Archive for the ‘Electricity Generation’ Category

Research into Nuclear Fusion is a waste of money

November 24, 2019

I used to be a Technological Utopian, and there has been no greater vision for a Technical Utopia than the prospect of limitless energy at low cost promised by Nuclear Fusion researchers.

But glowing descriptions of the Utopia which awaits us all, and statements by fusion Utopians such as:

Once harnessed, fusion has the potential to be nearly unlimited, safe and CO2-free energy source.

are deceptive. And I no longer believe this is just the self-interested optimism characteristic of all institutions.

It is a damaging deception, because money spent on nuclear fusion research could be spent on actual solutions to the problem of climate change. Solutions which exist right now and which could be implemented inside in a decade in the UK.

Reader: Michael? Are you OK? You seem to have come over a little over-rhetorical?

Me: Thanks. Just let me catch my breath8 and I’ll be fine. Ahhhhhh. Breathe…..

What’s the problem?

Well let’s just suppose that the current generation of experiments at JET and ITER are ‘successful’. If so, then having started building in 2013:

  • By 2025 the plant should be ready for initial plasma experiments.
  • Unbelievably, full deuteriumtritium fusion experiments will not start until 2035!
    • I could not believe this so I checked. Here’s the link.
    • I can’t find a source for it, but I have been told that the running lifetime of ITER with deuterium and tritium is just 4000 hours.
  • The cost of this experiment is hard to find written down – ITER has its own system of accounting! – but will probably be around 20 billion dollars.

And at this point, without having ever generated a single kilowatt of electricity, ITER will be decommissioned and its intensely radioactive core will be allowed to cool down until it can be buried.

The ‘fusion community’ would then ask for another 20 billion dollars or so to fund a DEMO power station which might be operational around 2050. At which point after a few years of DEMO operation, commercial designs would become available.

So the overall proposal is to spend about 40 billion dollars over the next 30 years to find out if a ‘commercial’ fusion power station is viable.

This plan is the embodiment of madness that could only be advocated by Technological Utopians who have lost track of the reason that fusion might once have been a good idea.

Let’s look at the problems in the most general terms.

1. Cost

Fusion will not be cheap. If we look at the current generation of nuclear fission stations, such as Hinkley C, then these will cost around £20 billion each.

Despite the fact the technology for building nuclear fission reactors is now half a century old, previous versions of the Hinkley C reactor being built at Olkiluoto and Flamanville are many years late, massively over-budget and in fact may never be allowed to operate.

Assuming Hinkley C does eventually become operational, the cost of the electricity it produces will be barely affected by the fuel it uses. More than 90% of the cost of the electricity is paying back the debt used to finance the reactor. It will produce the most expensive electricity ever supplied in the UK.

Nuclear fusion reactors designed to produce a gigawatt of electricity would definitely be engineering behemoths in the same category of engineering challenge as Hinkley C, but with much greater complexity and many more unknown failure modes. 

ITER Project. Picture produced by Oak Ridge National Laboratory [CC BY 2.0 (https://creativecommons.org/licenses/by/2.0)]Even in the most optimistic case – an optimism which we will see is not easy to justify – it is inconceivable that fusion technology could ever produce low cost electricity.

I don’t want to live in a world with
nuclear fusion reactors, because
I don’t want to live in a world
where electricity is that expensive.
Unknown author

2. Sustainable

One of the components of the fuel for a nuclear fusion reactor – deuterium – is readily available on Earth. It can be separated from sea water at modest cost.

The other componenttritium – is extraordinarily rare and expensive. It is radioactive with a half-life of about 10 years.

To  become <irony>sustainable<\irony>, a major task of a fusion reactor is to manufacture tritium.

The ‘plan’ is to do this by bombarding lithium-6 with neutrons causing a reaction yielding tritium and helium.

Ideally, every single neutron produced in the fusion reaction would be captured, but in fact most of them will not be lost. Instead, a ‘neutron multiplication’ process is conceived of, despite the intense radioactive waste this will produce.

3. Technical Practicality

I have written enough here and so I will just refer you to this article published on the web site of the Bulletin of Atomic Scientists.

This article considers:

  • The embedded carbon and costs
  • Optimistic statements of energy balance that fail to recognise the difference between:
    • The thermal energy of particles in the plasma
    • The thermal energy extracted – or extractable.
    • The electrical energy supplied for operation
  • Other aspects of the tritium problem I mentioned above.
  • Radiation and radioactive waste
  • The materials problems caused by – putatively – decades of neutron irradiation.
  • The cooling water required.

I could add my own concerns about neutron damage to the immense superconducting magnets that are just a metre or so away from the hottest place in the solar system.

In short, there are really serious problems that have no obvious solution.

4. Alternatives

If there were no alternative, then I would think it worthwhile to face down all these challenges and struggle on.

But there are really good alternatives based on that fusion reactor in the sky – the Sun.

We can extract energy directly from sunlight, and from the winds that the Sun drives around the Earth.

We need to capture only 0.02% of the energy in the sunlight reaching Earth to power our entire civilisation!

The complexity and cost of fusion reactors even makes fission reactors look good!

And all the technology that we require to address what is acknowledged as a climate emergency exists here and now.

By 2050, when (optimistically?) the first generation of fusion reactors might be ready to be built – carbon-free electricity production could be a solved problem.

Nuclear fusion research is, at its best, a distraction from the problem at hand. At worst, it sucks money and energy away from genuinely renewable energy technologies which need it.

We should just stop it all right now.

Should I still be using gas?

May 6, 2019

TL/DR The carbon emissions associated with electrical generation in the UK have fallen so much it is has become greener – but not necessarily cheaper – to cook and heat using electricity.

Electricity Generation

The carbon intensity of a source of electricity is a measure of how much carbon dioxide (measured in kg) was emitted to make one unit of electrical energy: an electrical kilowatt hour (kWe).

The chart below shows the carbon intensity of electricity generated by various techniques. The average carbon intensity depends on generating mix – and how that varies with time.

Carbon Intensity of different generating sources

When I began talking about Climate Change back in 2004, Coal, Gas and Nuclear were the main generating sources for UK electricity. And the average carbon intensity – if I remember correctly – was around 0.50 kg CO2 per kWe.

The generating mix in 2019 is radically different. The carbon intensity varies daily and seasonally between about 0.1 kg CO2 per kWe (at times of low demand and high renewable generation) and 0.4 kg CO2 per kW(at times of high demand and low renewable generation). The average value is less than 0.3 kg CO2 per kWand falling.

The chart below shows how the carbon intensity of electricity varied through the month of December 2018. The average value was 0.243 kg CO2 per kW.and the maximum and minimum values were 0.390 kg CO2 per kWand 0.094 kg CO2 per kWrespectively.

Carbon Intensity in December 2018

In my home

I can choose to heat by using electricity or gas.

  • If I heat using electricity then I can convert electrical energy into heat with 100% efficiency, so for every kW of electrical power I use, I generate 1 kW of thermal power (kWth). And hence release roughly 0.3 kg of carbon dioxide.
  • If I heat using gas then I can convert chemical energy in the gas into heat with high efficiency – but not generally 100%. So (looking at the chart at the start of the article) for every 1 kWth, I emit at least 0.47 kg of carbon dioxide.

Now the price per kWh (one kilowatt hour) that I am charged by EDF, the French government-backed company that supplies my electricity and gas is:

  • 26.6 pence for 1 kWh of electrical/thermal energy during the day.
    • Generally higher carbon intensity ~ 0.4 kg CO2 per kWe.
  • 5.0 pence for 1 kWh of electrical/thermal energy during the night.
    • Generally lower carbon intensity ~ 0.15 kg CO2 per kWe
  • 4.2 pence for 1 kWh of thermal energy (via gas) at any time.
    • Always at least ~ 0.46 kg CO2 per kW

So the reduction in the carbon intensity of the UK’s generating mix means that switching to electricity now makes ‘green sense’. i.e. If I generate 1 kW heat in my house using electricity then less carbon dioxide is emitted than if I just burned the gas directly

But in order to make financial sense I would need to make sure that I didn’t use any ‘daytime’ electricity.

Mmmm. Well at least I have a choice!

Resources

 

Is a UK grid-scale battery feasible?

April 26, 2019

This is quite a technical article, so here is the TL/DR: It would make excellent sense for the UK to build a distributed battery facility to enable renewable power to be used more effectively.

=========================================

Energy generated from renewable sources – primarily solar and wind – varies from moment-to-moment and day-to-day.

The charts below are compiled from data available at Templar Gridwatch. It shows the hourly, daily and seasonal fluctuations in solar and wind generation plotted every 5 minutes for (a) 30 days and (b) for a whole year from April 21st 2018. Yes, that is more than 100,000 data points!

Wind (Green), Solar (Yellow) and Total (Red) renewable energy generation for the days since April 21st 2018

Wind (Green), Solar (Yellow) and Total (Red) renewable energy generation for 30 days following April 21st 2018. The annual average (~6 GW) is shown as black dotted line.

Slide7

Wind (Green), Solar (Yellow) and Total (Red) renewable energy generation for the 365 days since April 21st 2018. The annual average (~6 GW) is shown as black dotted line.

An average of 6 GW is a lot of power. But suppose we could store some of this energy and use it when we wanted to rather than when nature supplied it. In other words:

Why don’t we just build a big battery?

It turns out we need quite a big battery!

How big a battery would be need?

The graphs below shows a nominal ‘demand’ for electrical energy (blue) and the electrical energy made available by the vagaries of nature (red) over periods of 30 days and 100 days respectively. I didn’t draw the whole year graph because one cannot see anything clearly on it!

The demand curve is a continuous demand for 3 GW of electrical power with a daily peak demand of 9 GW. This choice of demand curve is arbitrary, but it represents the kind of contribution we would like to be able to get from any energy source – its availability would ideally follow typical demand.

Slide8

Slide9

We can see that the renewable supply already has daily peaks in spring and summer due to the solar energy contribution.

The role of a big battery would be cope to with the difference between demand and supply. The figures below show the difference between my putative demand curve and supply, over periods of 30 days and a whole year.

Slide10

Slide11

I have drawn black dotted lines showing when the difference between demand and supply exceeds 5 GW one way or another. In spring and summer this catches most of the variations. So let’s imagine a battery that could store or release energy at a rate of 5 GW.

What storage capacity would the battery need to have? As a guess, I have done calculations for a battery that could store or release 5 GW of generated power for 5 hours i.e. a battery with a capacity of 5 GW x 5 hours = 25 GWh. We’ll look later to see if this is too much or too little.

How would such a battery perform?

So, how would such a battery affect the ability of wind and solar to deliver a specified demand?

To assess this I used the nominal ‘demand‘ I sketched at the top of this article – a demand for  3 GW continuously, but with a daily peak in demand to 9 GW – quite a severe challenge.

The two graphs below show the energy that would be stored in the battery for 30 days after 21 April 2018, and then for the whole following year.

  • When the battery is full then supply is exceeding demand and the excess is available for immediate use.
  • When the battery is empty then supply is simply whatever the elements have given us.
  • When the battery is in-between fully-charged and empty, then it is actively storing or supplying energy.

Slide12

Over 30 days (above) the battery spends most of its time empty, but over a full year (below), the battery is put to extensive use.

Slide13

How to measure performance?

To assess the performance of the battery I looked at how the renewable energy available last year would meet a levels of constant demand from 1 GW up to 10 GW with different sizes of battery. I consider battery sizes from zero (no storage) in 5 GWh steps up to our 25 GWh battery. The results are shown below:

Slide15It is clear that the first 5 GWh of storage makes the biggest difference.

Then I tried modelling several levels of variable demand: a combination of 3 GW of continuous demand with an increasingly large daily variation – up to a peak of 9 GW. This is a much more realistic demand curve.Slide17

Once again the first 5 GWh of storage makes a big difference for all the demand curves and the incremental benefit of bigger batteries is progressively smaller.

So based on the above analysis, I am going to consider a battery with 5 GWh of storage – but able to charge or discharge at a rate of 5 GW. But here is the big question:

Is such a battery even feasible?

Hornsdale Power Reserve

The Hornsdale Power Reserve Facility occupies an area bout the size of a football pitch. Picture from the ABC site

The Hornsdale Power Reserve Facility occupies an area about the size of a football pitch. Picture from the ABC site

The biggest battery grid storage facility on Earth was built a couple of years ago in Hornsdale, Australia (Wiki Link, Company Site). It seems to have been a success (link).

Here are its key parameters:

  • It can store or supply power at a rate of 100 MW or 0.1 GW
    • This is 50 times smaller than our planned battery
  • It can store 129 MWh of energy.
    • This is just under 40 times smaller than our planned battery
  • Tesla were reportedly paid 50 million US dollars
  • It was supplied in 100 days.
  • It occupies the size of a football pitch.

So why don’t we just build lots of similar things in the UK?

UK Requirements

So building 50 Hornsdale-size facilities, the cost would be roughly 2.5 billion dollars: i.e. about £2 billion.

If we could build 5 a year our 5 GWh battery would be built in 10 years at a cost of around £200 million per year. This is a lot of money. But it is not a ridiculous amount of money when considering the National Grid Infrastructure.

Why this might actually make sense

The key benefits of this kind of investment are:

  • It makes the most of all the renewable energy we generate.
    • By time-shifting the energy from when it is generated to when we need it, it allows renewable energy to be sold at a higher price and improves the economics of all renewable generation
  • The capital costs are predictable and, though large, are not extreme.
  • The capital generates an income within a year of commitment.
    • In contrast, the 3.2 GW nuclear power station like Hinkley Point C is currently estimated to cost about £20 billion but does not generate any return on investment for perhaps 10 years and carries a very high technical and political risk.
  • The plant lifetime appears to be reasonable and many elements of the plant would be recyclable.
  • If distributed into 50 separate Hornsdale-size facilities, the battery would be resilient against a single catastrophic failure.
  • Battery costs still appear to be falling year on year.
  • Spread across 30 million UK households, the cost is about £6 per year.

Conclusion

I performed these calculations for my own satisfaction. I am aware that I may have missed things, and that electrical grids are complicated, and that contracts to supply electricity are of labyrinthine complexity. But broadly speaking – more storage makes the grid more stable.

I can also think of some better modelling techniques. But I don’t think that they will affect my conclusion that a grid scale battery is feasible.

  • It would occupy about 50 football pitches worth of land spread around the country.
  • It would cost about £2 billion, about £6 per household per year for 10 years.
    • This is one tenth of the current projected cost of the Hinkley Point C nuclear power station.
  • It would deliver benefits immediately construction began, and the benefits would improve as the facility grew.

But I cannot comment on whether this makes economic sense. My guess is that when it does, it will be done!

Resources

Data came from Templar Gridwatch

 

The view from 10 kilometres

June 3, 2018

At the start of May I travelled by air to and from California.

The flight takes an extraordinary route, crossing the southern tip of Greenland, the vast shield of northern Canada, the American mid-west and the south-western deserts.

But despite the extreme terrain covered by the plane, for me the journey was easy. It was nothing more than an exercise in advanced sitting, and I am good at sitting.

And looking out the window, I saw two extraordinary things.

London to LA

Greenland

I had chosen a window seat on the right-hand side of the plane on the off-chance that visibility would be good as we flew over Greenland. I also brought my camera with a pointy lens.

The camera’s field of view on the ground was roughly 1 km at best, and I could see detailed features of the spring-melt of the sea-ice around Greenland.

Greeland Ice

At times I could see the surface texture of what I guess was a glacier as it reached the sea in an ice-cliff.

Greeland Ice 5

The scale of the ice was overwhelming. It didn’t look like a ‘snowy polar cap’ on the globe. It looked like a vast and utterly alien ice world.

I found it interesting to compare this ‘bird’s-eye’ view with the data gathered by satellites that have charted the decades long decline in the extent of the sea ice.

California-Nevada

As we flew over the Nevada-California border I was delighted  to catch a  glimpse of the immense Ivanpah solar power plant (Link & Wikipedia article).

One of three solar collectors at the Ivanpah solar power plant.

One of three solar collectors at the Ivanpah solar power plant.

The three solar collectors of the Ivanpah solar plant together with a vast solar photo-voltaic array

The three solar collectors of the Ivanpah solar plant together with a vast solar photo-voltaic array. It is clear that solar generation is not limited by available land!

Next to Ivanpah was a vast conventional solar photo-voltaic plant.

As I had been when I flew over Greenland, I was struck by the vastness of the landscape and the boldness of these engineering ventures in that inhospitable climate.

The link

Momentarily I allowed my self to hope – forgive me: I was on holiday.

I allowed myself to hope that solar engineering might really provide a way to de-carbonise electricity production.

From 10 km above the ground  it was breathtakingly clear that a lack of suitable land for solar power plants was not a limitation on production. Surely not even 1% of the available land was being used.

And as we flew over the Hoover Dam – with water sadly still at historically low levels – I allowed myself to imagine a world powered by renewable energy.

And as result, eventually there would be a slowdown in the rate of loss of arctic sea ice.

Hoover Dam  from 10 km

Hoover Dam from 10 km

It struck me that the first step required to make this happen was to imagine that it could even be possible.

From 10 kilometres up, briefly it all seemed clear

 

 

Not everything is getting worse!

April 19, 2017

Carbon Intensity April 2017

Friends, I find it hard to believe, but I think I have found something happening in the world which is not bad. Who knew such things still happened?

The news comes from the fantastic web site MyGridGB which charts the development of electricity generation in the UK.

On the site I read that:

  • At lunchtime on Sunday 9th April 2017,  8 GW of solar power was generated.
  • On Friday all coal power stations in the UK were off.
  • On Saturday, strong winds and solar combined with low demand to briefly provide 73% of power.

All three of these facts fill me with hope. Just think:

  • 8 gigawatts of solar power. In the UK! IN APRIL!!!
  • And no coal generation at all!
  • And renewable energy providing 73% of our power!

Even a few years ago each of these facts would have been unthinkable!

And even more wonderfully: nobody noticed!

Of course, these were just transients, but they show we have the potential to generate electricity which has a significantly low carbon intensity.

Carbon Intensity is a measure of the amount of carbon dioxide emitted into the atmosphere for each unit (kWh) of electricity generated.

Wikipedia tells me that electricity generated from:

  • Coal has a carbon intensity of about 1.0 kg of CO2 per kWh
  • Gas has a carbon intensity of about 0.47 kg of CO2 per kWh
  • Biomass has a carbon intensity of about 0.23 kg of CO2 per kWh
  • Solar PV has a carbon intensity of about 0.05 kg of CO2 per kW
  • Nuclear has a carbon intensity of about 0.02 kg of CO2 per kWh
  • Wind has a carbon intensity of about 0.01 kg of CO2 per kWh

The graph at the head of the page shows that in April 2017 the generating mix in the UK has a carbon intensity of about 0.25 kg of CO2 per kWh.

MyGridGB’s mastermind is Andrew Crossland. On the site he has published a manifesto outlining a plan which would actually reduce our carbon intensity to less than 0.1 kg of CO2 per kWh.

What I like about the manifesto is that it is eminently doable.

And who knows? Perhaps we might actually do it?

Ahhhh. Thank you Andrew.

Even thinking that a good thing might still be possible makes me feel better.

 

Hinkley C: An alternative response

August 1, 2016

My earlier article on Hinkley Point C received a well-conceived and written response that deserves to be somewhere better than a comment page: here it is:

Hi Michael,
I am no economist either but I will make a few comments on your article about the Hinkley C project. Your conclusion is that overall the project is neither the best thing nor the worst thing could do and therefore sort of Ok. This rather equivocal judgement is made on the basis that the ongoing cost (of £1.15 billion p.a. for 35 years) is probably worth the price because it frees the UK government is from any upfront investment or later costs due to failure or delays. I think this is a very naive view.

This project aims to provide at least 7% of the nation’s power. As far as I am aware the UK government has no Plan B to meet this energy gap. This makes the Hinkley Point C scheme simply “too big to fail”. And if it falters or fails it will be for the UK government to salvage it regardless of contracts agreed at the beginning. The deals will be renegotiated when problems arise and the government / nation needs this power so it cannot just walk away or buy an alternative power station off the shelf.

The situation strikes me as analogous to the Private Finance Initiative (PFI) used to build public sector infrastructure for the last few years. This was sold as a wonderful risk free way of financing new hospitals and schools by using the private sector. Certainly new infrastructure has been built (though often not what was wanted) but at enormous cost which will cripple the public sector for decades. The scheme was devised to avoid government borrowing (even though the costs of this are much lower that for the private sector) but still has to be paid for year in & year out. (It is estimated that the UK owes £222 billion to banks & businesses via the PFI. (The Independent 11 April 2015)

By seeking to avoid public borrowing to finance Hinkley C the government has made a political and ideological choice which reduces it’s control (through lack of ownership), inflates the cost (even if kicked a few decades into the future) and does nothing to reduce the risks (because the government / nation really needs this energy so has no choice but to stick with it).

Best Wishes
Charlie

PS
It is also the case that the UK government has explicitly underwritten £2 billion of costs through the Treasury’s (infrastructure) Guarantee Scheme. This was announced by George Osbourne on a visit to China in September 2015 as an incentive to get the Chinese to invest in the project. EDF itself, in its own press release on the deal refers to “further amounts [being] potentially available in the longer-term.” So there is real chance that the UK government will increase the amount of the project it will explicitly underwrite.

I basically agree with everything you are saying. And if I had had the time I might already have written some of it myself.

However the point of the article was that in narrowly financial terms, this deal isn’t as insane as it is being made to sound.

Concerning Plans A and B, here are some other thoughts.

  • If we want nuclear power, then the current EDF design is one of the very few options available. The real missed opportunity here is that the decision to build was delayed so long that the option for using UK technology was lost.
  • Like you, I find the government’s aversion towards state ownership bizarre. How can it be OK for foreign governments to own our infrastructure, but not the UK government? That is just bonkers. As you say, if this is critical infrastructure then the owners of the infrastructure – the Chinese and French governments – will be able to hold us to ransom in the future.
  • Assuming the project goes ahead, then – taking a positive view – the government will have freed up the capital resources to invest in what I think is the real challenge facing us: integrating energy storage into our generating mix. But that is a story for another evening.

Thanks for your thoughts.

Michael

==============================

[August 1st  2016: Weight this morning 73.4 kg: Anxiety: Very High]

I can’t bear to think about it

April 20, 2016

Over the last few years I have written a fair amount about the problem of global warming.

But in the last few months I have felt barely able to bring my mind to bear on the subject – let alone write about it.

The reason is that the news is overwhelmingly terrible, both in our knowledge of the unfolding reality and our utter inability to focus on the hundreds of do-able things we might be doing.

So for example working backwards through my bookmarks:

Global Warming February 2016 anomaly

The monthly-mean global land-surface temperature anomaly based on data from meteorological stations only. The base period 1951-1980 is shown as a thick red line. The data for this February 2016 is shockingly exceptional.

I could report more stories, but in short, I am overwhelmed.

Now before you say “but its it’s not all doom and gloom” please let me elaborate.

  • I know that the world – and even civilisation as we know it – will not end if the Earth warms by 1 °C. Or even 2 °C. Or probably even 3 °C.
  • And I also know that ‘bad news’ is great news for the media that bring ‘news’ to my attention and so I experience a cognitive bias towards ‘bad news’ because I encounter it more frequently.
  • And I also know that there is good news. For example, use of coal to generate electricity in the UK has fallen dramatically (See Gridwatch for data)
The amount of electricity (GW) generated from coal in the UK. The data are taken every 5 minutes since May 2011. The decline is very striking.

The amount of electricity (GW) generated from coal in the UK. The data are taken every 5 minutes since May 2011. The decline is very striking.

I understand all these things. But overall, I give us – by which I mean me, my generation and this government – a massive vote of disapproval.

IMHO this issue is completely solvable by actions available to our government right now. But they are choosing not to do them. And I just can’t bear to think about the entirely avoidable consequences.

Road to Nowhere

September 21, 2015
A road to nowhere. This road is 60 metres below the surface of the Finnish peninsula on Olkiluotu and leads to giant silo - the end of the road for low-level and intermediate-level radioactive waste in Finland.

A road to nowhere. This road is 60 metres below the surface of the Finnish island of Olkiluotu and leads to two giant silos – the end of the road for low-level and intermediate-level radioactive waste in Finland.

I wrote last week that one of the things we in the UK need to build in ‘someone’s back yard’ is a Nuclear Waste Repository.

Last week during a progress meeting for the European Metrodecom project, I joined a visit to the site of such a repository in Finland, on the island of Olkiluoto.

Olkiluoto Island houses two working nuclear reactors, each generating approximately 400 MW of electricity for more than 95% of the time. It is also home to the first construction of a new type of reactor which may (or may not) be built at Hinkley Point in the UK. When completed this third reactor should generate approximately 1600 MW of electricity.

But more important than nuclear generation, Olkiluoto is home to Onkalo (meaning ‘Cave’ or ‘Cavern’) the world’s first final disposal site for high-level waste.

The lower levels of Onkalo are still under construction and so sadly we were not able to visit the tunnels 400 m below the surface. But we did visit the 60 m deep repositories for low-level and intermediate-level radioactive waste .

Importantly, these are not ‘storage’ facilities, but represent sites for the final disposal of this waste. When they are full, they will be sealed off and left.

The visit

After three briefings on Olkiluoto in general and Onkalo  in particular, we boarded a bus for a tour of the site, ending up at the entrance to the so-called VLJ repository.

We were asked not to take pictures of the site, but once inside the repository we were told that we could ‘fill up our memory cards’.

We put on obligatory hard hats, and after a large roller-door was raised, we descended on a sloping roadway mined from solid granite.

The tunnel descends, carved out of solid granite.

The tunnel descends, carved out of solid granite.

After 15 minutes or so we reached a large chamber containing two gigantic silos, each about 20 metres in diameter and about 40 metres deep.

Panoramic picture of the Low-level (on the left) and intermediate level (on the right) wast repository.

Panoramic picture of the low-level (on the right) and intermediate level (on the left) waste repository. (Picture from Simon Jerome). Click for larger version.

Above ground, waste is packed into concrete crates about 2 m x 2 m which are then driven along the ‘road to nowhere’ aka the repository. And then lowered by crane into the silo where they are carefully stacked.

Waste is packed into these concrete containers and lowered into the silo

Waste is packed into these concrete containers and lowered into the silo

We weren't allowed to peek into the silos, so this my photograph of a stock photograph of the silo showing the stacks of waste.

We weren’t allowed to peek into the silos, so this my photograph of a stock photograph of the silo showing the stacks of waste.

Most of this waste is ‘operating waste’ from the two existing nuclear reactors on site: typically single-use garments used by maintenance workers and operators, and ion-exchange resin used in maintaining water purity.

The current plan calls for three similar silos to be built to accommodate the decommissioned remains of the two existing reactors at the end of their lives.

Onkalo

By the time that Olkiluoto 1 and 2 reactors are being decommissioned, the Onkalo deep repository will be ready to take all the high-level waste that the reactors have produced over their lifetime.

The fuel rods from the reactors will be removed and placed in water storage for about 10 years – a backlog of fuel awaits the availability of the repository. Bundles of fuel rods are then placed inside a strong cast-iron frame and sealed inside a 4 metre long copper cylinder.

Fuel rod bundles (one visible) are placed in a cast Iron frame (right) chosen for its strength. This is then plced inside a copper cylinder chosen for its corrosion properties.

Fuel rod bundles (one visible) are placed in a cast iron frame (right) which is then placed inside a copper cylinder. Cast iron is chosen for its strength and copper is chosen for its corrosion properties.

Significantly, no attempt is made to reprocess to the fuel. This is somewhat wasteful since useful nuclear material remains unburnt in the fuel rods. But this choice dramatically simplifies the disposal.

Simulated gallery in Onkalo. The tops of several cylinders are visible. When the gallery is full, the space will be back-filled with clay and sealed with a concrete plug.

Simulated gallery in Onkalo. The top of one cylinder is visible and locations of its neighbours can be seen in the distance. When the gallery is full, it will be back-filled with clay and sealed with a concrete plug.

Comparison with the UK

The contrast between the rational Finnish approach and the UK’s ‘let’s put this off and make it someone else’s problem’ approach could not be greater.

Admittedly, Finland’s ‘back yard’ is bigger than the UK’s: they have one tenth our population and twice our land area. And additionally they require a much smaller repository than the UK will require.

However, Finland has begun preparing for disposal of waste before their first generation of reactors have reached the end of their life.

In contrast the UK has been generating about 20% of our electricity from nuclear power for around 50 years, so we have benefited profoundly from nuclear power. Our first generation reactors are now being decommissioned and we have lots of spent fuel and other types of radioactive waste.

But despite spending hundreds of millions of pounds planning, in practical terms, we have done absolutely nothing about safely disposing of nuclear waste – including high level waste.

Some is stored in warehouses, but shamefully a great deal is stored in filthy outdoor pools.

Outdoor storage of nuclear waste at Sellafield

Outdoor storage of nuclear waste at Sellafield.

My visit filled me with a sense of national shame. But overall I feel pleased to have seen this site with my own eyes. Finland has shown the world that safe disposal of nuclear waste is possible, and not at an extravagant cost.

And if they can do it, then why can’t we?

 

Ready for final disposal

Ready for final disposal

The coolest sandpit in the world.

November 17, 2014

At the end of October 2014 I visited the British Geological Survey, (BGS) in Keyworth, near Nottingham.

I was attending a meeting about ‘geological repositories for either nuclear waste or carbon dioxide.

In the foyer of the BGS  was an ‘interactive sandpit’ in which the height of the sand was monitored by a  Kinect sensor (as used with an X-box games console). From the sand height measurements a computer then calculated an appropriate ‘contour’ image to project onto the sand.

The overall effect was magical and I could have played there for much longer than felt appropriate.

http://www.georepnet.org/

Schematic diagram of the ‘interactive sand pit’. A Kinect sensor determines the sand hight and a computer then calculates an appropriate image to project onto the sand.

The meeting itself was fascinating with a variety of contributors who had completely different perspectives on the challenges.

However what is holding back the construction of a UK repository for nuclear waste is nothing to do with the scientific or engineering challenges: it is a failure of political leadership.

The UK has been a pioneer of nuclear power, the technology through which  we reap the benefits of nuclear power.

But we have been a laggard at cleaning up the radioactive waste generated by the nuclear industry. In this field Sweden and Finland have led the way.

Admittedly their repositories will be smaller than the UK’s, and so easier to construct: I have been informed that the UK’s repository will need to be ‘about the size of Carlisle‘. But it is all do-able.

And when the UK eventually builds a repository, its cost will be inflated by the need to ensure the safety of the repository for a million years. What?…did I just say … one million years? ‘Yes’ I did. And ‘Yes’, that’s bonkers.

This time-scale makes for a number of unique challenges. At the meeting I attended, scientists were confident of the safety for a time-span somewhere between 10,000 and 100,000 years. And frankly, for me that would be good enough.

The ridiculous specifications required to be guaranteed before construction can begin, contrast with the laissez faire attitude towards burning carbon and affecting Earth’s climate. Why do we not have a moratorium on emitting carbon until we can be sure it is safe?

For example one area of uncertainty is the potential significance of microbiological fauna within rocks deep below the Earth, something about which we know very little. Do we have to wait until we can understand the millions of as yet undiscovered microbes before we can proceed?

Of course the main uncertainty – which is ultimately unresolvable – arises from the extreme lengths of time under consideration. This leads to consideration of extremely unlikely scenarios

For example, the Swedish repository company SKB is carrying out extensive research on what will happen to the repository if there is another ice age, and the repository is covered by several kilometres of ice.

First of all, given the problem de jour of global warming, this is frankly unlikely. And secondly, if Sweden is covered by several kilometres of ice, then of course all the people in Sweden would already be dead! At that point the safety of the repository would be frankly a moot point.

You can learn about this research in three short but intensely dull videos here.

Wind versus Nuclear: The real story in pictures

November 3, 2014
Graph showing the electricity generated by nuclear and wind power (in gigawatts) every 5 minutes for the months of September and October 2014. The grey area shows the period when wind power exceeded nuclear power.

Graph showing the electricity generated by nuclear and wind power (in gigawatts) every 5 minutes for the months of September and October 2014. The grey area shows the period when wind power exceeded nuclear power. (Click Graph to enlarge)

For a few days in October 2014,  wind energy consistently generated more electricity in the UK than nuclear power. Wow!

You may have become aware of this through several news outlets. The event was reported on the BBC, but curiously the Daily Mail seems not to have noticed .

Alternatively, you may like me, have been watching live on Gridwatch – a web site that finally makes the data on electricity generation easily accessible.

I was curious about the context of this achievement and so I downloaded the historically archived data on electricity generation derived from coal, gas, nuclear and wind generation in the UK for the last three years. (Download Page)

And graphing the data tells a powerful story of the potential of wind generation – but also of the engineering challenges involved in integrating wind power into a controllable generating system.

The challenges arise from the fluctuations in wind power which are very significant. The first challenge is in the (un)predictability of the fluctuations, and the second challenge is coping with them – whether or not they have been predicted. Both these challenges will grow more difficult as the fraction of wind energy used by the grid increases over the next decade.

As an example, consider in detail an event earlier in October shown in the graph at the top of the page

Graph showing the electricity generated by nuclear and wind power (in gigawatts) every 5 minutes for the months of September and October 2014. The grey area shows the period when wind power exceeded nuclear power.

Detail from the graph at the top of the page showing how earlier in October, wind power went from an impressive 6 GW to less than 1 GW in a period of around 18 hours . (Click Graph to enlarge)

The grid operators have a wind forecast running 6 to 24 hours ahead and would have planned for this. The forecasts are typically accurate to about 5% and so at the high end that amounts to a margin of error of 0.3 GW – which is within the reserves that the grid can cope with routinely.

However the fluctuations in wind power are becoming larger as the amount of wind power increases. The graph below shows the monthly averages of electricity produced by Wind and Nuclear since May 2011. Also shown in pink and light blue are the data (more than 300,000 of them!) taken every 5 minutes.

Monthly averages of electricity produced by Wind and Nuclear since May 2011. Also shown in grey are the data (more than 300,000 of them!) taken every 5 minutes. It is clear that the fluctuations in wind power are large - and getting ever larger. (Click Graph to enlarge)

Monthly averages of electricity produced by Wind and Nuclear since May 2011. Also shown in pink and light blue are the data (more than 300,000 of them!) taken every 5 minutes. It is clear that the fluctuations in wind power are large – and getting ever larger. (Click Graph to enlarge)

Incorporating wind energy is a real engineering challenge which costs real money to solve. Nonetheless, as explained in this excellent  Royal Academy of Engineering report, we expect capacity to double to ~20 GW by 2020, and to at least double again by 2030. So these problems do need to be solved

Because wind-generated electricity supply does not respond to electricity demand, as the contribution of wind energy grows we will reach two significant thresholds.

  • When demand is high, unanticipated reductions in wind-generated supply could exceed the margins within which the grid operates.
  • When demand is low, unanticipated increases in wind-generated supply could exceed the base supply from nuclear power which cannot be easily switched off

These challenges will require both economic and engineering adaptations. At the moment, because the marginal cost of wind power is so low, we basically use all the wind power that is available.

However, it is possible to ‘trim’ wind turbines so that they do not produce their maximum output. In a future system with 40 GW of wind generating capacity, we might value predictability  and controllability over sheer capacity. Then as the wind falls, the turbines could adjust to try to keep output constant.

These challenges lie ahead and are difficult but entirely solvable. And their solution will be essential if we really want to phase out fossil fuels by 2100.

But for the moment wind is providing on average about 2 GW of electrical power, which is around 6% of UK average demand. This is a real achievement and as a country we should be proud of it.

Perhaps someone should tell the Daily Mail.


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