Policy · CRU2025236
The CRU's data-centre connection rules, explained
The CRU's Large Energy Users Connection Policy (CRU2025236, 12 December 2025) applies only to data centres. Sites of 10 MVA or more must bring new dispatchable generation or storage at least equal to their grid import capacity, and match at least 80% of annual demand with new Irish renewables within six years. A judicial review was lodged in March 2026.
Updated 10 October 2026 · data build 2026-10-10 · how we know · corrections
The four rules
The path a new data centre must take since December 2025
A new data centre now comes as a package: its own dispatchable power sized to its grid import, 80% of its demand matched by new Irish renewables, a location the grid can take, and, from 27 Oct 2026, equipment that rides through faults.
The CRU's decision of 12 Dec 2025 (CRU/2025/236) replaced an open-ended pause with conditions. A site of 10 MVA or more must bring dispatchable generation or storage, de-rated to at least its import capacity and bidding into the market; a smaller one needs an autoproducer covering all its import capacity; and at least 80% of annual demand must be matched by new, unsubsidised renewables in Ireland. EirGrid's connection policy then treats Dublin as fully constrained, the Grid Code adds fault ride-through from 27 Oct 2026, and the CRU has proposed (no decision yet) that gas for plant behind a data centre's own meter be interruptible, while separately metered plant bidding into the market is exempt. The red-edged steps were added after the decision.
Sources: CRU/2025/236 decision, 2025-12-12 · EirGrid DCCOPP v3, 2026-05-20 · CRU2026145 (MPID 345), 2026-09-22 · CRU202657 (proposed), 2026-06-25 · Judicial review (policy timeline), 2026-03-10
Bring your own power
Small sites
80% new Irish renewables
Data centres only
CRU decision paper CRU2025236, 12 December 2025.
What it means, and for whom
Applies only to data centres of 1 MVA or more. Sites of 1-10 MVA need an autoproducer unit covering their MIC; 10 MVA and above need new, separately metered dispatchable generation/storage on-site or 'proximate', de-rated to at least their MIC and bidding into the market, and cannot energise or ramp until it is delivered. All must meet at least 80% of annual demand with additional, unsubsidised Irish renewables within six years of energisation or lose MIC. Location still decides; supersedes CRU/21/124 for new applications.
What changed. Ended the open-ended near-moratorium with a defined, demanding route: a data centre now comes as a package of demand plus a gas plant (or storage) plus new wind/solar PPAs. No change for gas connections; an interruptible gas product is to be consulted on separately. SOs had to publish processes by 31 March 2026.
| Developers | Viable only for well-capitalised players able to co-develop generation and contract new renewables; worked example: a 30 MVA site needs about 31 MW of gas turbine plus about 55 MW of onshore wind (p65). Wind barely reduces the firm requirement because of its low de-rating (0.056). |
| Energy suppliers | New market for data-centre-linked gas peakers and batteries (1-year capacity contracts only) and for CPPAs with new unsubsidised wind/solar; RESS/ORESS projects excluded. |
| Public | Data centres pay for their own adequacy and add renewables, but new gas plants are built and run, and up to 100% fossil supply is allowed in the first six years. Judicial review lodged March 2026. |
Since the decision
| 2026-01-13 | Large Energy User Action Plan (LEAP) 17 actions for a plan-led approach after 2030: Green Energy Parks that co-locate big users with renewables, storage and dispatchable generation; a National Planning Statement on parks; flexible/non-firm connections; private-wire legislation; LEU efficiency reporting under the EED; an annual data-centre roundtable. Confirms grid investment to 2030 makes no room for data centres beyond existing contracts and that Dublin opportunities are extremely limited. |
| 2026-03-10 | Judicial review lodged against CRU2025236 Three environmental groups sought leave in the High Court to quash the LEU decision, arguing it breaches the Climate Act and the Energy Efficiency Directive by allowing new data centres to run on fossil power for six years and leaving 20% unmatched, with back-up generator emissions ignored. |
| 2026-05-20 | DCCOPP v3, Data Centre Technical Assessment and Constrained Area Overview Implements CRU2025236 for transmission connections: a mandatory pre-application meeting (only for projects outside constrained areas), a three-part application (data centre + nominated generation + nominated renewables, each through ECP-GSS), 7.5 to 18 months to an offer, and MIC cuts or termination if generation or the 80% renewables test fails. The overview declares greater Dublin 'fully constrained' and estimates only 50-100 MW at each of Galway, Limerick and Cork on 220 kV, realistically from the mid-2030s. |
| 2026-06-25 | CRU202657: proposed direction on interruptible gas connections CRU is minded to direct GNI to make all new gas connections above 50 MWth interruptible, for a tariff discount, because 17 pending applications (5,466 MWth, mostly data centres and generators) would turn the 1-in-50 winter peak-day headroom (10%) into a 9% deficit by 2033, or an 18% deficit under GNI's risk-adjusted case (from 3% headroom). Market (SEM) generators, including separately metered data-centre generation under the LEU policy, are exempt; behind-the-meter data-centre gas would be interruptible. |
Is there enough renewable power to match?
The supply gap, TWh a year
Assumed capacity factors: wind 30%, solar 11% (curtailment not deducted). Plants with state support (RESS/REFIT) can't count. Pool MW is mostly estimated from turbine counts and site area. "Growth" is EirGrid's 2025 → 2034 forecast (9.4 → 14.6 TWh, as cited in CRU2025236), one basis throughout; the CSO's metered 2025 figure (7.662 TWh) is lower and not comparable.
Corporate PPAs by buyer (MW)
No announced PPAs found for Equinix, Digital Realty, CyrusOne, EdgeConneX, Vantage or Echelon. Older deals serve existing sites and don't count toward the new rule.
Annual vs hourly matching
A portfolio sized to meet Ireland's rule exactly (80% of annual energy, 80/20 wind/solar) matches about 70% of a flat load hour by hour, and covers 80% of load in only 50% of hours, so under Spain's draft it would fall in the top hourly-surcharge band in 12 of 12 months. Reaching 80% hourly-matched needs about 1.2x the load's annual energy in contracted output (1.5x what Ireland's rule requires); passing Spain's per-hour test in every hour is not reachable with wind and solar alone (even 3x gives 89% of hours).
| Mix | Contracted output, % of annual load | Load matched hour by hour | Hours ≥80% covered (Spain's test) |
|---|---|---|---|
| wind only | 80% | 65.3% | 45.4% |
| 80% wind / 20% solar | 80% | 69.5% | 50.1% |
| 80% wind / 20% solar | 100% | 76.1% | 59.9% |
| 80% wind / 20% solar | 150% | 84.9% | 74.2% |
| 80% wind / 20% solar | 200% | 89.5% | 81.4% |
| 80% wind / 20% solar | 300% | 93.9% | 89.2% |
| Rule | Matching | Threshold | Status |
|---|---|---|---|
| IE CRU/2025/236 (decision, 12 Dec 2025) | annual | at least 80% of annual demand | in force (connection policy); judicial review pending |
| ES Draft Royal Decree on data-centre sustainability and digital sovereignty (MITECO, urgent procedure) | hourly | 80% of total consumption from additional renewables (Art. 8) AND each hour at least 80% backed by renewables generated in that hour (Art. 9) | draft; public consultation 27 Aug-4 Sep 2026; final adoption not found as of 3 Oct 2026 (unchecked beyond press search) |
| DE EnEfG s.11(5) (in force since Nov 2023) | annual balance ('bilanziell') | 50% from 1 Jan 2024, 100% from 1 Jan 2027 | in force |
Flat 24/7 load; portfolio shaped like the national wind and solar fleet (EirGrid actual output, 2025-10 to 2026-09). The fleet is smoother than any single portfolio, so real figures would be lower. Spain's rule is a draft.
Could any operator pass an 80%-every-hour test today? model
Modelled on public data, none of the 6 operators with EPA-reported loads would pass an 80%-every-hour test today. Best placed on paper (every announced ROI deal counted as if fully built): Microsoft (70% of hours, 132% annual cover; counting only deals marked fully operational, 0% of hours and 13% cover, as 900 of its 967 MW are partly built, under construction or framework deals), Meta (32% of hours, 62% annual cover), Google (13% of hours, 25% annual cover). Passing every hour needs firm low-carbon supply close to 80% of load (77-81% after rounding) even with contracts topped up to 2x the load's energy and a 4-hour battery (still 86-88% of hours pass). With storage alone, a battery of 0.8x load would need about 121-126 hours (about 5 days) of storage: the longest Irish wind-and-solar lull sets the size.
| Operator (EPA-licensed sites) | Load 2025 | Irish CPPAs | Annual cover | Hours ≥80% | Extra MW for 80% hourly-matched | Firm low-carbon MW to pass every hour |
|---|---|---|---|---|---|---|
| Amazon (AWS) | 425 MW | 334 MW | 24% | 0% | 1,781 | 333 |
| Microsoft | 154 MW | 967 MW 67 operating | 132% 13% operating | 70% 0% operating | 0 | 121 |
| Meta | 135 MW | 455 MW | 62% | 32% | 365 | 106 |
| 26 MW | 58 MW | 25% | 13% | 122 | 20 | |
| Equinix | 19 MW | 0 MW | 0% | 0% | 98 | 15 |
| K2 Strategic | 18 MW | 0 MW | 0% | 0% | 93 | 14 |
Estimates from a model, not site data: no hourly site loads or PPA outputs are public. Load = 2025 grid electricity in EPA annual reports, assumed flat; CPPAs = announced Irish deals by buyer at assumed capacity factors (wind 30%, solar 11%), shaped like the national fleet; the main figures count every announced deal as if built, and the grey "operating" line counts only deals marked fully operational (the truth for partly built portfolios lies between). 0% means no announced Irish CPPA was found, not that the operator buys no renewable power. Extra MW = new 80/20 wind/solar contracts. Firm MW assumes contracts topped up to 2× the load's energy plus a 4-hour battery of half the load. On-site gas engines are firm but not renewable, so they do not count; no campus document states an on-site battery. Spain's additionality rule is not applied.
PlanSight planning · EirGrid RESS 1–5 · company and developer announcements · CRU2025236 · MITECO draft decree (Aug 2026) · EnEfG §11 · EirGrid Smart Grid Dashboard · as of 2026-10-10
Questions people ask
- What does a 30 MVA data centre need under the rules?
- The CRU's own worked example: about 31 MW of gas turbines on or near the site, plus about 55 MW of new onshore wind under contract (CRU2025236, p65).