IN Brief:
- RESS 6 will procure solar and onshore wind in separate auction pots.
- Price represents 85% of each project’s evaluation score.
- Battery storage can contribute up to 7.5 percentage points through system-integration criteria.
EirGrid will operate Ireland’s sixth Renewable Electricity Support Scheme auction under revised rules that separate solar and onshore wind procurement and give battery storage a formal role in project scoring.
Qualification will open on 30 July and run until 27 August 2026, followed by final qualification results on 21 October. The auction window will then open on 29 October and close on 5 November, with provisional results expected on 18 November and final awards scheduled for December.
Although the final procurement volume will be confirmed later, solar and onshore wind projects will compete in separate pots rather than through a single combined price-led process. The revised structure recognises differences in capital cost, development risk, generation profile, and construction timescale between the two technologies.
Price will account for 85% of each project’s evaluation score, while resilience will contribute 5% and system integration 10%. Battery storage can provide up to 7.5 percentage points within the system-integration category, with a further 2.5 points available for incorporating a secondary generation technology.
Hybrid design enters the auction framework
By attaching a defined score to storage, the auction encourages developers to assess batteries during project design rather than treating them as a later addition. Storage can alter export profiles, reduce exposure to curtailment, and provide controllable capacity, although its economic value will still depend on connection terms, dispatch rights, market access, and operating strategy.
Integrating a battery also changes the electrical design of the generating site. Additional power-conversion systems, transformers, switchgear, protection, metering, communications, fire-safety measures, and control systems must be coordinated with the renewable plant and its grid connection.
Because the storage criteria are not mandatory, projects without batteries can still compete where a lower price or stronger resilience score offsets the system-integration points. Developers will therefore have to determine whether the additional score justifies the capital cost, technical complexity, and operational obligations attached to a hybrid configuration.
That calculation will vary by location, since network congestion, anticipated curtailment, wholesale prices, and connection capacity differ across the system. A battery placed behind a constrained export connection may provide more value than an equivalent asset at a site with unrestricted access to the network.
Ireland’s storage pipeline is already expanding beyond the auction framework, with the Rathrush battery proposal adding further flexibility capacity at a strategically selected network location. RESS 6 could extend that approach by embedding storage within supported renewable projects.
Resilience joins price competition
The resilience and system-integration criteria derive from the EU Net-Zero Industry Act, which allows procurement to account for supply-chain and system value alongside bid price. Cost remains dominant, but developers can now distinguish projects through equipment sourcing and electrical configuration.
Non-price criteria introduce additional documentation and verification requirements, so the rules must remain sufficiently precise for bidders to price compliance and for the auction operator to assess competing projects consistently. Ambiguity around eligibility, evidence, or scoring could otherwise increase risk premiums or reduce participation.
Separating wind and solar may also influence the final generation mix. Solar can generally be built more quickly, while onshore wind can offer a different seasonal output profile; allocating separate pots prevents one technology from dominating solely through lower near-term bid prices.
The previous RESS round selected 23 projects totalling approximately 1.08GW, comprising 860.38MW of solar and 218.84MW of wind. Volumes under RESS 6 will depend on the final target, qualified pipeline, bid prices, and the effect of the revised scoring framework.
Successful bids will still need planning approval, finance, equipment supply, civil works, grid compliance, and energisation within contracted schedules. Hybrid projects will add further commissioning requirements, particularly where batteries participate in several markets or respond to different dispatch instructions.
RESS 6 moves the procurement process beyond a narrow comparison of renewable energy prices by assigning a defined value to technical configuration and resilience. The auction results will show whether storage becomes a routine part of supported projects or remains concentrated among developers facing the strongest network and curtailment constraints.
