2026-04-21YUKU NEWS

[Large-scale grid battery business] Tokyo Gas signs 240MW grid-scale battery offtake agreement with Bison energy

【大規模系統用蓄電池事業】東京ガス、Bison energyと240MWの系統用蓄電池オフテイク契約を締結

Bison energy announced it has signed an offtake agreement with Tokyo Gas covering four grid-scale battery storage stations totalling 240MW, scheduled to start operation in 2029. The long-term contract is seen as a way to stabilise revenue and ease project financing for the storage projects.

  • planned (operation scheduled 2029; offtake agreement signed)
  • 240 MW
  • Bison energy株式会社
  • 東京ガス株式会社

Full account

  • Article dated 2026/4/21; source: Bison energy news release.
  • Bison energy Co., Ltd. signed an offtake agreement for its grid-scale battery business with Tokyo Gas Co., Ltd.
  • Scope: 4 grid-scale battery storage stations, total capacity 240MW, scheduled to begin operation in 2029.
  • Tokyo Gas will be involved in operating the facilities under a long-term contract; the aim is seen as stabilising revenue of the storage business.
  • Key feature: securing long-term revenue visibility via the offtake contract. Grid battery revenue models typically combine the balancing market (需給調整市場), capacity market and wholesale power market, with market price volatility risk a known challenge.
  • Participation of a major energy company like Tokyo Gas under a long-term contract is expected to ease project finance and investment decisions; financing schemes combining project bonds and long-term offtake contracts are spreading in Japan.
  • Background: grid batteries absorb renewable output fluctuations and support supply-demand balance and frequency; with growing solar, large BESS projects are increasing in Japan to reduce curtailment and handle market price swings.
  • Bison energy Group: founded 2016, renewable development/investment company operating in Japan, Australia, New Zealand, Europe, the US, etc.; covers solar, wind, BESS and integrated renewable infrastructure, from development through EPC, operation and asset management.
  • With GX investment and renewable expansion, projects premised on long-term operating contracts may increase.
日本語で読む

【大規模系統用蓄電池事業】東京ガス、Bison energyと240MWの系統用蓄電池オフテイク契約を締結

  • 記事日付：2026/4/21、出典：Bison energyニュースリリース。
  • Bison energy株式会社が東京ガス株式会社と系統用蓄電池事業に関するオフテイク契約を締結。
  • 対象：2029年に運転開始予定の系統用蓄電所4件、合計容量240MW。
  • 東京ガスが長期契約に基づき対象設備の運用に関与し、蓄電所事業の収益安定化を図る狙いとみられる。
  • 特徴：オフテイク契約による長期的な収益見通しの確保。系統用蓄電池は需給調整市場、容量市場、卸電力市場を組み合わせた収益モデルが一般的だが、市場価格変動リスクへの対応が課題。
  • 大手エネルギー事業者の長期契約参画により、プロジェクトファイナンスや投資判断が進めやすくなる効果も期待。国内では蓄電池案件向けプロジェクトボンドや長期オフテイク契約を組み合わせた資金調達スキームが拡大。
  • 背景：系統用蓄電池は再エネ出力変動吸収、需給バランス・周波数維持の調整力。太陽光増加に伴い出力制御抑制や市場価格変動対応として大型BESS案件が相次ぐ。
  • Bison energy Group：2016年設立の再エネ開発・投資会社。日本、オーストラリア、ニュージーランド、欧州、米国などで事業展開。太陽光、風力、BESS、統合型再エネインフラを対象に開発からEPC、運営、アセットマネジメントまで一体的に手掛ける。
  • GX投資や再エネ拡大を背景に、長期運用契約前提の案件形成が増加する可能性。