Published: October 31, 2026 | Updated: October 31, 2026
POLICY & REGULATION
In Hokkaido, collisions between wind turbines and white-tailed eagles have started to change what wind farms produce. The white-tailed eagle is a nationally protected species in Japan. Hokkaido recorded 17 sea eagle collisions in fiscal 2024, the highest on record, and about half happened at one site. That site, the Hamasato wind farm in Horonobe, kept losing birds as it added one layer of mitigation after another, and has stopped daytime operation in both 2025 and 2026, according to press reports. Under current law, any extra measures after start-up are voluntary. In July 2026, a Ministry of the Environment panel pointed toward making them a duty. For anyone developing, financing or supplying onshore wind in Hokkaido, bird-driven shutdowns now belong in the energy assumptions.
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Eye-pattern markings and a deterrent system came first, then a system that stops turbines when a bird approaches. Collisions reportedly continued. Less than two years after start-up the farm went to full daytime shutdown, and it has been stopped in daytime again since February 2026.
The environment ministry’s Hokkaido office said pre-construction surveys focused on breeding pairs and migrating birds, leaving the collision forecast uncertain. An assessment figure depends on which birds were counted.
A ministry review panel said Japan should consider placing duties on operators that affect species under national recovery programmes, with powers to demand corrections. The white-tailed eagle is one of those species. The proposal is still a direction; no rule has been drafted.
Hamasato: layered mitigation, and daytime shutdowns two years running
Hamasato sits in Horonobe, in Hokkaido’s far north. A subsidiary of Eurus Energy Holdings operates it. Its 14 turbines, each rated 4.3MW, started up in May 2023.
| Date | Event | Source type |
|---|---|---|
| May 2023 | 14 turbines start operating | Ministry |
| FY2023 to FY2024 | 11 sea eagle collisions (8 in FY2024) | Ministry |
| 25 Mar 2025 | All 14 turbines stopped from one hour before sunrise to sunset | Press |
| 12 Jul 2025 | Daytime operation resumes at 13 of 14 turbines | Press |
| 11 Jan 2026 | One white-tailed eagle killed by collision | Conservation NGO |
| 4 Feb 2026 | All 14 turbines stopped in daytime again | Press |
| Sep 2026 | One of three blades on each turbine painted red; daytime stop since February still in place | Press |
The 2025 shutdown followed collisions that continued despite eye-pattern markings and a deterrent system, Nikkei BP reported. After the restart, the operator reportedly added a system that stops a turbine when a bird comes close. A further collision came in January 2026, and full daytime shutdown resumed in February. The Nature Conservation Society of Japan puts the total since start-up at 11 white-tailed eagles and one Steller’s sea eagle. Red blade paint followed in September; its effect is not yet known.
A daytime shutdown means giving up generation during hours when the wind is blowing. The operator has not published the length of the stops or the lost output. If the September report is right, though, the farm has been dark in daylight for at least February to September 2026.
8 of Hokkaido’s 17 collisions at one farm: why the forecast missed
The Hokkaido regional office of the Ministry of the Environment counted 11 sea eagle collisions at Hamasato between start-up and March 2025: three in fiscal 2023 and eight in fiscal 2024. Across Hokkaido, fiscal 2024 brought 17 cases, a record, so this one farm accounted for roughly half.
The same office also explained where the forecast went wrong. An environmental impact assessment is the process in which a developer surveys and publishes a plant’s likely impacts before building, then adjusts the plan in response to comments. At Hamasato, the flight surveys had focused on breeding pairs and migrating birds. That left uncertainty in the collision forecast, and the impact may not have been fully assessed, the office said.
In other words, the forecast depends on which birds were counted. Eagles that gather at feeding grounds, such as young birds, can fly very differently from nesting pairs or birds on migration. A miss at a single site can be large enough to move the total for all of Hokkaido (DeepWind’s interpretation).
A record 17 collisions, and no power to ask for a report: Japan’s species law review
On 28 July 2026, a Ministry of the Environment review panel published its report on the Act on Conservation of Endangered Species, the law that protects Japan’s threatened wildlife. The report is specific about the gap for wind.
Today, if harm to a rare species becomes clear after a wind farm starts, extra measures are up to the operator. The ministry can give advice and guidance under the act, but there is no penalty for ignoring it. Nor can it require reports from operators, so it has few ways to see what is happening on site. Hamasato’s stops and restarts have been the operator’s own decisions.
The panel’s proposed direction singles out species under national recovery programmes, where the state has a formal plan to rebuild numbers. White-tailed and Steller’s sea eagles have been under one since 2005. For such species, the report suggests a set duty of care, a list of measures operators must follow, and the power to demand changes to how a project operates if they fall short.
This is a direction, and the design is open. The report itself asks for rules that operators can anticipate and realistically comply with. Even so, wind farms operating in sea eagle habitat in Hokkaido may want to plan for the chance that further measures become mandatory.
Offshore, the state requires cameras from day one
Offshore wind is on a separate track, and the government has acted there already. Monitoring guidelines published by the environment and industry ministries in September 2025 make bird strikes during operation something the developer must monitor. Cameras and microphones go on the turbines at highest risk and record day and night for three years after start-up, floating projects included. Raw data goes to the state for central analysis.
Listed mitigation includes operation linked to camera detection and a higher cut-in wind speed, the wind speed at which a turbine starts generating. The ministry is trialling camera-based collision monitoring through fiscal 2027, and bids for the data analysis contract open on 17 December. Our guide to Japan’s centralized model explains how the state selects offshore sites.
The energy yield cases lenders use, such as P50 and P90, mostly reflect year-to-year swings in wind. Wildlife shutdowns are often outside them. At Hamasato, the stop was the operator’s decision and had no restart date fixed in advance. Hokkaido projects also face grid-driven curtailment (where Japan’s curtailment concentrates). For operating projects, lenders may consider checking whether the monitoring plan or operating agreements define shutdown triggers and a cap on lost hours. Exercise caution with yield cases that leave shutdowns to ad hoc decisions.
Three things to watch next
1. What conditions bring Hamasato back to daytime operation. Thirteen turbines restarted in 2025, and all stopped again in 2026. How red blades and a revised detection set-up count toward a restart will matter for other sites.
2. What a revised species law actually contains. Which species and areas, what operators must do, and how the ministry will see conditions on site. The report lists these questions; the bill will answer them.
3. What the state’s camera trial shows. The ministry’s trial runs through fiscal 2027. If cameras can reliably identify collisions, the method could become a benchmark onshore too for showing whether a measure works.
For onshore wind in Hokkaido, eagle risk has moved out of the assessment file and into the energy assumptions.
Hamasato learned the gap between forecast and outcome after start-up. Collisions continued through layered measures, and the operator answered by giving up daytime generation. The ministry’s own office traced the gap to how narrowly the pre-construction surveys were drawn. From here, the test is whether a measure can be shown to work; installing it is only the start.
Developers in Hokkaido may consider widening eagle surveys beyond nests and migration to year-round use of the site. Spending more at the survey stage is likely to cost less than stopping turbines after start-up. Exercise caution with plans that lock in voluntary measures alone while the species law review is open. If it becomes law, required measures could arrive after the project is built.
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