Hydrogen has long been seen as an 'alternative' and renewable green energy, but for many reasons has not yet become mainstream in the fight against climate change. Recently, there has been a surge of interest and many in the energy industry believe hydrogen is here to stay. What is hydrogen and how can it be used to combat climate change? What types of hydrogen are there, and how is each 'color' of hydrogen produced? What new technologies show promise in the drive by the Department of Energy and the 'Earth Shot' to drive down the cost of green hydrogen?