Where data centres' power comes from, and what limits the next one
The scale and the supply first, then each limit in turn: the CRU's bring-your-own-power rules, unused grid contracts, the grid's 900 MW stability limit, gas, renewables and emissions.
The picture in three steps
Scale, source, and the next constraint. Select a finding to inspect the underlying data.
WHAT DETERMINES THE NEXT BUILDGrid capacity and new clean supply
EirGrid's base case projects a 1,010 MW shortfall in 2026 before emergency measures. New connections face 80% annual renewable matching on a six-year glide path. Forecast growth to 2034 needs 4.16 TWh/year; permitted, uncontracted onshore wind is estimated at 3.7 TWh/year if built.
A flat load, day and night: about 28% of demand at its lowest
A year of EirGrid's live data: how much power Ireland uses through the day, and how much of it is data centres.Measured
4,064 MW
Average demand, last 12 months
peak 5,912 MW
22%
Of average demand is data centres
≈ 875 MW from CSO TWh
28%
Of the overnight floor
floor 3,136 MW (1st percentile)
33%
Of demand met by wind
imports avg 558 MW
A typical day: demand by hour (MW)
Data-centre load is drawn as a flat band at its 2025 average (CSO 7.7 TWh ÷ 8,760 hours). It runs all night, which is why Ireland's overnight floor is so high.
Wind share and imports by month
2025-10 · imports 638 MW32%
2025-11 · imports 592 MW35%
2025-12 · imports 565 MW39%
2026-01 · imports 553 MW33%
2026-02 · imports 473 MW41%
2026-03 · imports 507 MW40%
2026-04 · imports 451 MW38%
2026-05 · imports 561 MW28%
2026-06 · imports 454 MW31%
2026-07 · imports 603 MW22%
2026-08 · imports 745 MW18%
2026-09 · imports 575 MW36%
Wind as a share of demand. Imports are net over the EWIC and Greenlink interconnectors to Britain.
EirGrid Smart Grid Dashboard, Republic of Ireland, 15-minute data 2025-10-10 to 2026-10-09 · operational, not settled, figures
How Ireland makes its electricity
The fuel mix since 2015, what met the extra demand data centres added, and whether there's enough capacity.
40.2%
Of demand met by gas, 2025
wind 32.7% · imports 16.4%
85%
Of demand growth 2020–2025 was data centres
4.63 of 5.43 TWh
+768 MW
More imported at the overnight floor than in 2019
from exporting 176 MW
-1,010 MW
Capacity shortfall, 2026 (base case)
EirGrid adequacy, before emergency measures
The new demand ran on imports. Between 2020 and 2025, data centres were 85% of the growth in Irish electricity demand. Net imports rose 6.19 TWh while Irish wind added only 0.24 TWh and gas fell. At night, when data centres are a bigger share of load, Ireland went from exporting to importing ~592 MW.
Before emergency measures. The "secure" case is worse (−1,420 MW in 2026). Today's average data-centre load is ~875 MW.
Interconnectors
Moyle
Northern Ireland - Scotland
500 MW
2002
EWIC (East-West)
Ireland - Wales
500 MW
2012
Greenlink
Ireland (Wexford) - Wales (Pembroke)
504 MW
2025-01-29
Celtic
Ireland (Cork) - France (Brittany)
700 MW
2028-04 (assumed)
North-South (second 400 kV)
Ireland - Northern Ireland
900 MW
2031-2032
MaresConnect
Ireland - Wales
750 MW
2029 (promoter target; not in EirGrid studies)
Wind turned down (dispatch-down, % of available)
20155.1%
20162.8%
20173.7%
20185%
20196.9%
202011.4%
20217.3%
20228.3%
20238.9%
202410.1%
202511.4%
Ember monthly electricity data (CC-BY) · EirGrid Smart Grid Dashboard · EirGrid/SONI AIRAA 2026–2035 · EirGrid curtailment reports · CRU · SEAI · as of 2026-10-03
What power costs on the wholesale market
Irish day-ahead prices since 2019 against Britain, Germany, France, the Netherlands and the Nordics, how often they spike, and what a flat 24/7 load like a data centre would pay at spot prices.
Figure 1
How the wholesale price is set, and what a flat load would pay
The last, dearest unit needed sets the price each half-hour. A data centre draws the same power all day, so at spot prices it would pay the plain time average, €136.9/MWh over the last year; wind earned 14.7% less, €116.7.
In the day-ahead market, offers are ranked from cheapest to dearest and the price in each half-hour is set where that stack meets demand, so on still evenings older gas plant sets a high price and on windy nights the price falls. Across the last 12 months (2025-10-04 to 2026-10-09) the Irish price averaged €136.9/MWh, with 13.1% of half-hours above €200. A flat load like a data centre buying at spot prices would pay that time average, 1.3% below what the national demand profile paid (€138.7). Wind earned €116.7 because it produces most when prices are low; a flat load still has to buy power when the wind is not blowing, so a wind contract alone does not cover it. Most large users hedge, so this is a spot benchmark, not what any site pays.
EstimatePanel 1 is a schematic of how a pay-as-clear auction works (general description, unchecked against the SEM rulebook; "often" is not measured here). Energy prices only: bills add network, capacity, PSO, taxes and supplier margin.
What a flat 24/7 load pays vs the national load profile
€136.9 vs €138.7/MWh
€117
What wind earned per MWh (capture price)
-14.7% vs baseload
Flat load, high level. A data centre draws the same power at 4am as at 6pm, so on the spot market it pays the plain time average: €136.9/MWh over the last 12 months, 1.3% below what the national demand profile paid. The timing benefit is small; the level is what stands out. In 2025 Ireland's baseload was €114 against €89 in Germany and €61 in France, with more spike hours and almost no negative-price hours to soak up. Wind earned 14.7% less than baseload because it produces most when prices are low; a flat load still has to buy power when the wind is not blowing, so a wind PPA alone does not cover it.
Monthly day-ahead price, €/MWh
Ireland (SEM)Great BritainGermanyFrance
Ember monthly (load-weighted), 2019-01 to 2026-10. 2022 peaks clipped at €500.
Price and swings by market
Market
€/MWh 2025
2026 YTD
>€200
<€0
Ireland (SEM)
114
144
6%
0.7%
Great Britain
94
120
0.8%
1.9%
Germany
89
108
2%
5.8%
France
61
82
0.4%
5.8%
Netherlands
87
108
1.4%
6.7%
Denmark (Nordic)
82
108
1.7%
3.9%
Norway (Nordic)
48
95
0.1%
0.1%
Sweden (Nordic)
43
64
0.5%
3.7%
Finland (Nordic)
41
60
1.7%
5.2%
Baseload = simple mean of hourly prices; spike/negative = share of hours, 2025. Ember hourly data.
Data check: Ember's Irish monthly averages match SEMOpx's own day-ahead files to within €1.3/MWh on average, but its hourly Irish series sits one day late, so hour-level figures here use SEMOpx directly.
Every 15 minutes since 2020: how often the Republic imports power, how much when the wind drops and at the evening peak, set beside data-centre growth.
Figure 3
The Republic now imports power around the clock
In 2020 the Republic exported power overnight. Over the last 12 months it imported in every hour of the average day, and on still winter evenings it imports more than the two cables to Wales can carry (1,219 MW on average against 1,004 MW); the rest comes over the North–South line or is measurement difference.
The lines show average net imports into the Republic for each hour of the day: dashed for 2020, red for 2025-10-10 to 2026-10-09. The 2020 day dipped to about -304 MW (exporting) at night; the recent day never falls below 524 MW and peaks at 877 MW. The Republic was a net importer in 40.1% of quarter-hours in 2020 and 89.4% in 2025. When the wind is low imports average 1,045 MW, and on still winter evenings both cables to Wales were importing at 95% of their rating or more in 95.0% of quarter-hours (a small sample: 219 quarter-hours, about 55 hours).
EstimateNet import = system demand minus Irish generation each quarter-hour, so it includes the North–South line and metering mismatch.
Still winter evenings with EWIC and Greenlink both at full import
219 such quarter-hours; 25% of all · ≥95% of rating · last 12 months
Imports covered all the growth. From 2020 to 2025, demand on the grid rose 5.2 TWh and net imports rose 6.3 TWh, so Irish generation fell. Data centres added 4.6 TWh over the same years (78% of metered growth, CSO). Imports can't be traced to any one user; the two are set side by side, not matched.
Year
Net imports
Quarter-hours importing
Low wind
Evening peak
Data centres (CSO)
2020
-0.5 TWh · -2%
40%
297 MW
3 MW
3 TWh
2021
1.4 TWh · 4%
63%
506 MW
199 MW
4 TWh
2022
0.1 TWh · 0%
51%
220 MW
10 MW
5.3 TWh
2023
3.1 TWh · 10%
82%
586 MW
300 MW
6.3 TWh
2024
4.9 TWh · 14%
92%
754 MW
574 MW
7 TWh
2025
5.8 TWh · 17%
89%
903 MW
687 MW
7.7 TWh
Republic of Ireland only. Net import = grid demand minus Irish generation, every 15 minutes: EWIC, Greenlink (from 2025) and the North–South line. The Interconnectors section above counts the whole island (Moyle, EWIC, Greenlink), so its totals are larger. Import shares here use EirGrid operational data and differ slightly from the Ember annual shares used elsewhere on the site. Low wind = wind below 10% of demand. Evening peak = 17:00–20:00. MW are averages. Per-link data (from mid-2024): EWIC and Greenlink average 558 MW of the 720 MW, last 12 months.
Price or scarcity?
43%
Of hours Ireland was dearer than GB, 2022
83% in 2025
14 → 664 MW
Average net import, 2022 → 2025
IE−GB −14 → +20 €/MWh
95%
Of hours EWIC + Greenlink imported when Ireland was dearer
exported 53% when it was not · from 2025-01
Price decides whether, scarcity decides how much. In 2022 GB was the dearer market (€240 vs €226/MWh) and the Republic barely imported. Of the 650 MW rise since, the shift to hours when Ireland is dearer explains about 179 MW estimate; the rest is more imports at every price gap, as demand minus wind rose 291 MW, Irish non-wind generation fell 360 MW and Greenlink added a second link. Hour to hour, residual demand (demand minus wind) explains more of the import swings than the price gap does (40% vs 22% in 2025). In 2022 a GB price shock all but turned the imports off; a repeat would leave Ireland leaning on its own plant, which now runs 360 MW lower on average.
Year
IE − GB €/MWh
Hours IE dearer
Net import
Import when IE cheaper
Explained by spread
by residual demand
2020
−2
40%
−58 MW
−293 MW
31%
53%
2021
−1.6
60%
+157 MW
−177 MW
10%
48%
2022
−14.2
43%
+14 MW
−171 MW
21%
28%
2023
+18
81%
+353 MW
−127 MW
29%
30%
2024
+23.1
85%
+552 MW
+25 MW
26%
40%
2025
+20.1
83%
+664 MW
+4 MW
22%
40%
2026*
+24.2
84%
+729 MW
+89 MW
28%
54%
Hourly. Prices: Ember day-ahead, Ireland shifted back 24 h (Ember labels Irish days a day late; re-tested 2019–2026 against wind). “Explained by” = share of hour-to-hour variation in net import explained by each factor alone (R²); the two overlap. *Part year. Not tested: plant outages (no public 15-minute series) and EirGrid system alerts. Since Brexit, trade with GB is not market-coupled, so flows can run against the price gap.
The CRU's rules (decided 2025-12-12) make each new data centre supply firm power and match its demand with new Irish renewables.
01
Bring your own power
Data centres of 10 MVA or more need dispatchable generation or storage, on site or nearby, with de-rated capacity at least equal to their grid import capacity (MIC). It must take part in the wholesale market.
02
Small sites
From 1 MVA to below 10 MVA, an autoproducer unit covering 100% of the site's import capacity. Below 1 MVA the policy does not apply.
03
80% new Irish renewables
At least 80% of annual demand matched by additional renewable projects generating in Ireland.
04
Data centres only
Called a Large Energy User policy, but it applies only to data centres.
The gap, campus by campus Calculated
~500 MW
Firm power still to find in the pipeline
8 of 16 pipeline campuses state a demand · our arithmetic
861 MW
Demand those campuses state
planning, ACP and EPA documents · a ceiling, not use
429.5 MW
Dispatchable on-site generation their documents describe
gas engines and turbines, not backup diesel
390 MW
Of the gap is two projects
Herbata Naas and Microsoft Huntstown
The other 8 pipeline campuses state no demand yet, so 861 MW is a floor for the pipeline, not a total. For scale, EirGrid sees 150–300 MW of near-term room outside Dublin (Data Centre Constrained Area Overview, May 2026).
* derived from stated figures (see the source). Stated demand is the largest figure in a primary document and stands in for import capacity, which is not public per site. Firm gap = stated demand minus non-backup on-site generation with a stated MWe and capacity-market awards matched by licence. Our arithmetic. Contract status under CRU/2025236 vs CRU/21/124 is unchecked for non-operating campuses; operating campuses are assumed to be existing connections.
StackPath gap table, 2026-10-10: planning documents, An Coimisiún Pleanála inspector reports, EPA LEAP attachments, SEMO capacity-auction reports; every stated figure page-cited · method
What applications mention
Generators72
Substation / kV61
Gas24
Batteries / storage11
Solar / wind21
Keyword matches in the application description, so a lower bound: details often sit in the drawings and EIAR, not the description.
Capacity auction T-4 2029/30: new MW by technology
Demand Side Unit112
Gas Turbine68
Battery Storage26
Wind1
3,862 MW secured in total, 206 MW new, out of 1,194 MW of new capacity that qualified. Clearing price €135,500/MW/yr.
In the 2029/30 auction, only Crag Digital Avoca Limited (20 MW) won new capacity.
Combustion plant (diesel, gas, HVO) licensed or applied for at data centres
thermal input, not electrical output · EPA
2 GW
Of it meant to run as main or continuous power
thermal input
1225
Generators, engines and turbines
24 licences held or sought · 29 incl. withdrawn
0.3%
On-site fuel as a share of sites' energy input, 2025
fuel ÷ (fuel + grid electricity) · AERs
Gas as the power station. Equinix's Blanchardstown site ran nine gas turbines as its main power from February to November 2024 while it waited for grid capacity: that year it burned more energy as gas than it bought as grid electricity (fuel in, not electricity out). South Dublin Routing's Ballycoolen site, licensed in July 2026, gets over 99% of its power from on-site engines and has no grid connection for its IT load.
Licensed and applied plant by role, MW thermal
Gas as main power1,455
HVO as main power544
Gas, flexible/on call880
Gas peaker557
Diesel/HVO backup5,714
Thermal input, not electrical output: diesel sets deliver about 0.4 MW of electricity per MW of thermal input. Google's ratings are confidential and excluded.
On-site fuel as a share of energy input, by year
2023 · 14 sites0.31%
2024 · 15 sites2.57%
2025 · 16 sites0.3%
2024's jump is almost all Equinix's gas. The diesel backup fleets at Amazon, Microsoft, Meta, K2 and Google burned the equivalent of roughly 0.6–6.4 hours at full load a year, against 72–200 hours permitted.
Grange Castle Business Park South, Baldonnel Road, Dublin 22
Diesel/HVO backup
Licensed
120240
24
26
Grid MW avg: each site's grid electricity from its latest annual environmental report, as an average load. Read by Claude from EPA documents; every quote checked against its page.
EPA LEAP licences, inspector reports and annual environmental reports · as of 2026-10-03
Who holds the grid capacity
Since 2021 almost no new data centre has got a grid contract. So how much capacity do the existing ones already hold, and how much do they use?
38–46%
Of contracted grid capacity actually used, 2025
875 MW average vs 2,000–2,400 MVA
1–1.4 GW
Unused capacity already contracted
growth needing no new contract
1,948 MVA
Protected when the 2021 rules came in
1,884 MVA of it in Dublin
1
New data-centre contract under the 2021 rules
EirGrid
The moat the rules created. Freezing new connections protected whoever already held contracts. They are using well under half of what they hold, so existing operators can roughly double their draw while newcomers wait.
Unused capacity we can tie to named sites (MW)
Amazon (AWS) Cruiserath151
Microsoft Huntstown150
Meta Clonee45
Amazon (AWS) Belgard, Tallaght37
Only Amazon Cruiserath publishes both a contract (240 MVA, 2017) and its 2025 draw. Others compare draw with demand stated in planning or EPA papers, which is not a contract. Average draw understates peak use. MVA converted at power factor 0.95.
EirGrid AIRAA 2026–35 and Constrained Area Overview (May 2026) · CRU/21/124 · EPA annual reports · CSO · quotes checked · as of 2026-10-03
The grid's limit on big loads
EirGrid's weekly operating limits, and the one data centres have now hit: how much demand the grid can lose in a single fault.
Figure 4
Why the grid can only lose 900 MW at once
In a voltage dip data centres can drop off the grid in milliseconds. EirGrid plans for a worst case in which 90% of their demand goes at once (recorded faults dropped 16–52%), so about 1,000 MW of data centres fills the 900 MW limit, and that happened in Jun 2026.
When a fault dips the voltage, data centres protect their servers by switching to on-site batteries and generators, so their demand can vanish from the grid in milliseconds and frequency jumps. EirGrid's weekly operating rules cap the demand and exports the system can lose in one event at 900 MW; planning for 90% of data-centre demand at risk, roughly 1,000 MW of data centres uses it all, and EirGrid told the CRU that peak was reached in late June 2026. To stay inside the limit EirGrid keeps more spinning plant on (inertia floor 28,000 MWs), caps the instantaneous share of wind, solar, batteries and HVDC imports (SNSP) at 75%, limits battery charging and cuts interconnector exports. The step sketches are schematic, not measured traces.
Estimate"A 100 MW campus adds about 90 MW" is our arithmetic with EirGrid's 90% assumption.
Most demand the grid can lose at once after a fault
reached June 2026 at ~1,000 MW of data centres
480 MW
Biggest data-centre drop in one fault
2026-06-06 · 52% of their demand
28 GWs
Inertia floor, raised to absorb the drops
was 23 GWs until May 2026
75%
Cap on the instant share of wind, solar and HVDC imports (SNSP)
80% trial paused over data centres
Grid stability is now a hard limit on data centres, alongside capacity. In a voltage dip many data centres switch to back-up power in milliseconds. EirGrid estimates up to 90% of their demand could drop off in certain faults (the biggest recorded drop so far was 52%), so about 1,000 MW of data-centre demand fills the 900 MW limit. That was reached at the June 2026 peak. The CRU approved the fix, Grid Code rule MPID 345, on 22 September 2026: from 27 October transmission-connected sites must ride through faults. Most can't yet, so each existing data centre's non-compliant demand is capped while it works towards compliance, and the 900 MW limit itself stays.
Bar scale = the 900 MW limit. All five were single-phase faults; EirGrid expects a three-phase fault to cause bigger drops. Source: CRU202704 Table 1.
What a new campus adds
Campus
Potential drop
Share of limit
100 MW
90 MW
10%
200 MW
180 MW
20%
300 MW
270 MW
30%
inference Our arithmetic using EirGrid's 90% assumption, for a campus without fault ride-through. A compliant campus (90% of demand back within 500 ms) would add little. Under CRU/2025/236 a new data centre must also bring dispatchable generation or storage to match its demand, which is meant to stop it adding to the supply shortfall; the licences filed so far show that mostly means gas (see Gas, below).
Gas is becoming a constraint alongside grid stability and capacity. Who has contracts, who's queuing, and who the CRU's interruptible-gas proposal would actually hit.
2,100 MWth
Gas contracted by 11 data centres (max hourly load)
7 connected · GNI, Nov 2024
9.3 GWth
More enquired about, 22 sites
GNI, Nov 2024
5,466 MWth
Pending gas applications (17)
the ones the new rule would hit
799 MWth
Known gas plant that keeps firm supply
4 of 8 sites
The rule mostly misses today's gas burners. The CRU's interruptible-gas proposal applies only to new connections. Gas Networks Ireland has signed no new data-centre contract since July 2022, so sites already on gas, including the islanded Ballycoolen site, keep firm supply. Generators metered separately and selling into the market are exempt.
EPA licence
Operator
Gas MWth
Under the proposal
P1187
Microsoft Ireland Operations Limited
Existing firm contract: GNI's LNCA with Microsoft was executed 17 May 2021 (205 MW peak, 19 barg). The Direction is not retrospective. Gas is still not flowing: 12 engines idle awaiting high-pressure gas.
167
Firm or exempt
P1168
Equinix Hyperscale 1 (DB5) Limited
Already connected and burned grid gas in 2024, so it holds a pre-pause contract; the Direction is not retrospective. Any increase in contracted volume would be interruptible.
168
Firm or exempt
P1113
Echelon Clondalkin DC Services Limited
Gas comes from GNI and it must predate the July 2022 pause, so the original capacity is probably firm. But the 2025 licence swapped the 2020 design (12 x 21.3 = 255.6 MWth engines) for 448 MWth of turbines; any contracted increase would be interruptible. The contract size is not public.
448
Uncertain
P1165
Data And Power Hub Services Limited
Exempt: a gas-fired generator in the SEM. GNI is building a dedicated transmission pipeline to the Milltown AGI for the peaker. This is the design the exemption rewards.
269
Firm or exempt
P1204
EdgeConneX Ireland Limited
Behind the meter and not a SEM generator, so a new or increased connection would be interruptible. No public document shows whether EdgeConneX holds a pre-July-2022 GNI contract for ESSDUB97.
206
Uncertain
P1210
South Dublin Routing 4 No. 2 Limited
Takes gas from the GNI network today (temporary engines power DC1), so the contract predates the pause and stays firm. This is the most gas-dependent data centre in Ireland, and the proposal leaves its supply firm.
195
Firm or exempt
P1227
Vantage Data Centers DUB11 Limited
Behind the meter, so a new or increased connection would be interruptible. A GNI compound on site was re-permitted in Oct 2024, which suggests an existing GNI arrangement; its size and date are not public. EPA application still under assessment.
236
Uncertain
P1202
Crag Arklow Limited
No known GNI contract, and it would need a new transmission connection at Arklow. Interruptible if it re-applies with behind-the-meter generation. Exempt only if the engines are restructured as a separately metered SEM generator.
581
Likely interruptible
CRU202657 consultation · Gas Networks Ireland network plans and winter outlook · Dáil written answer 6 Nov 2024 · EPA licences · quotes checked · as of 2026-10-10
Who can supply the renewables
New data centres must match 80% of their demand with new, unsubsidised Irish renewables. Is there enough permitted wind and solar to sell them?
4.16 TWh
New renewables needed a year for 80% of demand growth to 2034
≈ 1.6 GW onshore wind
5.98 TWh
Permitted wind and solar with no state contract
4.4 GW · planning
1,909 MW
Corporate PPAs announced by data-centre operators
17 deals in the Republic
The supply gap, TWh a year
Needed: 80% of demand growth to 20344.16
Permitted, uncontracted wind + solar5.98
…of which onshore wind3.67
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)
Microsoft967
Amazon (AWS)334
Meta276
Facebook (Meta)179
Unnamed 'leading technology company'81
Google58
Keppel DC REIT14
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.
For a renewable developer: permitted onshore wind without a state contract is the scarce product. The 4.16 TWh need is more than all of it (about 1.4 GW, ≈3.7 TWh a year); solar would have to fill the rest.
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
Google
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
Offshore wind: Ireland's North Sea
Ireland has almost no gas of its own, but one of Europe's biggest offshore wind resources. How much is coming, when, and can data centres use it?
25 MW
Offshore wind running today
Arklow Bank, since 2004
25 MW
Our estimate for 2030
target ≥5 GW · EirGrid base 1,350 MW
1,175 MW
Offshore that data centres could contract
Oriel + Arklow Bank 2 · ~4.63 TWh/yr
3,524 MW
State-backed, so can't count for data centres
Codling, Dublin Array, NISA, Tonn Nua
Only the losers can help. The two projects that failed the State's first offshore auction (Oriel and Arklow Bank 2) must sell to a company, so they're the only named offshore wind that counts toward data centres' 80% rule. Their ~4.6 TWh a year roughly matches the ~4.2 TWh needed. But neither has planning permission or a signed buyer, and none is likely before 2031–32.
Offshore wind expected by year (MW)
2026 · data-centre eligible 025
2027 · data-centre eligible 025
2028 · data-centre eligible 025
2029 · data-centre eligible 025
2030 · data-centre eligible 025
2031 · data-centre eligible 375400
2032 · data-centre eligible 1,1751,200
2033 · data-centre eligible 1,1753,824
2034 · data-centre eligible 1,1753,824
2035 · data-centre eligible 1,1754,724
2036 · data-centre eligible 1,1754,724
Our estimate from each project's status (assumed start years are our judgement, explained in the data). EirGrid's base case is higher.
The projects
Project
MW
Support
Planning
Codling Wind Park
Fred. Olsen Seawind and EDF Renewables (50/50; ownership unchecked) · east (off Wicklow)
1,300
ORESS1
Pending at An Coimisiún Pleanála (OA29N.320768); lodged 2024-09-06, statutory due date 2025-04-01 (passed); no decision at 2026-10-10.
Dublin Array
RWE and Saorgus Energy (Kish/Bray Offshore Wind Ltd) · east (Kish and Bray Banks, off Dublin/Wicklow)
824
ORESS1
Pending at An Coimisiún Pleanála (OA06D.321992); lodged 2025-02-28, statutory due date 2025-09-09 (passed); no decision at 2026-10-10.
North Irish Sea Array (NISA)
Statkraft and Copenhagen Infrastructure Partners (unchecked) · east (off Dublin, Meath, Louth)
500
ORESS1
Pending at An Coimisiún Pleanála (OA29N.319866); lodged 2024-06-07, statutory due date 2024-12-12 (passed); no decision at 2026-10-10.
Sceirde Rocks (Skerd Rocks)
Fuinneamh Sceirde Teoranta (Corio Generation) · west (off Galway/Clare)
450
ORESS1
Planning application withdrawn (letter after 4 Dec 2025 meeting; reported 2 Jan 2026). ORESS 1 now has 3 contractors.
Oriel Wind Farm
Oriel Windfarm Ltd (ESB and Parkwind/JERA Nex) · east (off Louth)
375
none: can sell to data centres
Pending at An Coimisiún Pleanála (OA15.319799); lodged 2024-05-24, statutory due date 2026-09-21 (passed); no decision at 2026-10-10.
Arklow Bank Wind Park 2
Sure Partners Ltd (SSE Renewables) · east (off Wicklow/Wexford)
800
none: can sell to data centres
Pending at An Coimisiún Pleanála (OA27.319864); lodged 2024-06-06, statutory due date 2024-12-10 (passed); no decision at 2026-10-10.
Tonn Nua (SC-DMAP site A)
Helvick Head Offshore Wind DAC (ESB and Ørsted) · south (off Waterford)
900
Tonn Nua
Auction won Nov/Dec 2025; planning application not yet lodged (MAC with MARA).
South Coast DMAP sites B-D
not yet auctioned · south (Cork/Waterford/Wexford)
4,100
future ORESS (expected)
Designated in SC-DMAP (approved 31 Oct 2024); next auction expected 2027.
Arklow Bank Wind Park (phase 1)
operating since 2004 · east (off Wicklow)
25
none (existing)
Operating (2004).
EirGrid ORESS results and adequacy study · DCEE · An Coimisiún Pleanála case pages · CRU2025236 · quotes checked · as of 2026-10-10
What it does to emissions
Data centres' emissions from grid power and from on-site gas, against Ireland's legally binding sectoral ceilings.
1.463 Mt
CO₂ from data centres' grid power, 2025
23.2% of the electricity sector
37%
Of the yearly electricity ceiling for 2026–30
4 Mt a year average
0.95 Mt
A year from three licensed gas sites, at the EPA inspectors' stated figures (EdgeConneX's is its maximum, run-on-instruction case)
EPA inspectors' figures
63–95%
Of the commercial buildings ceiling, which their gas counts against (per EPA inspectors)
1.0 Mt a year average, rounded · sector already at 1.392 Mt in 2025
Two different ceilings. Grid power counts against the electricity ceiling; gas burned on site counts against the commercial and public buildings ceiling (per EPA licence inspectors). Three licensed gas-powered data centres would use about 95% of that sector's yearly budget for 2026–30. Today, on-site emissions are only about 9.5 kt: this is about what happens if they start.
CO₂ from data centres' grid electricity (Mt)
2017 · 1.8 TWh0.79
2018 · 2.2 TWh0.83
2019 · 2.5 TWh0.84
2020 · 3.0 TWh0.93
2021 · 4.0 TWh1.38
2022 · 5.3 TWh1.70
2023 · 6.3 TWh1.55
2024 · 7.0 TWh1.50
2025 · 7.7 TWh1.46
Data centres' share of metered electricity × electricity-sector emissions (EPA). Falling intensity has offset rising demand since 2022.
Stated CO₂ of gas-powered sites (kt a year)
Echelon Clondalkin · P1113379
EdgeConneX · P1204314
South Dublin Routing 4 No. 2 · P1210252
Data And Power Hub Services · P1165204
Microsoft · P118752
From EPA inspector reports. Licensed does not mean running: most have not started. Data And Power Hub is a grid peaker, so its gas likely counts under the electricity ceiling instead.
EPA GHG inventory and projections · Sectoral Emissions Ceilings (2022) · EPA licence reports · EU Union Registry · CSO · as of 2026-10-10