In recent history, the British electricity sector landscape has changed as more renewables, particularly solar and wind, are connected to the power system. Since 2004, electricity generated from renewables in the UK has increased tenfold, and in 2019 37.1% of total electricity generated was from renewable sources.  These changes have far-reaching implications for the operation of national electricity networks and for ensuring security of supply.

The larger renewable installations are connected to the high voltage transmission network that interconnects the whole of Britain. Smaller ones are connected into the regional lower voltage distribution networks that, typically, transfer power from the transmission network down to each individual electricity users.

The technology used to convert the primary energy source into electricity is very different for renewables such and wind and solar from that used for thermal sources such as fossil fuels and nuclear fission. A common feature of wind and solar generators is the use of power electronic converters. Although the uptake of renewables is in keeping with Britain’s emissions reduction and renewable energy targets, it has the side effect of displacing conventional fossil-fuelled generation and the technical characteristics that these synchronous machines provide to power system operation. As a result, the British Electricity System Operator, National Grid ESO (NGESO), frequently needs to pay conventional power plants to come online and deliver key system services to ensure the security of electricity supply.

Going forward, in April 2019 NGESO announced a target of being able to operate a GB electricity system with zero-carbon generation by 2025. In practice, this means that NGESO aims to operate the system without needing to take actions that would restrict the dispatch of zero-carbon generation in favour of providing balancing services using unabated fossil fuel power plants, avoiding the need to “constrain on” such generators in addition to any that the wholesale electricity market might already be using. In order to achieve this, new service specifications and procurement mechanisms will be required to give NGESO the option of accessing services from zero-carbon technologies rather than coal and gas plants.

Current and emerging system operability concerns in GB cover a broad range of topics. Work recently completed at the University of Strathclyde, outlined in this report, has reviewed: how NGESO currently uses balancing services to manage the power system; possibilities for the future provision of frequency response and reserve; prospects for short circuit current support from power electronic converters; and market changes required to avoid the need for NGESO to constrain on fossil-fuelled generation to support system operability in 2025.

 

The Scottish Energy Strategy aims to: strengthen the development of local energy; protect and empower consumers; and support Scotland’s climate change ambitions while tackling poor energy provision.
One of its priorities is to promote consumer engagement and protect consumers from excessive or avoidable costs. It also aims to promote the benefits of smarter domestic energy applications and systems for all consumers.

The Scottish Government commissioned several linked research projects to support its work on promoting consumer engagement and protecting consumers as part of Scotland’s low-carbon transition.

The programme of work, completed in 2019, consisted of:

  1. Reviewing current approaches aimed at identifying groups of energy consumers in the UK.
  2. Developing an approach to identifying specific groups of energy consumers, identifying eight specific groups or archetypes.
  3. Reviewing forthcoming changes in energy policy to identify those changes likely to impact on energy consumers. These changes were grouped into policy changes associated with:
    • smart energy; 
    • decarbonising energy supply; and 
    • energy efficiency.
  4. Considering the implications of a subset of these policy changes for each specific energy consumer group to highlight how they may impact differently on each consumer group.

The research highlighted that the energy policy landscape is changing significantly, and that forthcoming changes in energy policy are likely to impact on consumers in a variety of ways. The impacts of specific changes in energy policy on each of these groups of consumers can be modelled. Among other things, we model the implications of a switch to time of use (TOU) tariffs; increased uptake of electric vehicles (EVs); and the future for domestic heat pumps and solar photovoltaics (PV) systems for different consumer groups. Overall, the modelling shows that those with higher incomes are more likely to participate in the evolving smart energy market and benefit from new technologies and energy market solutions, raising equity and distributive concerns.

Our research outputs comprise five reports including a summary report which gives an overview of the project and the main findings.

Scotland has committed to achieving net-zero greenhouse gas emissions by 2045. Heat is at the core of Scotland’s energy system, accounting for approximately half of the energy consumed by homes and businesses. This makes heat the biggest element of Scotland’s energy use and its largest source of emissions. The Scottish Government (in line with advice from the Committee on Climate Change) has identified heat networks, or district heating, as one of the ‘low-regret’ options – low cost and with relatively large benefits – for heat decarbonisation. Its Climate Change Plan 2018[1] (CCP) focuses on significant reductions in emissions from buildings, both residential and non-domestic.

This study supports the emerging regional and national policies associated with the development and deployment of low-carbon heat networks (or district heating) by examining potential waste heat sources in Scotland that have received limited attention. Heat networks, or district heating, involve providing heat to homes and businesses via insulated pipes in the form of hot water or steam.

 The study assesses the waste heat potential of 10 different sectors (distilleries, breweries, bakeries, paper and pulp, laundry, supermarkets, data centres, electricity substations, waste-water treatment plants (WWTP), and landfill) using a variety of data sources and calculation steps.

 Waste heat potential:

  • The study has identified a waste heat potential of circa 1,677 GWh across some 932 sites in Scotland. 
  • The largest waste heat potential was estimated to be in the distillery and waste-water treatment sectors. Bakeries and paper and pulp are the other sectors with high waste heat potential.

Opportunities:

  • Data centres, breweries, supermarkets, laundries, bakeries and paper and pulp sites have relatively high heat demand in their local areas. As a result, these may provide potential for district heating (DH) opportunities.
  • 237 sites (equivalent to 25% of all the waste heat sites we identified, with a total waste heat potential of 146,554 MWh), have an existing DH scheme within 500m.

Recommendations:

  • Further investigation is recommended on the technological aspects of waste heat recovery from WWTPs, distilleries and paper and pulp mills, as these sectors have relatively higher theoretical waste heat potential. 
  • There is a need to review and assess the heat recovery technologies suitable for capturing waste heat from electricity substations. 
  • The viable distance for the distribution and use of waste heat will vary depending on several factors. Further research in this area and/or reviews of the technical and commercial aspects of recovering and re-using waste heat in district heating systems would be advantageous.
  • As only a simplified proximity analysis was undertaken, it would be advantageous to conduct additional analysis to explore the opportunities for supply / demand matching in more detail.

This report examines the role grid-scale battery storage could play in providing a resilient, affordable electricity network. In line with Scotland’s Energy Strategy and Net Zero emission targets, it considers the period to 2030 and 2045, reviewing current practice and experience, and current expectations for further developments.

Grid-scale battery storage is likely to be an important part of the evolution of the electricity system in the UK, with capacity in Scotland estimated to rise to 1,800-2,700 MWh by 2030, and 6,800-10,500 MWh by 2045. This is driven by several factors, in particular, the growth of variable renewable energy (wind, solar) and decarbonisation by electrification of heat supply and transport. Battery system costs are also expected to fall further.

It finds that, in the Scottish context, battery storage is likely to be particularly useful in the longer term in supporting weaker parts of the electricity system, such as on islands and in more remote areas with a high proportion of renewables. Few issues have been encountered so far in obtaining development consent for battery projects, it notes, with proximity to an adequate grid connection the factor most influencing siting.

There are many different ways to define and assess cost effectiveness. The Scottish Government needs a sound, evidence-based definition of cost effectiveness to use in the Energy Efficient Scotland programme, which proposes to bring all Scottish homes up to an Energy Performance Certificate Band C by 2040, where technically feasible and cost effective.

This report looks at the pros and cons of using different definitions of cost effectiveness in relation to energy efficiency investments in homes and non-domestic buildings.

We found that cost effectiveness definitions vary in how energy savings are predicted or measured, in what other costs and benefits are included, and in the metrics used. We identified nine methods of evaluating cost effectiveness, summarised in the table below, along with our assessment of the pros and cons of each.

 The definitions of cost-effectiveness is discussed in relation to:

  •  Packages versus single measures
  • Wider benefits to society
  • Differences in domestic and non-domestic sectors
  • Variations in application
  • Sources of funding
  • Acceptability of payback periods
  • Uses in practice
  • Practical lessons 

Bioenergy already contributes to energy supply in Scotland, meeting an estimated 4.4% of final energy demand in 2016.  This has been achieved through a number of bioenergy conversion technologies utilising a range of bioresources.

The Scottish Energy Strategy, published in December 2017, sets out the Scottish Government’s vision for a flourishing, competitive energy sector, delivering secure, affordable, clean energy for Scotland’s households, communities and businesses. The Strategy sets out the ambition for 50% of all energy consumed in Scotland to come from renewable sources by 2030. One of the actions to achieve this is developing a bioenergy action plan.

This study forms one of the first steps in developing the bioenergy action plan, setting out an evidence base on the nature and quantities of biological resources within Scotland that could be used for bioenergy, and the conversion technologies that could be deployed to utilise them.

Main findings:
  • Bioresources equivalent to 6.7 TWh per year (in primary energy terms) are currently used for bioenergy purposes. Just over three-quarters of this is wood.
  • Increasing the contribution that bioenergy makes by 2030 would require additional bioenergy plant to be built and deployed within the next decade.
  • Based on typical capital, operating and feedstock costs, all of the bioenergy conversion technologies considered produce energy or fuel at a price that is higher than that produced by conventional technologies, based on current fossil fuel prices.
  • Estimates of domestic bioresources suggest that several additional anaerobic digestion plant are technically feasible, but utilising the resource fully is likely to require the use of a mixture of feedstocks in some plant.
  • Advanced conversion technologies such as gasification for power or to produce synthetic natural gas and advanced biofuels production could be commercially proven by 2030.
  • Allowing for competing uses of some bioresources in other sectors of the economy, there is another 5.3 TWh per year (of primary energy), that is currently not collected or is disposed of as waste, that could potentially be utilised for bioenergy.
  • By 2030, further bioresources equivalent to 2 TWh per year (of primary energy) could be available.

The way we generate, distribute and consume energy is changing, and many observers anticipate accelerated changes ahead. These transformations are being driven by a combination of policy and regulatory pressures, rapid movements in the cost and performance of some energy technologies, and shifting patterns of consumption and behaviour.

This UKERC/CXC report presents results from a detailed survey exploring the differing views. It finds agreement that large scale renewables, buildings refurbishment and electric vehicles will play a major role in the UK energy system transition – but much less agreement in other areas, such as the role of behaviour change and modal shift in the transport sector, and the likely path for decarbonising buildings heat supply.

Read a blog about the project

Traditionally Scotland’s energy systems have relied on large centralised sources. The Scottish Government is now pursuing a policy of smarter, local models.  

This project is part of looking at the the opportunities for, and implications of, Scotland moving towards smart local energy systems, driven by sustainable decarbonised energy resources.  The research team has developed the Energy Flow Scotland (EFS) toolset which draws on other models to quantify energy flows, including both the anticipated demand and likely supply of energy.

The models quantify predicted energy flows at a district level, allowing for analysis of local energy demand and resources at a local level under different future energy scenarios. We have used the EFS toolset to analyse different credible future scenarios for Scotland’s energy system.

Key findings and conclusions
  • A highly decarbonised and decentralised energy system will require significant investment in the electrical distribution system to make it fit for purpose.
    Local areas that introduce a balance of new low carbon demand technologies (such as EVs and Heat Pumps) with low carbon renewable generation will reduce the impact on electrical substations and thus requirements to upgrade. Areas that connect significant volumes of new renewable generation, without an associated rise in EVs/HPs, will see large rises in exported energy.
  • A rise in low carbon demand technologies will impact electrical distribution substations, with a high number requiring reinforcement by 2040. However, a more centralised pathway that revolves around the integration of renewable generation concentrated in areas of natural resource will incur greater overall additional electrical system capacity requirement, despite perhaps less electrical substations requiring upgrade.
  • The electrical distribution system across rural areas will be impacted more than urban areas between 2018 and mid-2030s. However, a steady rise in low carbon demand technologies will result in a sharp impact on urban areas between mid-2030s and 2040.
  • Meeting future carbon reduction targets may be achieved using either a centralised or decentralised approach. However, this analysis forecasts that it will cost roughly 2.6 times more to upgrade the electrical distribution system using a decentralised approach in comparison to a centralised strategy.
The interim summary report includes:
  • Development of the EFS toolset of electrical, heat and transport demand models, and renewable generation models.
  • Use of the EFS toolset to model how electrical energy flows may change at electrical grid supply points (GSPs) throughout Scotland under a particular 2030 electrified energy future scenario.
  • Analysis of how decarbonisation and decentralisation may impact electrical flows at particular GSPs, as well as discussion on the distinct challenges and opportunities at both urban and rural areas.
  • Description on how local energy balancing may be used to reduce the need for future network reinforcements.

ClimateXChange commissioned Changeworks and the Centre for Energy Policy, University of Strathclyde to review existing European regulatory models and identify learning from each that are relevant to the Scottish context. The outputs will add to a body of existing research which will inform the Scottish Government’s proposals regarding regulation in the coming years.

This report details the findings from a review of seven European DH regulatory models, including a contextualised evaluation of each model. The research used evidence gathered through a literature review and interviews. 

As a product of the research, four key components of an effective regulatory system for district heating are identified as:

  • Long term planning and commitment to DH development
  • Successful use of tools which stimulate market development and investment in the sector
  • Co-ordination of national and municipal governments, and scope for industry interests to have a say in certain regulatory issues
  • Flexibility to allow for innovation, and account for market changes

These are the key lessons to be considered for the introduction of district heating regulation in Scotland.

This report looks at different approaches to modelling energy efficiency within TIMES, the whole energy system modelling framework used by the Scottish Government to inform energy and climate change policy decisions. The findings are based on six different energy efficiency scenarios for residential heating.

This has two objectives:

  1. To identify different approaches for energy efficiency scenario modelling in TIMES, and provide an assessment of strengths and limitations of each modelling approach.
  2. To give recommendations on how to use TIMES effectively for energy efficiency policy analysis.

There is no single energy efficiency scenario which is superior to the others, as each focuses on different policy targets which could come into conflict with each other. For example, the results of some scenarios prioritise energy efficiency improvements whereas others prioritise cost reduction or emission reductions. Policy makers should understand the compromises involved in using each of these scenarios and prioritise certain indicators over others.