Looking at other applications of hydrogen, the paper expects a combination of rapidly declining costs for green hydrogen, and continued development of refuelling infrastructure, to trigger broader uptake of hydrogen fuel-cell electric vehicles. “We estimate that more than 80% of hydrogen demand for mobility in mid-century will be for buses, trucks and other heavy vehicles,” said Aarnes (Figure 3).
Valorizing surplus power from renewables
Making hydrogen by electrolysis is widely promoted as a medium for creating value from surplus electricity produced by VRES. Hydrogen can be stored, transported and sold, while the alternative might be to curtail electricity production from such sources.
The paper supports this view. It calculates that the cost of electrolytic H2 production can be reduced widely by increasing electrolysis plant operating hours beyond those when surplus electricity is available.
“Consequently, green hydrogen producers may wish to consider securing a continuous supply of green electricity through green certificates, for example” suggested Aarnes.
Arguing that H2 from electrolysis will be able to compete on cost against gas reforming with CCS around 2030, the paper specifies conditions that would need to apply. For example, electrolysers would operate intermittently in step with fluctuating power prices, and H2 storage would be available for matching supply and demand.
In addition, the paper explores concepts for blue and green hydrogen production on an offshore platform, involving varying needs for power cables and pipelines/storage for H2 and/or carbon dioxide.
“We find that offshore reforming of natural gas with CCS to produce transportable hydrogen can be an economic business proposition depending on how far offshore the platform is,” said Aarnes. “In contrast, making hydrogen offshore through electrolysis powered by offshore wind installations requires a high hydrogen price, with the primary cost driver being the offshore wind farm.”
Hydrogen towards 2050
Hydrogen is generally more energy intensive to store and transport than other conventional fuels. Hence, the crux of the debate over its use for storing and supplying energy is that its value in pure form to users or to society must be sufficient to justify the energy losses in its production, distribution and use, Aarnes observed.
“Hydrogen as an energy carrier is one of a number of studies and papers that we are publishing to inform this debate and provide evidence-based analysis of what it will take for a global hydrogen economy to develop,” he added.
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- ‘Switching a city from natural gas to hydrogen’, DNV GL PERSPECTIVES, dnvgl.com, October 2018