Abstract: Increasing energy consumption, the depletion of natural resources, climate change and decreasing air quality are amongst the biggest economic and social challenges that we face today. At the same time, waste heat energy discharged into the atmosphere is one of the largest sources of clean, fuel-free and inexpensive energies available. Significantly, 70 % of all energy generated daily is lost as waste heat. A vast amount (around 63 %) of this untapped energy exists in the form of low-grade heat from sources below 100°C, which includes power generation (burning of fossil fuels), industrial processes (oil refining, heat exchanges) and domestic heating. Generating electrical energy from low-grade waste heat is therefore a key enabler to meet the growing global energy demand, whilst reducing Europe’s carbon footprint. Aim: To show that natural wood can be used to create thermoelectric converters of a new type with a high efficiency of converting heat into electricity. Findings: We are using cellulose membranes, made from the chemical treatment of wood, to convert waste heat into electricity. Nanochannels within the cellulose membranes are effective at separating ions in solution in the presence of a temperature gradient, which leads to the generation of a thermally induced voltage of up to 25 mV/K, significantly exceeding values reported for conventional thermoelectric converters based on solid materials. Conclusions & Implications: Natural wood, which is inexpensive, environmentally friendly and completely renewable, could potentially be used to create highly efficient thermoelectric energy converters for low-grade heat recovery on a large scale. References: Zeb, K., Ali, S.M., Khan, B., Mehmood, C.A., Tareen, N., Din, W., Farid, U., Haider, A., 2017. A survey on waste heat recovery: Electric power generation and potential prospects within Pakistan, Renewable and Sustainable Energy Reviews 75, 1142-1155. Additional Information: Dr Ievgen Nedrygailov presented this poster at the Environ 2022 conference in Belfast, Northern Ireland. This research was supported by Irish Government funding via the DAFM NXTGENWOOD research program (grant agreement: 2019PROG704) and European Union's Horizon 2020 research and innovation program project TRANSLATE. TRANSLATE is a €3.4 million EU-funded research project that aims to develop a new nanofluidic platform technology to effectively convert waste heat to electricity. This technology has the potential to improve the energy efficiency of many devices and systems, and provide a radically new zero-emission power source. The TRANSLATE project has received funding from the European Union's Horizon 2020 research and innovation programme under grant agreement number 964251, for the action of 'The Recycling of waste heat through the Application of Nanofluidic ChannelS: Advances in the Conversion of Thermal to Electrical energy’. More information can be be found on the TRANSLATE project website: https://translate-energy.eu/