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Top 100 Green Energy startups in UK
Sep 09, 2025 | By Alexander Gillet | 28 |
1
Funding: $4.5M
Barocal is a Zero-carbon refrigeration. Barocal's breakthrough solid refrigerants deliver unprecedented efficiency and are inexpensive and safe for people and the planet - a true paradigm shift
Barocal is a Zero-carbon refrigeration. Barocal's breakthrough solid refrigerants deliver unprecedented efficiency and are inexpensive and safe for people and the planet - a true paradigm shift
2
Funding: $2.9B
Octopus Energy develops cloud-based smart grid platform and provides fair prices forever and greener energy from the UK's largest investor in solar generation. It uses an innovative AI and data-based platform to balance loads around the grid.
Octopus Energy develops cloud-based smart grid platform and provides fair prices forever and greener energy from the UK's largest investor in solar generation. It uses an innovative AI and data-based platform to balance loads around the grid.
3
Funding: $2.9B
Zenobe Energy is the largest independent owner and operator of battery storage in the UK. It buys and manages grid-scale batteries for its commercial customers, such as utilities and electric-vehicle operators.
Zenobe Energy is the largest independent owner and operator of battery storage in the UK. It buys and manages grid-scale batteries for its commercial customers, such as utilities and electric-vehicle operators.
4
Funding: $979.5M
Arrival is a technology company, that creates Generation 2 Electric Vehicles. Devices on wheels — they outperform legacy technology to deliver an experience like no other, but are priced the same as fossil fuel equivalents.
Arrival is a technology company, that creates Generation 2 Electric Vehicles. Devices on wheels — they outperform legacy technology to deliver an experience like no other, but are priced the same as fossil fuel equivalents.
5
Funding: $677.1M
Newcleo is developing the latest generation of nuclear reactors providing a path to combatting both climate change and existing nuclear waste. It is working on so-called Small Modular Reactors (SMRs) and wants to use so-called MOX technology to make it possible to recycle spent uranium from conventional nuclear power plants.
Newcleo is developing the latest generation of nuclear reactors providing a path to combatting both climate change and existing nuclear waste. It is working on so-called Small Modular Reactors (SMRs) and wants to use so-called MOX technology to make it possible to recycle spent uranium from conventional nuclear power plants.
6
Funding: £447M
OVO Energy is an independent energy technology company and supplier. OVO also installs world’s most advanced storage heaters
OVO Energy is an independent energy technology company and supplier. OVO also installs world’s most advanced storage heaters
8
Funding: $445.5M
Highview Power’s CRYOBattery delivers, clean, reliable, and cost-efficient long-duration energy storage to enable a 100% renewable energy future. It is storing energy in “liquid air”—when you compress a gas enough, it turns liquid
Highview Power’s CRYOBattery delivers, clean, reliable, and cost-efficient long-duration energy storage to enable a 100% renewable energy future. It is storing energy in “liquid air”—when you compress a gas enough, it turns liquid
9
Funding: £287M
Field is a renewable energy company aiming to accelerate the build-out of renewable infrastructure needed to reach net zero. It is building battery storage projects across the UK
Field is a renewable energy company aiming to accelerate the build-out of renewable infrastructure needed to reach net zero. It is building battery storage projects across the UK
10
Funding: $330.9M
Nexeon is an electronics company that develops and manufactures lithium-ion batteries to reduce carbon anode energy inefficiency.
Nexeon is an electronics company that develops and manufactures lithium-ion batteries to reduce carbon anode energy inefficiency.
11
Funding: $292M
Pulse Clean Energy builds and operates power stations. We deliver power into the UK’s network when it is most needed.
Pulse Clean Energy builds and operates power stations. We deliver power into the UK’s network when it is most needed.
12
Funding: $287M
Tokamak Energy aims to accelerate the development of fusion energy. Tokamak Energy was founded by leading scientists from the world’s leading fusion research establishment at Culham to develop the potential to use fusion neutrons for a variety of applications from material treatments to medical applications or low cost hydrogen production. The technology is also applicable in the area of nuclear waste, where it...
Tokamak Energy aims to accelerate the development of fusion energy. Tokamak Energy was founded by leading scientists from the world’s leading fusion research establishment at Culham to develop the potential to use fusion neutrons for a variety of applications from material treatments to medical applications or low cost hydrogen production. The technology is also applicable in the area of nuclear waste, where it...
13
Funding: £200M
Deep Green has developed a “digital boiler” technology to use the heat produced by data centers for swimming pools, apartment blocks, distilleries, laundrettes, and bakeries.
Deep Green has developed a “digital boiler” technology to use the heat produced by data centers for swimming pools, apartment blocks, distilleries, laundrettes, and bakeries.
14
Funding: $231.8M
Venterra engineer, build, and support the operations of wind energy developments around the world.
Venterra engineer, build, and support the operations of wind energy developments around the world.
15
Funding: $215M
BBOXX designs, manufactures, and distributes plug and play solar systems. It also offers pay-as-you-go solar power. BBOXX Power DC product range is closed DC systems in standardised sizes. BBOXX Hub brings the smart capabilities of remote monitoring and control to larger capacity systems and projects. BBOXX Pulse is a comprehensive management platform that enables growth of next generation utility businesses.
BBOXX designs, manufactures, and distributes plug and play solar systems. It also offers pay-as-you-go solar power. BBOXX Power DC product range is closed DC systems in standardised sizes. BBOXX Hub brings the smart capabilities of remote monitoring and control to larger capacity systems and projects. BBOXX Pulse is a comprehensive management platform that enables growth of next generation utility businesses.
16
Funding: $152.2M
Oxford PV is the technology leader in the field of perovskite solar cells.
Oxford PV is the technology leader in the field of perovskite solar cells.
17
Funding: £100M
UK-based energy infrastructure startup that is building multi-energy filling stations for commercial vehicles
UK-based energy infrastructure startup that is building multi-energy filling stations for commercial vehicles
18
Funding: $113.6M
Nyobolt is a developer of high-powered battery technology used to serve automotive applications.
Nyobolt is a developer of high-powered battery technology used to serve automotive applications.
19
Funding: $107M
First Light Fusion (FLF) develops Inertial confinement fusion reactor that can produce power.
First Light Fusion (FLF) develops Inertial confinement fusion reactor that can produce power.
20
Funding: $90.7M
Fuse Energy offers commission-free energy; 10x cheaper; 10x better, and 100 per cent renewable energy.
Fuse Energy offers commission-free energy; 10x cheaper; 10x better, and 100 per cent renewable energy.
