# Top 21 Long-Duration Energy Storage Startups Worldwide by Funding (2026)

> The 21 best-funded long-duration energy storage startups worldwide, ranked by total funding raised: $631M combined.

Source: https://millionrounds.com/top-lists/long-duration-energy-storage-startups (Millionrounds; every figure on the page links to its filing or article)

- 1 [**EnerVenue** EnerVenue is an energy storage infrastructure company based in Fremont, California, founded in 2020.](https://millionrounds.com/company/enervenue) EnerVenue is an energy storage infrastructure company based in Fremont, California, founded in 2020. *Founded* 2020 Fremont, United States **$312M** last round Mar 2026
- 2 [**RayGen** RayGen is an Australian clean energy technology company based in Melbourne, founded in 2010.](https://millionrounds.com/company/raygen) RayGen is an Australian clean energy technology company based in Melbourne, founded in 2010. *Founded* 2010 Hawthorn East, Australia **$79M** last round Apr 2025
- 3 [**Ore Energy** Ore Energy is a Dutch climate technology startup founded in 2022 and spun out of TU Delft in 2023.](https://millionrounds.com/company/ore-energy) Ore Energy is a Dutch climate technology startup founded in 2022 and spun out of TU Delft in 2023. *Founded* 2023 Amsterdam, Netherlands **$43M** last round Aug 2026
- 4 [**RedoxBlox** RedoxBlox is a post-Series A startup based in San Diego, California, focused on transforming the energy sector with its innovative Thermochemical Energy Storage](https://millionrounds.com/company/redoxblox) RedoxBlox is a post-Series A startup based in San Diego, California, focused on transforming the energy sector with its innovative Thermochemical Energy Storage *Founded* 2020 San Diego, United States **$40M** last round Mar 2025
- 5 [**Hydrostor** Hydrostor is a Canadian energy storage company based in Toronto, founded in 2010.](https://millionrounds.com/company/hydrostor) Hydrostor is a Canadian energy storage company based in Toronto, founded in 2010. *Founded* 2010 Toronto, Canada **$37M** last round Feb 2026
- 6 [**e-Zinc** e-Zinc is an energy storage company based in Toronto, Canada, focused on developing zinc-based long-duration energy storage solutions.](https://millionrounds.com/company/e-zinc) e-Zinc is an energy storage company based in Toronto, Canada, focused on developing zinc-based long-duration energy storage solutions. *Founded* 2013 Toronto, Canada **$31M** last round Jun 2024
- 7 [**RFC Power** RFC Power is a global provider of long-duration energy storage solutions, focused on developing a low-cost hydrogen-manganese hybrid flow battery.](https://millionrounds.com/company/rfc-power) RFC Power is a global provider of long-duration energy storage solutions, focused on developing a low-cost hydrogen-manganese hybrid flow battery. *Founded* 2017 London, United Kingdom **$15M** last round Aug 2026
- 8 [**MGA Thermal** MGA Thermal is an Australian clean energy company focused on large-scale, long-duration thermal energy storage solutions.](https://millionrounds.com/company/mga-thermal) MGA Thermal is an Australian clean energy company focused on large-scale, long-duration thermal energy storage solutions. *Founded* 2019 Tomago, Australia **$12M** last round Mar 2026
- 9 [**Ambri** Ambri is an American startup focused on long-duration grid-scale energy storage using its proprietary Liquid MetalTM battery technology.](https://millionrounds.com/company/ambri) Ambri is an American startup focused on long-duration grid-scale energy storage using its proprietary Liquid MetalTM battery technology. *Founded* 2010 Marlborough, United States **$11M** last round Aug 2024
- 10 [**Sinergy Flow** Sinergy Flow is a Milan-based DeepTech startup founded in 2022, specializing in low-cost, sustainable redox flow batteries (RFBs) for long-duration energy storage (LDES).](https://millionrounds.com/company/sinergy-flow) Sinergy Flow is a Milan-based DeepTech startup founded in 2022, specializing in low-cost, sustainable redox flow batteries (RFBs) for long-duration energy storage (LDES). *Founded* 2022 Milan, Italy **$8.3M** last round Feb 2026
- 11 [**Sizable Energy** Sizable Energy is an Italian startup focused on long-duration energy storage by adapting pumped hydro technology for offshore use with sea salt brine.](https://millionrounds.com/company/sizable-energy) Sizable Energy is an Italian startup focused on long-duration energy storage by adapting pumped hydro technology for offshore use with sea salt brine. *Founded* - Milan, Italy **$8.0M** last round Oct 2025
- 12 [**Storelectric** Storelectric is a UK-based company founded in 2013, specializing in large-scale, long-duration green energy storage solutions.](https://millionrounds.com/company/storelectric) Storelectric is a UK-based company founded in 2013, specializing in large-scale, long-duration green energy storage solutions. *Founded* 2013 Manchester, United Kingdom **$7.7M** last round Mar 2025
- 13 [**AquaBattery** AQUABATTERY is a Dutch cleantech startup founded in 2014, focused on sustainable long-duration energy storage (LDES) solutions.](https://millionrounds.com/company/aquabattery) AQUABATTERY is a Dutch cleantech startup founded in 2014, focused on sustainable long-duration energy storage (LDES) solutions. *Founded* 2014 Alphen aan den Rijn, Netherlands **$6.4M** last round Apr 2024
- 14 [**RheEnergise** RheEnergise is a UK-based cleantech company founded in 2019, specializing in long-duration energy storage with its innovative High-Density Hydro® (HD Hydro®) technology.](https://millionrounds.com/company/rheenergise) RheEnergise is a UK-based cleantech company founded in 2019, specializing in long-duration energy storage with its innovative High-Density Hydro® (HD Hydro®) technology. *Founded* 2019 London, United Kingdom **$6.3M** last round Sept 2026
- 15 [**StorTera** StorTera Ltd is an Edinburgh-based company specializing in long-duration energy storage solutions.](https://millionrounds.com/company/stortera) StorTera Ltd is an Edinburgh-based company specializing in long-duration energy storage solutions. *Founded* 2013 Edinburgh, United Kingdom **$6.0M** last round Nov 2022
- 16 [**Cache Energy** Cache Energy is a technology startup based in Champaign, Illinois, focused on long-duration energy storage (LDES) and heat electrification.](https://millionrounds.com/company/cache-energy) Cache Energy is a technology startup based in Champaign, Illinois, focused on long-duration energy storage (LDES) and heat electrification. *Founded* 2021 Champaign, United States **$4.0M** last round Jun 2024
- 17 [**Rivus Batteries** Rivus Batteries is a Swedish deep-tech company based in Gothenburg, founded in 2019.](https://millionrounds.com/company/rivus-batteries) Rivus Batteries is a Swedish deep-tech company based in Gothenburg, founded in 2019. *Founded* 2019 Gothenburg, Sweden **$2.9M** last round Jul 2026
- 18 [**Aed Energy** Aed Energy is a clean energy technology company based in London, United Kingdom, founded in December 2022.](https://millionrounds.com/company/aed-energy) Aed Energy is a clean energy technology company based in London, United Kingdom, founded in December 2022. *Founded* 2022 London, United Kingdom **$901K** last round Apr 2024
- 19 [**The Heat Vault Company** The Heat Vault Company is a privately held Anglo-Swedish cleantech startup founded in 2021.](https://millionrounds.com/company/the-heat-vault-company) The Heat Vault Company is a privately held Anglo-Swedish cleantech startup founded in 2021. *Founded* 2021 Newcastle upon Tyne, United Kingdom **$660K** last round Sept 2024
- 20 [**Synchrostor** Synchrostor is an engineering R&D business that provides long duration grid-scale energy storage technology services.](https://millionrounds.com/company/synchrostor) Synchrostor is an engineering R&D business that provides long duration grid-scale energy storage technology services. *Founded* 2017 United Kingdom **$333K** last round Oct 2025
- 21 [**EnergyBank** EnergyBank is a renewable energy technology company focused on advancing global decarbonisation through innovative energy storage solutions.](https://millionrounds.com/company/energybank) EnergyBank is a renewable energy technology company focused on advancing global decarbonisation through innovative energy storage solutions. *Founded* 2019 Auckland, New Zealand **$41K** last round Jun 2023

**Total funding** how the list is ranked

**15 November 2026** updated nightly

**Rounds we track** source: Millionrounds

Companies whose own description names this theme, ranked by the total they have raised in rounds we hold. Nobody pays to be on a list.

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## More lists worldwide

[See all](https://millionrounds.com/top-lists?r=Global)

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