For hydrogen to play a meaningful role in a sustainable energy system, all elements of the value chain must scale coherently. Advocates support electrolytic (green) hydrogen or (blue) hydrogen that relies on methane reformation with carbon capture and storage; however, efforts to definitively choose how to deliver this scaling up are premature. For blue hydrogen, methane emissions must be minimized. Best in class supply chain management in combination with high rates of CO2 capture can deliver a low carbon hydrogen product. In the case of electrolytic hydrogen, the carbon intensity of power needs to be very low for this to be a viable alternative to blue hydrogen. Until the electricity grid is deeply decarbonized, there is an opportunity cost associated with using renewable energy to produce hydrogen, as opposed to integrating this with the power system. To have a realistic chance of success, net zero transition pathways need to be formulated in a way that is coherent with socio-political-economic constraints.@en

The industrial sector is responsible for 21% of all global carbon dioxide emissions, and, as such, emissions mitigation is as important in this sector as in the power generation sector. Individual industries are sufficiently diverse that bespoke capture strategies must be created for them, with different technologies more appropriate for different industries. One major difference between industrial and power carbon capture and storage (CCS) is that industries often have numerous sources of varying sizes and CO2 concentration, requiring some degree of aggregation or multiple capture units in order to capture large proportions of flue gases, implying an important trade-off between capture rate and cost. Within the chemical manufacturing industries, there exist streams of high-purity CO2 which can be used for demonstration CCS schemes at a lower cost than other flue streams, and as a first mover towards wide scale deployment. However, attempting to calculate the cost of industrial CCS is difficult since there are a wide range of reported costs from literature, with little consensus even within technologies for the same industry. Policy challenges remain broadly similar to those encountered in the power industry, though due to the global markets for industrial products, some market mechanism would be required in the event of unilateral decarbonisation in order not to penalise first-mover entities.@en