Time to build this barrage
A reliable 4,000MW baseload supply of electricity to the national grid can be made available using the exceptional tidal power that can be released using a barrage in the Severn Estuary between Aberthaw and Minehead.
The design and manufacture of water-turbine/ generator units and the construction of a predominantly steel structure barrage would provide thousands of UK employment opportunities. The low cost of the electricity produced would underpin all engineering industry growth plans in South Wales.
A barrage design must ensure that wildlife and the wider environment are protected.
A 2019 outline design provides two shipping channels 54m and 27m wide plus sixteen 4m wide marine-life transit channels. All channels are designed to open simultaneously and stay open for two hours at every high tide and low tide. This brings upstream and downstream levels together during this period, enabling aquatic life and shipping to pass freely through the barrage.
Control of flows from the sea into the upper estuary provides the means of preventing the 2021 maximum upstream levels from being exceeded even if climate change increases the sea level in the Bristol Channel by up to 5m.
I hope IMechE members agree with me that a 4,000MW tidal barrage should be part of UK electricity generation. It should be operational before 2030.
Dr Edward Grist, Congleton, Cheshire
Invest in molten salt reactors
It is very worrying if Jennifer Johnson is correct to suggest that western countries are dithering over the future of nuclear power (Industry Pulse, Professional Engineering No 5, 2021).
She is certainly correct to say that “funding provides a significant barrier to the expansion of the UK nuclear fleet”. This can easily be resolved. The government should establish a National Energy Authority (NEA), a statutory body responsible to parliament. The NEA can be made up of power engineers and other professionals who would plan, design and commission the building of all nuclear plants.
The investment for these plants would be provided via a ringfenced Treasury fund at government borrowing rates and the capital cost and borrowing would be repaid from a proportion of the price of electricity, and this would not impact on public-sector borrowing. This provides a two-fold advantage. Firstly, the low government borrowing eliminates the very high cost incurred from private investment and, secondly, this would result in the wholesale price of electricity from these plants being approximately half the price normally expected from pressurised water reactors.
The report also mentions the development of small modular reactors. I would suggest that a more important development meriting consideration are molten salt reactors. These reactors are being developed by Moltex and the first plant may be in operation in Canada in a few years’ time.
Important features of these plants are that the nuclear generation operates at atmospheric pressure. The fuel used can be uranium, thorium or spent fuel from civil and military plants. This eliminates the need for deep geological storage of waste, and these plants cannot produce fuel-grade material for nuclear weapons. Operationally the plants can provide flexible output to balance the grid and provide back-up for intermittent renewable supplies. On current information these plants will provide a wholesale price of electricity which is similar to gas generation (excluding carbon tax) which would provide the lowest near-zero carbon generation available.
Moltex are applying for licences for these plants which may take years. Because their availability would make a considerable contribution in helping tackle climate change I would suggest that these licences are fast tracked in the way vaccines were fast tracked to tackle the pandemic.
Charles Scott, Edinburgh
Full Steam ahead
A new worldwide community has been set up to gather together all the supporters and sources of support for pupils, teachers and Steam ambassadors: www.schoolsliaisoncommunity.net
There are sections on Steam organisations, professional bodies like the IMechE, Steam resources, Steam presentation videos, social groups, local networks and so on.
We also encourage members and colleagues in education to join the new Linked-In group where we can share best practice and identify websites, organisations and other support that we have not yet listed.
Exciting pupils to consider Steam subjects to study and as a career is vital for the future success of the pupils and their homelands.
We ask everyone to help by encouraging pupils at careers fairs, mock interviews and presenting career history and hot-topic lectures either in-school or using the internet.
Derrick Willer MBE
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Content published by Professional Engineering does not necessarily represent the views of the Institution of Mechanical Engineers.