Speaking at a recent Riviera Maritime Media webinar, Elliott Bay Design chief electrical engineer Will Ayers discussed hydrogen power and why mineral reserves were unlikely to hamper the uptake of electric vessels
I have been asked why, considering the large volume of weight per kilowatt hour of batteries, we do not employ a fuel-cell system on vessels, where a large amount of energy is needed and battery space and weight is a significant drawback.
The main concern here is the loss of efficiency in the production of hydrogen: there is about a 30% loss simply by creating the hydrogen; another 30 or 40% is lost in the compressing or liquefaction processes, and more loss occurs during transit. And finally, when you move the hydrogen on board a vessel, you experience about another 40% loss when running it through a fuel cell.
If we contrast this with a hybrid electric engine, where you are charging a transmission network, there is usually about 94% efficiency. The batteries meanwhile are about 96% efficient and the converter technology is about 98.5% efficient. So, it is a bit like night and day in terms of the more obvious disadvantages of hydrogen fuel cells across the supply chain.
Hydrogen does have specific advantages when it comes to energy density; it can be stored more easily for example, but as far as efficiency goes, hybrid electric is the clear winner, at least for the time being.
There is also potential for direct connection between the hybrid electric engine and this amazing new world of renewables that is now developing.
The good news for hybrid electrics is that the two major cost components – lithium-ion batteries and inverter technology – are both becoming cheaper.
In California for example, when we look at utility demand through a typical day, we see this year that solar is basically cratering in the middle of the day for utility demand. We are also seeing negative wholesale pricing in electricity; electricity producers are actually paying the utility to take electricity off their hands.
We can expect to see a continual shift from standard rates to time-of-use and time-of-day rate pricing. If you are an operator working 16 or 20 hours a day, there will be huge potential to tap into decreasing prices at those times of the day when usage falls.
I have also heard concerns being raised about a looming shortage of nickel sulphate and its impact on the take-up of electrical propulsion in shipping. In reality, even if a temporary shortage occurs, there are so many reserves out there that a price increase of just 20 or 30%, would make the slightly harder-to-reach minerals economically viable. There is a huge amount of the Earth’s crust and so many minerals still in it, so I am not overly concerned about that issue.
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