Alternative Energy & Storage

In this week’s New Civil Engineer magazine (NCE) there are some interesting articles on exciting alternative energy schemes. These include the Swansea Tidal Lagoon, the Meygen Phase 1A tidal turbines in the Pentland Firth and a floating Solar array on a reservoir in Walton on Thames, which although more costly than covering fields with solar panels, seems to me to be a better use of space.

For each scheme there were figures quoted concerning cost, capacity, lifespan and the number of homes which could be powered. There were also comparisons with the Hinkley Point C nuclear scheme.

I played around with the data and a few comparisons struck me. Firstly if the generating capacity of the Swansea Tidal Lagoon is around a tenth of Hinkley C, why can it power a fortieth of the number of homes? Similarly the floating solar panels have a similar generating capacity to the tidal turbines, yet power half as many homes. Well, the good thing about nuclear power is that you crank it up to optimum operating power and it delivers that power hour after hour, day after day. The tide varies hour by hour and according to the phase of the moon. So although it is highly predictable, it is only delivering its maximum capacity for a fraction of the time. Nevertheless, that predictability is very useful because solar and wind power are nothing like as predictable.

Swansea Tidal Lagoon Tidal Turbine Meygen Phase 1A Hinkley Point C Nuclear Floating Solar Panels
Capacity MW










Homes powered





Cost / MW / YEAR





Cost / Homes Powered / YEAR





Homes / MW





The big problem with electrical power is demand following. I looked at the UK power demand statistics for 2012 and 2013 and the summer minimum demand occurs at about 5AM and is around 27 Gigawatts and the winter maximum is around 58 Gigawatts at about 5PM. In 2015 the total electrical demand was 308,000 GWh equivalent to an average of 35GW per hour over the whole year. So you have to cater for this minimum 27GW, average 35GW and maximum 58 GW scenario. That is before you start worrying about what the demand is going to be in however many years it takes to build new power stations.

Nuclear is not good at demand following, that is you can’t turn it up and down as easily as with gas or coal fired power stations. And we already know that the tide is what it is and the wind and sun are very unpredictable, in the UK anyway. So that’s where energy storage comes in. The NCE article also focussed on new grid battery scheme in Leighton Buzzard. It covers the area of 3 tennis courts, cost £13m, and has a power capacity of 6MW and an energy capacity of 10MWh.

There was also a piece on a cryogenic facility in Manchester that uses surplus energy to freeze air into liquid air at -196 degC and stores in insulated tanks. When required it can be converted to gaseous air again at 700 times its liquid volume and drive turbines to produce electricity.

So, conveniently ignoring energy losses, and spare capacity for maintenance outages and future growth, you could deliver the 2015 UK electricity requirements with something like 123 Swansea Tidal Lagoons (or 11 Hinkley Point C’s) and 2,166 Leighton Buzzard style battery banks. You wouldn’t of course, you’d want a good mix of generation, but storage of one sort or another is key.

The process of deciding how you invest in energy infrastructure is complex. Whilst nuclear looks like the cheapest option for baseload, it has significant disposal costs down the line. Investment in certain technologies might provide a competitive advantage in selling that technology elsewhere in the world. The process of deciding on an investment strategy and making the case for it is project sponsorship. If that’s of interest to you, see my book here.



About David West

I'm a Civil Engineer, Project and Risk Manager with an MBA. I will be using this blog to share my thoughts about a number of subjects of interest to me. I hope that you will find them interesting too.

Posted on January 16, 2017, in Uncategorized. Bookmark the permalink. Leave a comment.

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