Heating our buildings without creating greenhouse gas emissions is vital in reaching net-zero. In this blog ClimateXChange research fellow Jonathan Bowes looks at the Scottish domestic heat targets, and options for reaching them.
Heat demand currently makes up over 50% of final energy demand in Scotland1 and decarbonising heating will be vital to meeting the governments legally binding target of a 75% reduction in emissions by 20302.
There are a number of ways to achieve zero emission heating. These include;
- replacing natural gas boilers with hydrogen created from low carbon electricity;
- using direct electric heating or heat pumps in houses;
- burning sustainable biomass; or
- connecting houses to heat networks supplied by any of the three heat sources above.
Hydrogen
The Scottish Government Hydrogen Policy Statement sets out the intention to generate 5GW of renewable and low-carbon hydrogen by 2030. How and where this hydrogen will be used is uncertain.
Hydrogen (H2) production is expected to ramp up – particularly in the north east of Scotland -with projects like H2 Aberdeen pioneering Hydrogen buses and development of Acorn hydrogen. However, if hydrogen production is slow to take off, it may mean it could have a limited impact in terms of meeting Scotland’s 2030 heat ambitions . Similarly, it may be that biomass will likely be reserved for sectors other than heating, and the capacity for production in Scotland currently falls far short of the heat demand. If hydrogen and bioenergy are unable to make a significant contribution to the 2030 heat target, this would mean that heat networks and heat pumps, using electricity mostly supplied by renewables, are likely to be the most suitable solutions for decarbonising domestic heat.
The challenge therefore is to determine a pathway that is balanced between short term and long term decisions. Choices made now must be on the basis of meeting the 2030 target while accounting for the uncertainty beyond 2030. This will require “low regret” options concerning technology choices for heating to be made to off-set climate change risks.
Low-regret options
There are two types of “low regrets” choices that could be prioritised for retrofit:
- The first is installing heat pumps in houses burning heating oil or LPG that are not connected to the gas grid (around 170,000 in Scotland3). If hydrogen does become a dominant vector for heat, it will be distributed by existing gas network, but this network is very unlikely to be expanded to connect remote houses that are not connected now. In addition, LPG and heating oil emit far more CO2e for equivalent heat supply than natural gas, further incentivising targeting these properties first to meet emissions reductions targets.
- The second low regret choice is developing heat networks in areas with a high density of heat demand. These networks offer a cost effective solution in locations with concentrated heat demand such as blocks of flats or offices and can make use of heat obtained from rivers, waste industrial heat and even mine water geothermal energy. These sources would be coupled with large industry scale heat pumps and could be supplemented with hydrogen heating in the future if that becomes a feasible long term solution.
Reaching the 2030 targets
So how does all of this stack up? How close to the 2030 targets do these low regrets options get us? The total emissions budget for buildings in 2030 is 2.6 MtCO2e4, compared to 8 MtCO2e in 2020. Based on published documents from Scottish Government, the pathway to achieve the heating element of these reductions looks like this:
- Almost all off gas grid domestic properties using oil or LPG will be converted to zero emissions heating (170,000) – likely to be mostly air source heat pumps.
- In addition to all high emissions off gas properties, least 1 million additional domestic properties currently connected to the gas grid and 23% non-domestic properties (50,000) will need to convert to zero emissions heating5 by 2030.
- 6 terrawatt hours (TWh) of heat will be supplied by heat networks annually by 2030 (equivalent to 400,000 – 600,000 average houses depending on size) across both domestic and nondomestic heat demand. This is a statutory requirement of the recently passed Heat Network Act
- From 2024, all new build properties will use zero carbon heating6
To reach an estimate of the number of installed heat pumps, we can remove the heat network suitable properties from the total of 1.167 million properties, giving between 517,000 and 717,000 domestic properties required to install heat pumps by 2030 to meet the climate targets. There may be the opportunity to reduce that number through the use of hydrogen, if both the production of hydrogen develops quickly and we find ways to convert parts of the gas network to deliver 100% hydrogen to homes.
Scaling up the roll-out
The proposed pathway is clearly challenging. Currently Scotland installs 3000 low carbon domestic heating systems a year across all technology types. To meet these targets, that rate must quickly ramp up over the next few years.
All of this will require huge amounts of work – digging up roads to lay pipes for heat networks and new hydrogen ready gas pipes, upgrading electricity networks, training new engineers, and building technology supply chains. We also need to reconcile the large upfront costs of heat pumps compared to gas boilers, and ensure that vulnerable and fuel poor consumers are protected.
1) https://scotland.shinyapps.io/sg-scottish-energy-statistics/?Section=WholeSystem&Chart=EnConsumption
3) Scottish Government. (2020), Scottish Household Survey (2019), Table 3.1., (Scottish Government), URL: https://www.gov.scot/publications/scottish-household-survey-2019-annual-report/ (last accessed: 20/06/2021).
4) Update to the Climate Change Plan 2018 – 2032: Securing a Green Recovery on a Path to Net Zero, page 253, https://www.gov.scot/publications/securing-green-recovery-path-net-zero-update-climate-change-plan-20182032/documents/
6) https://consult.gov.scot/energy-and-climate-change-directorate/new-build-heat-standard/
Jonathan Bowes is a ClimateXChange Research Fellow, working to understand how heat decarbonisation will impact Scottish electricity networks.
December 2020 saw the publication of many documents that had been delayed due to COVID, including the CCC 6th Carbon Budget, the BEIS energy white paper, and the update to the Scottish Climate Change Plan.
In this blog, part of UKERC’s Decoding Policy Series I want to offer an overview of the Scottish Climate Change Plan update, for those who missed it. The update presents a path to meet Scotland’s climate change targets to 2032 and beyond. The Climate Change Committee (CCC) 6th Carbon Budget is referenced to offer comparison to a similar UK wide document.
The Scottish context
Scotland’s own emissions targets differ from the UK as a whole. The CCC has on many occasions suggested a more ambitious date for net zero in Scotland, due to the potential for negative emissions and renewables in the region. In 2019, a legally binding net zero date of 2045 was set by the Scottish Parliament, with interim carbon reduction goals of 56% by 2020, 75% by 2030, and 90% by 2040 compared to 1990 levels.
In particular, the 2030 goal of a 75% reduction exceeds CCC recommendations. The 6th carbon budget called the target “extremely challenging” and pointed out that neither their Balanced or Tailwinds net zero pathways for the UK would meet the target, reaching 64% and 69% respectively in 2030.
The Scottish Government also has to deal with the challenge of devolved and reserved powers. They do not have devolved powers to legislate for every sector (for example they can legislate on energy efficiency in buildings, but not electricity networks). Devolved policy areas cover only cover around 60% of total required abatement.
Buildings
In 2018 heating buildings caused more than 20% of Scottish carbon emissions. By 2030 the update says over 1 million homes – 50% of the domestic housing stock – will be retrofitted with electric heat pumps.
This is clearly a huge challenge, moving from 2,000 to 200,000 annual installs in 10 year by 2030 – double the uptake rate the CCC have recommended for the rest of the UK.
From 2024 new build properties must use low carbon heat, local area energy planning and energy efficiency measures will play a key role and strong commitments are placed on energy poverty reduction. More detail on enabling pathways will be offered in the Heat in Buildings Strategy, due for publication in early 2021.
Transport
The “Sustainable Travel Hierarchy” continues to be at the centre of the Scottish Government’s transport strategy, showing a commitment to moving beyond single occupancy vehicles as the core of the transport system. By 2030 they have targets to reduce car kilometers by 20% and to have phased out new petrol and diesel cars on the road while focusing investment on active travel and public transport.
Electricity
The electricity sector in Scotland is already mostly decarbonised, with more than 90% of 2019 electricity coming from renewables. The challenge it faces is not the reduction of emissions, but scaling up as demand shifts from the gas networks and internal combustion vehicles onto the electricity network to facilitate decarbonisation of other sectors.
The key target is for the “2017 commitment to ensure all renewable energy accounts for the equivalent of 50% of our energy demand across electricity, heat and transport is successfully delivered” by 2030.
Land use
Scotland’s potential for carbon sequestration through forestry and peatland is one of the key reasons for the more ambitious targets. New commitments include planting 18,000 hectares of new forest a year from 2024/25 and a commitment to scale up peatland restoration.
Negative emissions
Negative emissions technologies, in particular the use of bio energy with carbon capture and storage will be used from 2029 and quickly scale to storing 10 MtCO2e a year by 2032 – equivalent to almost one quarter of Scotland’s 2018 emissions.
The same level is achieved for the entire UK by 2032 under CCC plans, including the planned retrofit of Drax power station.
The reliance on an unproven technology being deployed at scale has attracted criticism from a number of campaign groups including Friends of the Earth Scotland.
What next?
2021 will see the eyes of the world on Scotland with COP 26 being held in Glasgow in November. The pace of change and ambition shown in this document is exciting and if offer an exciting vision, hopefully over the next 12 months we will see more concrete pathways developed to match that ambition.
Read the Climate Change Plan update
Read the Climate Change Committee’s Sixth Carbon Budget