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Archive for June, 2012

I found this article interesting: Women And Clean Energy: Overcoming The Double Standard.

I don’t know if it’s just that I care more about renewables, but I have been gaining the impression that renewables are held to far higher standards than any of their more established competitors. This holds for planning constraints imposed (met masts often have “bird diverters” attached, but I’ve yet to see them on a telecoms mast), and it certainly holds for the press coverage. The “women must be twice as good as a man to be thought half as good” idea does seem to fit this reasonably well.

But it is true that in both cases it’s a subjective thing which is being measured, so it’s harder to demonstrate an effect. I don’t know of any research done into the public dialogue for wind, nor of any comparisons of the planning procedure for wind farms compared to other technologies. Still it was interesting that someone else, in the US at least, has a similar impression.

I don’t know if you care greatly, but the gender balance in wind resource assessment isn’t too bad in my experience in Scotland: I’d say women have made up about 30-40% of analysts. Engineering teams and people working on operational wind farms still seem to be overwhelmingly male though.

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Firstly, I’d like to draw your attention to the following blog on the Guardian’s site: Why there’s only one honest objection to wind farms.

I have been forming much the same opinion over the last few years. Sure, there are a few that sound like good objections until you give them any sort of thought:

  • health impacts have never been proven at any sort of scale and what studies have been done are generally low statistics, self-reported or otherwise flawed. I’m not discounting the fact that psychosomatic effects are very powerful, but it’s simply not logical to hold a particular industry or technology to account for psychosomatic effects, however powerful.
  • government subsidies go to all forms of power generation in one guise or another. Besides, you only get subsidised for power generated which gives a powerful incentive to take great care in your developments and particularly in your initial spend. You don’t get subsidies to build wind farms; that risk is the developers’ and the banks’ own. The big driver of rising fuel bills has been gas prices, not renewables.
  • paying sums of money to the already rich land owners — well there you have an issue with capitalism, not with wind farms. I’m not disagreeing that it’s better to give money to the poor than the rich, who would? But that’s the system we’ve got and wind developers have no greater moral responsibility to tackle unfairness than anyone else.
  • intermittant, unpredictable, small scale. Turns out wind farms, and the wind, are predictable enough; they are also highly responsive and can be quickly shut down or curtailed (run at reduced power) if necessary. They can’t provide more energy if the wind isn’t there, but they’re a powerful tool for the grid when it comes to balancing supply and demand.
  • carbon cost of building and land space. There’s a carbon cost to all building projects but an airport, for instance, takes up a lot of land and then creates pollutants. Wind farms later reduce carbon output. And while they do take up a lot of land if you look at the boundary, in fact most of the land remains available for crops and livestock as normal.
  • noise and shadow flicker. Shadow flicker is known to be a hazard to health in some cases, but only at high frequencies, far higher than large wind turbines get to even at high wind speeds. Because the sun follows a predictable path, it’s easy to demonstrate when it will happen and where and to be honest it’s pretty rare. It’s also easily reduced by closing curtains during the appropriate time of year, or facing a different direction. Since I live and work in the city I find it hard to take the noise complaints seriously as a mass issue (rather than on the level of individual nuisance): at high wind speeds the wind itself is louder if you’re outside or near a forest. Most of the time the noise of a working wind farm even actually inside its borders, isn’t much more than a medium-busy road, and we’ve learned to all but tune out road noise.

There are others, obviously, but none that I can think of which aren’t similarly easily rebutted.

I don’t think the author of the blog intends to suggest that people who object to wind farms and quote other reasons than looks are actively lying, just that they’re failing to acknowledge that they give disproportionate weight to minor issues because ultimately they don’t like 1) wind farms themselves or 2) their position in our landscapes.

Confirmation bias is a known phenomenon where we hear what we want to hear and discard evidence which contradicts our own preferences. I am aware of this, and I do make a conscious effort not to apply it to wind farms. The evidence I’ve seen for any of the objections up to now has generally been poor and even with a genuine effort to keep an open mind it hasn’t raised any real concerns.

I do worry about the number of people who are willing to argue “Wind farms are pointless: we should be investing in tidal farms!” or championing some other form of technology. We are investing money in researching tidal farms, and wave generation, and offshore wind farms, and even nuclear fusion, and these things are, indeed, very important to our future supply. But none of these technologies can generate the electricity we need now. They’re still in the pipeline. Wind farms can, and are. If, in ten, or twenty, or fifty years, wave or tidal becomes a significant contributer to our electricity networks, it will be built on lessons learned through onshore wind farms on how to cope with variable supply, and with supply that relies on weather conditions. Stopping the development of onshore wind farms would make it harder, not easier, for wave and tidal to reach deployment scale.

Apologies for my lack of presence on twitter at the moment, I’m really pushed for time with one thing and another and it’s only my one-post-per-week New Year’s Resolution that’s keeping the blog going.

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Wind farm layouts are pretty controversial. The bare fact is that putting turbines in the most lucrative positions which catch the most wind generally means putting them on top of hills. Which makes them visible for miles around.

There’s not really much that can be done about this conflict.

Besides, developers of wind farms don’t, as a general rule, actually buy the land they’re building on. Usually they rent it under contract from the landowner. And although the area of the wind farm is usually large, there’s usually a fair bit of spare ground around the turbines which can continue to be used for livestock or crops. In Scotland, we have laws protecting the right to access land; this means that if you want to go mountain biking at an operational wind farm the law is on your side (up to the point where you do any malicious or criminal damage etc obviously).

Once a contract has been drawn up with the landowner or landowners for a particular wind farm, it’s time to design a layout. This remains a challenging issue.

There are a number of criteria which are likely to restrict your options before the wind can be taken into account. These will include bird and wildlife surveys; land use and availability for roads; waterways and steep valleys which restrict access to heavy plant; planning restrictions on tip height; noise considerations; nearby residents; ground suitability; and local considerations such as archaeology, sites of scientific interest, and so on.

From there, the best practice is to use actual wind measurements to model how the wind flow changes across the site. Because you need at least a year’s worth of data from a met mast before you can really use the data (to cover all seasons), the reality of this part will vary substantially depending on how far into the project we are. If the project has two years’ of measurements at one or more masts on site, then great. Otherwise there are other sources of wind information we can use: bought data from a Met office measurement station; a virtual met mast built from a model; reanalysis data based on satellite measurements; extrapolation based on a combination of measurements. If the worst comes to the very worst the rule of thumb that “higher elevation = windier” would provide at least a guide.

Once you have an idea of the wind flow, you need to decide where to put the turbines. There are a number of things to take into consideration when doing this.

Each individual turbine removes a little of the energy from the wind it encounters, resulting in a slower wind speed for those turbines behind it. It also increases the turbulence, which further reduces the effectiveness of the turbines behind: it’s harder to extract energy from turbulent air. The combination of these is called the “wake” effects in the industry. To reduce the impact, it’s considered best practice to leave between 4 and 7 rotor diameters’ worth of gap between the turbines. Larger spacing is generally left in the predominant wind direction so that the overall wake effect is lower. (Offshore the spacing is larger, because wakes travel further offshore for reasons to do with atmospheric effects. Best practice will also vary from region to region based on the appropriate climate drivers.)

Trees and slopes will have several impacts on your positions. The top of a hill will be the windiest location, but steep slopes can provide huge challenges for accessing the turbines for construction or maintenance. Steep slopes also tilt the wind to an angle, and above 17° or so start to cause real problems for accurate wind flow or turbine performance modelling. Forestry increases turbulence directly above the forest, and can have other effects on the wind flow (increased change in wind speed with height, for instance, and boundary effects at the edge of the forest) which reduce the efficiency of the turbines.

Dwellings should generally be avoided as far as possible. I think the guideline in Scotland is 500m (note: there are experts on these constraints, and I’m not one), but a much larger buffer zone is wise. The issues of noise and shadow flicker are only relevant with regards to nearby homes. The danger of ice throw from blades or of blade throw is not thought to be a risk beyond tip height of the turbine (so if the turbine is 160m tall and you’re more than 500m away the risk to your property from these things is vanishingly small). To be honest I think the main driver here is the good will of the community. Big wind farms are generally built by bespoke developers, and there is much to be lost in appearing to trample over communities.

You want to maximise both the number of turbines and their output. Developers (or the banks who lend to them) take on the financial risk of a project when they sink their money into constructing the wind farm; they get nothing back until they start to produce electricity. If the costs of building and maintaining the wind farm turn out to be more than the wind farm can generate, the project is a failure. So the energy output is actually critical to project success.

Ultimately, then, from an industry perspective, the challenges of layouts are as follows:

  • Comply with all planning restrictions
  • Keep the local community on-side as far as possible
  • Space the turbines 5 by 3 rotor diameters, which for an 82m rotor diameter machine (about average for large wind farms at present) is 410m by 246m
  • Keep the turbines away from steep slopes, forestry, and dwellings as far as possible
  • Install as many turbines as you can to increase your maximum production
  • Put your turbines as high up as you can manage

I’ve often seen the accusation “poorly sited” levied at wind farms in newspaper letters. Reading between the lines, I suspect that this is because the writer objects to wind farms on hills where they can be seen, rather than that they know a secret way of establishing the best place to put wind farms that the industry hasn’t stumbled on yet.

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I think the people most impacted by the current government’s completely inexplicable austerity drive are the people who rely on state money, whether as benefits or because the state pays their wages. I am in the very fortunate position to be privately paid, and in a high-skill, high demand area.

Even so, I’ve found that the austerity measures are having an impact.

I guess the first thing I’ve noticed is that my money isn’t worth as much, and my time isn’t worth as much. Wage rises are very low, generally less than inflation; and the rate of interest you get on any money you can afford to save is actually laughable. (My “interest paying current account” was demoted to “current account” when it stopped paying interest, and I recently saw a poster advertising an actual ISA with 3% interest which only a few years ago would have been miserly for instant access savings.)

At the same time, the public discourse is highly demotivational and depressing. “Do more with less”. Services being cut at every turn. Tabloids turning on the unemployed, the sick, and the disabled, as though the tiny fraction of GDP which represents benefits for the genuinely needy is anything to do with the size of our defecit. On a personal level, individuals have to stretch their money to pay for their own higher education, their own retirement, childcare for any children, their day-to-day living expenses, the astronomical cost of housing… It’s depressing to feel like your time is not worth as much and at the same time to know that you have to pay for your past, present and future (and that of any dependants) out of a shrinking pool of income at a time of high inflation.

And of course by cutting benefits the government is telling me in no uncertain terms that if I fall sick or lose my job, I’m on my own. And I actually can’t save up for that possibility because I’m too busy saving for home repairs, pensions, student loans and you know, actual living expenses.

The thing is, if you’ve always had money you won’t see that. If you are in the fortunate position of having always had a little bit put by either by your parents or through some other means then you’ll never see cost as an ultimate problem. Similarly if you bought your house in the early days of the boom and sailed up the housing ladder on equity then you won’t appreciate how different it looks when you stretched yourself to the limit at the end of the boom to buy your house and watched its value fall through no fault of your own. The rich don’t see money as a problem, it’s always there when they need it. It’s more a way of keeping score.

Any household which covers its debts by letting its members starve and die is doing something wrong. That’s what this government’s austerity politics are doing, as disabled people are villified by their neighbours for the pittance we spare them. The government is letting us down; failing in its duty of care to its own citizens.

It sounds like socialism, and it is. Because how can it be bad for the resources of the many to be used to help those with nothing? You can only villify socialism if you genuinely believe we all have equal opportunity to be rich. And you can only believe that if you walk around with your eyes closed and your fingers in your ears.

(For context, I just read this. Alongside some other things I’ve read, the whole thing really worries me. I have worries about the independence debate, most notably regarding how little information seems to be available about what the former Great Britain might look like after independence, but this government would drive me to a YES vote on the grounds that at least Scotland might not have to face the worst. And if it’s impacting me, the picture of the squeezed middle, how much more must it be hitting the genuinely poor?)

Normal service will be resumed shortly…

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