The rapid expansion of the Internet of Things (IoT) has created an urgent unmet need for sustainable, maintenance-free power sources. With an estimated 75-100 billion devices expected by 2030, many in remote or low-resource environments, traditional batteries present significant environmental, logistical, and economic challenges, including electronic waste, carbon emissions, and costly maintenance. University of Cambridge researchers, Professor Chris Howe and Dr Paolo Bombelli have addressed this challenge through Biophotovoltaics (BPV). This technology uses photosynthetic microorganisms such as cyanobacteria and algae, grown as biofilms on electrodes, to generate electricity directly from ambient light and water. By wiring living cells to engineered materials, the team has created self- sustaining “living solar cells” capable of producing continuous micro-currents suitable for ultra-low-power electronics and IoT devices. This research has since been translated into the spin-out company e-Pho Ltd, which is developing robust photobiological sources of electrical energy to replace small disposable batteries. Before engaging with NBIC, BPV prototypes were limited to short-term laboratory demonstrations with modest power outputs, stability issues, and no clear link to real-world applications. A key barrier was demonstrating reliable, long-term performance under practical conditions. NBIC played a pivotal role in overcoming these challenges, enabling the team to successfully demonstrate a real-world application of BPV technology. Notably, a single small BPV unit powered a microprocessor continuously for over 12 months under ambient indoor light, eliminating the need for battery replacement. This breakthrough validated the technology’s potential for off-grid and ultra-low-power applications. Powering the Internet of Things with Living Solar Cells BPV systems have the potential to reduce reliance on fossil-derived batteries, lowering electronic waste and emissions while enabling reliable environmental monitoring and smart infrastructure. For the private sector they open new markets in IoT and edge computing with reduced maintenance costs. Public and third- sector organisations benefit through sustainable sensing solutions for climate, biodiversity, and pollution monitoring, alongside opportunities for education and public engagement in circular bio-economies. NBIC’s involvement directly enabled high-impact publications, including “Powering a Microprocessor by Photosynthesis” (Energy & Environmental Science, 2022) and a complimentary paper, “Is it realistic to use microbial photosynthesis to produce electricity directly?” (PLoS Bio, 2023), both of which received strong academic and media attention. Crucially, this support also underpinned successful translation activities, including the co-founding of e-Pho Ltd, the development of working prototypes, and importantly the securing of competitive industry engagement and translational funding grants (EPSRC-IAA, BBSRC-FoF). Dr Paolo Bombelli said: “NBIC’s support was pivotal in moving our research from academic curiosity to a demonstrable, commercially viable technology. Their funding, expertise, and network helped us overcome critical technical barriers and provided the springboard for launching e-Pho, turning years of lab work into a real pathway for sustainable impact”. Dr Paolo Bombelli is a Postdoctoral Researcher at the University of Cambridge and Co-founder of e-Pho Ltd. He specialises in biophotovoltaics, pioneering clean electricity from photosynthetic biofilms. Through e-Pho, he commercialises battery-free power for IoT/ low-power-electronics. Professor Chris Howe is Professor of Plant and Microbial Biochemistry at the University of Cambridge. He has over 40 years’ research experience on photosynthesis and is Co-founder of e-Pho Ltd. Dr Paolo Bombelli Professor Chris Howe Electrodes coated with a photosynthetic biofilm. 23 CASE STUDY
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