Top 37 Green Energy startups in San Francisco
Feb 24, 2026
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29
1
Funding: $4.9B
Recurrent Energy, a subsidiary of Canadian Solar Inc. (global renewable energy company) that is building one of the world's largest and most geographically diversified platforms for developing, owning and operating solar and energy storage projects. It is a leading global developer, owner and operator of solar and energy storage systems, with over 14 GW of project capacity under long-term operation and maintenance agreements.
Recurrent Energy, a subsidiary of Canadian Solar Inc. (global renewable energy company) that is building one of the world's largest and most geographically diversified platforms for developing, owning and operating solar and energy storage projects. It is a leading global developer, owner and operator of solar and energy storage systems, with over 14 GW of project capacity under long-term operation and maintenance agreements.
2
Funding: $3.5B
Archer is an aerospace company that developed an electric vertical takeoff and landing aircraft tailored for urban air mobility systems.
Archer is an aerospace company that developed an electric vertical takeoff and landing aircraft tailored for urban air mobility systems.
3
Funding: $1.7B
Redaptive is an Energy-as-a-Service provider that funds and installs energy-saving and energy-generating equipment and manages energy use in buildings.
Redaptive is an Energy-as-a-Service provider that funds and installs energy-saving and energy-generating equipment and manages energy use in buildings.
4
Funding: $1.2B
TeraWatt Infrastructure operates an electric vehicle charging infrastructure for medium and heavy-duty transport and fleets.
TeraWatt Infrastructure operates an electric vehicle charging infrastructure for medium and heavy-duty transport and fleets.
5
Funding: $523.5M
Aurora Solar is a SaaS company that uses aerial imagery to assess solar installation projects.
Aurora Solar is a SaaS company that uses aerial imagery to assess solar installation projects.
6
Funding: $450M
Inertia is a fusion-energy company that builds and generates commercialized fusion powers. Inertia is taking the most direct, scientifically-proven path to commercializing fusion, leveraging the only successful achievement of fusion ignition, using a process that was pioneered at the U.S. Department of Energy’s (DOE) Lawrence Livermore National Laboratory (LLNL).
Inertia is a fusion-energy company that builds and generates commercialized fusion powers. Inertia is taking the most direct, scientifically-proven path to commercializing fusion, leveraging the only successful achievement of fusion ignition, using a process that was pioneered at the U.S. Department of Energy’s (DOE) Lawrence Livermore National Laboratory (LLNL).
7
Funding: $230.3M
SPAN develops smart electrical panels that unlock whole-home, room and appliance energy data designed to lower your energy bill.
SPAN develops smart electrical panels that unlock whole-home, room and appliance energy data designed to lower your energy bill.
9
Funding: $78M
Weave Grid is dedicated to enabling large-scale electrification of transportation through direct & efficient system integration. The company taps into electric vehicle charging data and can optimize EV charging for customers such as utilities.
Weave Grid is dedicated to enabling large-scale electrification of transportation through direct & efficient system integration. The company taps into electric vehicle charging data and can optimize EV charging for customers such as utilities.
10
Funding: $67.1M
Carbon Lighthouse is on a mission to stop climate change by making it easy and profitable for building owners to eliminate carbon emissions caused by wasted energy. The company’s unique approach to Efficiency Production goes deep into buildings to uncover and continuously correct hidden inefficiencies that add up to meaningful financial value and carbon elimination that lasts.
Carbon Lighthouse is on a mission to stop climate change by making it easy and profitable for building owners to eliminate carbon emissions caused by wasted energy. The company’s unique approach to Efficiency Production goes deep into buildings to uncover and continuously correct hidden inefficiencies that add up to meaningful financial value and carbon elimination that lasts.
11
Funding: $63.8M
Bright is a solar-power subscription business that aims to offer homeowners with renewable energy.
Bright is a solar-power subscription business that aims to offer homeowners with renewable energy.
12
Funding: $60.1M
Leap is a marketplace for universal distributed energy resources to participate in the energy market. Leap allows every connected device to help balance the grid, and get paid for it.
Leap is a marketplace for universal distributed energy resources to participate in the energy market. Leap allows every connected device to help balance the grid, and get paid for it.
13
Funding: $58M
Hydro Wind Energy develops hybrid energy system that harnesses offshore altitude wind using kites or vertical axis wind rotors combined with subsea oceanic pressure to provide reliable, low-cost clean electrical energy and grid scale energy storage.
Hydro Wind Energy develops hybrid energy system that harnesses offshore altitude wind using kites or vertical axis wind rotors combined with subsea oceanic pressure to provide reliable, low-cost clean electrical energy and grid scale energy storage.
14
Funding: $50M
General Matter is a nuclear energy company that produces enriched uranium fuel for nuclear energy applications.
General Matter is a nuclear energy company that produces enriched uranium fuel for nuclear energy applications.
15
Funding: $50M
Aetherflux is building a constellation of small LEO satellites to beam solar energy to Earth using infrared lasers. This approach differs from traditional space-based solar power (SBSP) concepts, which rely on massive geostationary platforms transmitting power via microwaves. The US Defense Department has allocated funding for the development of this technology to ensure the energy supply to remote military bases and contested areas. Additionally, the Aetherflux satellites will have an orbital computing node that utilizes continuous solar power and radiative cooling to enable high-performance data processing in space. The node uses optical inter-satellite links and advanced relay networks to ensure continuous availability, consistent with ground-based application servers.
Aetherflux is building a constellation of small LEO satellites to beam solar energy to Earth using infrared lasers. This approach differs from traditional space-based solar power (SBSP) concepts, which rely on massive geostationary platforms transmitting power via microwaves. The US Defense Department has allocated funding for the development of this technology to ensure the energy supply to remote military bases and contested areas. Additionally, the Aetherflux satellites will have an orbital computing node that utilizes continuous solar power and radiative cooling to enable high-performance data processing in space. The node uses optical inter-satellite links and advanced relay networks to ensure continuous availability, consistent with ground-based application servers.
16
Funding: $48.5M
Ever is an automotive retail platform that facilitates the buying and selling of used electric vehicles through an online marketplace.
Ever is an automotive retail platform that facilitates the buying and selling of used electric vehicles through an online marketplace.
18
Funding: $29M
Camus provides a grid orchestration platform to help electric utilities operate and build a reliable, affordable, and zero-carbon grid.
Camus provides a grid orchestration platform to help electric utilities operate and build a reliable, affordable, and zero-carbon grid.
20
Funding: $14M
Tyba was founded to improve energy storage modeling and operating methods, enabling developers, owners, and operators to optimize their assets and realize greater returns.
Tyba was founded to improve energy storage modeling and operating methods, enabling developers, owners, and operators to optimize their assets and realize greater returns.
21
Funding: $10.8M
Halcyon provides an AI-assisted search and information platform to navigate energy transition decision-making for investors and analysts.
Halcyon provides an AI-assisted search and information platform to navigate energy transition decision-making for investors and analysts.
22
Funding: $9.6M
Sylvatex has developed a renewable nano-chemistry platform with applications in industry processing, materials stability, and fuels.
Sylvatex has developed a renewable nano-chemistry platform with applications in industry processing, materials stability, and fuels.
23
Funding: $6.9M
Marathon Fusion designs, engineers and scales next-generation technologies to enable the deployment of fusion power plants. In deuterium-tritium fusion, high-energy neutrons drive "multiplication" reactions to close the fuel cycle by producing the tritium needed to sustain operation. Making use of those neutrons to drive a multiplication reaction on mercury-198, this approach produces mercury-197 which then decays in a few days to the only stable isotope of gold. Using Marathon's approach, power plants can generate five thousand kilograms of gold per year, per gigawatt of electricity generation.
Marathon Fusion designs, engineers and scales next-generation technologies to enable the deployment of fusion power plants. In deuterium-tritium fusion, high-energy neutrons drive "multiplication" reactions to close the fuel cycle by producing the tritium needed to sustain operation. Making use of those neutrons to drive a multiplication reaction on mercury-198, this approach produces mercury-197 which then decays in a few days to the only stable isotope of gold. Using Marathon's approach, power plants can generate five thousand kilograms of gold per year, per gigawatt of electricity generation.
24
Funding: $5.2M
Station A is an online marketplace that connects building operators with businesses offering solar paneling, battery storage and electric vehicle charging.
Station A is an online marketplace that connects building operators with businesses offering solar paneling, battery storage and electric vehicle charging.
25
Funding: $4.5M
Byterat is a data platform for battery engineers that provides battery testing data.
Byterat is a data platform for battery engineers that provides battery testing data.
26
Funding: $4.4M
Emobi is an electric vehicle company that designs, manufactures, and markets zero-emission urban mobility solutions.
Emobi is an electric vehicle company that designs, manufactures, and markets zero-emission urban mobility solutions.
27
Funding: $4M
Aikido Technologies develops innovative floating wind technologies.
Aikido Technologies develops innovative floating wind technologies.
28
Funding: $4M
Pila Energy develops innovative battery systems and software to provide energy security and energy management for homes and businesses.
Pila Energy develops innovative battery systems and software to provide energy security and energy management for homes and businesses.
29
Funding: $4M
HomeBoost offers a do-it-yourself energy assessment system that helps homeowners identify leaky windows and find rebate opportunities and other ways to cut their energy bills. It ships to homeowners custom hardware that, coupled with a smartphone app, scans the home and then home energy experts review and produce the report.
HomeBoost offers a do-it-yourself energy assessment system that helps homeowners identify leaky windows and find rebate opportunities and other ways to cut their energy bills. It ships to homeowners custom hardware that, coupled with a smartphone app, scans the home and then home energy experts review and produce the report.
30
Funding: $2.5M
Aether is AI design and workflow software for solar installers worldwide.
Aether is AI design and workflow software for solar installers worldwide.
31
Funding: $1.3M
Nimbus is developing advanced optical technology for ultra efficient energy logistics.
Nimbus is developing advanced optical technology for ultra efficient energy logistics.
32
Funding: $1.3M
Nano Diamond Battery (NDB) is nanotechnology corporate developing green, safe and lifelong battery made by recycling waste.
Nano Diamond Battery (NDB) is nanotechnology corporate developing green, safe and lifelong battery made by recycling waste.
33
Brightmark is on a mission to "reimagine waste" with its groundbreaking plastic renewal technique. Brightmark collects plastic materials and processes them into pellets through shredding. These pellets are then placed in an oxygen-starved container, providing an eco-friendly alternative as low-grade fuel.
34
Batteryze is a battery health diagnostics platform that focuses on the monitoring, Evaluation, and diagnostics of a battery.
35
Cosmic is the first end-to-end platform for building and managing fully electric, autonomous-powered homes.
36
MeterLeader is an online portal that offers online challenges integrated with real-time electricity data to motivate people to save energy.
37
Merino Energy is a home energy company that focuses on electrifying home heating & cooling. Merino is offering its heat pumps for a flat rate, which includes the cost of professional installation. A certified contractor can get the system up and running in under an hour, according to the company.
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