German homes are fossil energy guzzlers – a big hurdle on the path to greenhouse gas neutrality. Nearly two thirds still heat with fossil fuels, and most of them also need to be modernised to lower energy demand. The government is working to extend the energy transition to buildings with a ban on new oil-fired heating and tax incentives for renovations and low-emission technologies. It aims to have a 'nearly' climate neutral building stock by 2050 after emissions in the sector have stagnated for nearly a decade. But which source of heat will be Germany's best bet in the race to climate neutrality – deep geothermal energy, heat pumps or hydrogen? Original