Archive for February, 2012

I’m talking about this Herald article.

SSE’s renewables arm have applied for an offshore wind turbine testing facility near Hunterston power station. Planning was applied for as usual and was granted.

According to the article, though, the villagers are worried that although planning is granted for five years it was simply a sneaky corporate scheme to get a wind farm approved through the back door. Which is simply paranoia: SSE renewables are an enormous developer of onshore and offshore wind energy, with SSE recently announcing that they have more wind generation capability than the Hydro power which gave them one of their operating names of Scottish Hydro Electric. If they’re going to build a wind farm that’s what they’ll apply for in planning. They’re far too big a company and far too reliant on their own good name to be able to risk that in underhanded tactics. Also, if they wanted an onshore wind farm, why on Earth would they claim they wanted an offshore testing facility on land? It seems a bit paranoid to suggest this duplicity. Certainly there can be no evidence for it as the facility hasn’t been built yet: I’m sure if the turbines are erected and then duly either removed or planning permission re-applied for in five years time, SSE will get a heartfelt apology from the villagers for their accusation.

Quoted in the article:

    But Mr Telford said: “The inhabitants of the village of Fairlie will have our homes and our home environment blighted, our population made ill by noise and coal dust, our local climate altered, our property devalued.

    “We are being made unwilling guinea pigs as a part of this extremely dangerous experiment.”

Coal dust? From a wind turbine? (OK, fair enough, three wind turbines.) “Our local climate altered”? I assume the gentleman doesn’t mean that it’ll be slightly less windy as some of the energy will be producing electricity so we can all watch Corrie. Property devaluation… well, yes. I’d maybe accept that as an issue if we weren’t talking about land a bare 3 miles from a large (and incidentally incredibly ugly) nuclear power station. If you’re interested, the photomontage showing what the turbines will look like from Fairlie is available online. It’ll look like:
Photomontage of the proposed facility as seen from Fairlie.

There do remain people who fervently believe, despite no scientific evidence, that wind turbine noise can make people ill. The interaction between health and belief and the environment and the mind is a complex one, and not one I’m going to go into here. But really, the rest of his argument is a bit of a storm in a teacup. Not only that but since planning has been granted, isn’t it all a bit late as well?

The most ludicrous part, to my mind, is the opening sentence, though: “Residents on the Firth of Clyde claim their human rights are under threat from the giant structures – thought to be the second-highest of their kind in the world.”

Their human rights? To a sea view?

That’s easily the most middle class argument I’ve ever heard. The article quotes the clause in question: “Everyone has the right to respect for his private and family life, his home and his correspondence. There shall be no interference by a public authority with the exercise of this right…” However it is not clear to me where exactly the public authority is interfering. No homes are being knocked down, no forced evictions; the land in question is currently sort of industrial wasteland so there’s little could be done to make it worse. No, I can’t see a single part of this clause which is actually relevant to the proposed development. It reads like that middle and upper class assumption that owning property gives you inherent rights to all developments within eyesight of said land. And where have we heard that one before?

No wonder the court of human rights gets such a bad press.

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If I ask you what colour the sky was, you’d say blue. If I asked what colour it was right now where you are, the only way for you to answer correctly would be to go and look. That’s science: the go and look bit. Science is where we try and get past the rote answer and use evidence to understand what’s going on.

There have always been people who don’t like the go-and-look philosophy. Most of the time they’re the same people who would prefer we all take on the listen-to-them philosophy. It rankles with a certain type of person that they can’t just say anything they like without being fact-checked. It used to be religious authority who were most guilty of this; now it seems to be marketers & PR people working for rich corporations, billionaires and politicians. Or at least so the documents about the Heartland Institute released this week would lead us to conclude. (I’ll not go through this, you can read more about it here if you’re interested.

I don’t like this war. To me, if you want to know what colour the sky is, you go and look. If you can’t do that, you use the scientific method to find the most probable answer. You don’t ask yourself, what is the most beneficial answer? And then shout out to everyone who’ll listen that the sky is in fact black-and-white-stripes, punching anyone who disagrees with you in the mouth. The trouble is that in human affairs, what matters most isn’t what you can prove, it’s what you can get people to believe. And the anti-climate-change lobby have been very, very effective at getting the public to accept the idea that there’s any scientific controversy. There isn’t. Human action is causing the climate to change. (The graph in that last link is particularly compelling.)

Over and over again, I encounter the idea that renewables are only being developed for the subsidies; like there are fat cats putting up useless wind farms and then laughing at us all the way to the bank. I’ve seen no evidence for this. Firstly the subsidies are generally paid out alongside the electricity being generated, so that if you build a wind farm in a bad location or if you don’t maintain it you get far less in terms of subsidies. Secondly the expense of building the project and the risk of failure all fall on the developer, and many wind farms do fail at various points after significant time and money has been invested in them; not really something that encourages risky development and then running off with the cash. Thirdly, the renewables lobby, like the climate change lobby, are nowhere near as effective as their various counterparts. And fourthly, electricity prices are driven by gas prices. Renewables aren’t driving profits or costs to any large extent, and a lot of their profits goes back into the next development. Profits which are being invested in infrastructure aren’t lining fat cat pockets.

If there are powerful people with lots of spare money about, they’re not coming from the renewables industry. They’re more likely to be coming from the oil and gas sector. Those are the people who don’t want us to invest in renewable energy which doesn’t require a constant fuel source. Those are the people with both the motivation and the money to actually get their voice heard. And the evidence seems to suggest that they’re using that voice: they’re using it to lie to you.

The worst thing about it is that if we don’t know the facts we make poor decisions. We all want our grandchildren to live on a planet that’s at least as good as the one we have. No-one wants the luxury of a private jet if the direct cost is watching their grandchildren starve in a climate-change induced drought. If we change things now, we can do it slowly, keep the level of technology we have. If we don’t…

Well, the way I see it, if we don’t reduce our reliance on oil and gas we face much bigger problems than just climate change. We face the increasing instability of the Middle East, and hugely fluctuating prices. We face increasingly desperate technologies (like fracking) used in increasingly unsuitable environments. We face dwindling global supplies and perhaps even wars over what remains (the question of who owns North Sea oil if Scotland gains independence will seem tame in comparison). On a human level there could be a global crisis of a level not seen since the second world war. And on top of that we could have hurricanes, tornadoes, droughts and monsoons, rising sea levels and dwindling water supplies.

Unless we work to avert it. Now. Little by little.

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I talked here about the job that myself and my colleagues actually do, in terms of why it would be complex to predict how the wind will flow across a potential site. I’d like to continue that topic a little and talk about how we actually measure the wind.

The first rule of good science is to make good measurements. In the wind industry, that means we want to know as much as possible about the wind which will encounter the rotors of the planned turbines. The most common instrument to use for this is a cup anemometer, which is actually a fairly simple mechanical device. Most commonly it’s made up of three cup-shaped objects which sit horizontally in the wind and spin round a central axis. By counting the number of spins we get a measurement of the wind speed. You’ll most likely have seen them; you see small ones quite commonly by the roadside, near small wind vanes.

Of course, a cup anemometer can only measure the wind speed that it’s actually sitting in. To measure at the heights of a wind turbine we need to mount it on a mast, preferably one which reaches to the turbine hub height. We also need several instruments at different heights, so that we can see how the wind flow changes with height. Then there’s the wind vanes, which give the wind direction, generally we want two of them. Multiple instruments have several advantages: they provide measurements at different locations, they can be used to sanity check measurements, and there is redundancy built in if something fails.

In fact the wind industry has generally had far higher requirements for measurement accuracy than the Met Office when it comes to wind speeds. There are wind industry professionals who visit masts in various locations and assess how accurate the measurements are, how consistent across the dataset and whether the data could be used as a reliable indication of how the wind behaves. The accuracy of the eventual dataset will depend on whether the mast is correctly sited, how the instruments are mounted on the mast, what sort of instruments are used and at what height, and whether the data are regularly checked and maintained.

Recently, lidar and sodar technology have started to really take off in the wind industry. These are alternatives to a mast, to an extent, and they work in a similar way to radar: by bouncing a wave off a moving target and looking for the reflection. Lidar units use light, generally infrared wavelengths, and sodar units use a sound-based wave. They’re collectively termed “remote sensing”, because they can sense the wind speed without sitting in the wind flow.

As it turns out, met masts with their instruments and the less intrusive remote sensing units are complementary technology rather than competitors. Met masts are large and unwieldy and cost a lot to install, but once they’re properly installed they continue to take data and require very little maintenance or additional expense. Temporary met masts which are installed for a wind project often take data for three years or even longer. Lidar and sodar can be bought outright or hired. Their huge strength is that they’re comparatively portable: lidar units in particular can generally be moved across a muddy field by two people, and they are not generally mentioned in planning requirements. A resource analyst might have two or three places on a site where the wind will be challenging to model or which are a long way from the mast but a mast can’t be installed there — in this case a short lidar deployment can really help in forming a full overview of how the wind is behaving.

Met masts are relatively simple things. Wind industry met masts are generally much smaller and less intrusive than the big telecommunications masts you see. However they have their challenges. They can be deployed in incredibly remote locations, which can make getting the required construction vehicles to the required location challenging; sometimes helicopters are required to transport the mast to site. (Note that one of the first things done when constructing the wind farm itself is building the roads. The turbines can then go along the roads. The met mast pre-dates this step, though.)

Remote sensing is obviously also a huge advantage offshore — the wind can be measured from the surface of an oil rig or even on a nearby shore rather than expensive and time consuming offshore met masts being required. The taller wind turbines of today, and the challenging terrain they’re sited in onshore, also benefit from remote sensing measurements which can be made far higher than a mast would support without any increase in cost.

There are technical differences between met masts measurements and remote sensing measurements which the wind industry as a whole are starting to get a handle on. It’s one of the more interesting elements of my job, watching the techniques and the technology changing and evolving. In many respects the wind remains something of a mystery to us.

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I often read anti-wind letters to newspapers, which get linked to in various round-ups of renewables news which land in my inbox each day. Most of the time, they simply annoy me. The one above, on the other hand, made me want to clap my hands when I read it. It hits quite a few of my own personal list of things that make a good argument: it’s based on fact, it doesn’t rely on hyperbole or insult to make its point, and it bases most of its point on things which can be objectively verified or argued.

This is a good paragraph, for instance:
“Whilst [the assertion that wind turbines produce energy for 70-85% of the time] may well be true, it is grossly misleading. It should be pointed out that for much of this time the turbines will not be producing much electricity at all. For example when the wind speed falls by half, the generation falls to a level of around 10% of capacity (a cubed power law). And additionally we already know that the timing, or volume, of electricity generated is seldom matched to demand, often high when we don’t need it and low when we do. And don’t mention the shut-downs when the wind is too strong.”

The energy available in the wind does indeed follow a cubic relationship with the wind speed, meaning that if you multiply the wind speed by half, you get an eighth of the energy available in the wind. It’s not quite as simple as that, however. The turbine of course doesn’t actually remove all of the energy in the wind and convert it to electricity; in fact the Betz limit tells us that no theoretical machine ever could. Rather, it follows a power curve which remains at or near zero until the wind reaches a certain level, rises steeply (but not as steeply as the Betz limit) until a given point and then generates at capacity above that. That means that the energy in the wind is reduced by an eighth if the wind speed drops by half, but the power generated by a turbine will not drop by the same amount.

“Grossly misleading” is an interesting term when applied to a true statement. It suggests the statement was intended to detract attention from some other idea or issue. Without access to the original content I can’t really comment on that. However it is true that wind turbines generate electricity most of the time. Personally, I consider it misleading to equate the behaviour of a wind turbine power curve with the energy in the wind, but I suspect the writer is talking from knowledge of general engineering principals rather than specific knowledge of wind turbines so I think it’s forgivable.

A second point is made that Scottish wind farms generally quote a capacity factor of 30% whereas in the first part of 2011 Irish wind farms only managed about half this.

Again, this suggests limited knowledge of the intricacies of wind energy. It is not currently possible to predict how windy it will be next year, or the year after that (when your planned wind farm will be available for generation). Weather systems are chaotic, and resist any attempts at accurate predictions on a timescale longer than a few days. Before construction, the capacity factor quoted is usually based on what’s known in the industry as a “P50” value. This a target value which we expect the wind farm will meet about half the time over a long-term period. Essentially the pre-construction capacity factor is an expected annual average. Comparing it to a short-term value is not going to yield meaningful results; it’s an apples-to-oranges comparison. Really if you want to compare how realistic it is you’d want to go back ten years and calculate the average yearly capacity factor over the whole ten-year period for a few sites at similar exposure and elevation, and for a similar turbine model. (People like me earn their living doing that for developers, for banks lending money, for potential purchasers and others with a vested interest in knowing how much a wind farm is likely to generate. We are needed because it’s not straightforward to predict wind farm output.)

In fact this map suggests the Scottish wind resource is slightly better than the Irish wind resource. We have the same climate drivers, but wind speed increases with elevation and Scotland is higher than Ireland. Still, the actual output will vary from location to location.

I disagree with the letter. I think there are a couple of things the writer got wrong. Still, it’s a letter which I feel I can meaningfully answer; where there are misconceptions these can be addressed. No vitriol, no hatred, no assumption that everyone-thinks-like-me. A letter which leaves some potential for compromise, for discourse and even to agree-to-disagree. I think that’s worth savouring for a few moments.

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I see so often on anti-wind opinion pieces a variation on the theme of “it’ll never work”. It might be “wind power will never work” or “we’ll have blackouts if we rely too heavily on wind power”. It might be a comment on wind power’s intermittency or unpredictability.

All of which ignores the one blatantly obvious fact: wind power is currently here, and currently working.

That one fact marshalls all of the variations of “it’ll never work” into some sort of logical reductionist argument with unspoken assumptions. The first and most obvious unspoken assumption is “apart from under current conditions”. The contribution of wind power has been gradually increasing without experiencing blackouts (even under extreme wind conditions). This leads me to the conclusion that the speaker is generally assuming that there’s some sort of event horizon, beyond which the cataclysm will occur. I’ve never been able to figure out what precisely that event horizon looks like, because that particular assumption is never made clear. Still, the speakers do have a few facts on their side — there’s more to making wind power work on a country-wide scale than simply building the wind farms and plugging them in.

As we increase the market share of wind power, the important thing is that we are continually checking that today and tomorrow we can keep the lights on. Whatever we’re changing, we need to know we have it under control, even given the difficulties of predicting the wind. This will get more important, not less, as other renewable technologies begin to form part of our electricity supply, because instead of simply worrying about how windy it is, we may also have to consider what state the tide is in, if there are large waves offshore, and whether there’s been a lot of sun.

I was therefore glad to see the news that planned upgrades to Scotland’s electricity grid have been fast-tracked. Grid upgrades don’t tend to get an easy time from the planning process; people don’t like pylons any more than they like wind turbines. Still, we cannot ever lose sight of the sheer scale of the changes we, as renewable energy generators, are pressing on to our aging grid structure. Not only is the power source (relatively) unpredictable and intermittant, it’s also situated on windy hillsides far from the population centres of demand.

Coping with these challenges requires greater connectivity between countries, a more flexible network, and of course more capacity in the windy but sparsely populated north of Scotland. Energy storage and demand mitigation are other techniques which are actually happening to a greater or lesser extent.

It’ll never work, if the grid remains the same old aging structure and we simply keep piling in more wind farms. Thankfully the clever people who operate and maintain the grid know that too, and are working on it. It’s not a “so we should just give up” situation, it’s another “let’s rise to meet the challenge”.

It can work, and it is working. With ingenuity, attention to detail and positivity, it can continue to work.

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