Bartlomiej Szostek is Co-Founder and CTO at tem, an AI-native energy transaction platform revolutionizing how businesses buy renewable energy. tem has raised $94M total funding and serves over 2,600 UK customers including Boohoo Group, Fever-Tree, and Newcastle United FC.

Bartlomiej was a founding employee at Limejump, a virtual power platform that was successfully acquired by Shell in 2019. He also worked at RWE Supply & Trading and holds a Master of Science in Computational and Software Techniques in Engineering from Cranfield University.

As CTO, Bartlomiej leads the technical development of tem's AI-powered transaction engine Rosso, which reduces business energy costs by up to 30%. tem facilitated over 2TWh of energy transactions in 2025, equivalent to powering all of Liverpool for a year.

tem raised a $75M Series B in February 2026 led by Lightspeed Venture Partners, valuing the company at over $300M. The company is expanding to Texas and Australia after achieving profitability potential in the UK market.

tem's platform connects businesses directly with over 22,000 renewable generators, bypassing inefficient wholesale markets. The company is building the infrastructure to become the Stripe of energy, enabling transparent and efficient energy transactions globally.