Following the tides
Although I am not convinced that barrage schemes are the way to go for tidal generation, one benefit is that high tide occurs at different times all around the UK (Your Voice, Professional Engineering No 6, 2021). Furthermore, tidal heights are predictable, allowing for atmospheric conditions. Tidal streams, particularly at depth, are less prone to atmospheric variations. The corollary of this is that, although the power output of one system is sinusoidal, the output of many systems located around our coasts would essentially be a straight line.
Can Charlie Newton substantiate his claim that “If you have an e-bike, you are five times more likely to ride it than a regular bike” (Supercharge, Professional Engineering No 1, 2022)?
I, for one, would choose my road bike over an e-bike every time. It certainly affords me a better workout – I cycle to work 60% of the time in the winter and 90% of the time in the summer. It is obviously more sustainable, not having the precious commodities required for energy storage and rotating machinery.
Roger Lewis, Diss, Norfolk
Hydrogen will come at a price
You gave space to the hydrogen economy, with articles on the North West HyNet project, making steel with hydrogen, and hydrogen internal combustion engines (Professional Engineering No 1, 2022). Given that an engineer is someone who makes something for 25p that a scientist will do for a pound, where is the realisation that hydrogen will be far more expensive than any of the fuels it replaces?
Using steam reforming to produce hydrogen, with natural gas at £14/MWh, the hydrogen cost is £40/MWh. The difference comes from a 25% loss of energy in the conversion process and the capital cost of the plant. Carbon capture will add another £10/MWh.
Obviously, hydrogen from electrolysis has to cost more than the electricity from which it is made, where again the increase comes from the capital expenditure on the electrolysis units and a 30% loss on conversion. If electricity from renewables can be kept low, hydrogen will definitely compete with steam reforming. In practice, given the sort of price industry is charged for power in this country, hydrogen will be in the £60-70/MWh bracket.
The hydrogen economy will not make much difference to the chemical engineering companies in HyNet, as they currently use steam reforming. The rest of us, whether in industry or just ordinary domestic consumers, should be wary of the politically supported “promise of hydrogen”.
Dr Fred Starr
How the Vulcan bomber can continue to inspire the young
As a fellow of the IMechE, I am emailing you about an exciting project I’m involved with. It is related to the Vulcan bomber, XH558, which received an IMechE Heritage Award in 2011. This was the last flying Vulcan in operation but unfortunately it had to be grounded for good in 2015.
Plans are now afoot for the next chapter in this aircraft’s fantastic story, to create a new visitor centre for it at Doncaster-Sheffield Airport – The Vulcan Experience. This will uniquely combine an immersive heritage site with interactive attractions designed to educate and inspire the next generation of young engineers, including the Green Technology Hub which will inspire youngsters to find solutions to climate change, and a long-overdue memorial to the V-Force and their crews.
A design competition for local schools is under way. They have been challenged to design an exhibition stand for one of the Vulcan’s unique artefacts, a bomb-bay fuel tank. The winning school is having its design manufactured by a local engineering company to provide a lasting attraction in the new Vulcan Experience.
The whole project is gathering momentum and creating a lot of interest within the local engineering community, so I thought it would be a great subject of interest for the general IMechE engineering community too.
Steve Wainwright, Doncaster, South Yorkshire
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