Hokkaido Electric Power
A Japanese electric utility responsible for power generation, transmission, distribution, and retail supply across Hokkaido.
Last updated October 8, 2026
AI crawler reads
No AI crawler has read this profile since Oct 28, 2026.
Overview
Hokkaido Electric Power Company, commonly called Hokuden or HEPCO, is the regional electric utility associated with Hokkaido, Japan. Established in 1951 during the postwar reorganization of Japan’s electric-power industry, the company developed the generation, transmission, and distribution infrastructure needed to serve a large, sparsely populated island with severe winters, dispersed communities, heavy industrial users, and significant seasonal changes in demand. Its headquarters are in Sapporo, Hokkaido’s largest city. The company’s traditional business has covered the full electricity value chain within its service area: operating or procuring generation, managing the regional transmission and distribution network, and selling electricity to households, businesses, and industrial customers. Hokkaido’s geography has encouraged a diversified generation portfolio. HEPCO has historically operated hydroelectric facilities, coal- and oil-fired thermal stations, diesel generation, geothermal generation, and smaller wind and solar assets. The company’s facilities include the Tomari Nuclear Power Plant, the Tomato-atsuma, Naie, Sunagawa, Date, Shiriuchi, Tomakomai, and Onbetsu thermal stations, the Mori geothermal facility, and numerous hydroelectric plants and dams. The Kyogoku pumped-storage project is among its notable hydroelectric assets. Before the 2011 Fukushima Daiichi accident, nuclear power represented a material share of the company’s generation mix. Tomari is Hokkaido’s only nuclear power station and has three reactors with an aggregate stated capacity of 2,070 megawatts. The reactors were taken offline during the post-Fukushima regulatory and inspection process and became central to debates about Hokkaido’s energy security, replacement generation, electricity prices, and the role of nuclear power. With nuclear output unavailable, HEPCO relied more heavily on thermal generation, hydroelectric resources, conservation, and market or interconnection arrangements, exposing the company to fuel-price and supply-resilience pressures. The utility’s operating environment is unusually demanding. Winter heating loads can be substantial, while the island’s distance from Japan’s main grid limits the ability to import large volumes of electricity from other regional utilities. Hokkaido is connected to Honshu through the Hokkaido–Honshu interconnection, but the link has historically provided only limited support relative to the scale of a severe regional disruption. These characteristics make reserve margins, black-start capability, fuel logistics, transmission reliability, and distributed generation especially important to HEPCO’s strategy. In September 2018, the Hokkaido Eastern Iburi earthquake caused a widespread blackout across Hokkaido. The event highlighted the risks of relying on a closely coupled regional system and prompted scrutiny of power-system resilience, frequency control, emergency procedures, and interconnection capacity. HEPCO subsequently remained an important participant in efforts to strengthen system reliability and diversify supply, including the expansion of renewable-energy integration and reinforcement of transmission and interconnection facilities. Japan’s electricity-market reforms have also changed the company’s competitive setting. Retail electricity liberalization opened portions of the market to new suppliers, requiring HEPCO to compete for customers while continuing to operate essential network infrastructure under Japan’s regulated electricity framework. Its brand therefore combines the characteristics of a regional public utility, an infrastructure operator, an energy retailer, and a generation business. HEPCO is listed on the Tokyo Stock Exchange and the Sapporo Securities Exchange. Its continuing priorities include dependable winter supply, financial stability, emissions reduction, renewable-energy integration, network investment, and the future of the Tomari nuclear station.
History
Hokkaido Electric Power Company was created in 1951 as part of the postwar restructuring of Japan’s electric-power sector. Its purpose was to develop and operate a regional electricity system for Hokkaido, an island characterized by low population density outside major cities, long transmission distances, harsh winters, and geographically separated industrial and residential centers. From its base in Sapporo, the company expanded a vertically integrated utility model encompassing power generation, high-voltage transmission, local distribution networks, and electricity sales. HEPCO’s generation system evolved around a mixture of hydroelectric and thermal resources. Hydroelectric development used Hokkaido’s rivers and mountainous terrain, including numerous dams and stations on the Ishikari, Tokachi, Shizunai, and Niikappu river systems. Pumped storage, notably the Kyogoku project, helped the utility manage fluctuations in demand and generation. Thermal stations using coal, oil, and other fuels supplied dispatchable power for base, intermediate, and peak requirements. The principal thermal sites listed for the company include Tomato-atsuma, Naie, Sunagawa, Date, Shiriuchi, Tomakomai, and Onbetsu. The Tomari Nuclear Power Plant became the company’s nuclear generating center and Hokkaido’s only nuclear station. Its three reactors have a combined stated capacity of 2,070 megawatts. Nuclear generation represented a significant portion of HEPCO’s pre-2011 supply portfolio; a company profile for fiscal 2011 reported that 26 percent of generated electricity came from nuclear sources, compared with 31 percent from coal, 15 percent from hydroelectricity, 8 percent from oil, and 2 percent from new-energy sources. The Fukushima Daiichi accident transformed the regulatory and commercial context for Japanese nuclear operators. Tomari’s reactors were shut down and did not resume commercial operation, leaving HEPCO more reliant on fossil-fuel generation, hydroelectricity, conservation, and electricity imported through interconnection facilities. The post-2011 period placed financial and operational pressure on the company. Replacing nuclear output with thermal generation increased exposure to fuel procurement, foreign-exchange movements, and wholesale-market conditions. At the same time, Japanese electricity reforms introduced greater retail competition and separated, or prepared to separate, parts of the industry’s traditional functions. HEPCO had to preserve reliability as a regulated network operator while adapting its retail and generation activities to a more competitive market. System resilience became a particularly visible issue in September 2018. The Hokkaido Eastern Iburi earthquake caused a blackout that spread across the island. The incident demonstrated how the loss of key generating units and system-frequency disturbances could affect a geographically constrained grid. It led to renewed attention to interconnection capacity with Honshu, distributed and renewable generation, emergency response, black-start arrangements, and the need for adequate reserves during peak winter demand. HEPCO’s modern role consequently extends beyond conventional generation. The company remains responsible for supplying electricity throughout Hokkaido, maintaining a large transmission and distribution system, integrating renewable resources, and planning for severe-weather and earthquake risks. Its portfolio includes the Mori geothermal plant, small wind facilities, photovoltaic installations, extensive hydroelectric assets, and conventional thermal stations. The company’s continuing strategic questions include the future of Tomari, the cost and emissions implications of thermal dependence, renewable-energy curtailment and network capacity, electricity-price management, and the reliability of the Hokkaido–Honshu connection. HEPCO is listed on the Tokyo Stock Exchange and the Sapporo Securities Exchange and remains the principal branded electric utility for Hokkaido.
- 2018
Hokkaido-wide blackout after earthquake
[2]The Hokkaido Eastern Iburi earthquake caused a large-scale blackout, highlighting the resilience challenges of the island’s power system.
- 2011
Nuclear generation became unavailable after the Fukushima accident
[1]The Fukushima Daiichi accident and subsequent Japanese nuclear-safety processes led to the shutdown of the Tomari nuclear reactors, materially changing HEPCO’s generation mix.
- 1951
Company established
[1]Hokkaido Electric Power Company was established as the regional electric utility for Hokkaido during Japan’s postwar electricity-industry reorganization.
Products and positioning
A regional, infrastructure-intensive electric utility serving Hokkaido through integrated generation, transmission, distribution, and electricity-retail operations.
Electricity retail · 1951
Electricity supply
HEPCO supplies electricity to households, commercial premises, public institutions, and industrial customers throughout its Hokkaido service territory. The offering has traditionally been provided through regulated regional utility tariffs and, following Japanese retail-market reform, through customer plans competing with alternative electricity retailers. Service reliability is especially important during Hokkaido’s severe winter conditions.
Electric grid services · 1951
Transmission and distribution
The company’s regional network transports electricity from generating facilities and interconnections to local distribution systems and end users. Its responsibilities include network operation, maintenance, fault restoration, system balancing, and the integration of generation resources across a large island geography with separated population centers.
Power generation
Hydroelectric power
HEPCO operates an extensive hydroelectric portfolio associated with 53 dams and multiple river systems. Listed facilities include the Kyogoku pumped-storage project and stations such as Hoheikyo, Kamiiwamatsu, Niikappu, Nokanan, Okuniikappu, Shizunai, Takami, Takisato, Tokachi, Tomura, and Uryu. These assets provide renewable generation and operational flexibility.
Power generation
Thermal power
Coal-, oil-, and diesel-fired stations provide dispatchable generation for the Hokkaido system. Listed facilities include Tomato-atsuma, Naie, Sunagawa, Date, Shiriuchi, Tomakomai, and Onbetsu. Thermal generation became more important after the shutdown of the Tomari reactors, although it also increases fuel-cost and emissions exposure.
Nuclear power generation
Tomari Nuclear Power Plant
Tomari is Hokkaido’s only nuclear power station and has three reactors with a combined stated capacity of 2,070 megawatts. Nuclear power was historically a major component of HEPCO’s generation mix, but the reactors were taken offline after the 2011 Fukushima accident and subsequent regulatory processes.
Renewable energy
Renewable generation
HEPCO’s renewable portfolio includes hydroelectricity, the 2.5-megawatt Mori geothermal facility, three listed wind facilities totaling 1.58 megawatts, and nine listed photovoltaic facilities totaling 146 kilowatts. These assets support diversification, although their contribution has historically been smaller than hydroelectric and thermal generation.
Brand decisions
2018
Strengthen grid resilience after the Hokkaido blackoutStrategyBackground
The Hokkaido Eastern Iburi earthquake caused a widespread blackout and demonstrated the vulnerability of the regional system to the loss of major generation and frequency disturbances.
Action taken
The event prompted increased attention to emergency restoration, reserve capacity, system-frequency management, interconnection reinforcement, and the role of distributed and renewable generation.
Aftermath
Power-system reliability and the Hokkaido–Honshu connection became more prominent in discussions of the company’s operating strategy and Japan’s regional grid resilience.
2011
Replace unavailable nuclear output with other resourcesStrategyBackground
The shutdown of the Tomari reactors after the Fukushima Daiichi accident removed a substantial source of Hokkaido’s generating capacity.
Action taken
HEPCO increased reliance on thermal generation, hydroelectric resources, conservation, and electricity obtained through interconnection and market arrangements while the nuclear units remained offline.
Aftermath
The change increased the company’s exposure to fuel costs and emissions and made supply resilience and the future of Tomari central strategic issues.
Recent events
- Unconfirmed
Hokkaido Electric Power Company lifts guidance[4]
Reported:
Hokkaido Electric Power Company (TSE:9509) lifted its guidance, according to a Yahoo Finance article asking whether the upgrade is already priced in.
Sources4 sources
Cite this profile: Cite the canonical profile. /brand-wiki/北海道電力 · Editorial policy · How profiles are compiled