TNEI has supported several clients through all stages of the Electricity System Restoration (ESR) tender process both in the South East and the Northern tenders.
We have provided technical advice and expertise to clients in assessing the capability of their sites to meet the requirements of the different ESR services – Primary, Top Up, Anchor (DR) and Top Up (DR).
Since launching in 2022, TNEI has supported several clients through the different stages of the ESR tender process. So far, we have assessed the capability of over 3.5GW of transmission and distribution connected assets to support in restoration service provision.
The EOI stage is an early, high-level indication of site capability to allow ESO to determine the level of interest and likely capabilities of sites in different areas. Here TNEI supports clients in extracting the relevant information from existing OEM reports or design specifications, and gathering this into the ESO template.
The ITT1 stage is a more involved process of providing details on exact specifications for site capabilities. This stage allows providers to assess their sites and what modifications might be required to ensure they meet the ESR minimum requirements. For example, is it likely that the site can provide sufficient inertia or short circuit level?, And if not, how might this be achieved?. TNEI supports clients in this stage by reviewing either designs or OEM reports (depending on the status of the site – in planning, in construction, operational), and aligning these to the ESR requirements. Where gaps are identified, TNEI would propose how to address these. A key part of ITT1 is scoping the different studies and activities required for ITT2, which we carry out in close liaison with our clients.
The final ITT2 stage involves the detailed analysis of a site’s capabilities to provide robust evidence that it can meet the minimum ESR requirements. This allows NGESO to holistically review the service requirements versus capabilities across a region to form strong restoration zones. Critical to this is the detailed steady state and dynamic modelling of the site and this is where TNEI’s support is invaluable. Our power system modelling specialists are able to navigate the modelling and analysis process, liaising with the clients and their OEMs to ensure the correct data and models are being used. We perform short circuit, reactive capability, voltage control and frequency control studies, as well as assess the block loading capability of sites (as required) and various other studies, depending on the service being tendered. TNEI advises on suitable courses of action to mitigate issues or non-compliance. We provide detailed reports to support the studies and the overall submission to NGESO.
Throughout each of the stages, and particularly in ITT2, we advocate for close communication with our clients which builds a truly collaborative team to work through the process. This collaboration also supports our clients in their wider submission – contributing to costs in their commercial offer and to timelines for their implementation strategy.
The ESR tenders are a first-of-a-kind set of proposals which now invite a wide range of generator types to participate in restoration services, and also include distribution connected assets. TNEI was able to bring unique perspective on the technical aspects of these new, more inclusive, tenders to our clients from our involvement in the Distributed ReStart project, out of which these were borne.
Our specialist expertise in power system modelling and analysis has allowed us to guide our clients through the process, translating the ESR technical requirements into studies which can be performed to demonstrate their site’s capabilities.
