Tokyo is a top-five global hub, but the 50Hz eastern grid (TEPCO) is the tighter, pricier half. It issued Japan's first-ever power shortage warnings in 2022 and cannot freely draw on the western surplus across the limited frequency link.
See Japan system conditions →Constrained access on a tight island grid; Tokyo/Inzai is the eastern demand centre.
Tighter availability: first-ever power shortage warnings in 2022 (cold, low solar, post-quake shutdowns), with the large Kashiwazaki-Kariwa restart still pending.
Highest cost: eastern-area wholesale runs above the west given the tighter balance.
Highest momentum: Tokyo anchors the eastern data-center cluster.
Higher carbon: more LNG and coal, less nuclear online than the west.
Average customer interruption (SAIDI) of 24 minutes per year in FY2024, excluding major event days as filed.
measured · Japan OCCTO quality of supply
The 50Hz east is structurally tight: it issued Japan's first-ever power shortage warnings in 2022, big eastern nuclear (Kashiwazaki-Kariwa) is still returning, and only about 1.2 GW of frequency converters (rising toward 3 GW by 2027) link it to the western surplus, so the east cannot freely borrow firm capacity from the west.
What this means: A large new load should expect genuine exposure to forced power cuts (curtailment), price spikes, and delays in getting connected, and should design in backup power or firm supply contracts.
event-based · Tokyo first-ever power shortage warning 2022 (Nippon.com) · Japan east-west converter capacity (Wikipedia)
We have not compiled what firm service actually promises here: whether it is firm, non-firm or interruptible, the conditions under which you can be curtailed, the redundancy required of you, and the transfer time behind any N-1 commitment. Treat this as an open diligence item, not as an indication that service is firm.
Utility feeds, UPS, storage, on-site generation, islanding, black start and the residual energy you still expect to lose are properties of a specific site design, not of a market. This layer only exists once there is a site, and we never assert it for you.
What this means: The supply picture looks likely to tighten; a new load should lock firm supply early and expect competition for capacity.
The average customer loses about 24.0 minutes of power per year (FY2024). This is the standard regulator outage measure (SAIDI); lower means a more reliable grid.
Averaged across several territories. No single customer experiences this figure. The per-territory table in the reliability overlay above gives each operator’s own filed record, which is what a site-specific read needs.
Source: Japan OCCTO quality of supply
Severe
This market's friction level, wait band and full story are free here. The precise typical wait in months, and every market ranked side by side, are the Analyst Desk.
Power connections in inner Tokyo take about 5 to 10 years, and reports from Chiba cite a 10-year wait as the capacity limits of TEPCO's 66kV network plus substation and transmission construction exceed the building timeline. Transmission-connection applications reached about 15 GW at end-FY2025, up 20 percent year on year. TEPCO Power Grid has said it aims to halve data-centre connection lead times, the main forward watch item.
Data-center share of demand pressure: Very high. Sources: Introl: Japan data-center power crisis · Shulman Advisory: TEPCO PG halving connection lead time. The full cross-market connection dataset is available through the Connection Friction Feed.
$135 to $190 per MWh
Midpoint about $160 per MWh
Tokyo is one of the world's largest data-center markets, but Japan's reliance on imported LNG makes delivered power among the most expensive in the coverage. A large high-voltage load negotiates a special contract below the roughly 28 yen per kWh small-business rate, but still well above US or Nordic levels, and the monthly fuel-cost adjustment adds volatility.
This market's band is free here; the ranked cross-market table with every market's precise midpoint is the Analyst Desk. See the ranked view.
Basis: triangulated from public sources, in US dollars per MWh delivered to a large high-load-factor load, excluding refundable taxes. Sources: Japan business electricity price (GlobalPetrolPrices) · TEPCO fuel cost adjustments (2026).
Moderate
2 of 3 data layers measured
Full
3 of 3 dimensions: reliability, connection, cost
June 2026
per-layer vintages below
| Layer | Method | Vintage | Freshness | Source |
|---|---|---|---|---|
| PGIQ Rating opinion | opinion | June 2026 | Current | PGIQ methodology |
| Reliability | measured | FY2024 | Fresh | Japan OCCTO quality of supply |
| Connection friction | measured | 2025/26 | Fresh | Introl: Japan data-center power crisis |
| Realized cost | modelled | 2026 | Fresh | Japan business electricity price (GlobalPetrolPrices) |
Freshness reflects each layer's refresh cadence: reliability annual to three-yearly, capacity-auction and queue yearly, tariffs every year or two. The full cross-market freshness dashboard is at /data-quality.
Not compiled for this market. Identify the serving operator before relying on any figure here, because a market-level read is an average over territories.
How the connection process is organised: the applicable service and connection entities depend on the candidate location and the power pathway. We have not compiled the structure for this market; that is a gap in our wayfinding, not a fact about the market.
The real-world events that test our Tier 4 call for Japan East (Tokyo, 50Hz): 1 supports it and 1 challenges it. Each is dated and cited, so you can check the rating against what is actually happening on the ground.
Japan restarted Unit 6 of Kashiwazaki-Kariwa, its largest nuclear station, on 9 Feb 2026, reaching full operation around mid-March. It is TEPCO's first reactor to resume after the post-2011 shutdowns, and adds roughly 9,500 GWh a year of firm, non-emitting generation to the 50Hz eastern system that Tokyo loads sit on. Japan now has 15 operating reactors totalling 33 GW. FOLLOW-THROUGH, NOT PROMISE: this one is delivering. The caution sits next door, where TEPCO has pushed Unit 7 (another 1,356 MW) back to 2029 or 2030, and where national policy assumes up to 30 reactors running by FY2040 against 15 today, 3 approved, 6 under review and 8 that have not applied.
TEPCO has delayed the restart of Unit 7, a second 1,356 MW reactor at the same station, to 2029 or 2030. Recorded separately from the Unit 6 restart because the two are routinely reported together as one recovery story, and they are not: one is generating and one is a date that has already moved. Japan's FY2040 policy target of about 20 per cent nuclear needs up to 30 reactors operating against 15 today.
How Japan East (Tokyo, 50Hz)'s reliability-adjusted score and tier have moved, month by month. Part of your Analyst Desk.
Every field above carries its own source and freshness. Price, imports and exports are modelled in every market because no feed supplies them. Carbon intensity is derived from the fuel mix.
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