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Low Total Cost of Hydrogen by Exploiting Off Shore Wind and PEM Electrolysis Synergies.
Phone: (781) 529-0529
Phone: (781) 529-0529
The use of hydrogen as an energy carrier for stationary and automotive applications is beginning to be realized increasingly. Traditionally hydrogen use has been held back due to large capital costs for the fuel cells, as well as a large operating cost due to the cost of hydrogen. Great strides in PEM fuel cell technology have greatly reduced the former, while the drastic reduction in renewable energy costs has the potential of lowering the latter.Currently, generating hydrogen by electrolysis from energy supplied by the grid is simply too expensive. Specifically, PEM electrolysis coupled to off-shore wind has numerous synergies that have yet to be fully explored, quantified and modelled. In a current motif, an off-shore windmill generates “dirty” AC power at the turbine level. It is considered “dirty” because neither voltage nor frequency are firmly regulated.This is then transformed to “clean” DC power, generally at ~ 600 V. DC Power from the individual windmills is then aggregated at an offshore station and transmitted back to shore (DC transmission is favored underwater as AC power suffers significant losses due to the high polarizability of water) where it is converted to “clean” AC for transmission across the grid. An electrolyzer station would then take this clean AC power, transform back to DC voltage (typically 100-200 V depending on stack size) to generate hydrogen at moderate (40 bar) pressure. A great opportunity then exists to directly couple the off shore windmill with an electrolyzer. Co-locating the electrolyzer to allow it to directly operate off of the windmill’s DC power and transmit at high to moderate pressure to shore could bypass the “clean DC to clean AC” transformer on the windmill, as well as the “clean AC to clean DC” transformer in the electrolyzer, significantly lowering the cost and efficiency of both unit operations, while providing hydrogen storage. The power transmission costs would also be lowered, as transporting energy via pipeline is multiples less expensive than electricity transmission. In Phase I we will begin with a cost model for offshore wind and begin to apply it for offshore hydrogen generation. The cost of transporting and storing hydrogen compared to electrons will be compared, as well specific costs and technical challenges of operating a large electrolyzer system offshore. In phase II and possible Phase III work we will demonstrate a small electrolyzer system operating directly off of a wind turbine and optimize system configuration (Power, Pressure and Storage) to generate optimal “bankable” projects. Offshore generate hydrogen could have a major impact in mobility, especially at port locations, replacing diesel fleets. In addition for ammonia generation, which is generally done near coastlines. Using green hydrogen in these applications can greatly reduce greenhouse gas emissions.
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