Best Energy Companies in San Jose, United States
The 44 best Energy companies in San Jose, United States in 2026, ranked by funding and momentum. Funding, investors, founders, valuation, tech stack and live signals. Top: SunPower Corporation.
Our analysis of 171 Energy companies
$71.4b in tracked funding; 82% of the stack-profiled cohort runs cloud-native; funding activity peaked in 2025.
Ranked: Best Energy companies in San Jose
| # | Company | Disclosed funding | Last round | Stage | Founder | Founded | Tech stack | Patents & IP focus | Recent signals |
|---|---|---|---|---|---|---|---|---|---|
| 1 | SunPower Corporation SunPower Corp. | $873M | 109 mo ago | Public | — | 1985 | ContentfulApple iCloud MailMicrosoft 365+30 | 3,500 patents Solar photovoltaic mounting hardware, cable management, and energy system integration. | — |
| 2 | Silicor Materials Producer of silicon for the manufacture of solar photovoltaic (PV) cells | $361M | 75 mo ago | Deadpooled | — | 2006 | — | 141 patents Advanced silicon purification and directional solidification processes for solar-grade silicon. | — |
| 3 | Trina Solar Manufacturer of photovoltaic products, energy storage, system solutions, and digital services | $40M | 142 mo ago | Public | Jifan Gao Founder & CEO | 1997 | DrupalApple iCloud MailPHP+18 | — | 1 expansion |
| 4 | Scifiniti Manufactures smart wafers | $27M | 158 mo ago | Series B | Sharone Zehavi ex-CEO | 2007 | PHPYiiBootstrap+15 | — | — |
| 5 | Gridtential Silicon Joule battery technology for safer, lower-cost, high-performance energy storage | $22M | 107 mo ago | Series B | Peter Borden Co-Founder and Chief Technical Advisor | 2010 | — | — | — |
| 6 | eIQ Energy Smart energy solutions provider offering expert engineering for resilient power systems | $20M | 146 mo ago | Series A | Gene Krzywinski Co-Founder and CEO | 2007 | — | — | — |
| 7 | RSI Solar Manufactures large-area, thin film, CdTe Solar | $19M | 161 mo ago | Deadpooled | Kurt Weiner Co-founder | 2009 | — | — | — |
| 8 | Biofuelbox Manufacturer of hyaluronic acid and related products for pharmaceutical, cosmetic, and veterinary applications | $15M | 200 mo ago | Deadpooled | Steven Perricone Ex Co-Founder & CEO | 2006 | — | 4 patents Efficient conversion of cellular lipids into biofuels using specialized reactors | — |
| 9 | Bentek Manufactures electronic products of solar systems | $8M | 75 mo ago | Acquired | — | 1985 | — | 28 patents High‑voltage power distribution hardware: busbars, insulated piercing connectors, and seal glands. | — |
| 10 | Ionobell Developer of batteries | $7M | 29 mo ago | Seed | Robert Neivert CEO | 2017 | — | 55 patents Silicon and porous silicon materials for high‑capacity battery electrode manufacturing | — |
| 11 | Marel Power Solutions Provider of power generation from batteries | $654K | 19 mo ago | Funding Raised | — | 2019 | — | — | — |
| 12 | Deuterium Energetics Developer of nuclear fusion reactor technology using deuterium | $116K | 62 mo ago | Seed | Steve Peterson Founder & President | 2015 | — | 10 patents Patents concentrated in computing, sensing & instrumentation | — |
Top 12 Energy companies in San Jose
#1
Funding Raised · San Jose, California · founded 2019 · 15 employees$654.1Kraised▾
Provider of power generation from batteries
- Jan 2025Grant (prize money)$198.1K
- Jul 2023Grant (prize money)$200K
- Nov 2021Grant (prize money)$256K
#2
Seed · San Jose, California · founded 2017 · 6 employees$7.3Mraised▾
Developer of batteries
- Mar 2024Seed$3.9M
#3
Deadpooled · San Jose, California · founded 2006 · 4 employees$361Mraised▾
Silicor Materials (formerly known as Calisolar) is a manufacturer of solar and aluminum products, including the high-quality, low-cost solar silicon. The company has silicon purification operations at the company’s wholly owned subsidiary, Silicor Materials Canada (located in Ontario, Canada) and a state-of-the-art research and development center in Berlin, Germany.
- May 2020Grant (prize money)$386.9K
- Sep 2015Series D$105M
- Sep 2013Conventional Debt$6.1M
- Feb 2013Conventional Debt$2M
#4
Public · San Jose, CA · founded 1985 · 4554 employees$872.5Mraised▾
SunPower Corp. (Nasdaq: SPWR) provides a diverse group of customers with complete solar solutions and services. Residential customers, businesses, governments, schools and utilities around the globe rely on SunPower's more than 30 years of proven experience. From the first flip of the switch, SunPower delivers maximum value and superb performance throughout the long life of every solar system.
#5
Public · San Jose, California · founded 1997 · 69 employees$40Mraised▾
Manufacturer of photovoltaic products, energy storage, system solutions, and digital services. The company researches, develops, produces, and sells photovoltaic modules. It provides energy storage solutions for utility-scale power plants, commercial applications, industrial uses, and residential needs. System solutions include trackers, distributed generation systems, and centralized power plants. Digital energy services comprise new energy operation and maintenance, microgrids, and electricity trading.
- Oct 2014Post IPO$115M
- Jun 2014Post IPO$146.3M
- Jul 2006PE$40M
#6
Series B · San Jose, California · founded 2010 · 7 employees$22.1Mraised▾
Silicon Joule battery technology for safer, lower-cost, high-performance energy storage. This company is revolutionizing energy storage by transforming conventional lead batteries with its innovative Silicon Joule technology. This approach delivers a safer, longer-lasting, and higher-power energy source compared to traditional options. The technology revitalizes conventional lead chemistry, achieving extended life cycles, dynamic charge acceptance, and reduced weight. The batteries can be manufactured using existing production lines, eliminating the need for expensive new facilities. Applications span automotive, RVs, reserve power systems, floor sweepers, energy storage systems, wheelchairs, scooters, and golf carts, enabling an emission-free world. The company's technology offers a sustainable solution for powering personal mobility vehicles, homes, and offices, addressing the pressing challenges of renewable energy storage.
- Sep 2017Series B$12M
- Jan 2017Series A$6M
- Feb 2016Seed$1.5M
- 2014Seed$1.5M
#7
Series A · San Jose, California · founded 2007 · 11 employees$20Mraised▾
Smart energy solutions provider offering expert engineering for resilient power systems. The company delivers expert engineering solutions focused on creating resilient and dependable power systems. They aim to reduce costs and enhance efficiency through their smart energy solutions. Their capabilities encompass a range of engineering services designed to optimize power systems. They provide solutions for dependable power systems. They offer services to enhance efficiency with smart energy solutions. The company focuses on providing clean energy solutions. They are a technology company offering engineering services. They are in the B2B sector.
- Jun 2014Grant (prize money)$1.7M
- Sep 2011Series A$6M
- Mar 2010Series A$4M
- Aug 2009Series A$10M
#8
Series B · San Jose, California · founded 2007 · 11 employees$26.5Mraised▾
Developer of crystalline silicon (c-Si) materials technology designed to enhance performance and lower the cost of silicon-based products for energy and related markets. The company's technology is a low cost, drop-in replacement photovoltaic (PV) silicon wafer, enabling businesses to produce and sell modules that will have a significant impact on the solar market.
#9
Deadpooled · San Jose, California · founded 2009 · 19 employees$19.4Mraised▾
RSI uses its patented deposition process, Rapid Efficient Electroplating on Large-areas (REEL) which dramatically reduces the cost of making and installing solar panels. RSI works with regional manufacturing partners to deliver the lowest cost locally manufactured photovoltaic modules.
- Mar 2013Conventional Debt—
- Mar 2013Series A$4M
- Jan 2012Series A$15.4M
#10
Acquired · San Jose, California · founded 1985 · 189 employees$8Mraised▾
Bentek designs and manufactures BoS products which include string combiners, recombiners, disconnect systems, inverter racking and other accessories. The company offer solar solutions for commercial, utility and residential clients.
- May 2020Conventional Debt$8M
#11
Deadpooled · San Jose, California · founded 2006$14.7Mraised▾
Manufacturer of hyaluronic acid and related products for pharmaceutical, cosmetic, and veterinary applications. It produces ultra-pure sodium hyaluronate for pharmaceuticals, advanced wound healing products, and veterinary pharmaceuticals and medical devices. The company also offers hyaluronic acid derivatives for research, novel hyaluronan forms for innovative uses, and anti-aging ingredients for cosmetics. A joint nutrition supplement is also part of its portfolio. In addition, it manufactures electrospinning devices for nanofiber production. The company's production process emphasizes biotechnological methods and high-quality standards.
- Dec 2009Series A$5.2M
- Oct 2007Series A$9.5M
#12
Seed · San Jose, California · founded 2015 · 3 employees$115.9Kraised▾
Developer of nuclear fusion reactor technology using deuterium. It generates energy by reacting carbon nanotubes and deuterium, with the byproducts of alpha particles and helium.
- Jun 2021Seed$115.9K
Funding & investor landscape
Notable founders
Market landscape — 10 sub-themes by coverage
Share of Energy coverage by sub-theme.
Regulatory-risk over time rising
Funding & growth over time
funding rising · growth rising
How research on Grid Energy Storage is moving in the United States
A read on the academic research around Grid Energy Storage — which themes are gaining ground, the institutions and researchers driving them, and how the tone is shifting. Based on 5,941 United States-affiliated papers.
- Electric Power Research Institute204
- Pacific Northwest National Laboratory202
- Argonne National Laboratory193
- Northeastern University151
- Massachusetts Institute of Technology124
- Battery (electricity)57→359
- Electrolyte37→318
- Electrochemistry30→240
- Cathode32→224
- Anode37→209
- Renewable energy40→492
- Battery (electricity)59→507
- Power (physics)8→227
- Electrolyte27→244
- Electrochemistry37→240
- Battery (electricity)35→184
- Renewable energy24→156
- Electrolyte13→114
- Electrochemistry10→80
- Cathode9→72
Where energy storage is researched across United States
Location clusters by institution affiliation — each city's volume, stance tone, and a quick read on its hot topic, what's advancing, the opening opportunity, and the main concern.
Who's filing energy storage patents in the United States
United States energy storage patent filing is accelerating — 8,522 filings from 3,681 assignees (2016–2025), led by General Electric, ESS Technology, GM Global TECH Operations; annual filings 687→1058.
- General Electric592
- ESS Technology276
- GM Global TECH Operations233
- Fastcap Systems205
- UNIV California180
- Rondo Energy157
- United Technologies154
- Battelle Memorial Institute146
Common questions
Rohit lives in the feed. He covers what's moving right now — the funding rounds, launches and shifts breaking across the trade press — and ties them back to where the sector is heading.