How estimates are made
Most public reports of an incident never say what it cost or how long the site was down. So every entry on the register carries a modelled estimate, marked as modelled, worked out the same way every time. When someone who knows the real figure tells us, the real figure replaces it.
What the estimate covers
- Damage to the asset itself, in pounds, as a range: the equipment that was damaged, at its replacement cost in the year of the incident.
- Downtime, in days, as a range: how long the site was out of service or, for grid equipment, how long the power supply was cut. Replacing the damaged equipment itself can take much longer.
Not included: lost revenue, damage to other property (a building under a rooftop array, homes near a substation), clean-up, fines and legal costs. Events that damage many assets at once, such as a hurricane or a national grid collapse, are not priced from one entry and say so.
How it is worked out
- What was damaged. Read from the entry: a battery system, a whole turbine, a blade, a gearbox, an inverter, a transformer, switchgear, a cable.
- How big it is. From the verified record where one exists, otherwise from the entry, otherwise the typical size for that kind of asset in that year. A typical size makes the range wider and the confidence low.
- What it costs to replace. From published cost ranges for that kind of equipment in that year (below).
- How much of it was damaged. From the kind of incident and its severity, and from the reporting where it says the equipment was destroyed.
The cost ranges used
| Equipment | Replacement cost used |
|---|---|
| Battery storage, systems from 2023 | £110k to £250k per MWh |
| Battery storage, 2020 to 2022 | £150k to £320k per MWh |
| Battery storage, 2017 to 2019 | £200k to £500k per MWh |
| Battery storage, before 2017 | £300k to £650k per MWh |
| Onshore wind turbine | £0.5m to £1.3m per MW, typical turbine 2 to 5 MW (smaller before 2015) |
| Offshore wind turbine | £1.5m to £2.5m per MW, typical turbine 8 to 15 MW (smaller before 2021) |
| Onshore blade failure | £150k to £1m |
| Utility solar | £450k to £800k per MW |
| Solar inverter, transformer or cabling | £20k to £600k |
| Transmission transformer (275 kV and above) | £1.5m to £8m |
| Distribution transformer | £15k to £400k |
How well it works
Checked on 27 September 2026 against every verified record on the register where a source states the real figure.
- Losses: 27 of 30 reported losses fell inside the modelled range. In the misses checked by hand, the reported figure included things the estimate leaves out, such as a building under a rooftop array or the farm around a battery.
- Downtime: 40 of 42 reported downtimes fell inside the modelled range.
- A hurricane that damaged a whole region's grid was correctly left unpriced.
The check runs again every day as new figures are reported, and the ranges are wide where the reporting is thin. An estimate is a starting point for a question, not a valuation, and it is never a finding about who was at fault.
Currency
Estimates are worked out in pounds. Subscribers also see the range in the currency of the country where the incident happened, converted at the European Central Bank's reference rate of the date shown. Where the European Central Bank publishes no rate for that currency, the second figure is in US dollars.
Know the real figure?
If you own, insure or ran the asset, or you have seen the figure in a published source, email editorial@energyincidentregister.com with the entry's reference and where the figure comes from. Once checked, the real figure replaces the estimate. Corrections are free for anyone, always.
Who sees what
Every entry page shows the rough band, for example "£1m to £10m". Subscribers see the exact range, the downtime in days, the confidence and how each estimate was worked out. Plans start with a 14 day free trial.