Meet the team

The STA is overseen by a Board of Directors and decisions are made on a one member, one vote basis.

The Board is supported by the STA team and a number of Working Groups which each focus on key areas such as rooftop PV, solar thermal, policy, public relations, new build and the grid.

Find out more about the team here. If you’d like to get in touch, visit Contact Us.


  • Chris Hewett

    Chief Executive
    Chris has 25 years’ experience in advocacy, policy research, thought leadership and campaigning on a wide variety of sustainability, energy and environmental issues. He was Head of Climate Change for the Environment Agency, providing advice to Government on climate change mitigation and adaptation. He has worked for a number of leading NGOs & government agencies, including successful advocacy for the Green Investment Bank at Green Alliance, global aviation research for the Committee on Climate Change, and more recently leading policy and advocacy for the Finance Innovation Lab.

  • Léonie Greene

    Director of Advocacy & New Markets
    Léonie Greene was previously Head of External Affairs at the Renewable Energy Association between 2007 and 2013. Before that she was Political Adviser at Greenpeace, initiating their Decentralised Energy campaign. She also worked for the Deputy Mayor of London on Sustainable Development and the conception of the London Climate Change Agency.

  • Aleksandra Klassen

    Business Development Manager
    Before joining the STA, Aleksandra completed a Masters in Energy, Trade and Finance at Cass Business School in London. Her research there on the application of market-based, off-grid Solar PV in refugee camps earned her a UK graduate start-up scheme.

    Prior to her studies, she produced market intelligence reports focused mainly on energy commodities, renewables and pharmaceuticals in seven countries across South East Asia, Northern Europe and the Middle East.

  • Nicholas Gall

    Senior Policy Analyst
    Prior to joining the STA, Nicholas worked in policy analysis and advocacy at two leading Canadian environmental charities, and completed internships at the International Energy Agency and the London office of the Climate Policy Initiative.

    Nicholas holds an MSc in economics and policy of energy and the environment from University College London, and a BA in economics from Dalhousie University. His MSc dissertation addressed the impact of project financing costs on solar PV deployment across Sub-Saharan Africa.

  • Gemma Stanley

    Policy Analyst
    Gemma holds a BA from Durham University and an MSc in Public Policy from UCL, during which her studies focused on regulation, climate change and the media’s influence on environmental behaviour.

    Before joining the STA, Gemma worked as a Regulatory Analyst at Solarplicity, a renewable energy supplier and solar PV installer.

  • Jack Dobson-Smith

    Public Affairs & Communications Officer
    Jack joined the STA in 2018, having previously undertaken communications and partnership-oriented roles at CDP and the Climate Disclosure Standards Board.

    Holding a Bachelors in Journalism and a Post-Graduate Diploma in Sustainability and Environmental Management, Jack is also an accredited Practitioner member of the Institute of Environmental Management and Assessment (IEMA).

  • Esther Rosewarne

    Business Engagement Officer

    Esther holds a BA from the University of Bristol. She has a background in working with with startups and social enterprises, and has delivered a variety of projects, events, and communications across the sustainability sector. This has included promotional work for innovative urban agriculture initiatives, as well as the coordination of regional and national events focused on women in sustainability.

The STA Board

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    Gareth Williams
    Managing Director
    Caplor Group
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    Jonathan Selwyn (Chair)
    Solar Consulting Ltd

  • Syed Ahmed
    Energy for London
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    Paul Hutchens
    Eco2 Solar

  • Vicki Ramsden
    Performance Manager
    Wise Energy

  • Richard Jenkins
    Ecolution Renewables

  • Matt Black
    Armstrong Energy

  • Giles Clarke
    AlSi Consulting
  • Chris Clark
    Emtec Energy
  • Christelle Lawson
    Country Manager (UK)

  • Stuart Elmes
    Founder and CEO
    Viridian Solar

  • John Forster
    Forster Group
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  • Jonathan Bates
    Photon Energy