Dave Elliott: A Norwegian study found that more renewables were needed in the green hydrogen cases than in the mixed green hydrogen/fossil CCS cases. And in terms of cost, the study found that, though green hydrogen can help integrate higher shares of wind and solar, this strategy brings ‘considerable costs’ due to capital under utilization of the expensive electrolysers and, in some cases, the extra transmission links needed. The trade-offs are quite complex. Dealing with variable renewables adds to the cost, and, on balance the study concludes that, in a mixed Green and Blue hydrogen system, ‘flexible power and hydrogen production with CCS offers substantial benefits to a future energy system with high VRE shares. In addition, it produces large quantities of clean hydrogen to decarbonise sectors other than electricity’. So it sees Blue Hydrogen playing a key role. It may be that, in reality, we will have a mixed Green and Blue hydrogen system for a while, since the emphasis at present is on Blue hydrogen, which is seen as cheaper for the moment. It is true that, as the study says, ‘hydrogen produced from electrolysis will always be more expensive than the electricity used to produce it, whereas natural gas can be converted to hydrogen at a significantly lower cost than it can be converted to electricity’. But, with the CCS costs included, the balance may change- green hydrogen should be competitive with blue hydrogen by 2030, if not earlier. As it is, this study assumes that CCS is viable on a large scale, including the transport of CO2 over long distances to suitable wells offshore. And that electrolysers won’t get cheap and flexible! UK electrolyser pioneers ITM Power, who in a paper in the Fell Cell Bulletin recently flagged up an interesting new angle: ‘Hydrogen derived from water electrolysis neither results in oxygen depletion nor increases the atmospheric concentrations of water vapour and CO2’. Conversely, in addition to the associated CO2 production (even given CCS), ‘the use of hydrogen derived from fossil fuels (with or without carbon capture and storage, CCS) depletes the oxygen resource and increases water vapour emissions to the atmosphere, which enhances the rate of global warming’.
Renew Extra 8th May 2021 read more »
The cars of the future could be powered by hydrogen extracted from waste in a process being tested by UK water companies. A new trial led by Northumbria Water is taking ammonia in sewage and using to create hydrogen, which could be used to fuel green buses, boilers and even aeroplanes. Ammonia, a toxic substance, is currently processed into nitrogen which can be safely released into the atmosphere, but the water company hopes the more useful hydrogen could make its sewage treatment cheaper and more sustainable. Working alongside scientists at the Universities of Warwick and Cranfield, researchers are beginning a trial to test the process on a small amount of the sewage coming through the company’s plant in Howdon, on Tyneside. The process works by first stripping the ammonia out from the sewage stream and then “cracking” the ammonia at high temperatures.
Telegraph 8th May 2021 read more »