Burning Wood

Prenergy's proposed wood burning power station at Port Talbot is in the news again. It was originally approved by the UK government in November 2007. Then last September it was granted a licence by the Environment Agency Wales, on the condition that it operated within strict emission limits. But the EAW has changed that decision and is now saying that it is "minded to approve" new limits which are very much less stringent than in the original licence.


The changes proposed are:

•  Increasing emission limit for nitrous oxide (N2O) from 20mg/m3 to 40mg/m3
•  Increasing emission limit for sulphur dioxide (SO2) from 6mg/m3 to 50mg/m3
•  Increasing emission limit for hydrogen chloride (HCl) from 7mg/m3 to 10mg/m3
•  Allowing the burning of wood pellets as well as wood chip

Now we might well argue about at what point any level of emissions is damaging to health, but one thing is clear: EAW should not have imposed the original operating conditions unless they considered them to be the maximum emissions permissible without causing levels of pollution that could damage public health.

So this u-turn by EAW should be a source of great concern. If, as they now claim, the relaxed harmful emission limits will not compromise air quality standards it means that their original decision was arbitrary rather than based on any scientific evidence. After all, we are not talking about small changes. In the case of sulphur dioxide, they are now prepared to see the emissions increase more than eight times. It must surely be obvious that the EAW have been put under pressure to change their original decision, and that they have given way to that pressure.

The Practical and the Political

Now why would this be? There are two reasons: one practical and one political. The practical reason is that it is proving very hard to get high quality fuel that would burn with such low emissions. That sort of wood does exist, but the problems is the scale of the operation. This would be the largest wood-burning power station anywhere in the world, consuming three million tonnes of wood each year. Raising the level of emissions enables Prenergy to use cheaper wood.

My belief is that Prenergy have convinced the EAW that they are unable to get hold of the amount of high quality wood on which the original calculations had been based, and that the relaxed emissions standards are tailored to wood that can be sourced at a cheaper price. The thinking must be that rather than maintain limits that would mean it was impossible to operate the plant, it is better to relax the limits to the point where it is commercially feasible to operate it.

But why should there be such an imperative for the plant to operate at all? The reason for this is entirely political.

Both the UK and Welsh governments have set themselves targets for the production of electricity from renewable sources and are therefore anxious to do whatever it takes to meet those targets. A large 350MW power station of this sort would, on paper at least, go a long way towards it. But the sums didn't quite work out. That is why the new UK government provided an additional large financial incentive for biomass in August last year, by guaranteeing that Renewable Obligation Certificate levels would be fixed for 20 years rather than being subject to reviews every four years ... this longer lifespan being referred to as "grandfathering". Prenergy's owners, the Italian private equity firm Clessidra, welcomed this change because they have been trying to sell the project on for the past year, and were having considerable difficulty finding a buyer for it.


But for me, the political initiatives to promote this sort of energy are fundamentally misconceived. Energy produced from burning wood can at best only be described as semi-renewable. The theory is simple enough. If the wood cut down and used as fuel is replaced by new trees, then those new trees will absorb as much CO2 as the wood that has been burned. The first problem is that it takes 15 or 25 years, perhaps more, before the carbon balance gets back to zero. The second problem is that cutting down and transporting the trees, converting them to chips or pellets, and then transporting them half way round the world to be burned in Port Talbot also consumes fuel; and therefore contributes additional CO2 to the atmosphere. Even so, there is still a net benefit, but it up to half of it could be lost. EAW say that greenhouse gas emissions will only be 50-80% less than those of a coal or gas power station.

So at best the process can only by described as semi-renewable, yet we see both the UK and Welsh governments treat this way of producing electricity as if it were fully renewable. It's a con. It is being promoted, given financial incentives, and allowed relaxations on strict emissions standards simply in order for both Welsh and UK governments to be able to say they are meeting their targets for fully renewable energy.

More than we need

Although it could be argued that the UK as a whole might need the additional energy that would be produced by a new power station at Port Talbot, Wales certainly doesn't need it. We already produce far more electricity in Wales than we need, as well as having the potential to produce all our electricity from fully renewable sources without any harmful emissions at all.

So why are we in Wales producing electricity for export to England by burning a dirty fuel brought half way across the world? From the point of view of the planet, why isn't the wood being burned in North America or China where it will be grown? That would save the economic and carbon cost of transporting it. From the point of view of electricity generation on this island, why isn't the plant being built at a port in say the Thames estuary, close to where the electricity will be consumed? That would save transmission losses in the grid.

We have until 11 February to respond to EAW's proposal, and the details of how to do so are here.

As I researched this, I looked again at some excellent contributions to the debate which I'd recommend to anyone who wants more background information. One is by Duncan Higgitt in a comment to this post on Syniadau last June.

Then there are two articles by Bethan Jenkins, one on her website and another on Wales Home.

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Jac o' the North, said...

My guess would be that governments in both London and Cardiff are now realising that with wind power they've backed a loser, for it is unreliable and very expensive.

Ergo if we are to have green or renewable energy we have to go for other options. Nuclear is the obvious one but to keep the hippies happy then biomass and wave energy will become increasingly attractive.

MH said...

Very funny, Jac. Your so-called "loser" is consistently providing more renewable energy than any other source at present, and is set to provide much more in future with the new Round Three offshore windfarms. But of course we have to develop other renewable energy sources too, tidal in particular.

And I doubt that you'll find any hippies who are happy with large scale wood-burning using imported fuel. The old hippies I know tend to burn other things, on a somewhat smaller scale, to keep them happy ;-)

Unknown said...

The waste problem seems to have been somewhat ignored - 3 million tons of wood will produce an awful lot of ash, and it is classed as hazardous waste, and must be disposed accordingly - which means transporting it to Swindon, I believe, by road - add in g considerabl to traffic nuisance in Port Talbot.

I haven't been able to find out exactly what happens to it there, but it all adds to the energy input of this scheme. Is it all being accounted for when evaluating its green credentials?

Jac o' the North, said...

MH, wind turbines may indeed be producing more than other sources of renewable energy, but this is hardly surprising given the numbers of the damned things.

The problems are twofold; first, in the best conditions turbines never reach 30 per cent of their alleged capacity; second, in the freezing, still weather we had before Christmas they produced nothing, and people noticed they weren't turning. Time is running out for wind turbine subsidies.

As for hippies burning things, you're absolutely right.

In addition to what you alluded to there's more incense burnt in Corris on a weekend than in an Orthodox cathedral at Easter. Add to that the fact that hippies do love their wood-burning stoves and you have a massive pall of smoke over the Dyfi valley.

That don't show much concern for the environment.

MH said...

Siônnyn, I haven't been able to find out very much about Prenergy, particularly their proposed modus operandi. Do you have any links? If you have info in the form of pdfs which are no longer on the web (Prenergy's site isn't working) please send it to me by email and I'll put them up on the server I use.

Syniadau - snail - inbox - dot - com

MH said...

I accept that you don't like them, Jac, but don't let those thick clouds of smoke obsure the facts.

Like it or not, the amount of electricity produced by wind is going to increase dramatically in the next few years. Even when you take the capacity factor into account, the windfarms in the Irish Sea zone north of Ynys Môn [map here] will produce more electricity per year than Wylfa ever did.

Jac o' the North, said...

It's not a question of liking or disliking wind turbines, MH, it's a question of their efficacy and cost.

Look at it this way. Build a convential or nuclear power station and that's it, the cost of building that installation for power 24/7. Build wind turbines and - because of their unreliability - backup is needed in a ratio of 1:1.

Consequently, the more wind turbines we build the more backup is needed. Put it all together, construction, transportation, subsidies plus backup, and wind is the most expensive form of power generation known to man . . . and will always be unreliable.

Face it, MH, the honeymoon period is over. When people are shivering and they see wind turbines at a standstill they don't need me, or anyone else, to tell them the blindingly obvious.

That wind turbines have lasted for so long is due solely to their visibility, which makes them attractive to politicians wishing to appease the green lobby. But that visibility is also their Achilles heel.

Duncan Higgitt said...

Another excellent piece on this subject, MH. I'm not one usually given to conspiracy theories, but it's hard to escape the conclusion that this power station will be built, no matter how ill-planned it is, no matter how hard it will be to source its fuel, no matter how everybody across the Swansea Bay and its hinterland remains opposed to it, and no matter how many other hard questions about its classification as a renewable persist.

I was up in the Ogmore Valley last week, where there are plans to drill for coal bed methane. The local community group there told us that there is a growing belief among people in post-industrial areas that their role is to be there to be dumped on. There are few jobs or other attractions, so they think large corporations with still-to-be-fully-tested technologies can use them as guinea pigs. I've heard the same thing in Aberafan, over and over again.

The EAW is gutless and worse-than-useless on this issue, particularly as it hides behind its own invented terminology as a means of explaining why it rolls over time and time again. But no amount of linguistic finery can disguise the lack of forethought gone into this development, nor the number of times the developers have to keep going back with changes. Let us hope that, if it really is to be built, investors will continue to avoid it while all the rectifications are made - because the EAW seems determined not to make stipulations.

And it doesn't help that we have an environment minister who is never anything less than dogmatic in her support for so-called renewables - not that she will have anything to do with this scheme because, as we all know, Wales is not responsible enough to decide on 50mw and over power projects.

I'd like to join you in urging people to submit their comments. Let's hope it makes a difference this time.

MH said...

Up until now, I was wondering whether you were just saying things to be humorous, Jac. But you seem determined to stretch the joke too far.

You say, "Build a conventional or nuclear power station and that's it". It isn't.

What about the small matter of the fuel: the economic cost of it, the environmental cost of it and the cost of getting rid of (or not being able to get rid of) the waste? What about the small matter of decommissioning costs, which for nuclear are far higher than the cost of building or running the station?

Far offshore wind will have a capacity factor of about 40% and will produce electricity maybe 90% of the time; but when you say that other plants produce electricity 24/7 you seem to assume that their capacity factor is 100%. It isn't. Of course backup is needed, but you've singled out just one form of generation as requiring it. Backup is needed just as much for fossil, bio and nuclear fuel plants as it is for renewable energy.

MH said...

Thanks, Duncan.

Jac o' the North, said...

No form of generation other than wind needs 100 per cent backup.

MH said...

Is that just an assertion, or do you plan to justify it, Jac? Ask yourself this question: 100% of what? Of all wind turbines everywhere, or only of wind turbines in a certain area?

You're just looking at one thing in isolation rather than at the whole picture. Everything depends on the size of the grid we are connected to. As the grid gets bigger, the risk to the system posed by any particular power plant, windfarm or area of windfarms producing nothing is reduced. We are already part of a grid that includes the RUK, Ireland and continental Europe, and are planning more HVDC interconnectors particularly across the North Sea to Scandinavia. That's particularly useful because of their huge hydro resources.

Jac o' the North, said...

I am not an engineer but even I could understand this when it was explained to me.

In the past, with a mix of nuclear, gas and coal stations there would be a certain backup needed in case of a power station or two going down.

Wind is different because ALL wind turbines could be inactive at the same time. Every wind turbine in the UK could be still, for days on end, during very cold weather, and be producing nothing at times of highest demand. So there must be backup. What's more, such total inefficacy would not be tolerated from any other form of energy production - so why should we accept it from wind?

As for grids and connections you may have a point (and I don't know enough to debate it), but the biggest importation to this island is from France, and her reliable nuclear power stations.

France made the right choice. Now Germany and Denmark have realised their mistakes and are abandoning wind 'energy'. As will the UK sooner or later. One day even that lot down in Cardiff docks will realise they've backed a bummer.

Until then we all have to pay through the nose for the most unreliable form of electricity generation on earth just to please a few green charlatans and those they've conned or intimidated into backing them.

Let's arrange to return to this debate in five years time, because I know which way the wind is blowing.

MH said...

That's exactly the point, Jac. Even in the event that all the wind turbines in the UK are not turning, wind turbines in Ireland, Germany and Denmark probably would be. And if they weren't either, what's so wrong with using backup from other sources? That backup is not dedicated to a failure of wind, is it? The very same capacity is just as much a backup for the occasions when other power generators go off line. It's a matter of probabilities, but spreading the risk more widely reduces the overall need for additional capacity.

As for England's interconnexions with France, you seem to assume that only electricity from nuclear comes across. Electricity doesn't work that way. The electricity will have come from all the sources that fed into the grid ... including, dare I say, some from wind.

And from where do you get the idea that Denmark and Germany are abandoning wind energy? Or why put energy in quotes as if electricity from wind were in some way different? I'm prepared to bet a bottle of good whisky that in five years' time we will be producing more of our electricity from wind ... and pressing ahead with plans for more again. 30% will be about right. If you want to start saving, I'd like this, I normally buy the cheap version.

But please don't think I support wind energy at the expense of other renewable power generation. As I've said [for example, here] tidal power is what Wales now needs to concentrate on. If we've started building our first tidal lagoon in five years' time, I'll be so happy that I'll buy you a bottle.

Unknown said...

"Now Germany and Denmark have realised their mistakes and are abandoning wind 'energy'."


MH said...

Perhaps Jac got half the idea from this article in the Telegraph in September, Ramblings. But if you read it carefully, it gives a lot of prominence to protest groups but the only thing it says about the industry is that Dong are changing their focus from onshore to offshore wind. That's a good thing, wind farms out at sea are better because the winds are stronger, and there's nothing for people on land to object about.

But Denmark's appetite for wind is undiminished and they're still pressing ahead wih more. For example Dan Tysk and Anholt, the latter being their largest one to date.

MH said...

Here are a few articles I've found on new windpower projects in Germany: 1, 2, 3.

I'd heard that offshore windfarms were acting as conservation areas, because they can't be trawled, so it's good to see that confirmed in the second article. It says that Germany is planning 1,600 offshore turbines and for 25% of its electricity to be generated by wind by 2020.

Draig said...

Interesting thread. I sympathise with Jac's views on wind, but I think it has a place. Jac is also right that such generation needs backup.

While many engineers will tell you that all electrical grids need some source of "baseload" to balance against more intermittent sources of supply, others will tell you that it's a false concept that comes about because of the large-scale, centralised structure of the grids we use today, or else then the nature of the generation capacity attached to the grid.

In any case we do have a very large source of completely renewable energy that can fill the gaps when the wind drops. It's called pumped storage.

We have a 1.6 GW plant at Dinorwig, in the north. The principle is simple, at periods of low demand, spare generation capacity is drawn from the grid to pump water into the upper reservoir, and when demand spikes (i.e. Mancs and scousers popping out to put the kettle on) that water is released.

In a Welsh context, we probably have all the "baseload" we need. The problem is that the grid is configured to the needs of the bigger centres of demand i.e. the English regions, so the electrcity heads east, and not south. But it's food for thought eh?

Anonymous said...

Biomass to electricity is about 25-30% efficient. Biomass to heat, in domestic units or in smaller-scale (but still multi-megawatt) CHP systems is between 80 and 93% efficient.

With finite resources we should not be supporting biomass to electricity; we should be saving raw materials for the most productive possible use.

Solar PV and wind are better options for electricity, though solar PV costs more for the 'buck'.

In terms of CO2 emisssions of biomass combustion, I draw attention to the report here - http://www.birdlife.org/eu/pdfs/Bioenergy_Joanneum_Research.pdf - it suggests that there may be no net carbon benefit for a considerable time (hundreds of years...?)

MH said...

Draig, I think the term baseload is less and less helpful as our power comes from more different sources, and as we develop smarter ways of monitoring and responding to the grid we are part of. We do not consume electricity in a constant way, so any power plant that produces electricity at a constant rate 24/7 is as much of a problem (although a different problem) as the intermittency of wind generation. The key is flexibility to ensure that supply matches the constantly varying demand.

You make a good point about pumped storage, but the plants at Dinorwig and Ffestiniog are really only useful for storage on a daily scale. They provide an instant (within a few seconds) response to variations in demand, but neither could operate at full capacity for more than a few hours. So they can't provide standby capacity for use in the worst case scenario of no wind for a few days. But conventional hydro (like Maentwrog, with water from Trawsfynydd) can. We don't have much of this in Wales, but Scotland does, and so does Norway and Sweden which is why the North Sea Grid will enable a huge jump in our wind generation capacity. Rather than work on a daily cycle these work on a seasonal cycle: typically full over winter and at the start of spring but becoming empty at the end of summer. They can easily cope with a week of no wind, so long as the turbines have the capacity to produce what they would normally produce in a few weeks or months in that week.

Nuclear is the very worst form of energy for being flexible. Then comes coal, which is much better than nuclear but still much worse than anything else. It might be accurate to describe these as "baseload" but the word has a negative rather than positive meaning. They have to be baseload because they lack the flexibility to be anything else. I reckon burning wood chips or pellets would have about the same flexibility as burning crushed coal, as both are solid fuels.

Gaseous fuels are very much better in terms of flexibility, so it is our gas-fired plants that we need to look to in the intermediate term as we move towards generating our electricity from renewables. As we increase the share of electricity from renewables we can change the way we operate our gas-fired plants from "baseload" to "load-following" (the jargon for adjusting the output to suit the demand). For better or worse we in Wales now have Severn Power's new plant at Newport and are going to get the Pembroke plant and, as you say, in these we have all the backup capacity we'll ever need for the further expansion of wind power.

Now of course there will be those who say that since we have these, we don't need wind. But the point is that although these gas-fired plants are relatively cheap to build compared with renewables, they are expensive to run, because of the financial and environmental cost of the fuel they consume. Renewables like hydro and tidal lagoons are the opposite, they are expensive to build but then produce very cheap electricity with no environmental cost for decades, maybe centuries, to come.

MH said...

You're absolutely right, Anon. I think that if we build any fuel burning power plant (bio or fossil), we should do it on a smaller scale or in locations where we can make use of what would otherwise be wasted heat. The tragedy of Severn Power, Pembroke and Port Talbot is that their scale and location makes finding a user for that waste heat a practical impossibility. Worse, as the waste heat from Pembroke will raise the temperature of the water in Milford Haven to a point where it affects the marine habitat. As we've been talking about Denmark, it's worth noting that they were ahead of the game decades ago when they sited their conventional power stations in a way that allowed what would otherwise be wasted heat to be used for district heating and industrial purposes.

The document you've linked to is very detailed, but I've skimmed through it and what you said about centuries is in section 4.1.2 (and maybe elsewhere too). At the very least, nobody doubts that it will take decades. So large scale biofuel plants of the type proposed for Port Talbot will be making things worse at the very time when the most urgent action to reduce CO2 emissions is required.

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