Published: January 11, 2026 | Updated: June 14, 2026

PROJECT EXECUTION

In Japan’s offshore wind market, the “Promotion Zone” (促進区域, sokushin kuiki) designation sits at the center of the country’s offshore wind development framework. Based on the Act on Promoting the Use of Sea Areas for the Development of Marine Renewable Energy Power Generation Facilities, the national government coordinates sea area use and establishes a long-term occupancy framework — providing the institutional stability that large-scale offshore wind investments require.

Policy Design
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Execution Reality
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Bankability Test

Key Takeaways

1. Promotion Zone designation does not remove risk — it clarifies where risk resides
The designation resolves sea area conflicts and unlocks the procurement process. It does not resolve execution-phase challenges in CAPEX, port logistics, installation, grid connection, or financing. In practice, institutional clarity makes these downstream risks more visible, not smaller.

2. All 12 projects share the same institutional label, but their difficulty is not uniform
Water depth, wave conditions, port proximity, installation distance, grid constraints, and project scale vary substantially across sites. The “Promotion Zone” label alone cannot determine project readiness or investment attractiveness.

3. Projects fall into three distinct risk types — and the nature of that risk differs fundamentally
Type A (near-standard conditions, but resource competition risk), Type B (case-specific constraints determine viability), and Type C (high potential × high implementation difficulty) define a framework for evaluating which risk type a developer or investor can absorb.

4. The Akita coast is the market’s nearest benchmark — but project clustering creates its own risk
With multiple projects in close geographic proximity, port yard capacity, installation vessels, O&M base slots, and grid capacity face structural competition. “Better conditions attract more projects” — and more projects generate more resource conflict.

5. Japan’s market growth ceiling is set by port and installation capacity, not by policy targets
The Promotion Zones list functions as a constraint map, not a policy checklist. As more projects advance simultaneously, physical implementation capacity — not ambition — determines what actually gets built.

At first glance, it is tempting to treat “Promotion Zone” as a stamp of low risk or even project readiness. In practice, designation means something more specific and more limited: the institutional entry conditions have been met. Water depth, wave conditions, port logistics, installation distance, grid constraints, project scale, and supply chain fit still differ enormously across sites — and those differences are what determine whether a project is commercially viable.

Rather than presenting Japan’s Promotion Zone projects as a simple list, this Pillar article asks the structural question: “Why does difficulty differ by project, even within the same policy framework?” Individual project details are covered in linked child articles; the purpose here is to provide the comparative framework and a market-wide overview.

The 12 Promotion Zone projects covered in this article are listed below.

▶ Japan’s Offshore Wind Promotion Zone Projects (with individual project links)

Sea Area	Capacity	Turbines	Technology	Details
Goto, Nagasaki (Floating)	16.8MW	8	Floating	Read more
Noshiro/Mitane/Oga, Akita	494MW	38	Fixed-bottom	Read more
Yurihonjo, Akita	845MW	65	Fixed-bottom	Read more
Choshi, Chiba	403MW	31	Fixed-bottom	Read more
Happo/Noshiro, Akita	375MW	25	Fixed-bottom	Read more
Oga/Katagami/Akita City	315MW	21	Fixed-bottom	Read more
Murakami/Tainai, Niigata	684MW	38	Fixed‑bottom	Read more
Saikai/Enoshima, Nagasaki	420MW	28	Fixed-bottom	Read more
Yuza, Yamagata	450MW	30	Fixed-bottom	Read more
Tsugaru, Aomori	615MW	41	Fixed-bottom	Read more
Hiyama, Hokkaido	910–1,140MW	76	Fixed-bottom	Read more
Matsumae, Hokkaido	315–320MW	21	Fixed-bottom	Read more

All 12 projects belong to the same institutional framework, but their commercial difficulty is far from uniform. The following sections explain why — and how to read that variation as market structure rather than project-level noise.

Contents

What the Promotion Zone Framework Actually Provides (and What It Doesn’t)

Understanding Japan’s offshore wind market requires a precise grasp of what the Promotion Zone framework actually delivers. The designation is based on Japan’s Act on Promoting the Use of Sea Areas for the Development of Marine Renewable Energy Power Generation Facilities, through which the national government coordinates competing maritime uses and creates a long-term occupancy framework — typically 30 years — for offshore wind development.

For a capital-intensive sector with long payback periods, this institutional stability is necessary. But “necessary” is not the same as “sufficient.”

What Promotion Zone Designation Guarantees

Legal resolution of sea area use conflicts between maritime stakeholders
A structured competitive tender process for developer selection
Long-term occupancy rights (30 years) as the institutional foundation for project financing

These conditions are critical at the pre-development stage — without them, the project cannot move forward. But they represent entry conditions, not commercial guarantees.

What Promotion Zone Designation Does Not Guarantee

Construction and O&M cost levels (CAPEX and OPEX)
Port logistics and installation vessel availability
Grid connection terms and curtailment risk
Site-specific natural conditions (wind resource, wave climate, seabed geology)
Financing terms and weighted average cost of capital (WACC)

Policy Limit

The Promotion Zone framework resolves sea area coordination and sets up the competitive tender — it does not resolve the conditions that determine commercial viability: CAPEX and OPEX levels, port and installation logistics, grid connection terms, or the WACC that determines whether a project can clear a bankability threshold. If anything, institutional clarity makes these downstream challenges more visible, not smaller. “Promotion Zone = low risk” is a misread of what the framework actually delivers.

Risk Is Clarified, Not Eliminated

The correct framing is not “Promotion Zone = lower risk” but rather “Promotion Zone = clearer picture of where risk lives.” Sea area conflicts and regulatory uncertainty are resolved; cost structure, construction logistics, and financing conditions are exposed more clearly as a result.

For sophisticated market participants, Promotion Zone designation is not the signal they are waiting for — it is the precondition that makes serious project evaluation possible. The real signal is what a given project’s conditions look like after designation. And those conditions vary enormously across Japan’s 12 designated sites.

Five Axes for Comparing Promotion Zone Projects

Since all 12 Promotion Zone projects share the same institutional label, meaningful comparison requires a consistent analytical framework. The five axes below capture the factors that actually determine execution difficulty and commercial viability.

① Water Depth and Wave Climate (defines the technology choice)

Water depth is the most fundamental axis — it determines whether a project uses fixed-bottom (monopile, jacket) or floating foundations, which cascades through cost structure, supply chain requirements, and construction method. Wave climate and tidal conditions add further complexity: a shallow site with severe wave exposure may be harder to build than a deeper site with benign seas. Evaluating a project by water depth alone, without wave climate, leads to systematic underestimation of installation risk.

② Port Conditions and Installation Distance (determines feasibility, not just cost)

Offshore wind construction requires port infrastructure for component assembly, storage, load-out, tow-out (for floating), and crew transfer. If suitable port capacity does not exist within a manageable distance, the project cannot advance on a commercially realistic timeline — this is a feasibility constraint, not merely a cost driver. Installation distance compounds this: longer transit times increase weather exposure, fuel cost, and vessel downtime. For Japan’s more remote sites, the combined port-and-distance constraint is among the most difficult to resolve.

③ Grid Connection and Curtailment Risk (impacts revenue)

Even in designated zones, grid connection capacity, transmission upgrade timelines, and output curtailment exposure differ substantially by site. Japan’s regional grid systems have significant capacity constraints in certain areas — particularly in Tohoku and Hokkaido — where existing generation and limited interconnection create chronic curtailment conditions. A project that generates electricity but cannot consistently deliver it to the grid sees its IRR compress in ways that are difficult to forecast at planning stage.

④ Project Scale and Development Maturity (risk type, not just risk level)

Japan’s 12 Promotion Zone projects range in scale from 16.8 MW (Goto) to over 1,100 MW (Hiyama). Scale economies favor larger projects, but initial capital exposure and complexity rise proportionally. Development maturity — measured by environmental assessment progress, geotechnical survey completion, and stakeholder engagement status — determines the current risk profile. A project at an early development stage carries a qualitatively different risk than one nearing final investment decision, regardless of size.

⑤ Technology Choice and Supply Chain Fit

Whether the planned turbine size, foundation design, and installation method can be realistically sourced and executed with Japan’s current and near-term supply chain is a practical constraint often underweighted at the planning stage. A technically feasible solution that has no credible manufacturing or installation pathway in Japan does not constitute a viable project. For floating wind projects in particular, this gap between technical possibility and supply chain readiness remains significant.

With these five axes in hand, Promotion Zone projects can be compared not as “institutional categories” but through the lens of practical execution difficulty and conditions for commercial realization.

Japan’s Promotion Zone Projects by Region

Japan’s Promotion Zone projects are not evenly distributed — they cluster on the Sea of Japan coast and Hokkaido, with limited representation on the Pacific side. This distribution reflects accumulated advantages in wind resource, water depth, port infrastructure, and grid configuration. Understanding the geographic logic helps explain why certain regions are advancing faster and which constraints will bind first as the market scales.

① Akita Prefecture (Japan’s fixed-bottom benchmark)

Akita concentrates four Promotion Zone projects (Noshiro–Mitane–Oga, Yurihonjo, Happo–Noshiro, and Oga–Katagami–Akita City), making it the closest thing Japan has to a standard fixed-bottom environment. Water depths, wind resource, and port availability align more favorably here than elsewhere. Akita has become the reference point for Japan’s offshore wind cost benchmarking.

The counterpart risk is resource competition: as multiple projects advance in the same corridor, port yard space, self-elevating platform (SEP) vessel slots, O&M base capacity, and grid interconnection windows face structural competition. The very conditions that make Akita attractive also make it the earliest site for market-level execution bottlenecks.

👉 Akita Noshiro–Mitane–Oga Offshore Wind Project
👉 Akita Yurihonjo Offshore Wind Project
👉 Happo–Noshiro Offshore Wind Project
👉 Oga–Katagami–Akita Offshore Wind Project

② Hokkaido (high potential, high implementation difficulty)

Hiyama and Matsumae represent Japan’s largest-scale Promotion Zone projects by capacity. Wind resource is among the best in the country, and project dimensions suggest potential for significant economies of scale. However, installation distance, severe winter weather, limited port infrastructure, and grid constraints combine to make Hokkaido one of the most execution-challenging clusters in Japan’s Promotion Zone portfolio.

Hokkaido is often cited as a future pillar of Japan’s offshore wind capacity. In the near term, the practical question is not whether these sites are good — they are — but whether the execution infrastructure can be assembled to build them on any commercially defensible timeline.

👉 Hokkaido Hiyama Offshore Wind Project
👉 Hokkaido Matsumae Offshore Wind Project

③ Tohoku Sea of Japan (adjacent to Akita, but not interchangeable)

Yuza (Yamagata), Murakami–Tainai (Niigata), and Tsugaru (Aomori) occupy the same Sea of Japan coast as Akita but cannot be evaluated as simple extensions of the Akita model. Port conditions, installation logistics, grid connection pathways, and winter sea conditions differ project by project. The defining characteristic of this cluster is that site-specific conditions dominate — standardization across projects within this group is limited.

👉 Aomori Tsugaru Offshore Wind Project
👉 Yamagata Yuza Offshore Wind Project
👉 Niigata Murakami–Tainai Offshore Wind Project

④ Pacific Coast — Choshi, Chiba

Choshi stands out as Japan’s only significant Pacific-side Promotion Zone project. Proximity to Japan’s main consumption centers is a real advantage. The counterpart is Pacific swell: wave conditions on the Pacific coast impose narrower installation windows and higher vessel and structural specifications than equivalent Sea of Japan sites. Choshi is not straightforwardly “better” or “worse” than Sea of Japan projects — it represents a different risk type that requires Pacific-coast-specific operational planning.

👉 Chiba Choshi Offshore Wind Project

⑤ Kyushu / Western Japan (Japan’s floating wind front-runners)

Goto City (floating, 16.8 MW) and Saikai–Enoshima (Nagasaki) represent Japan’s floating offshore wind vanguard. Goto has accumulated real operational experience with floating technology — a scarce commodity in any market. Saikai–Enoshima carries scale potential. What both share is the challenge of transitioning from “technically demonstrated” to “commercially replicable at scale” — a gap that requires supply chain development, cost reduction, and financing structures not yet available in Japan at commercial depth.

👉 Goto City Offshore Floating Wind Power Project
👉 Nagasaki Saikai–Enoshima Offshore Wind Project

What the Full Project List Reveals About Japan’s Market Structure

Taken together, the 12 Promotion Zone projects reveal structural patterns that project-by-project analysis can obscure. The geographic clustering of fixed-bottom projects on the Sea of Japan coast is not incidental — it reflects the coincidence of favorable wind resource, manageable water depth, available port infrastructure, and grid access along Japan’s northwest coast. The Pacific side, with its stronger swell and different grid topology, produces a different risk profile that has yielded far fewer designated projects.

By looking at the list as a whole, the following structural facts become visible:

Fixed-bottom projects are concentrated on the Sea of Japan side
Project scale (capacity) varies widely — from ~315 MW to over 1,100 MW — and turbine counts from 21 to 76
Floating is currently exceptional and limited in scale at the Promotion Zone stage
Port and installation capacity is the implicit prerequisite underpinning the entire project map

A common misread is to treat Niigata Murakami–Tainai as a Pacific-side project because it is on Honshu. It is a Sea of Japan-side project. Comparing it to Choshi as if they share metocean characteristics leads to systematic errors in cost and technology assessment.

The table below presents the full Promotion Zone project list with links to individual project articles.

▶ Japan’s Offshore Wind Promotion Zone Projects (complete list)

Sea Area	Capacity	Turbines	Technology	Details
Goto, Nagasaki (Floating)	16.8MW	8	Floating	Read more
Noshiro/Mitane/Oga, Akita	494MW	38	Fixed-bottom	Read more
Yurihonjo, Akita	845MW	65	Fixed-bottom	Read more
Choshi, Chiba	403MW	31	Fixed-bottom	Read more
Happo/Noshiro, Akita	375MW	25	Fixed-bottom	Read more
Oga/Katagami/Akita City	315MW	21	Fixed-bottom	Read more
Murakami/Tainai, Niigata	684MW	38	Fixed‑bottom	Read more
Saikai/Enoshima, Nagasaki	420MW	28	Fixed-bottom	Read more
Yuza, Yamagata	450MW	30	Fixed-bottom	Read more
Tsugaru, Aomori	615MW	41	Fixed-bottom	Read more
Hiyama, Hokkaido	910–1,140MW	76	Fixed-bottom	Read more
Matsumae, Hokkaido	315–320MW	21	Fixed-bottom	Read more

If you wish to check the overview and latest progress of all projects designated as “Promotion Zones,” “Promising Zones,” and “Preparation Zones” under Japan’s Offshore Renewable Energy Act, please refer to the Japan Offshore Wind Project Map.

The most important structural observation from this list is that Japan’s offshore wind market is not expanding uniformly in line with policy targets — it is forming first in the places where execution conditions are most favorable. The Sea of Japan coast dominance among fixed-bottom projects is evidence of this. As projects advance and resource competition intensifies, the sites that appear easiest will become the most contested.

Execution Risk

The single most important structural fact the Promotion Zones list reveals is that port and installation execution capacity — not the number of designated projects — determines Japan’s market growth ceiling. Twelve projects ranging from 315 MW to over 1,100 MW cannot advance simultaneously without creating structural competition for port yards, SEP vessel slots, O&M bases, and grid interconnection windows. As that competition intensifies, CAPEX and schedule risk rise for individual projects — in ways that policy design cannot resolve.

For related zone categories, DeepWind also covers Promising Zones and Preparation Zones:

👉 Japan’s Offshore Wind “Promising Zone” Projects
👉 Japan’s Offshore Wind “Preparation Zone” Projects

A Three-Type Framework for Promotion Zone Difficulty

To navigate Japan’s Promotion Zone landscape with analytical precision, it helps to categorize projects by the type of risk they present — not just the level. Three categories emerge from comparing the 12 projects across the five axes above.

Type A: Near-standard conditions, but resource competition risk — Fixed-bottom with manageable depth, accessible ports, credible grid paths. Primary risk is that project clustering generates competition for shared execution resources.
Type B: Workable site, but case-specific constraints determine viability — Site conditions are not prohibitive, but individual factors (wave exposure, port distance, stakeholder complexity, grid configuration) can shift the economics significantly. Execution outcomes depend heavily on project-level design and management.
Type C: High potential, high implementation difficulty — Multiple execution constraints overlap: installation distance, severe weather windows, port limitations, grid constraints, technology readiness. These sites represent Japan’s long-term opportunity but require resolving challenges that cannot be sequenced around.

This classification is not a ranking of project quality — it is a framework for understanding what kind of risk each project presents, and therefore what developer capability, capital structure, and operational experience is required to advance it.

Type A: Akita — the market’s nearest standard

Akita’s four Promotion Zone projects sit closest to what Japan can treat as a fixed-bottom standard. The risk is not that conditions are bad — they are the best available — but that competition for shared resources intensifies as multiple projects target the same corridor simultaneously.

👉 Noshiro–Mitane–Oga ／ Yurihonjo ／ Happo–Noshiro ／ Oga–Katagami–Akita City

Type B: Choshi — location advantage versus Pacific swell

Choshi is Japan’s clearest Type B case. Proximity to the Kanto demand center is a genuine advantage. Pacific swell imposes narrower installation windows, higher structural specifications, and greater operational planning complexity than Sea of Japan sites. Whether Choshi is commercially viable depends not on whether the site is good or bad in absolute terms, but on whether the project design can adequately account for Pacific-coast specific constraints.

👉 Choshi, Chiba

Type B: Tohoku Sea of Japan (Tsugaru, Yuza, Murakami–Tainai) — adjacent to Akita, but not interchangeable

These three projects share the Sea of Japan coast with Akita but cannot be evaluated as simple Akita analogs. Port conditions, installation routes, grid interconnection pathways, and winter sea state intensity differ by site in ways that make standardization across this cluster limited. Each project requires site-specific execution planning — and the degree of that specificity is what makes them Type B rather than Type A.

👉 Tsugaru, Aomori
👉 Yuza, Yamagata
👉 Murakami–Tainai, Niigata

Type C: Hokkaido — scale potential constrained by execution infrastructure

Hiyama and Matsumae offer Japan’s largest-scale Promotion Zone opportunities. The wind resource justifies the ambition. The execution challenge is that installation distance, winter weather windows, and infrastructure limitations all need to be resolved simultaneously — and no single constraint can be worked around without addressing the others. These are not projects for developers who cannot absorb extended pre-construction periods and high upfront uncertainty.

Bankability Note

For Type C projects such as Hokkaido, execution uncertainty translates directly into financing cost. When multiple constraints (installation distance, winter weather, port infrastructure, grid) cannot be resolved sequentially, lenders cannot model residual risk with precision — which compresses acceptable DSCR (debt service coverage ratio) thresholds and raises WACC. Projects that cannot demonstrate ≥1.35x DSCR under base-case assumptions face structural difficulty accessing project finance at the cost of capital required for viability. Robust execution planning is not a developer preference — it is a bankability prerequisite.

👉 Hiyama, Hokkaido ／ Matsumae, Hokkaido

Type C: Kyushu floating wind — technically ahead, commercially proving ground

Goto City’s floating installation puts it in a category of its own in terms of demonstrated experience. Saikai–Enoshima carries scale potential for the next generation of floating projects. Both face the same transition challenge: from technically operational to commercially replicable. Floating wind’s supply chain, financing structures, and cost trajectory in Japan are not yet at the stage where commercial-scale replication is straightforward.

👉 Goto City Offshore Floating Wind Power Project
👉 Nagasaki Saikai–Enoshima Offshore Wind Project

Promotion Zones Are Not the Goal — the Entry Point Where Project Difficulty Diverges

Japan’s Promotion Zone framework provides what offshore wind investment requires at the institutional level: legal certainty over sea area use, a structured competitive tender, and a 30-year occupancy right. These are genuine contributions to project bankability. They do not, however, determine whether any given project will reach commercial operation — or at what cost.

What this Pillar article has shown is that the 12 Promotion Zone projects are institutionally equivalent but commercially heterogeneous. The differences in water depth, port access, wave climate, grid conditions, and supply chain fit produce three meaningfully distinct risk types — and developers, lenders, and policymakers who do not distinguish between them will systematically misread where Japan’s offshore wind market is actually heading.

The practical implication is that the question “which Promotion Zone project is best?” is not the right question. The right question is: “which type of execution risk is compatible with our capital structure, operational capability, and timeline?” A Type A project in Akita and a Type C project in Hokkaido are not comparable on a single axis — they represent different bets on different dimensions of Japan’s offshore wind development challenge.

Japan’s offshore wind market will advance not because all projects move forward together, but because specific conditions — in specific sites, with specific execution partners — unlock first. The Promotion Zones list is where that process becomes visible. Reading it as a constraint map, rather than an institutional checklist, is the starting point for serious market analysis.

DeepWind View

The Promotion Zones list is not a project inventory — it is a structural map of where Japan’s offshore wind market can and cannot form, and in what sequence.

The A/B/C classification matters because the risk type determines what resolves it. Type A competition risk is a market-level coordination problem — no individual developer controls the port yard and grid capacity their neighbors are competing for. Type B case-specific risk is a project design problem — it can be engineered around, but the engineering costs money that needs to be priced into the bid. Type C implementation risk is a prerequisite sequencing problem — you cannot build a Hokkaido project without first solving port, vessel, and grid in a way that cannot be done independently for a single project.

This means the correct policy response to each type is different. Addressing Type A requires coordination mechanisms across projects, not individual project support. Addressing Type B requires flexibility in project design and permitting timelines. Addressing Type C requires infrastructure investment decisions that precede any individual project’s bankability — the market will not provide them on its own.

DeepWind tracks these distinctions project by project, because the difference between “Japan has 12 Promotion Zone projects” and “Japan’s offshore wind market can realistically build at scale” runs through exactly this analysis.

Japan’s Offshore Wind Promotion Zones : A Complete Project List and Structural Market Analysis