Renewables, Drax and Myth Busting No 1

It appears Drax wish to bust some myths about renewable energy (see HERE) They are tweeting about them one by one. So I thought I'd have a go too and dig under the headlines at least for the first so-called "myth" they wish to bust: Here it is.

The First "Myth" they want to bust is...

"Myth 1 — Renewables are unpredictable"

[quote]
There’s more to renewables than solar panels and wind turbines. Tidal power is much more predictable than either, and geothermal power — using heat from the Earth’s core to generate electricity — is almost completely reliable.
As for predictability, sustainable biomass uses compressed wood pellets to generate electricity whenever it is needed. It’s completely predictable. You can use it to produce electricity on demand, to control frequency in a split-second or for baseload power. It’s as reliable as coal or gas, but with a fraction of the carbon emissions.
[unquote]

Yes it is true! There is more to renewables than wind and solar (both of which are hopelessly intermittent)

It is also true tidal power is more predictable and geothermal is reliable too! And that Biomass can provide baseload.  But we still have some problems here. So let us look at these predictable and reliable examples of RE goodness.

Tidal

Sadly in the UK we have barely any tidal power at all. That is because in most places tidal power is simply unfeasible. Consequently little is planned and even this is horrendously expensive and arguably technically dubious.

To cap it all the maximum that could be generated by tidal is 12% of demand. But anyone who believes we could get anywhere near 12% is really living in the world of Tooth Fairies and Easter Bunnies. (h/t to  Dr Jim Hansen HERE)

But lets look at what Tidal there is and what is planned/proposed

MayGen

In Scotland there is a tidal stream scheme (MayGen - HERE). Currently it has a maximum capacity of 6MW ( similar output to that from a single locomotive engine) But the dream is to expand this to is a maximum capacity of 398MW. Either way its capacity factor will be around 20%. (So averaged output power will be about 1.2MW/80MW)

There is a big incentive to build the dream. Tidal Stream generation is the only type of generation that makes offshore wind look cheap.

MayGen will be paid no less than 5 ROCs subsidy (or £225) per MWh. This means that typically they will be paid £260 per MWh whereas normal generators (gas/nuclear) get paid about £43 per MWh.

To be fair MayGen is verging on experimental. It is the very tip of the state of the art.

We know Tidal Stream power may be predictable. But is it viable? Or affordable? I'll leave you to decide.

But one thing is certain: It ain't going to be the golden bullet to save intermittent RE anytime soon.

Swansea bay Tidal Lagoon

Then there is the proposed Swansea Tidal lagoon. This will have a (very, very) brief maximum output of 320MW. But its capacity factor will be less than 20%. Averaged over a year its output power will equate to approximately 60MW. The estimated cost of building this thing is £1.3 Billion (Ouch!).

That is about the same cost as building a 1.2GW (i.e. 20x the output) CCGT gas plant.

Compared to the Scottish tidal stream scheme though, the Swansea lagoon will be cheap with only 1.8 ROCs subsidy per MWh. It will be only 3 times the cost of normal generators.

Again. Predictable it may be. Affordable? Viable? Or even environmentally benign? You decide.

(Euan Mearns did a wonderfully complete analysis of the Swansea Tidal Lagoon  HERE.)

Geothermal

Just like Tidal power, in the UK we have little to no geothermal power generation.

In fact the UK is geologically a bad place for geothermal energy. True - we can tap shallow underground heat for heat pumps and space heating but electricity generation? Really?

As far as I can tell the prospect for any significant geothermal power generation in the UK is Nil.

End of.

Biomass

Then we come to the meat and potatoes of the Drax myth busting. Their glorious Biomass.

Happily I have to say that just about everything they say is true. I (sort of) believe them in their sustainablity claims as well. But there are problems.

But first - a pedantic point:
---------------------------------
[quote]
.....It’s as reliable as coal or gas, but with a fraction of the carbon emissions.
[unquote]

DON'T BE SILLY! Of course burning biomass emits Carbon Dioxide and MWh for MWh virtually the same as coal!! The fact that you offset that by replanting does not mean that magically no Carbon Dioxide or pollutants get emitted when you burn wood pellets! You could equally offset coal by planting trees - you just can't use the same space.
----------------------------------------

But back to what I see as a major problem with biomass.

Bear in mind to simply maintain the current Drax 2GW generation in a sustainable manner will require an immense 12000 sq Km of forest. (Wikipedia HERE)

How much more biomass can we (morally or practically) import from abroad?

I don't know.

But I would suspect that we are already at the limits of sustainably maintaining a supply of wood to the existing Drax wood burning plant.

So there you go. If you want non-intermittent RE in the UK, in reality you've got Biomass.

But how much more Biomass can we build before we start seriously damaging the environment?

Anyone who knows the answer to that one please tell me.

I'd love to know.

Energy Storage: The Trouble with Power to Gas

There is a fundamental law of Physics called the Law of Conservation of Energy.

It's a real bitch.

Basically it demands that whatever the system you use, you can never get more energy out of it than you put in. So many beautiful dreams have come to naught - just because of this one damn law.

Even so there should be an adjunct to the law of conservation of energy. Something more like a serious health warning really.

Something like:

"Whenever you change from one form of energy to another - you will get screwed."

And I mean really screwed.

If on your last foreign holiday you thought changing currency was robbery then believe me, that was as nothing compared to the losses when changing energy form.

Truly, energy can neither be created or destroyed. But Oh Boy can it get "mislaid" dispersed or changed into unwanted useless forms whenever you try to convert one form into another.

You always (and I mean ALWAYS) end up with less than you started with. Mostly you end up with significantly less.

How good a system is at converting energy is its energy efficiency. It can never-ever be more than 100%.

90% is mind bogglingly good.

An old 19th century steam engine by comparison is about 10% efficient - on a good day.

By burning fossil fuels and liberating their stored chemical energy as heat and then changing that heat (from burning coal or gas) into electricity - you will lose about 50% of the energy as waste heat up the chimney. Still, we do it because electricity is far more useful to us than a lump of coal or a pocket of trapped gas.

Now, what would be the best way to store the energy in (say) gas for a rainy day?

Would it be by just not burning it until needed? Or would be by converting it to electriciy (50% loss) and then post generation converting it back to something else? (say another 50% loss)

I hope it is obvious that by doing a "gas->electricity->something else" you will get royally screwed. In this example you would end up with 25% of what you started with.

You are far, far better off not burning the gas until needed.

Wind turbines and solar PV do not have the luxury of having their energy pre-stored like coal, gas or nuclear. If there is excess generation by wind or solar they either waste the available energy by not converting it or they have to convert it to electricity and then convert it again to some other storeable energy form.

So, with wind (or solar) you have no option but to bear the pain and go with:

"wind->electricity->something else".

One of the much hyped "something elses" for wind/solar is called Power to Gas (Wikipedia article Here).

Twitter is alive with excited windies who see Power to Gas as the the "Great Breakthough" - The mythical silver bullet that will slay the demon problem of energy storage for wind/solar.

To be fair, Power to Gas is technically clever. It takes any excess electricity from wind/solar and via some clever chemistry uses it to generate flammable gas - either hydrogen or methane. This can then be stored and used at some later date either for heat or electricity generation..

The trouble with Power to Gas is is not the cleverness of the technology. The trouble is that damn law of physics about energy conservation. Especially the health warning attached to it.

Turning electricity to potential chemical energy (gas) is at best 75% efficient but more realistically it is around 60%. Then turning that gas back to electricity again reduces the overall efficiency to around 40% at best or more realistically about 30%. In other words we lose about two thirds of the energy - Of course the missing 2/3rds is not destroyed. It is simply just dissipated and lost to the system.

Remember this proposed technique is there to bale-out an already massively subsidized generator. Even if you totally ignore the actual cost of plant and plant operation the price of the re-generated electricity would have to be three times that of the source price just to stay level.

In reality though the price of Power to Gas has been estimated at anything from £500-1000 MWh. Or from 10 to 20 times as expensive as current gas/coal/nuclear generation.

A whole order of magnitude more expensive. Breathtaking!

Power to Gas is a nice idea. It may even have some practical niche applications. But storing excess energy from wind and solar? Dream on.

And all because of that damn law about the Conservation of Energy.

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)

Prof David MacKay on the Laws of Physics

Prof David Mackay FRS is Regius Professor of Engineering in the Department of Engineering at the University of Cambridge and chief scientific adviser to the UK Department of Energy and Climate Change.

He is also the author of  the famous (and free) "Sustainable Energy (Without the Hot Air)" . The whole book (12Megs) is available HERE

But he has also recorded a number of lectures on the viability and practicality of renewables, particularly he has focussed on the land areas needed to meet specific goals. These are goals that meet specific energy requirements. Here he is talking about systems that are other than window dressing or merely fashion statement technology.

My favourite quote is:- "I'm not anti renewables but I am pro arithmetic"

The recording is 18 minutes but is well worth a watch (unless you are a green dreamer that is)

How Wind Turbines Increase Global Warming

Below, using some peer reviewed data I hope to show you why an Industrial Wind Turbine, replacing coal plant, will actually increase Global Warming for well beyond the lifespan of the Industrial Wind Turbine itself.

First of all, just to be nice, we are going to assume that some highly dubious pro-wind propaganda is true.

We will assume a turbine has a productive life of 25 years.
We will assume that it directly offsets coal plant on a one-for one basis.
We will assume it needs no spinning reserve at all.
We will totally forget about the concrete/Neodymium mining/ steel/fibreglass/copper etc.
We will ignore the methane ( a strong greenhouse gas) that gets released from disturbed peat bogs where IWT's are sometimes placed.

Most of all we will completely forget about the environmental damage to wildlife. We will also totally ignore those pesky Human Beings who think they have a right to have a say about what gets built near them (Nimbys - damn them all!)

For those of you who are either falling about laughing or about to burst a blood vessel at this point, please bear with me and read on.

At this point we need to bring in the current ruckous over shale gas.

The data here I use here is taken from this paper: Coal To Gas: The Influence of Methane Leakage by Tom L. Wigley of the (U.S.A) National Center for Atmospheric research.

The main thrust of Wigleys research was to study what effect different rates of Methane loss (rogue methane) would have on a coal to gas conversion. His initial paper dealt with only a 50% coal replacement over 50  year period with a linear rate of replacement. The electronic suppliment dealt with a much more drastic changeover where coal was totally replaced by gas in 50 years.

The surprising outcome from this research is that in the first 40 -60 years or so, as gas replaces coal the main driver of global warming is the reduction in Aerosols emmitted from coal plant. A primary constituent of coal Aerosols is Sulphur Dioxide which is a very potent anti-greenhouse gas. So the removal of the aerosols actually increases global warming. It is only after about 60 years before the reduction in Carbon Dioxide overwhelms this warming.

The best graph to illustrate the problem is actually in the electronic supplement to this paper (see graph ESM2) This graph assumes total replacement of coal with gas over 50 years.

This is the graph (the top half refers only to proposed global temperature increase and is irrelevent here)

Notice with Natural Gas there are three issues surrounding it's affect on Global warming:

1. Carbon Dioxide (CO2) reduction by displacing coal (causes reduction)
2. Seepage of Methane (CH4) from either pipes or wells. (causes increase)
3. Reduction of Aerosols (mainly Sulphur Dioxide SO2) by replacing coal. (causes increase)

You can see this clearly on the left hand portion of the above graph. While this graph includes rogue methane from natural gas, clearly, even when you take the methane out of the picture the net affect  on progressively replacing Coal plant for any non sulphurous generating plant for the first 40-60 years will be an increase in Global Warming.

Let us replace the Gas for Industrial Wind Turbines.

(We will ignore IWT peat bog methane release - although we shouldn't)

Over the 25 year life time of our idealised super Industrial Wind Turbine, these will be no reduction in Global Warming from a decrease in Carbon Dioxide generation at all. But over the same period, the reduction in Sulphur Dioxide emissions from the replaced coal plant will cause a much higher and significant rise on Global Warming.

This is true for Gas, Nuclear, Hydro, Wind and Solar. Anything, that in a rolling program reduces Sulphur Dioxide emissions will cause more Global Warming (not less) in the first 40-60 years after coal replacement starts.

A Gas plant will last 40+ years. Nuclear 60+ years, Hydro 100+ years. Plus all the three will give a consistent and reliable output without requiring any form of backup.

Even assuming the cloud cuckoo land concept of an IWT having a lifespan of 25 years, it will need to be replaced at least twice before any productive gains from Carbon Dioxide reduction will be made. The same applies to Solar.

But worse than that, the IWT's will always need backup from Gas anyway. It is very easy to visualise that even if a madcap scheme involving the building of hundreds of thousands of our idealised turbines took place, there would be no decrease in global warming at all this century. But there would be an increase in at least the first 40-60 years..

This all assumes the lies wishful thinking of the wind turbine industry are true. In my own opinion, the most likely outcome is that Industrial Wind Turbines will have no impact positive or negative on global warming at all, simply because they are so damn ineffective.

Of course, removing Sulphur Dioxide is actually a very good thing. Even if it causes a temporary rise in Global Warming. Today hundreds of thousands of people die from coal based aerosols and the sooner they are removed the better.

But really, do we need to try and do it with half baked, wildly expensive and short lived plant like IWT's? Just about anything Gas, Hydro or Nuclear is more effective. The only technology that may be even more ineffective than IWT's is solar.

The end result of this, even if you believe the Wind Industry, is that Industrial Wind Turbines are NOT going to help prevent global warming within their 25 year life span. Or during the life span of the replacement or even the replacement after that. In fact assuming they actually do replace coal plant they will increase global warming for the next two generations at least.

Note: A less valid version of this argument is currently being used by the Greens against fracking. Their argument is less valid because gas is reliable, dispatchable and requires no backup other than standard fail-safe spinning reserve. It is also plentiful, is useable in transport as well as power generation and can be stored. It is also vital as a backup for the useless wind turbines even though it already cuts CO2 emissions by 60% from coal by itself. 

But it appears that the Greens now think Sulphur Dioxide is "A Good Thing". (God help us all)