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About Us

UK-based Isentropic Ltd is a private engineering company founded in 2005 by James Macnaghten and Jonathan Howes to exploit and further develop the PHES technology conceived by Jonathan Howes in the late 1990s.

Senior Management & Board

  • James Macnaghten James Macnaghten
    James has been Isentropic Ltd CEO since 2005. An engineer by training and entrepreneur by inclination, he has built up and successfully run a number of businesses since the early 1990s, in sectors as varied as energy, tourism and watersports.
  • Jonathan Howes Jonathan Howes
    After early roles in aerospace R&D, Jonathan moved to aerospace regulation. Serving, amongst other roles, as Lead Structures Specialist for the certification of the Airbus A380, Jonathan founded and ran his own aerospace consultancy before moving to develop his inventions with Isentropic Ltd full time.
  • Mark Knox Mark Knox
    Previously Head of Energy Innovation, Transactions and Carbon Capture and Storage at Department of Business Innovation and Skills (BIS). On fulltime secondment to Isentropic from BIS.
  • Louis Greig Louis Greig
    Non-Executive Director
    Louis is an experienced investment banker, and is currently a Managing Director at J.P. Morgan Cazenove.
  • Reg Edwards Reg Edwards
    Director of Power Business
    A long career in the Oil and Gas and Power sectors for client, EPC contractor and developer organisations covering many roles including engineering, Project Management, construction, business development, company management and executive roles including being office manager of the Shaw Group Power Division European Headquarters.
  • Guy Winstanley Guy Winstanley
    Head of Engineering
    Guy has been with Isentropic Ltd since 2009. He is an experienced Professional Engineer with 20 years of operational, project and engineering experience in manufacturing products, processes and facilities. He has managed large workforces in modern production facilities, manufacturing forklift trucks, automotive and aerospace components.
  • Nick Lawrence Nick Lawrence
    Chief Engineer
    Trained in the racing engine industry, designed, analysed and developed high-speed units for F1, NASCAR and IRL. Ran multiple successful advanced engine valve system projects for automotive OEMs, responsible for the design, analysis, procurement including generation and patenting of associated IP. Joined Isentropic in 2012 as Chief Engineer, responsible for heat engine and gas turbine storage systems.
  • Deborah Lowther Deborah Lowther
    Head Patent Counsel
    Deborah has been Head Patent Counsel at Isentropic Ltd since 2011. A chemist by training, she is a Chartered UK and EP Patent Attorney with previous experience in industry and private practice.


The ETI has funded the development and demonstration of our Isentropic PHES prototype.

  • Energy Technologies Institute

    The ETI is a public-private partnership between global energy and engineering companies and the UK Government. Its role is to act as a conduit between academia, industry and the government to accelerate the development of low carbon technologies.


If you are interested in investing in Isentropic Ltd, please contact us.

Intellectual Property

At Isentropic Ltd we actively protect our innovations and we have an extensive and well-balanced patent portfolio including 39 different patent families, with 75 granted patents and 100 pending applications in the major patenting territories. Key patented technologies include our early innovative Heat Engine, GTI-Storage and PHES systems and our unique Thermal Store technology.


We are not currently advertising for any specific role.

However, if you have a strong engineering background and think that you could contribute to the development of Isentropic Ltd and its technologies, please contact us with a CV and covering note.