Why Can’t We Just Burn Hydrogen? Challenges When Changing Fuels in an Existing Infrastructure

The current global consumption of natural gas as a fuel is roughly 4 trillion cubic meters per year. In terms of energy, the demand for natural gas exceeds the global demand for fossil fuels for transportation. Despite this observation, the challenges to natural gas end use that arise when changing the composition of the fuel are largely absent from public, policy, and research agendas, whereas for transportation fuels the issues are more appreciated. Natural gas is delivered via complex networks of interconnected pipelines to end users for direct and indirect heating in household and industrial sectors, and for power generation. This interconnectedness is a crucial aspect of the challenge for introducing new fuels.
In this paper we discuss the issues that arise from changing fuel properties for an existing population of end-use equipment. To illustrate the issues, we will consider the changes in (combustion) performance of domestic combustion equipment and gas engines for power generation in response to substituting natural gas by hydrogen or hydrogen/natural gas blends. During the discussion, we shall also indicate methods for characterizing the properties of the fuel and identify the combustion challenges that must be addressed for a successful transition from the current fuel mix to whatever the future mix may be.