Emissions from transport must reduce significantly to achieve Scotland’s target of net zero greenhouse gas (GHG) emissions by 2045. While Transport Scotland states that zero-emissions solutions are preferable (such as battery and fuel cell electric vehicles, and direct electrification) these are not feasible in some sectors such as aviation and shipping.

In these situations, low-carbon fuels (LCFs), which emit less GHG than fossil fuels, may be more appropriate. The type of feedstock and the conversion technology used to produce the fuel affects the amount of GHG that is emitted.

The purpose of this report is to review the evidence and policy surrounding LCFs in transport.

Conclusions

• LCFs in Scotland will be essential in decarbonising the aviation and maritime sectors.
• In the short term, the reliance is likely to be on established biofuel-based technology to meet the demand. The key issue is maintaining a sustainable feedstock as demand increases both domestically from the heat/power sector and from the global economy.
• Green hydrogen and such derivatives are known as renewable fuels of non-biological origin (RFNBOs), which generally offer greater carbon savings compared to biofuels and the third category of LCFs, recycled carbon fuels (RCFs). Longer term, the demand would ideally be met by RFNBO-based technology, as this does not generally have the same constraints surrounding feedstock availability as biofuels or RCFs. However, research and investment into the required technology and infrastructure will be essential in realising this potential.

For a complete list of findings and further information, please download the report.

If you require the report in an alternative format such as a Word document, please contact info@climatexchange.org.uk or 0131 651 4783.

Social housing comprises almost a quarter of Scottish homes and the housing sector represents around 15% of Scotland’s greenhouse gas emissions. While the sector has already made strong progress in reducing emissions, the entire housing stock will need to use zero direct emissions heating (ZDEH) systems to reach Scotland’s net zero target by 2045.

This report defines archetypes for dwellings in the social housing sector enabling identification of suitable energy efficiency measures and an appropriate ZDEH system.

The archetypes represent a first step towards future development of a ‘pattern book’ or similar approach, which social landlords could use as a starting point for lowering emissions from their properties.

The findings will support the review of the Energy Efficiency Standard for Social Housing 2 (EESSH2) and help ensure the new standard is based on the strongest available evidence.

Findings

The researchers reviewed archetyping studies and used a dataset of all Scottish social housing from Home Analytics Scotland to define key physical archetype parameters such as property type, wall and floor construction.

When applied to the whole stock, these parameters give a total of 24 archetypes, of which 12 represent over 90% of the total number of dwellings. For each archetype, the report provides a list of recommended energy efficiency measures appropriate to the building’s physical characteristics.

The suite of ZDEH systems that can, in principle, apply across most or all archetypes are air and ground source heat pumps, district heat networks and direct electric heating. A limited potential role for biofuels and hybrid heat pumps is also discussed.

The resulting method, whereby social landlords can identify a route to ensuring properties are suitable for a net zero future, is summarised as follows:

1. Identify archetype using property type, wall construction and floor construction in order to produce suite of suitable measures.
2. Note constraints such as room-in-roof, no wet heating system, mixed tenure property, conservation area or listed status, off gas grid to amend suite of measures.
3. Select appropriate ZDEH system such as air or ground source heat pump, heat network, direct electric heating or hybrid heat pump to ensure home is net zero ready.

Further details on the findings are in the report attached.

If you require the report in an alternative format such as a Word document, please contact info@climatexchange.org.uk or 0131 651 4783.

Update: Please note that a small change has been made to Table 13, OPEX for Lined Rock Caverns, in May 2024.

As the share of renewables increases in power generation, periods when there is too little energy or more than can be accommodated, known as intermittency and curtailment respectively, are becoming a challenge to fully realising Scotland’s renewable potential.

This report investigates the options for storing energy in the form of hydrogen in Scotland and its potential for reducing curtailment of renewable energy.

It also investigates the role of hydrogen peaking power for electricity generation during times of low renewable energy generation.

Summary of findings

The study found that hydrogen storage will play an important role in balancing an energy system that has large amounts of intermittent renewable energy.

All hydrogen storage technologies are anticipated to support the flexibility of the energy system. The size of the role and use cases will vary significantly between technologies, with most of them supporting long-term, weekly, monthly and seasonal storage.

Different storage solutions have different suitability for deployment in Scotland. Much of this is driven by geology, use case and timescales.

For a full list of findings, please download the report attached.

[If you require the report in an alternative format such as a Word document, please contact info@climatexchange.org.uk or 0131 651 4783.]

This report looks at different options for conducting whole building assessments of multi-owner and mixed-use buildings, through a literature review and structured conversations with stakeholders.

These assessments are needed to plan the improvement of building fabric efficiency and installation of zero direct emissions heating systems.

Summary of findings

Current assessment methods cannot be used for the purpose of retrofit design because they are designed for comparison rather than absolute calculations of building performance. The assessment of multi-owner and mixed-use buildings requires two methods, which cannot currently be combined to produce a single assessment.

The report outlines three options for how a whole building assessment methodology could be developed in Scotland:

• A low-cost option, based primarily on assumed data rather than measured data. It involves updating existing methods to complete a whole building assessment.
• A detailed assessment approach with PAS 2035 – a British framework for delivery of quality retrofits of domestic buildings
• An assessment approach that draws on best practice from the international examples the researchers found.

Further details on the findings can be found in the report attached.

If you require the report in an alternative format such as a Word document, please contact info@climatexchange.org.uk or 0131 651 4783.

Please note that a small change has been made to Table 13, OPEX for Lined Rock Caverns, in May 2024.

This report provides an analysis of international approaches to regulating domestic energy efficiency and heat decarbonisation that are comparable with Scotland’s aims, as outlined in the Scottish Government’s Heat in Buildings Strategy.

Particularly of interest were regulations focused on existing domestic buildings (more so than new build) and regulations that promote a phase out or ban the use of fossil fuel-based heating.

The research identified regulations and policies relevant to heat and energy efficiency internationally, investigated their effectiveness and, where possible, identified why some approaches work and others fail.

The report highlights key considerations or precedents within the international policy area to better determine how similar regulations could work in Scotland.

It provides key learnings from other countries, regions and cities, which will be useful to the development of successful regulations by the Scottish Government.

Summary of key findings

• The most common type of domestic heat regulations are bans prohibiting the use or installation of certain heating systems or certain fossil fuels, and mandates that set minimum emissions levels from these heating systems.
• For energy efficiency, the most common type of regulation is mandating minimum energy efficiency levels.
• Bans and mandates are similar in nature and impact. Generally, mandates provide more flexibility to the householder as to how they meet regulations. Both bans and mandates are effective in reducing the use of fossil fuelled heating systems and/or reducing carbon emissions from homes.
• Regulations and policies are heavily focused on new builds rather than retrofitting existing buildings. In many cases, implementing measures in new build was a precursor to implementing them in existing housing.
• There isn’t a regulation or measure focusing only on multi-family homes, although these types of homes are usually included as a target in the regulations.
• There is little evidence of legal challenges to the measures and policies analysed in this study. In the rare instances when it happened, citizens challenged the regulation for fears of housing cost increase, but there was general support for the objectives of the regulation. However, it should be noted that the regulations implemented to date have mostly been tackling old and inefficient appliances and more ambitious regulations are likely to be needed to meet more stringent climate change targets.
• A few of the regulations allow hybrid heating systems. For example, in Germany, if a low-carbon alternative isn’t technically feasible, the heating system needs to be hybridised to include at least one renewable source.
• With bans and mandates, there is usually a phase-in period between 1 and 10 years before the measure is enforced and compliance monitored. Financial support schemes have been implemented by governments alongside bans and mandates.

For further details on the findings and a list of recommendations, please read the report attached.

The Scottish Government requires new buildings to use zero direct emissions heating (ZDEH) systems from 2024, as part of the New Build Heat Standard regulation. This is to help meet its greenhouse gas emissions targets and achieve net zero emissions by 2045.

Through the Islands (Scotland) Act 2018, the Scottish Government is required to assess the impacts of any new policy on island communities to understand the challenges of implementation.

This study sought to understand which zero direct emissions technologies are best suited to the unique consumer and geographical characteristics of Scottish islands and remote communities. Impacts on local infrastructure and supply chains are also considered as well as factors that may constrain the uptake of these technologies.

The outputs of this work are derived from a combination of a literature review and interviews with local authorities, housing associations, builders and heating installation and maintenance companies who operate in these areas.

Overall, the research has demonstrated that the uptake of ZDEH technologies in new buildings in island and remote areas of Scotland do not face more significant barriers than in other parts of Scotland.

For a full list of findings please download the report.

In Scotland, wind energy is sometimes significantly higher than the transmission network’s capacity to transport the electricity to the rest of Great Britain. When this happens, payments are made to wind farms operators to compensate them for having to reduce their site’s power output to the level the network can absorb. This reduction is known as curtailment.

To prevent zero-carbon renewable energy going unused, curtailed energy could be an attractive source of electricity. It can reduce the overall cost of hydrogen production, through installing electrolyser units, which can utilise this power that would otherwise be curtailed.

The hydrogen produced can then be used for a variety of applications, including industry, heat and transport.

This report looks at whether curtailed energy from large-scale renewables in Scotland could be used to produce hydrogen economically. For further details, please read the report attached.

Key findings 

• The deployment of electrolysis will potentially lead to a significant decrease in curtailment of renewable energy due to increased electricity load behind network constraints. This will depend on the location of deployment and revenue mechanisms.
• Given that wind generation in Scotland is likely to grow faster than network reinforcement, there is likely to be a significant volume of curtailed energy in the late 2020s and possibly into the 2030s. Having facilities co-located with electricity generation may make the production of hydrogen from curtailed energy cost-competitive with other sources.
• However, these volumes of curtailed energy may be transitory in both timing and location due to expansion of the transmission network. As the transmission network is reinforced, there will be less network-related curtailment.
• The frequency of curtailed energy is generally higher in northern Scotland due to additional network constraints, so electrolysers used for hydrogen storage located further north will have potentially higher load factors and a lower cost of hydrogen production, at least in the near-term.
• If curtailed energy is used for other options and less for hydrogen production, hydrogen production might not be cost-competitive.
• Substantial hydrogen storage will be needed to buffer between production and demand. Near-term hydrogen electrolysis deployments are likely to be dependent on individual customers such as local heating systems or transport providers. In the absence of a wider hydrogen network, hydrogen will need to be stored either by the supplier or the customer.
• By the early 2030s, transmission-connected wind capacity is likely to significantly exceed off-peak electricity demand, meaning that curtailment will likely remain an ongoing feature of system operation. The availability of curtailed energy will depend on the wider context for energy system management and electrolysis will compete with a broad range of options, such as interconnection, battery storage, demand-side response and new pumped hydroelectricity capacity. The business case for using electrolysis for hydrogen storage will depend on the general growth of the hydrogen economy, transition of gas networks and broader market mechanisms that may be implemented across Great Britain’s electricity and gas systems. The near-term use of curtailed energy for electrolysis can generate significant learning and preparation for a future where hydrogen may be used as a large-scale energy vector for system balancing.

Building-level energy storage allows consumers to capture cheap electricity or heat when it is available and store it for later use.

This report examines the extent to which such technologies could help to reduce household energy costs when installed alongside zero-carbon heat technologies.

We also present results from a simulation exercise to determine the cost effectiveness of electric batteries, heat batteries and thermal storage installed alongside heat pumps.

The key findings show that currently there is little commercial benefit to the householder installing storage without localised electricity generation. However, the potential role of domestic storage in smoothing peak demand periods on the grid indicates that building-level storage will be required to support the decarbonisation of heat through electrification.

Recommendations

• Once published, the monitoring results from ongoing projects with building-level storage should be reviewed for evidence of financial savings for consumers. This includes the UK Department for Business, Energy and Industrial Strategy (BEIS) electrification of heat pilot, OVO Energy’s trial with Powervault and various project that are funded by the Scottish Government.  
• Ensure the Distribution Network Operators (DNOs) in their transition to District Systems Operators (DSO) actively provide support for local and national flexibility markets by engaging with aggregators when planning for the increased future demand on the grid.
• Where feasible, installers and property owners should be encouraged to pair thermal storage with heat pumps. Although there is limited evidence of the direct financial savings that this can provide for consumers, the benefits of improved system efficiencies, heat pump longevity and the ability to ease pressure on the grid during peak periods will provide indirect financial benefits.
• Grant funding or some form of financial incentive may be necessary to encourage the installation of thermal storage with heat pumps.
• Further research is conducted to understand what the identified savings from existing and ongoing research might mean for rates of fuel poverty.

Green hydrogen, produced by electrolysis exclusively with renewable electricity, is expected to play a key role in the Scottish Government’s mission to achieve net zero emissions targets.

Hydrogen is a versatile energy vector that can be used in a range of applications without emitting carbon dioxide at the point of use.

Scotland has set an initial ambition of producing at least 5 gigawatts of renewable and low-carbon hydrogen by 2030 and 25 gigawatts by 2045.

Meeting these targets will not only contribute to emissions reductions but also has the potential to safeguard future industry and employment. Scotland’s geography, geology, infrastructure, and expertise make it particularly suited to rapidly developing a low-carbon hydrogen economy. This could see Scotland become a global leader in hydrogen, and secure economic opportunities across the UK.

This report explores the costs of producing green hydrogen in Scotland. It considers the key drivers of cost and explores how the production cost and the supply chain could develop to 2045.

The study investigated each part of the supply chain, to understand the current costs and barriers, as well as to identify where policy support could help the green hydrogen economy to grow.

It has defined four hydrogen production pathways which reflect the main supply chain models that are expected to emerge in a green hydrogen economy: centralised system, distributed pahtway, export model and decentralised model.

Main findings and recommendations

• The cost of hydrogen is expected to at least halve between 2022 and 2045 for the three pathways connected directly to wind farms.
• Electricity costs are the biggest driver of hydrogen cost reductions from 2030 onwards.
• Scaling up the industry is expected to lead economies of scale and drive manufacturing cost savings across the supply chain.
• Domestic infrastructure to transport hydrogen is currently limited and needs to be rapidly developed to ensure the continued emergence of the green hydrogen sector in Scotland.
• Price competitiveness with natural gas in industrial-scale applications is unlikely before 2045 without government support.
• Subsidy support will be required to encourage adoption of green hydrogen in the short term.
• Scotland has potential to become an exporter of hydrogen to Europe.