Method · version 1.1 · October 2026

How every figure is made

Irish Grid uses one data series, one denominator and published assumptions. Volumes are reported; costs and Bitcoin figures are modelled, marked ≈ and shown with the assumptions below. Where no reliable figure exists, the site shows none. The code that produces every number is public on GitHub.

1 · The data: one series

Every volume on the site is wind dispatch-down in the Republic of Ireland, by calendar year, from the annual Renewable Energy Constraint and Curtailment reports published jointly by EirGrid and SONI. Solar is left out so that years are like-for-like (it was not reported on the same basis in earlier years). Northern Ireland and all-island figures appear only as labelled context.

Year	Wind dispatch-down	% of available wind	Basis	Source
2025	≈ 1,500 GWh	11.3%	Provisional	Preliminary 2025 wind dispatch-down rates for Ireland (11.3% of available wind: constraint 6.6%, curtailment 4.7%), as reported by Climate Jargon Buster; volume estimated by Irish Grid pending the official 2025 reportVolume (≈1,500 GWh) is Irish Grid’s estimate. Replace with the official report figure when it is published.
2024	1,266 GWh	10.1%	Reported	EirGrid & SONI, Annual Renewable Energy Constraint and Curtailment Report 2024 (April 2025)The report states dispatch-down in Ireland was roughly equally due to curtailment and constraint.
2023	1,124 GWh	8.9%	Reported	EirGrid & SONI, Annual Renewable Energy Constraint and Curtailment Report 2023 (April 2024)Curtailment/constraint split for Ireland not captured here; cost uses the assumed split.
2022	988 GWh	8.3%	Reported	EirGrid & SONI, Annual Renewable Energy Constraint and Curtailment Report 2022 (May 2023)Curtailment/constraint split for Ireland not captured here; cost uses the assumed split.
2021	752 GWh	7.3%	Reported	EirGrid & SONI, Annual Renewable Energy Constraint and Curtailment Report 2021 (August 2022)Curtailment/constraint split for Ireland not captured here; cost uses the assumed split.
2020	1,448 GWh	11.4%	Reported	EirGrid & SONI, Annual Renewable Energy Constraint and Curtailment Report 2020 (May 2021)Covid-19 lockdowns cut demand in 2020, which raised dispatch-down; the report notes this.

Headlines use the latest reported year (2024). A provisional year is shown, labelled, and never leads.
Reported figures cannot be overwritten by the database. The reviewed figures live in the code; a database row can only fill a year that is missing or provisional, and only with a reported figure. Every change to a reported figure is therefore a public code change.
No short-period figures. EirGrid does not publish dispatch-down by day or week in a form this site can verify, so the site shows none, rather than an estimate that looks like data.
No per-plant figures. Output and dispatch-down are not published by site; the map shows locations and capacity only.

2 · The cost to billpayers (modelled)

No public source gives the compensation paid each year for wind dispatch-down, so the cost is modelled from the volume. Constraint (local network limits) is generally compensated for generators with firm access; curtailment (system-wide limits) is largely uncompensated for newer generators. The volume is split between the two — using the reported split where the report gives one — and each part is multiplied by an assumed compensated share and rate. Three cases give the range.

constraint_MWh   = volume × constraint_share
curtailment_MWh  = volume − constraint_MWh
compensated_MWh  = curtailment_MWh × share_paid_curtailment
                 + constraint_MWh  × share_paid_constraint
cost_€           = compensated_MWh × compensation_€_per_MWh
per_household_€  = cost_€ ÷ 1,841,152

Assumption	Low	Central	High
Compensation rate	€55/MWh	€75/MWh	€95/MWh
Share of constraint compensated	80%	95%	100%
Share of curtailment compensated	0%	20%	40%
Constraint share, where not reported	35%	50%	60%

Worked example — 2024

Wind dispatch-down (reported): 1,266 GWh
Constraint share (reported): 50%
Cost, central case: ≈ €55M
Range, low–high: €28M–€84M
Per household, central: ≈ €30

One denominator: 1,841,152 private households (CSO, Census of Population 2022, Profile 3 — Households, Families and Childcare). “Per household” is an equivalent for scale. Costs are recovered across all customers, including businesses, so it is not a line on any household's bill.
Replacement cost is context only. When a constraint turns a wind farm down, another generator is turned up. The site values the constrained volume at a reference wholesale price of €95/MWh and never adds it to the compensation range. Curtailed volume is excluded: that power could not have been used.
Rounding: modelled € figures are rounded to two significant figures and marked ≈.

3 · Bitcoin revenue and costs (modelled)

The orange figures answer one question: what would a fleet earn if it used the dispatched-down energy at today's Bitcoin price and network? It is a counterpart for scale, not a claim about the past — the network and price in earlier years were different.

Gross revenue

used_MWh      = volume × capture_factor
work_TH       = used_MWh × 3.6×10⁹ J ÷ efficiency_J_per_TH
fleet_TH/s    = work_TH ÷ seconds_in_year
share         = fleet_TH/s ÷ network_TH/s
BTC           = blocks_in_year × block_subsidy × share × (1 − pool_fee)
revenue_€     = BTC × price_€

Miner efficiency: 17.5 J/TH
Capture factor: 90%
Pool fee: 1.5%
Block subsidy: 3.125 BTC (fees excluded)
BTC price, 4 October 2026: €75,800
Network hashrate: 800 EH/s
Market data: Stored snapshot — live data unavailable

Net result

fleet_MW      = used_MWh ÷ hours_with_surplus
capex_€/yr    = fleet_TH/s × hardware_€ ÷ hardware_life
              + fleet_kW × site_€ ÷ site_life
opex_€/yr     = used_MWh × (operations + network + generator payment)
net_€         = revenue_€ − capex_€/yr − opex_€/yr
break_even_€  = (capex_€/yr + opex_€/yr) ÷ BTC

Hours a year with surplus: 2,000
Hardware: €14 per TH/s, over 4 years
Site and connection: €250/kW, over 10 years
Operations: €8/MWh
Network charges: €20/MWh
Payment to the generator: €10/MWh

Worked example — 2024 volume, today's market

Fleet needed: ≈ 570 MW
Share of the network: 0.93%
BTC a year (after pool fee): ≈ 1,503
Gross revenue: ≈ €110M
Costs a year: ≈ €170M
Net: ≈ -€58M
Break-even BTC price: ≈ €110K

Every cost is an Irish Grid assumption, not a quote; readers can change each one in the calculator on the policy option page.

4 · The 20-year scenario

Wind and solar capacity: 7 GW (2026) · 22 GW (2030) · 43 GW (2040) · 63 GW (2050)
Blended capacity factor: 25%
Dispatch-down rate at today's capacity: 10.1% (2024 reported rate)
Rise per extra GW, business as usual: 0.8% points (capped at 50%)
Share used by flexible demand: 60%
Network hashrate growth: 15% a year
BTC price change: 0% a year
Block subsidy: Halves in 2028, 2032, 2036, …

Capacity anchors follow the Climate Action Plan (about 22 GW of wind and solar by 2030) and the offshore targets for 2040 and 2050. The dispatch-down slope is an Irish Grid assumption: a grid that is reinforced would see far less.

5 · Sources

Changes to the method

1.1 · October 2026: One series (Ireland, wind, calendar years, 2020 onwards). Synthetic daily and weekly figures and per-plant estimates removed. Cost shown as a low–high range using the reported split where available; one denominator (households, Census 2022). Bitcoin figures labelled gross, with a net model and break-even price; halvings in the scenario. Market snapshot refreshed. 2020 and 2021 added.
1.0 · launch: First published method.

The full history of every change is in the code history.

Corrections

Found an error?

Open an issue on GitHub or use the form on Get involved. Corrections to figures are made in public, with the change visible in the code history.