The TRANSITION project ran from January 2018 to September 2023. This five-year innovation initiative explored the market and technology requirements needed to enable flexibility within the electricity system.
Funded with £14.5 million through Ofgem’s Network Innovation Competition (NIC), the project supported the wider shift from Distribution Network Operator (DNO) to Distribution System Operator (DSO). Led by Scottish and Southern Electricity Networks (SSEN) the project contributed to SSEN’s mission to deliver a safe, reliable electricity supply to 3.9 million customers across the north of Scotland and central southern England.
TRANSITION played a key role in shaping SSEN’s move toward DSO by demonstrating how communities can support efficient use of local electricity networks, manage energy costs and contribute to delivering net zero.
TRANSITION’s aims were:
> Inform the design requirements of a DSO-facilitated flexibility marketplace and network interface.
> To develop the roles, responsibilities and rules within the marketplace and implement.
> Test these requirements through a programme of trials in Oxfordshire.
TRANSITION was designed to complement and collaborate with its sister project, Local Energy Oxfordshire (LEO), one of the UK’s most wideranging energy trials focused on accelerating the transition to a zerocarbon energy system. Through LEO, SSEN worked with nine partners from business, academia, social enterprise and local government to understand how electricity networks can optimise capacity and support local net zero ambitions.
The project demonstrated how a Smart Local Energy System (SLES) can enhance economic, environmental and social outcomes while improving customer participation in flexibility markets. TRANSITION supported LEO by developing the trading platform and services needed for new participants to engage in flexibility trading.
Together, the projects built a strong evidence base on the technological, market and social conditions required for a more flexible, fair and low carbon electricity system. LEO concluded in March 2023, with its Summary Report on Key Learnings available below:
Project Documents
Click below to access a zip folder of all documents relating to the TRANSITION Project.
TRANSITION Documents SSEEN0 : ENA Smarter Networks PortalWhat the outcome of TRANSITION means for you
The energy system that supports our net zero future must be smart, flexible and interactive. TRANSITION was a ground-breaking innovation project that worked to develop new tools, platforms and services that could allow people, businesses and communities to interact and trade with their local electricity network, if they wish.
Domestic and small business customers who want to passively participate in the DSO Flexibility Market
Simplified contractual arrangements were essential to enabling wider participation and unlocking flexibility from aggregators and suppliers. For a liquid market to thrive, flexibility had to be priced fairly, reflecting both local and broader socio-economic benefits, as well as the value gained by other market actors such as the ESO. Through the TRANSITION project, we successfully tested the neutral facilitation of a marketplace, demonstrating that it could deliver a variety of flexibility and capacity services across different timescales.
This was underpinned by robust digital models of the low-voltage network at street level, which provided accurate forecasts to support greater uptake of low-carbon technologies (LCTs). To help customers engage, we provided clear information on what flexibility meant—how it could help save money, reduce costs, and support Net Zero—along with accurate details on required changes, costs, and timelines. Finally, we implemented processes to ensure customer data was handled safely and securely.
Key Learnings and Outcomes
Flexibility from low-carbon technologies (LCTs) in homes and businesses, such as heat pumps, is often small individually, but when combined, it makes a significant contribution to achieving Net Zero. Third parties, including aggregators, help customers participate in the flexibility market, enabling them to earn money from their connections. By improving understanding of how and when electricity is used across the network, we connect more LCTs, such as solar panels and electric vehicle chargers, to homes.
The capabilities developed through the TRANSITION project allow us to manage the network more efficiently, ensuring better value for customers. To support engagement, TRANSITION also uses a ‘Plain English’ approach to simplify key terms and concepts related to the DSO transition.
Flexibility providers (DER owners & Technical Aggregators) who can provide flex to the DSO Flexibility.
The TRANSITION project provided a strong evidence base for flexibility market design and demonstrated the benefits of collaboration, supporting a whole-systems approach in ED2. Simplified contracts and transparent rules were key to unlocking flexibility and enabling wider participation. Fair pricing that reflected local and wider socio-economic benefits was essential for a liquid market.
TRANSITION proved that a neutral marketplace could deliver diverse flexibility and capacity services, supported by robust LV network models for accurate forecasting and greater uptake of low-carbon technologies. Automation of modelling, constraint prediction, and optimisation tools enabled efficient use of flexibility at scale.
To make participation easier, standardised services, improved data, and fair valuation supported investment. A single marketplace with multiple routes to market increased opportunities, while clear communication and transparent processes built trust.
Key Learnings and Outcomes
Alternative routes to market, such as different platforms, provide more opportunities for participants to access flexibility services. We have developed a robust process that clearly defines what needs to be done, when, and by whom to enable flexibility effectively. The S&D tool offers a formal and transparent way to contract and deliver flexibility, ensuring clarity and trust.
The ability to stack different revenue streams is essential for creating a liquid market where both market participants and the network benefit. To support this, contractual mechanisms must be easy to understand, concise, efficient, and accessible, making participation straightforward for all involved.
Commercial aggregators who want to participate in the DSO Flexibility Market.
The TRANSITION project provided a strong evidence base for flexibility market design and highlighted the importance of collaboration for a whole-systems approach in ED2. Simplified contracts and fair pricing were key to unlocking flexibility and enabling wider participation. Neutral marketplace trials proved the delivery of diverse flexibility and capacity services, supported by robust LV network models and diverse data sources that improved planning and uptake of low-carbon technologies.
Automation of modelling, constraint prediction, and optimisation tools was shown to be critical for efficient flexibility at scale. Standardised services, improved data, and fair valuation supported investment, while a single marketplace with multiple routes to market increased opportunities. Clear communication and transparent processes built trust and confidence.
Key Learnings and Outcomes
Alternative routes to market, such as different platforms, provide more opportunities for participants to access flexibility services. We have developed a robust process that clearly defines what needs to be done, when, and by whom to enable flexibility effectively. The S&D tool offers a formal and transparent way to contract and deliver flexibility, ensuring clarity and trust.
The ability to stack different revenue streams is essential for creating a liquid market where both market participants and the network benefit. To support this, contractual mechanisms must be easy to understand, concise, efficient, and accessible, making participation straightforward for all involved.
Aggregators play a crucial role in enabling small distributed energy resources (DERs) at the grid edge to participate in flexibility services. Aggregated volumes of domestic participation often prove more reliable than relying on a small number of large providers, which highlights the importance of widespread engagement. However, some contractual terms in the TRANSITION Flexibility Service Agreement, such as access and liability, are not well-suited for domestic aggregators. In addition, compliance with General Data Protection Regulation (GDPR) requirements increases the workload for both aggregators and DSOs when registering DERs, requiring additional time and resources.
FSO, regulation and planning partners who are developing a whole system approach.
The TRANSITION project provided a strong evidence base for flexibility market design and highlighted the importance of collaboration for a whole-systems approach in ED2. Simplified contracts and fair pricing were key to enabling wider participation and creating a liquid market. Neutral marketplace trials proved the delivery of diverse flexibility and capacity services, supported by robust LV network models and diverse data sources that improved planning and uptake of low-carbon technologies.
Learnings included feedback on commercial requirements, barriers to participation, and the need to adapt shared data to policy changes. The project also developed expertise to identify whole-system energy solutions across homes, businesses, heat, and transport.
Key Learnings and Outcomes
There is a strong appetite for standardising flexibility market elements—such as products, terminology, and solutions—to enable markets to scale effectively. Interest in DSO-Enabled Services remains high; however, limited liquidity during project trials resulted in insufficient trades. While DSOs can operate functioning markets to mitigate network constraints, increasing liquidity requires reducing barriers and ensuring flexibility is fairly rewarded.
Service requirements and primacy rules need review to allow market participants to engage across multiple markets. In addition, Local Authorities have a key role in overseeing Local Area Energy Planning (LAEP), but they require a clear mandate and access to open data to fulfil this responsibility.
Distribution System Operators (DSOs) who are developing their DSO functionality
The TRANSITION project provided a strong evidence base for flexibility market design and demonstrated the value of collaboration for a whole-systems approach in ED2. Simplified contracts and fair pricing were key to enabling participation and creating a liquid market. Neutral marketplace trials proved the delivery of diverse flexibility and capacity services, supported by robust LV network models and diverse data sources that improved planning and uptake of low-carbon technologies.
Automation of modelling, constraint prediction, and optimisation tools was critical for efficient flexibility at scale. The project also highlighted the need for clear frameworks, access to data and solutions to accelerate DSO functionality, and opportunities for innovation and new business models, alongside a better understanding of system requirements and data flows.
Key Learnings and Outcomes
Framework Agreements enable procurement of flexibility closer to real time, helping scale up market participation. TRANSITION has developed a robust End-to-End (E2E) process that serves as a strong foundation for industry-wide flexibility processes. The S&D and PSA tools created by TRANSITION streamline contracting and delivery, reducing lead times and supporting near real-time procurement.
Forecasting accuracy improves significantly with access to real-time data, such as that provided by NeRDA and ElectraLink. Additionally, the ENA baselining tool offers a solid basis for future development, though users need to consider its limitations and ensure methodologies are suitable for different DER types.
Current or potential technology yellow needs updated Supply Chain Partners, who are developing technology solutions to enable the DSO Flexibility Market
The TRANSITION project provided a strong evidence base for flexibility market design and demonstrated the value of collaboration, paving the way for a whole-systems approach in ED2. Simplified contracts were key to enabling wider participation and unlocking flexibility from aggregators and suppliers. Trials proved that neutral marketplace facilitation could deliver a range of flexibility and capacity services across different timescales.
This was supported by diverse data sources that improved short-term planning and decision-making, along with robust LV network models enabling accurate forecasts and greater uptake of low-carbon technologies. Automation of PSA modelling, constraint prediction, and optimisation tools was critical for efficient flexibility at scale.
The project also highlighted the need for market standardisation, early engagement to drive innovation, and a clearer view of future flexibility opportunities. Finally, it delivered a better understanding of the tools DSOs required, their system needs, and data flows.
Key Learnings and Outcomes
DSOs require fit-for-purpose IT solutions to run auctions through the Neutral Market Facilitator (NMF), simulate and resolve constraints using the PSA tool, and select contracts for dispatch via the S&D tool, all closer to real time. Python serves as the backend language for PSA and S&D tools due to its ease of use, compatibility, and global support.
Standardisation of data interaction, naming conventions (such as CIM), and programming languages supports efficient data sharing and reduces development time. Accurate connectivity data is essential for ensuring the reliability of network models and PSA results. Forecasting accuracy improves significantly with access to real-time data, such as that provided by NeRDA and ElectraLink.