Mainspring Energy, Inc.
Fuel-flexible power generation systems for distributed energy applications
- Sector
- Energy
- Headquarters
- MENLO PARK, CA
- Latest Form D
- $108M, Jul 2021
- Total capital
- $133M
- Federal grants
- None on recordNo awards found in SBIR/STTR, NIH, NSF or DoD records.
- Private capital raised
- $133M
- 2 Form D · last Jul 2021
- 64 months since last filing
- Federal contracts
- None on recordNo federal contract awards found.
- Granted patents
- 32
- 8 pending · first 2022
- Rank in peer group#1 of 166
Capital timeline
Latest events
- Private capital raisedForm D · SEC · 2nd filing$108M
- Private capital raisedForm D · SEC · 1st filing$25M
Node area is scaled to amount. Form D reports securities sold, which can differ from an announced round; filings are numbered in the order they were made.
Standing among 166 peers
Line = medianEnergy · System
- Granted patents#1 · top 1%
Cumulative measures favor older companies. Rankings describe position today, not outcome. Below the median, ranks show as a band rather than a number.
Founders and team
Researcher links verified by same-company patents and grants- Adam SimpsonResearcherExecutive Officer, DirectorLinked by 1 patent
- Alexander WeissDirectorNamed in SEC Form D filings
- Eric KosmowskiDirectorNamed in SEC Form D filings
- Jagdeep SinghDirectorNamed in SEC Form D filings
- Nael KassarDirectorNamed in SEC Form D filings
- Samir KaulDirectorNamed in SEC Form D filings
Show all 8 people
- Shannon MillerExecutive Officer, DirectorNamed in SEC Form D filings
- Shyam KamadolliDirectorNamed in SEC Form D filings
What it has protected
USPTO · 32 granted of 40- GrantedHigh-power Core SystemUSPTOUS 12,719,334
- PendingPiston Sealing Ring Assembly Having A Gap Cover ElementUSPTOApplication 19454745
- GrantedAnti-friction Sealing RingsUSPTOUS 12,698,829
Show all 40 patent records
- High-power Core SystemAug 25, 2026 · US 12,719,334Granted
- Piston Sealing Ring Assembly Having A Gap Cover ElementAug 13, 2026 · Application 19454745Pending
- Anti-friction Sealing RingsAug 4, 2026 · US 12,698,829Granted
- Energy Storage And Conversion In Linear GeneratorsJul 9, 2026 · Application 19365458Pending
- Core Synchronization For Linear GeneratorsJun 25, 2026 · Application 19328936Pending
- Piston Sealing Ring AssembliesJun 2, 2026 · US 12,644,518Granted
- Sealing Ring Assemblies Configured For Pressure LockingMay 19, 2026 · US 12,631,163Granted
- Core Synchronization For Linear GeneratorsMar 24, 2026 · US 12,587,118Granted
- Sealing Ring Assembly With Spring ElementMar 19, 2026 · Application 19328903Pending
- Linear Electromagnetic Machine SystemMar 5, 2026 · Application 19336818Pending
- Piston Sealing Ring Assembly Having A Gap Cover ElementFeb 24, 2026 · US 12,560,235Granted
- Integrated Linear Generator SystemFeb 17, 2026 · US 12,556,063Granted
- Energy Storage And Conversion In Linear GeneratorsNov 18, 2025 · US 12,473,855Granted
- Linear Electromagnetic Machine With A Stator Having Stator Teeth Arranged To Provide An Anti-clocking Force.Oct 14, 2025 · US 12,445,029Granted
- High-efficiency Linear GeneratorSep 23, 2025 · US 12,421,890Granted
- Linear Generator System Having A Polygonal LayoutSep 4, 2025 · Application 19067605Pending
- Systems And Methods For Flexure-based Bearing MountingAug 14, 2025 · Application 19058787Pending
- Integrated Linear Generator SystemMay 22, 2025 · Application 19030716Pending
- Auto-braking For An Electromagnetic MachineApr 22, 2025 · US 12,283,911Granted
- Systems And Methods For Flexure-based Bearing MountingMar 18, 2025 · US 12,255,514Granted
- Control Of Piston Trajectory In A Linear GeneratorJan 28, 2025 · US 12,209,548Granted
- Sealing Ring Assemblies Configured For Pressure LockingJan 7, 2025 · US 12,188,457Granted
- Core Synchronization For Linear GeneratorsDec 17, 2024 · US 12,170,501Granted
- Piston Sealing Ring AssembliesSep 3, 2024 · US 12,078,250Granted
- Piston Sealing Ring Assembly Having A Gap Cover ElementSep 3, 2024 · US 12,078,249Granted
- Integrated Linear Generator SystemJul 2, 2024 · US 12,027,956Granted
- High-efficiency Linear GeneratorJun 4, 2024 · US 12,000,331Granted
- Manifold Interface SealMay 7, 2024 · US 11,976,730Granted
- Open-faced Piston AssemblyApr 2, 2024 · US 11,946,435Granted
- Springs For Piston Ring BiasingJan 16, 2024 · US 11,873,906Granted
- Energy Storage And Conversion In Linear GeneratorsJan 9, 2024 · US 11,867,116Granted
- Piston Sealing Ring Assembly Having A Gap Cover ElementSep 26, 2023 · US 11,767,915Granted
- Reinforced Sealing RingsSep 5, 2023 · US 11,746,904Granted
- Integrated Linear Generator SystemSep 5, 2023 · US 11,750,065Granted
- Control Of Piston Trajectory In A Linear GeneratorAug 29, 2023 · US 11,739,705Granted
- Auto-braking For An Electromagnetic MachineMay 16, 2023 · US 11,652,432Granted
- Piston Seal With Solid Lubricant ApplicatorApr 4, 2023 · US 11,619,303Granted
- Linear Electromagnetic Machine SystemMar 28, 2023 · US 11,616,428Granted
- Energy Storage And Conversion In Linear GeneratorsFeb 14, 2023 · US 11,578,646Granted
- Sealing Ring Assemblies Configured For Pressure LockingDec 20, 2022 · US 11,530,691Granted
Related companies, and why
- KORE Power, Inc.Similar federal contract value in Energy · null in contracts
- Aaron PalumboSimilar federal contract value in Energy · null in contracts
- NTRE Tech LLCSimilar federal contract value in Energy · null in contracts
- E3TECSERVICE, LLCSimilar federal contract value in Energy · null in contracts
- WASATCH MOLECULAR, INC.Similar federal contract value in Energy · null in contracts
- CYBITRON LLCSimilar federal contract value in Energy · null in contracts
Regulatory activity · Energy
- Air Plan Approval; Michigan; Redesignation and Maintenance Plan for the Partial St. Clair 2010 1-Hour Sulfur Dioxide (SO2) NAAQS Nonattainment AreaEnvironmental Protection Agency
- Air Plan Approval; Delaware; 2006 24-Hour Fine Particulate Matter Limited Maintenance Plan for the Philadelphia Nonattainment AreaEnvironmental Protection Agency
- Air Plan Approval; Oklahoma; Updates to the State Implementation Plan for New Source Review Permitting and General SIP ProvisionsEnvironmental Protection Agency
- List of Approved Spent Fuel Storage Casks: NAC International, Inc., MAGNASTOR® Storage System, Certificate of Compliance No. 1031, Amendment Nos. 16 and 17 and Revisions to Amendment Nos. 0 Through 16Nuclear Regulatory Commission
- Epyrifenacil; Pesticide TolerancesEnvironmental Protection Agency
- Fluoxapiprolin; Pesticide TolerancesEnvironmental Protection Agency
Rules are matched to sector, not to company. Recent activity in a sector is context rather than a signal about this business — until rules are matched to what a company actually builds, the section is shown as context and nothing more.
Sources
Federal grants from SBIR/STTR, NIH, NSF and DoD records. Federal contracts from USAspending.gov. Private capital from SEC Form D. Patents from USPTO. Publications from OpenAlex. Regulatory activity from the Federal Register. Press matched on company name.
How to read this page
Figures show associations in public records, not causes or predictions. Nothing here is investment advice. An em-dash means no record was found under this company's name, not that none exists.
Data freshness
SEC Form D filings through . SBIR and STTR awards through .