Chalkboard 1 - The Many Colors of Hydrogen

Abstract

The last few years have given rise to an increased number of energy roadmaps and pledges by many countries committed to reducing emissions of greenhouse gases (GHGs), and to achieving net-zero emissions in accord with the Paris Agreement that aims to limit global warming to 1.5°C, compared to pre-industrial levels. The most recent Intergovernmental Panel on Climate Change (IPCC) reporta notes that global warming is likely to reach 1.5°C between 2030 and 2052 if it continues at its current rate.1 To limit and stabilize the long-term temperature increase, the recent International Energy Agency (IEA) and IPCC reports stress the need for achieving carbon-neutrality by 2050.1-3 Achieving this transformation requires a series of policies and efforts involving various technological advances for decarbonizing many sectors, as outlined in many recent roadmaps providing a comprehensive analysis for decarbonization pathways.2-28 A recurring theme in these roadmaps is the pivotal role of hydrogen and its potential to help steer the world toward achieving and realizing the decarbonization pathways (Fig. 1).