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Our People
Toby Siddall
CEO
Toby Siddall
CEO – Sustainable Advantage
As CEO, Toby brings 30 years of experience building more sustainable businesses. Prior to joining Sustainable Advantage he led global Sustainability Strategy for Accenture and served on their UK, Ireland & Africa Executive leading both Sustainability Services and the Energy, Utilities and Natural Resources business, accelerating growth through the energy transition and sustainable value creation. His career also spans strategy and advisory, M&A and business unit leadership roles at Goldman Sachs, Centrica plc and for private equity across North America, Europe, South Africa and the UK.
Sharon Dekker
ESG Director
Sharon Dekker
Contracts Director – Sustainable Advantage
Sharon Dekker is ESG Director at Sustainable Advantage, having established the Group’s ESG Advisory Division and built it from the ground up into a multidisciplinary team of sustainability specialists. Leading advisory work that turns ESG complexity into commercial priorities linked to revenue, cost, risk and long-term value. Experienced across the full private equity investment lifecycle, from due diligence through to value creation and exit. Responsible for connecting ESG Advisory with the Group’s Energy, Waste and Utility Solutions businesses, delivering integrated advice and implementation that transitions clients from strategy to measurable results.
Matthew McDermott
Contracts Director
Matthew McDermott
Contracts Diretctor – Sustainable Advantage
Matt McDermott is the Contracts Director at Sustainable Advantage and head of the Utilities Division. With over 15 years’ experience in the industry, Matt is leading the division to deliver utility solutions across the commercial, construction, development and data sectors, driving growth through value engineering, risk mitigation and reducing client spend. Matt’s experience includes managing the delivery of utilities on Battersea Power Station scheme, saving a client over £1m of utility spend on a single construction project and supporting several construction clients to move away from the use of temporary diesel generators.
Rob Morgan
Head of Energy, Procurement & Risk
Rob Morgan
ESG Director – Sustainable Advantage
Rob Morgan is Head of Energy, Procurement and Risk at Sustainable Advantage, leading the Energy Division, supporting our clients renewable energy procurement, bill to pay and associated data and reporting requirements, including compliance. Rob has over 25 years B2B energy supply experience with deep procurement and supply structuring experience. Rob’s experience includes supply side and customer side. At Centrica Rob was responsible for hedging and optimisation of a 20TWh retail hedge book, with a value in excess of £1.5bn.
Steve King
Sales Director
Steve King
Sales Director
Steve King is Sales Director at Sustainable Advantage, where he leads the firm’s commercial strategy, business development and sales operations. He works closely with the Board and senior leadership team to deliver sustainable growth. Steve also plays a hands-on role helping clients identify opportunities to improve environmental performance, operational efficiency and long-term value creation. Having started his career in strategy consulting, Steve moved into commercial leadership roles and has helped grow two consulting businesses through to successful exits.
Alex Scott
Chief Technology Officer
Alex Scott
Chief Technology Officer
Alexander Scott is Chief Technology Officer at Sustainable Advantage, leading the Technology & Data function. He drives the continuous evolution of our core sustainability platform and business systems, accelerating AI adoption to streamline reporting while delivering tangible business value to clients. Previously CTO at the UN Principles for Responsible Investment (UNPRI), Alex led the development of their global reporting and data visualisation platforms used by over 5,000 signatories. With 25+ years of experience, he specialises in technology transformations that drive business change, operational excellence, and lasting impact.
Seema Sangar
Chief Financial Officer
Seema Sangar
Chief Financial Officer
Seema Sangar is Chief Financial Officer at Sustainable Advantage, bringing more than 20 years of leadership experience across technology, financial services, and consultancy focused businesses. A strategic finance leader specialising in strengthening profitability, optimising working capital, improving cash flow and building scalable finance functions that support strategic ambitions. An experienced leader in M&A, business transformation and commercial finance, Seema has successfully integrated acquisitions, supported IPOs and partnered with executive teams to drive operational efficiency, enhance governance and create long-term shareholder value.
Lorna Hyde
HR Director
Lorna Hyde
HR Director
As HR Director at Sustainable Advantage, Lorna Hyde brings over 15 years’ experience leading people strategy, talent development, organisational change and employee engagement across corporate and SME environments. Drawing on expertise gained across energy, SaaS, real estate, financial services and healthcare, she leads the company’s people agenda, fostering a high-performing and inclusive culture. She combines commercial insight with a people-first approach and plays a key role in supporting Sustainable Advantage’s growth, employee experience and long-term success.
Fanny Guezennec
ESG Director – France
Fanny Guezennec
EGS Director – France
Fanny Guezennec is ESG Director at Sustainable Advantage and Head of the French Office, which she launched in 2025. She drives the firm’s growth in France, across business development, client delivery, brand expansion and team growth. With over 20 years of experience, Fanny advises mid-market and international organisations on sustainability and ESG transformation. Before joining Sustainable Advantage, she held senior roles at ERM and other leading consultancies, supporting clients across diverse sectors. She also helps develop innovative ESG solutions and bring new offerings to market, helping clients turn sustainability ambitions into tangible business value.
Henry Saint Bris
Founder & Executive Chairman
Henry Saint Bris
Founder and Executive Chairman
Henry Saint Bris is the Founder and Managing Partner of Ansa, Senior Advisor at Macquarie Asset Management (MAM), and independent Board Member for various companies.
As former Chief Strategy Officer for the Suez Group, member of the Strategic Committee, and Group Marketing and Institutional Relations SVP, Henry pioneered circular economy initiatives with the European Commission, the World Economic Forum (Advisory Board Member) and the Ellen MacArthur Foundation. Henry founded Ernst & Young Environment in Paris in 1992.
Henry holds a diploma from Sciences Po Paris, a Master’s degree in business administration from University Paris IX Dauphine, a postgraduate degree in Environment Management and Engineering from Ecole des Mines de Paris and completed the Harvard Business School AMP.
He is a board member at the US-based Environmental Research and Education Foundation (EREF), and a regular lecturer about resources, the environment, and the circular economy, at Sciences Po and Harvard.
François-Xavier Carayon
Managing Partner
François-Xavier Carayon
Managing PartnerFrançois-Xavier joined Ansa in 2023.
Combining a background in economics, politics and social anthropology with eight years of experience in strategy consulting, François-Xavier has built expertise in financial services, environment and transportation.
He works with corporates and global investors across asset classes (Private Equity, Infrastructure, Private debt…) on ESG strategy, transactions and green financing.
Prior to joining Ansa, François-Xavier spent seven years at Mars & Co, an international strategy consulting firm. François-Xavier holds a BA in Philosophy, Politics and Economics from the University of Warwick and a MPhil in Social Anthropology from the University of Oxford.
Mihika Shilpi
Partner
Mihika Shilpi
Partner
Mihika joined Ansa Services in 2022, and has collaborated with the team since 2020.
Leaning on her interdisciplinary background, she has built expertise in value creation and decarbonisation across assets in energy, digital infrastructure, and industrial sectors. Her work focuses on linking sustainability initiatives to financial performance, supporting investment decisions, portfolio strategy, and transactions.
At Ansa, Mihika leads multi-asset engagements, developing quantitative models and tools used for capital allocation, reporting, and exit processes. She works closely with investment teams and portfolio companies to integrate sustainability into business strategy and operations.
Before joining Ansa, Mihika worked in digital strategy and brand consulting across Europe and Asia. She studied Mathematics at Harvard University and holds graduate diplomas in Computer Science and Digital Communication.
Constance Géraud
Director
Constance Géraud
Director
Constance joined Ansa in 2025.
She brings deep expertise in leading multi-stakeholder engagements and designing responsible investment strategies. At Ansa, she advises investors and asset managers on ESG due diligence , fund- and portfolio company-level reporting, and impact investment strategy.
Before joining Ansa, Constance spent five years at Business for Social Responsibility, a global sustainable business network and consultancy, and two years at PwC within its sustainability and strategy practice.
Constance holds an MSc in Environmental Technology from Imperial College London, an MA in European Public Policy from King’s College London, and a BA in Political Science from the University of Sussex.
Aideen O’Hora
Co-Founder & Partner
Aideen O’Hora
Co-Founder & Partner
An environmental scientist by background, Aideen is an expert in sustainable business, energy, and climate innovation. Over her career, she has created national programmes to inform policy and drive progress on corporate sustainability. She is passionate about creating change by connecting the dots between climate and business. A pioneer in the area of climate innovation, she’s a big believer in the opportunities that climate tech provides for Irish entrepreneurs and businesses.
Aideen previously worked with The Green Way (Ireland’s first climate tech cluster), Sustainable Nation Ireland, the Sustainable Energy Authority of Ireland, Abbott Laboratories, Novartis and Cork County Council.
Laura Heuston
Co-Founder & Partner
Laura Heuston
Co-Founder & Partner
Laura is a leading authority in Ireland on sustainable finance. An accountant and tax expert by background, she specialises in EU and global sustainable finance policy and regulation. She has a unique ability to cut through complexity and provide practical actions for corporates, investors, and financial services firms. Over the last decade, she has been at the forefront of raising awareness and building knowledge on sustainable finance across Ireland.
Laura previously worked with Sustainable Nation Ireland, Airtricity, and KPMG. She is a Fellow Chartered Accountant and a Chartered Tax Consultant.
Karen Deignan
Co-Founder & Partner
Karen Deignan
Co-Founder & Partner
Karen is an expert in sustainability strategy, communications, and reporting. With a background in organisational psychology, she has spent her career working with global corporations to engage leaders and employees in driving sustainability transformation. Karen specialises in developing actionable sustainability programmes that reflect a company’s purpose, culture, and commercial goals. She’s passionate about making sustainability simple and understandable for everyone.
Karen previously worked in the UK with the Carbon Trust and with independent consultancies Salterbaxter, di:ga, and Corporate Culture. She is a trained B Corp Consultant who can support companies on their B Corp certification journey.
Kristian Danielson
Co-Founder & Partner
Kristian Danielson
Co-Founder & Partner
Kristian is Founder and Managing Partner at SustainX. With a background as an engineer, he brings experience from the wind industry, including Vestas, and combines technical expertise with commercial business understanding. He leads sales activities and helps businesses connect sustainability with business priorities, turning complex challenges into practical solutions and opportunities for value creation.
Line Amtorp Poulsen
Co-Founder & Partner
Line Amtorp Poulsen
Co-Founder & Partner
Line is Co-founder and Partner at SustainX. With a background as a production engineer, she brings experience in sustainability, business development and leadership, including from Carlsberg. She works with SustainX’s strategic clients, helping businesses integrate ESG into their strategy and translate sustainability ambitions into practical action. Her approach combines technical expertise and business understanding with a strong focus on people and organisational development.
Adis Suhonjic
Co-Founder & Partner
Adis Suhonjic
Co-Founder & Partner
Adis is Partner at SustainX. With a background in finance, he contributes business insight and supports the company’s development. He oversees finance, legal, marketing and overall operations. He brings a commercial and operational perspective to the leadership team, ensuring alignment between the company’s ambitions, financial management and business operations.
