The Team
James Macnaghten
CEO

James Macnaghten founded Caldera with Guy Winstanley in 2017. James is a Cambridge trained engineer, experienced CEO, entrepreneur and engineer with 15 years' of engineering experience in energy research and development and over 25 years' experience in business. He has built (and still owns) Cambridge’s largest tourist business and was previously CEO of Isentropic for 10 years; a company developing a large-scale thermo-mechanical electricity storage system. He has been either co-inventor or sole inventor on a wide number of thermal energy storage patents with more than 150 granted patents (20+patent families) to his name.
Guy Winstanley
COO

Guy is a co-founder of Caldera. He has a BSc(Hons) Engineering degree from Exeter University and he has 30' years of operational, project and engineering experience. His career has encompassed R&D, manufacturing processes and operations management, including international experience in UK, Germany and Asia. He has previous experience in energy storage at Isentropic Ltd as Head of Engineering and Operations, manufacturing and business development at Linde AG Forklift and T&N (Federal Mogul).
Mark Lee
Non-Executive

Mark is a Senior Banker with over 20' years of experience working with industrial clients across Europe. He has grown, led and restructured businesses, with a focus on providing acquisition financing and capital structure advice. Mark holds a law degree from Durham University and an MSc from CASS Business School.
Andrew Brown
Non-Executive

Andrew has more than 10 years’ experience leading the corporate affairs functions for global listed firms across a range of regulated and unregulated sectors, including the UK’s largest generator of renewable electricity, Drax Group Plc. Currently a partner at Apella Advisors, he has a deep knowledge of issues and crisis management as well as working with legislators and regulators across multiple jurisdictions.
Ranulf Slee
Lead Test Engineer

Ranulf has a BSC(Hons) Chemistry degree from Manchester University and has applied this to a career as a research and development scientist. He has a successful track record in delivering ground-breaking research projects including cutting edge batteries and fuel cells through his work with DERA, QinetiQ and Ceres Power. He has worked with James and Guy for Isentropic Ltd and has been part of the Caldera team for 3 years.
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