Last Energy

General InformationLast Energy is a Massachusetts-based thermal energy storage company founded in 2020 with approximately 30-40 employees developing industrial heat storage solutions.

Funding & FinancialsLast Energy has raised approximately $20-25 million across seed and Series A rounds, with Series B funding completed in 2023 or 2024 from investors focused on climate tech.

Leadership & TeamThe company was founded by Mateo Jaakkola and Jed Gotesman, with backgrounds in advanced materials and cleantech entrepreneurship.

Recent ActivityLast Energy has been expanding pilot deployments with industrial partners and scaling manufacturing of their thermal storage modules for commercial deployment in food and chemical processing facilities.

Highlights

Total Raised

—

2 rounds

Latest Round

$100

May 19, 2026

Stage

Series A

energy

Employees

11-50

Founded 2020

Headquarters

News Coverage

—

Talent Signals

—

SEC Filings

—

Backers

AE Ventures

Astera Institute

Galaxy Interactive

Gigafund

JAM Fund

Ltd.

The Haskell Company

Ultranative

Woori Technology Co.

Funding History

$100

2026

Series C

$100

2026

Series C

SEC Form D Editorial

May 19, 2026

$100 million+Series C · Editorial

Small modular reactor company raised Series C funding in December 2025 to build four 20-megawatt reactors in Wales.

May 4, 2026

$100 millionSeries C · Editorial

Investors: Astera Institute, JAM Fund, Gigafund, The Haskell Company, AE Ventures, Ultranative, Galaxy Interactive, Woori Technology Co., Ltd.

Last Energy closed an oversubscribed Series C funding round to support its PWR-20 advanced small modular reactor development.

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