-source, ground-source, of which the most suitable option depends on the characteristics of the site. Some of the towns are considering site-specific options such as mine water from ex-mines.
Retrofitting can often be a lower carbon alternative to new builds when on whole-life carbon basis, as it is typically associated with much lower ‘embodied’ emissions – those emissions associated with the extraction, processing, transport, and end-of-life of materials. By building less, the carbon in buildings will also be reduced.
Retrofitting buildings can bring several benefits, including:
Addressing the climate energy.
Reducing energy bills for consumers.
Providing opportunities to access ESG finance.
Improving health benefits.
Creation of jobs and skills.
Providing opportunities to integrate green infrastructure.
Pathway to retrofit
Existing homes:
The UKGBC Net Zero Whole Life Carbon Roadmap report outlines the required changes needed for the UK to reach net zero emissions by 2050. These include:
97% of homes to be retrofitted by 2040
Building performance targets
Installing fossil fuel boilers: End of sales of gas and oil boilers in 2030.
Installing hydrogen boilers: Hydrogen boilers used in homes near industrial clusters from 2040, reaching 12% of homes by 2050.
Heat pumps: the goal is to install 80% of all homes by utilising heat-pumps by 2040.
PV: goal is to have 30,000 MW PV installed on domestic properties by 2050.
Lighting: 5% reduction in domestic lighting usage by 2035, 10% by 2050.
Unregulated energy: Domestic gas cooking phased out by 2040 with all households using high efficiency electric induction cooking hobs by 2045
Existing non-residential buildings:
Build performance targets
Install fossil fuel boilers: End of sales of gas and oil boilers in 2030.
Hydrogen boilers: 7.5% of non-domestic buildings are set to have hydrogen boilers by 2038.
Heat pumps: 70% of all non-domestic benefit to from heat pumps by 2045.
PV: 6.7% annual increase in PV installations on non-domestic building.
Unregulated energy: Gas cooking phase out in 2030-2040.
2. Exploring Net Zero technology options
The energy hierarchy set out in the London Plan 2021 offers a prioritised set of steps to guide the design process of retrofit projects in order to maximise carbon reductions. The steps include:
Be Lean: Prioritise demand reduction by looking at ways to design for lower operational energy use, e.g. through highly insulated building fabrics and utilising windows for natural insulation.
Be Clean: Use and supply energy efficiently by using all-electric systems with zero reliance on combustion systems, for example integrating highly efficient and optimally sized Air Source Heat Pumps and storage.
Be Green: Integrate on-site renewables such as rooftop solar PV. Demand reduction will allow a greater proportion of total energy supply to be provided by renewables. Can choose a green energy tariff for your electricity supply. There is an upcoming blog that will outline potential approaches for renewable energy procurement that will provide more information.
Offset: Any residual carbon can be offset by a cash in lieu contribution to the local authority’s carbon offset fund.
Be Seen: Robust monitoring and verification of energy performance.
Image 1: Energy hierarchy (Figure 9.2 in London Plan 2021)
Understanding energy use within your Town and how to best decarbonise these areas:
Commercial Office: These spaces are often cooling dominated.
Pools: Require constant heating load, and therefore may present a good opportunity for heat sharing with neighbouring cooling-dominated uses.
Retail: Potential for more relaxed internal set points. Some very variable loads and can have high lighting loads.
Mixed use: Heat sharing opportunities, including diversity. All building types should be considered to be used as a shared heating/cooling network.
Technology options
There is a vast range of options that you can retrofit into existing buildings to increase energy efficiency and decarbonise the energy supply. This list is growing all the time, but some of the most well-established options are:
Heat pumps: Deliver heat much more efficiently without burning fossil fuels.
Variable speed fans: Runs at different speeds to control the flow of heated or cooled air throughout the home.
EC motors: (Electronically commutated): designed to run on alternating current power supply. Essentially a permanent magnet, brushless direct current motor that incorporates on-board electronics.
Heat recovery: Waste heat is recovered and used for an alternative application.
Demand control system: feedback control method to maintain indoor air quality that automatically adjusts the ventilation rate in response to changes in conditions such as occupant number.
Smart systems: Thermostatic device fitted to heating system and connected wirelessly.
What can Local Authorities do?
1. Implement direct Control
2. Procurement and Commissioning & Commercialisation.
3. Place shaping: using powers to control development and transport.
4. Showcasing: Sharing good practices and replicating ideas.
5. Create partnerships: Leading, bringing people and organisations together.
6. Engage and communicate with people within the Town: Translating global and national climate change targets for local relevance with stakeholders to raise awareness.
How Local Authorities can integrate Net Zero into Towns Fund projects
1. Retrofit of council owned buildings: Because these buildings are in direct control of the council, there is a more direct opportunity to retrofit. You can find more information in the Net Zero playbook.
2. Consider an ESCO model (Energy Service Company): This would involve contracting an energy service company to take responsibility for retrofit process, all the way from design through construction and into operation.
3. Funding: Third-party support can be secured by outlining goals to reach the BREEAM, UKGBC Net Zero framework, EnerPHit. If approved, a grant would then be up for offer.
4. Planning permission: Integrating Net Zero through planning permission involves utilising the Local Plan, for example through ‘Net Zero considerations’ or ‘supplementary planning guidance’. This is a longer process so requires forward planning. It is also possible to integrate requirements to meet the threshold standards: UK GBC Net Zero, BREEAM, PassivHaus EnerPhit Standard
5. Encourage private sector commitment: This would involve fostering private sector pledges through the skills board or chambers of commerce.
Conclusion
Reaching net zero emissions by 2050 will require bold action across all sectors, and widespread retrofit of our buildings to increase their energy efficiency and decarbonise their energy supply is a crucial part of the low carbon transition.
The intention of the Net Zero Programme under the Towns Fund is to help towns integrate important net zero considerations into their projects, in order to accelerate local climate action and raise ambition to reach net zero.