Half of all the energy we use globally goes on heating and cooling. We need heating for all sorts of things; from keeping our homes warm to industry which needs super high temperatures. At the moment, the heat we use is mostly powered by polluting fossil fuels, a huge driver of climate change. But can renewables deliver the high temperatures and a constant supply which are so vital? In this episode we visit the world's first commercial-scale sand battery in Finland and find out how it’s using renewables to heat 100 homes and a public swimming pool. Presenters Luke Jones and Graihagh Jackson are joined by: Erika Benke, Journalist, Finland Professor Amin Al-Habaibeh, Professor of Intelligent Engineering Systems, Nottingham Trent University Professor Dan Gladwin, Department of Electronic and Electrical Engineering, University of Sheffield And BBC Brasil journalist Nathalia Passarinho on the swearing in of Luiz Inacio Lula da Silva as President and his climate promises. Email us: theclimatequestion@bbc.com Producer: Lily Freeston Researcher: Natasha Fernandes Production Coordinators: Siobhan Reed and Helena Warwick-Cross Series Producer: Alex Lewis Editor: Bridget Harney Sound Engineers: Tom Brignell and Graham Puddifoot