Algae (photosynthetic microorganisms) are able to generate electrons that can be harvested by a suitable electrochemical setup and be used as a source of electrical current. This concept forms the basis of Bio Photo Voltaic (BPV) devices. The electrical output obtained from these photosynthetically driven bio-electrochemical systems has improved considerably over the last few years, with the maximum reported being in the region of ca.4A m-2 for systems operated with photosynthetic bacterial cells.

A number of aspects have been considered for enhancing the electrical output and making the BPV systems suitable for real-world applications. These include the availability of electrons from the organisms involved, the transfer of electrons outside the organisms to the electrode, and the nature of the materials used to build the electrochemical setup.

To focus on possible areas of application we will present ongoing projects where BPV systems constitute a useful source of electricity. We will discuss, for example the use of BPV systems to power an Arm Cortex M0+, a microprocessor widely used in Internet of Things applications. The BPV generated enough power to run the Arm Cortex M0+ for over six months in a domestic environment under natural light. In addition, we will also discuss the possibilities for scaling up of devices to provide electrical output in the range of milliwatts-to-watts. This would open up applications such as running mobile phone chargers or low level lighting. These might be particularly attractive in rural areas of low- or middle-income countries (LMICs) or in disaster relief, where small amounts of power, and the ability to charge a phone, could be particularly useful. It’s worth noting that in many LMICs mobile phones are an increasingly important resource for healthcare delivery.