# James Macnaghten

> James Macnaghten is the co-founder and CEO of Caldera, a Hampshire-based climate-tech company turning cheap renewable electricity into stored industrial heat using blocks of volcanic rock and recycled aluminium. A Cambridge-trained mechanical engineer with 25+ years in business and 20+ patent families to his name, he spent a decade running grid-storage pioneer Isentropic before founding Caldera in 2017. He also owns Scudamore's Punting Co, Cambridge's largest tourist business. In 2025 Caldera closed a Series A backed by Germany's GEA Group and landed its first major order, a 10 MWh storage boiler for an NHS hospital.

- **Role:** Co-founder and CEO at Caldera (Caldera Heat Batteries Ltd)
- **Organizations:** Caldera, Scudamore's Punting Co, Isentropic (former)
- **Nationality:** British
- **Education:** Mechanical Engineering, University of Cambridge
- **Known for:** Co-founder and CEO of Caldera, decarbonising industrial heat with rock-and-aluminium heat batteries, Co-inventor or sole inventor on 20+ patent families in thermal and electrical energy storage, Led Isentropic for a decade developing grid-scale pumped-heat electricity storage

## Career timeline

- **1988-1991** — Studied Mechanical Engineering at the University of Cambridge
- **1990s-2000s** — Built and acquired Scudamore's Punting Co, Cambridge's largest tourist business (still owns it)
- **2001-2011** — CEO of Isentropic for ~10 years, developing a large-scale thermo-mechanical (pumped-heat) electricity storage system
- **2017** — Co-founded Caldera with Guy Winstanley to decarbonise industrial heat
- **2025-03** — Closed Series A with a 12 million euro / ~10 million pound investment from GEA Group
- **2025** — Secured first order: a 10 MWh electric Storage Boiler for an NHS hospital

## Achievements

- Co-founder and CEO of Caldera, decarbonising industrial heat with rock-and-aluminium heat batteries
- Co-inventor or sole inventor on 20+ patent families in thermal and electrical energy storage
- Led Isentropic for a decade developing grid-scale pumped-heat electricity storage
- Owns Scudamore's Punting Co, Cambridge's largest tourist business
- Closed a Series A backed by industrial-engineering giant GEA Group (2025)
- Landed Caldera's first 10 MWh Storage Boiler order with an NHS hospital

## Latest updates

- **2025-03** — Caldera closed a Series A with a ~12 million euro investment from GEA Group, which took a stake in the company.
- **2025** — Caldera received its first order for a 10 MWh electric Storage Boiler from an NHS hospital.

## Links

- Website: https://caldera.co.uk
- LinkedIn: http://www.linkedin.com/in/james-macnaghten-7aaa65a

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Profile page: https://yespress.io/james-macnaghten
Published by YesPress — https://yespress.io
Last updated: 2026-06-12