Published on 24 August, a new report by Energy Storage Ireland and the Irish Wind Energy Association (IWEA) called for action to strengthen Ireland’s electricity grid. The second of a series of four studies which make up the government’s 70 by 30 Implementation Plan, Saving Power outlines how to minimise dispatch down and increase the use of renewable electricity by 2030.
The report called for three key policy measures to reduce curtailment of renewable generation: the development of a DS3+ programme to relieve existing operational constraints to run the system with up to 95% Non-Synchronous Generation (SNSP); to launch the Greenlink Interconnector by 2023, the Celtic Interconnector by 2026 and the introduction of an interconnection policy regime by Q420.
Raising the System Non-Synchronous Penetration (SNSP) from <75% to <95% will be essential for Ireland to meet its target of a 70% renewable electricity system by 2030. EirGrid currently has plans to raise this to 75% in 2021 and has set a goal of reaching 95% SNSP by 2030. Reducing Minimum Generation (Min Gen) from approximately 1,400MW to 300MW has also been outlined. In Figure 1, the challenge of integrating 70% RES-E on the system was quantified by taking the system as it is anticipated to exist in 2020 and attempting to reach 70% RES-E by adding increased wind generation. Both lines represent a 70% RES-E system with the level of curtailment related to changes in Min Gen levels, all other system assumptions based on 2020 system. This resulted in curtailment levels of 44% (Figure 1). Approximately two-thirds of curtailment is removed through the use of a 95% SNSP limit and a 300MW Min Gen limit. Reducing these limits by the provision of sufficient system services is required to integrate 70% RES-E on the system.

The report noted that DS3+ will require new procedures, policies and controls to help manage the system, alongside commercial frameworks to incentivise the deployment of new flexible capability. IWEA has called for System Operators and the Regulatory Authorities to implement a programme to achieve SNSP of >95%; ensure resourcing is in place to deliver DS3+ programme objectives; to work with industry to identify existing barriers; prioritise the dispatch of sources of System Services from low or zero carbon sources; and ensure sufficient System Services are procured to integrate 70% renewable electricity by 2030.
For interconnection capacity, the National Climate Action Plan contained a Marginal Abatement Cost Curve for Ireland to achieve 70% RES-E by 2030. This incorporates the delivery of the Greenlink Interconnector by 2023 and Celtic Interconnector by 2026 to unlock opportunities for surplus renewable generation, minimise curtailment and enable the integration of increased renewable generation.
However, the report highlighted that current Irish policy around interconnection remains unclear and called for the development of a robust interconnection policy framework with high-level agreements between jurisdictions to streamline development, which would reduce uncertainty for public and private developers. The Transmission System Operator (TSO) should also “keep a clear separation of roles, firstly as a developer of interconnector projects and secondly as a transmission system operator.”
To also further interconnector operation, the report explored the implementation of Single Intraday Coupling (SIDC), alongside maximising SO countertrading until SIDC is utilised, in order to export up to 90% capacity during curtailment events. IWEA believes an interim solution is required, which would see both EirGrid and SONI trade to adjust interconnector schedules before dispatch, based on up to date forecast to minimise renewable dispatch down. Additionally, TSOs should monitor and report on interconnector performance during curtailment events to allow the market to identify opportunities for improvement.
To minimise constraints, the report recommended raising transmission grid capacity. A number of key steps were outlined: to begin early transmission development based on the future renewable pipeline, to improve EirGrid’s six-step framework for grid development, alongside the creation of a new grid development strategy. Additionally, EirGrid and ESBN should provide alternative solutions to help deliver RES-E targets and minimise dispatch down, through the use of energy storage and demand side response.
The report also discusses three areas in need of major change: Market Redesign, Dispatch down certainty and Grid 2050. It stated that there is no clear market design implemented for a power system with more than 50% variable renewable electricity and the existing market design is not providing incentives. The report called for the government to provide an alternative route to market via REFIT and RESS (backed by the PSO) to create investments in renewable electricity. Corporate PPAs, carbon price floors and renewable electricity obligations on suppliers could also be ways to stimulate a market for 10-15 year contracts. The report also called for SEMO, via EirGrid and the Commission for Regulation of Utilities (CRU) to create a team to focus on a new market design to facilitate a 70 by 30 power system.
To counteract dispatch down uncertainty, the report recommended that the CRU establish a roadmap to illustrate how dispatch down will be managed over the next decade in order to give certainty to renewable developers, who can then deliver renewable energy at the lower cost to consumers. This will also place the management of the curtailment and constraint levels in the hands of the System Operators, who can then justify investments in solutions such as grid development or programmes.
For Grid 2050, the report advocated for the use of storage technologies in combination with renewable generators for use in electricity, transport, and heat to minimise dispatch down through energy balancing. The report suggests integration of new technologies combined with renewable electricity will minimise dispatch down if appropriate supports are in place. Longer term, government support and regulation via price signals such as new market mechanisms, new tariff structures and new system services will be required to unlock further potential of energy storage technologies and to increase their commercial viability. Additionally, the report advocated for EirGrid and ESB Networks to plan for a fully decarbonised electricity system, to support the electrification of heat and transport and create new forms of demand for wind energy. The network operators should also incentivise flexible demand that can respond to variations in renewable generation and develop additional interconnection or long-term storage to avoid excess renewable power being wasted. The report added that without further policy measures to improve the system in managing increased levels of renewables, dispatch down levels will increase significantly which will create further barriers to renewable generation.
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