The Trouble with Energy Storage

Energy Storage - The Holy Grail for intermittent electrical generators.

Reading the tweets and articles from the wind and solar industries (and their avid followers) you could be forgiven for thinking that large scale energy storage was a done deal. Something that just needed the bureaucrats in Westminster or Berlin or Washington to rubber stamp.

Sadly though, large scale wind/solar energy storage is not only not a done deal it is not even on the horizon. Even if it was it would still be very far from being a “solution” to intermittent and dilute electrical generation. But more on why that is in a later post.

First of all lets be clear about what I mean by energy storage.

In a way, all current thermal generation and hydro depend on “energy storage” The difference between energy storage at (say) a coal plant and a wind farm is that the coal plant stores its energy pre-generation (i.e. as raw fuel) whereas a wind turbine has to convert its energy into a non-electrical form after excessive generation in order to store it. So the wind turbine has to convert its excess energy into some form of fuel to be stored for later use. The coal plant simply does not use the fuel until it is needed.

(by the way I am using coal plant here because it is a good comparator – not because I am a fan of coal generation – I prefer nuclear)

Typically the front runners for renewable energy post generation fuel storage revolve around two technologies:

1. Pumped hydro (pumping water up hill into a reservoir)
2. Or as is the fashion - in some form of Battery.

Pumped Hydro.

Pumped hydro is an old and proven technology. It existed a long time before the current wind/solar obsessions. Originally pumped storage facilities ( like Dinorwig in Wales) were built to store energy when the price was low (typically at night) and then sell that stored energy at peak demand (when prices were high). Using this model, pumped hydro works very well. It is a profitable and very worthwhile addition to the Grid.

But things change when you try and use it to store excess solar and wind energy. You essentially break the pumped hydro economic model, especially with solar PV. (See Speigel Online article here )

You have to buy in energy when prices and demand is high while sacrificing your profitable market as well. Then you then have to sell on when prices and demand is low.

It does not work. Even if you created some subsidy regime to support this broken model, the number of potential pumped hydro sites are very limited anyway.

But at least, individual pumped hydro sites can store relatively large quantities of electricity.

Although UK pumped hydro could not deliver the energy quickly enough to actually take over the whole UK grid, they do hold enough energy to power the entire UK grid for about 1 hour. 

While that may not sound much, it is overwhelmingly better than any form of battery storage.

When we get to battery style storage the practicality and price viability of large scale energy storage falls off a very high cliff.

Batteries

The biggest battery in Europe is in Leighton Buzzard in the UK. It can store 10MWh of electricity. It could (say) store half the output from a single small 10MW wind farm running at maximum output for two hours. It cost £20 Million. An average UK demand is around 30GWh. So this single battery would power the entire UK grid for about 1.2 seconds.

OK, you may say – let us distribute/duplicate it and use a cheaper technology After all why not have a cheaper 10MWh battery for every (say) 5 wind turbines? You know - Spread it out a bit.

Lets look at the (arguably) most viable and cost effective large scale battery technology available today – Vanadium Redox flow batteries.

(Incidentally - this is VERY clever technology and has many potential applications – I am not knocking the technology – only the application) .

Flow batteries store the energy in the electrolyte. The consequence of this is that theoretically the only limitation to the their storage capacity is the amount of electrolyte you can to store. 

Currently Vanadium Redox batteries store about 20 Wh per litre of electrolyte. So for 10MWh you need to store around 500,000 litres of highly corrosive Sulphuric Acid based electrolyte.

Lets say technical innovation decreases that by a factor of 10. You would still need to pump/store/process 50,000 litres or nearly 100 tonnes of electrolyte. 

That is for 10 MWh. Or 1.2 seconds of nationwide supply.

So, why not just store more electrolyte? Simple eh?

But remember, this stuff is lethal. It is massively corrosive and is a liquid. Then remember this is one SMALL wind farm.

Multiply that by thousands of wind farms. Then avoid killing anyone or regularly risking massive environmental pollution. That really is a challenge!

Of course there are other technologies (Lithium-ion being the other main and more expensive player) but whatever you look at, the problems of large scale energy storage are immense. They are effectively intractable.

Remember, what I have discussed above is the LATEST and most promising technologies. On Twitter people often eulogize about lead-acid batteries or compressed air, but really their capabilities are far below pumped hydro or flow batteries.

But Tom Murphy on his appropriately named blog Do The Math has done a very good analysis of a theoretical (USA) National Lead Acid Battery and its practicalities On this Link

A very interesting post on the EROEI (Energy Returned On Energy Invested) on  storage with RE has been written by John Morgan  On This Link

Large scale post generation energy storage is not viable.

Bit even worse – not only is it not viable, it is also potentially very, very (and appallingly) dangerous.

But more on that in another post.

(Here I am not considering issues with charge/discharge rates, resource availability or lifetime cycle expectancy – they all just make things worse)

New Nuclear Sites Confirmed

The government has confirmed the sites for eight new nuclear reactors.

And about time too. See Fuels & Power article Here

All the political dithering and posturing over the last ten years (yes ten) has seriously compromised our ability to produce the base load electricity we will so desperately need now.

All over the country old and obsolete plant is being forced into ever longer service because there is nothing to replace it.

Inevitably old plant is less safe than new plant. For exactly the same reasons that a new Ford Mondeo is massively safer than a 1960's Ford Prefect.

But because of the political dithering and toadying to narrow minded environmental bigotry, we now can ill afford to close any of the old plant whether it is coal, gas, oil or nuclear.

Inefficient as it may be, the 50-60 year old plant has to soldier on.

Why can we not close it down anyway?

Because without it, the country's electricity supply simply could not cope.

If ten years ago we had embarked on a steady and measured programme of renewing our nuclear stock and replacing old coal plants with Generation IV nuclear plant, today we would perhaps (like the French) have the lowest electricity prices in Europe, and also the lowest electricity generation CO2 emissions.

Along with that we would have no dirty coal plant and our dependancy on foreign gas would be diminished. As we currently have "in stock" about 60 - 80 years worth of nuclear fuel just sitting on the shelf, we would also be self sufficient in energy.

But it is no use crying over spilt milk.

What we need to do now is to get those in high office to understand the need for much more new Generation IV nuclear plant. France has 58 nuclear reactors with another 3 in various stages of build.

The French have shown that Nuclear works and is highly cost effective. Their huge success lays bare the lies and propaganda about "subsidised nuclear".

If nuclear is so "subsidised" how come the French (80 % nuclear) have the cheapest electricity in Europe?

How come in windmill ridden  Denmark electricity bills are among the highest?

We don't just need eight new Generation IV reactors, we need to start with at least twice that number.

But that is just a start.

I suppose a confirmation about eight new reactors is better than yet more dithering.

But it is still a long way from what we really need.

The April Wind Farm Robbery

On the 6th-7th April, over a period of a few hours we were all collectively held to ransom and robbed of nearly £1 million.

I expect that nobody told you of this crime. Believe me, there are a lot of people who want it to be kept quiet.

I know I tend to drone on about how hopeless wind turbines are, but this is not simply about the "normal" over-payment.

This is about legalised extortion.

Over a few hours on the night 5-6th April you paid approximately £1 million to a group of windfarms simply to get them to stop generating.

Under normal circumstances, wind farms get paid a stupendously generous £55 per MW/hr when they actually manage to produce power. Normal generators get about half that.

But on 5-6th April they were asked to stop generating, though they would get paid for the lost production. One wind generator demanded (and was paid) £800 per MW/hr simply to put the breaks on and stop generating.

This extortion was, of course, legal. An ordered theft. As is always the case when the common folk get screwed over by rich exploitative bastards who can manipulate the system.

Here is the list of shame.

All of these wind farms demanded payment many times what they would normally get paid simply to shut down generation. They demanded it in full knowledge that the Grid had no option except to pay because they could not close down any more traditional generation.

Why couldn't they shut down other generation?. Because it needed to stay on line in case the wind stopped blowing. They had to keep reliable generation on line. It would have been dangerous to do otherwise.

So how and what exactly happened?

On the 6th of April the wind began to blow unexpectantly. It began to blow in the night. As it was in the night, nobody wanted the electricity. But legally, the grid has to absorb the energy from wind turbines whenever they produce power. So on April 6th the National Grid had to absorb the power whether it was needed or not.

Normally any other form of power generation has to book slots where it guarantees to produce a certain amount of power. If it fails to produce that power, then an auction takes place where others step in the make up the short fall - at a price. The defaulting generator has to pay.

On the other hand, if more power is being generated than is needed, a generator can be paid to shut down or reduce output. This is also decided at an auction where the lowest bid wins. Most generators actually bid less than their typical charge per MW/hr as they save on fuel and wear and tear on the plant.

But wind power is different. Due to their intermittency, they simply could not compete in a true market so they do not have to book slots. They are allowed to sell power whenever they are in a position to produce. If the wind fails to turn up, they get out penalty free. But if the wind turns up when nobody needs the power, then somebody else has to shut down.

Because wind power is so unreliable, the grid has to be able to provide backup (or spinning reserve) at a moments notice, just in case the wind stops blowing. On the 6-7th April, the grid was suddenly inundated with wind generated energy. At that time they were also coping with a sudden increase of power from hydroelectricity due to a sudden heavy rain fall. The Scottish grid had wound down the traditional power plants to an a safe minimum. They could not safely reduce traditional power generation any more, because they always have to be able to guarantee supply.

But somebody had to shut down or the grid frequency would dangerously rise. Some of the wind farms, which had caused the crisis, were asked to reduce power. Consequently they were asked for bids in a power reduction  auction. They knew that nobody else could shut down. Greedily, their bids ranged from 180 -1000 per MW/hr.

Remember, the bids in the above table are the winning bids. They were the lowest. Others were even higher.

Essentially these bastards, having caused the problem then set about extracting as much money as they possibly could from the people trying to rectify the situation.

Because of the wind turbine carpet baggers privileged position, you can guarantee this will happen again and again and again. Each time the grid will be held to ransom. At the end of the day it is you who will pay. The more wind generation that gets put on the grid, the more this will happen.

Get used to being screwed.

The carpet baggers will be back for more.

The full story is HERE on the Renewable Energy Foundation.
How the ROC subsidy works is explained HERE