‘Build a wall’…… In order to power 155,000 homes?

In early January of this year it was announced that the construction of a 11.6km2 tidal lagoon in Swansea Bay, Wales had made it through the planning stage [1]. There was a very high level of acceptance for the project, with large amounts of support coming from the locals and the government, what with it being the first of its kind [2]. This project seems too good to be true, but is this really the solution to getting Britain to meet its targets that have just come out of the Paris agreement in 2016 [3] or is this going to be another case of the failed Severn Barrage? [4]

Figure 1: A Plan for the Lagoon


The proposed lagoon is going to be created by sucking up gravel and sand from Swansea bay and pumping it into high strength cylinders which are then stacked and covered in rocks. The seawater enters and leaves the lagoon through the turbine housing as seen in Figure 2 and, using a series of gates allows the plant to generate electricity 4 times a day.


Figure 2: A Schematic of One of the Turbines

I won’t go into technical details as there is a video here that covers all the aspects of the plant it a very detailed way. My big concern with this is why is it the first of its kind in the world, when all the statistics point towards it being the best renewable energy source [5]? Well, we are fortunate to have the 2nd largest tidal range in the Bristol channel with that of Swansea Bay being 7-9 meters, [2] meaning the plant would actually be cost effective. It would have an estimated life of 120 years [2], which at the end of that (unlike a nuclear reactor) parts could be replaced and the lifetime extended. The cost of the power it produces is also fairly low, with an estimated cost of £96.50 per MWh [6] compared to £92.50 per MWh for nuclear at nearby proposed Hinkley point C [7]. This cost is slightly higher than nuclear, but it was announced on the 1st of February that the government would subsidise this (seeing as its renewable as opposed to nuclear) [8]. The initial subsidy was £160 per MW over 35 years, but it’s now just under £100 per MW over 90 years [9]. Most people would see this as a cut, and that is essentially what it is, but it means the plant will be producing subsidised power for 75% of its life as opposed to 30%. Whilst the energy will not be as cheap in the short term, over the course of its life it will be much more cost effective.

Figure 3: The Proposed ‘Severn Barrage’ in 1981

Going back to the Severn Barrage (in Figure 3), which was a proposed £30 billion tidal power plant stretching from Weston Super-Mare to Cardiff that would have provided 5% of all the UK’s electricity [4]. This project was scrapped in 2010 due to the ecological impacts on the wetlands around the Bristol channel [4]. The designers behind the Swansea Bay plant however, have located this lagoon in a way that neither the River Neath or Tawe flow into it. There are also plans to implement conservation schemes, including a lobster hatchery in the lagoon, but personally I cannot see these lasting. Overall, this development has huge potential, plus if it works, there are several other potential sites all located within the Bristol channel [1].

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The Dutch run their trains on 100% wind power, why can’t we do that?

On the 11th of January 2017 the Dutch transport company NS (Nederlandse Spoorwegen) announced that 100% of its trains, and therefore all of the trains in the Netherlands run on renewable wind power [1]. When I read this I thought, ‘If the Netherlands can do this, then why can’t Britain, the windiest country in Europe?’

Wind Turbines in Holland

The obvious answer would be to build more turbines, but this is not the case. Firstly, the Dutch train transport sector is considerably smaller than the British with an annual consumption of 1.2 billion kWh of electricity [1]. Whereas in the UK, only 51% of the trains have been electrified with the remainder still being run on diesel or coal [3]. I used some calculations and consequently worked out that the electrical equivalent on the UK’s railways is over 12.1 billion kWh per year as of 2015 [4]. Using this information and data from the European Wind Energy Association [5] on turbine output and efficiency we can determine that in order to power the entire Dutch railroad system only 200 turbines will be needed, of which the country currently has over 2,200 [6]. The UK on the other hand would need approximately 2033 turbines of which there are already 13,614 in place as of 2015 [7].

That was quite a lot of numbers, but it illustrates my point of why there are no immediately obvious reasons of why the UK cannot keep up with the Netherlands in providing sustainable public transport. However, I personally believe it’s to do with the current infrastructure in both countries. The majority of the UK’s railroads are designed for diesel trains and so do not have the overhead cables directly supplying electricity plus many of our trains run on inefficient diesel engines. The cost of electrifying these rails is huge, with £4 billion being put aside in 2014 to convert just 11% of existing railways [3].

One of the NS Electric Trains

In a post-Brexit world where the UK’s economy is potentially facing difficult times, the electrification of the railways is probably not the department of transports biggest issue. The Dutch have been working towards this goal of 100% renewable train electricity for over 10 years, and consequently have been developing the infrastructure as they go along. I guess this means that the UK still has a long way to go.


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Get down off your high horse Tesla. You’re not as green as you make out!

The concept of a vehicle that runs on pure electricity is something that has only just arrived in mainstream news in the last decade, with more efficient and faster designs being brought out every year. At the forefront of this new technology is Elon Musk’s company Tesla, which is bringing out the newest version of the Tesla Model 3 in mid-2017.  For people wanting to reduce their carbon footprint, this vehicle with its 215-380 mile range (depending on battery size) that emits zero emissions seems like the perfect solution [1].

The New Model 3

However, most people are not aware of the hidden environment costs behind such vehicles. The Model 3 may not have internal combustion, but it still relies on electricity generation through other means, which in the UK is predominately fossil fuels. As of the 20th January 2017 the UK produces 66.55% [3] of its electricity through coal and gas-fired power stations. Using statistics from the US Energy Information Administration (EIA) we know that in order to produce 1 kWh of electricity 0.07 gallons of petroleum has to be burnt, or just over 1 pound of coal in a power station [4]. Therefore, in order to charge one of these new *Tesla’s you will need between 4.2 and 7 gallons of fuel to be burnt:- this gives the vehicle an average of 53 miles per gallon (mpg). This is poor for something that’s supposed to be ‘environmentally friendly’ when comparing it to the similarly designed petrol Jaguar XE which averages 55mpg [5].

The fuel consumption per mile does vary between vehicles, but one factor that cannot be overlooked is the requirement of rare earth metals in an EV’s construction. All commercially available EV’s run on lithium-ion batteries which are extremely powerful, and most importantly, lightweight to ensure a high-efficiency. As well as lithium there are also large amounts of neodymium and dysprosium used in the vehicles assorted lightweight components which again have huge environmental implications through their extraction [6]. Currently, ownership of such vehicles is low in the UK, with just over 1% of road users owning a fully electric vehicle. Nevertheless, at the current rate of growth, lithium and neodymium usage is expected to increase tenfold before 2050 [7]. This brings me onto my final point of where these rare metals are going to come from. Lithium is not the easiest mineral to obtain as it has to be extracted in a process that involves pumping water deep into the ground and then refining the end product. Not only does this refinement require high amounts of energy but it also produces a lot of mine waste in the process [8].

A Lithium Mine in Chile

The fact is, when it comes to EV’s, it is highly dependent on where the vehicle is made and used. In countries that rely on a lot of renewable energy sources the only large environmental cost will be the raw material extraction. However, an EV in many of the worlds developed and developing countries is simply not an appropriate solution to reducing your carbon footprint at the moment [10]. So I guess for the time being you will have to stick with your Jaguar XE…. What a hardship!

*The Tesla Model 3’s specs are yet to be released, the above stats are for 2016’s ‘Model S’.

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