DIY roof mount wind power? anyone?



The website looks distinctly DIY too.
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We were somewhere around Barstow, on the edge of the desert, when the
saying something like:

If you really want a constant thrumming racket, yes.
--

Dave

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Jim wrote: <snip>

Sorry - I came to this late - I am seriously looking for a device to install here at home and it seems to me that only 2 makers are in the running, but I would like to be proved wrong.
Renewable Devices (hooked up with SSE to the tune of 9M) and Windsave (currently looking to float for 55M).
What sets them apart is the connection directly into the mains so they export energy when it is not being used internally (no batteries). Supposedly there is a quicker payback.
All the above auguments about efficiency, turbulence, noise, etc apply.
What makes them less than ideal consumer products is the price. I calculate that the RD genny comes in at 9,000 installed. OK, grants & payback may offset that, but that is not an attractive price for 1.5KW.
Similarly, but better positioned, is the Windsave at about 1500 for 1KW.
Come on. Whereas this thread is engineering based, due to the interests of contributors, and the 'big windfarm debate' across the country is landscape based, I feel this is a marketing issue. If these were made in volume the cost should not be more than a dishwasher. Every house should have one.
If you look at a micro wind generator there is not much that is more complex than is found in a DVD player or such common appliance.
The argument should be to get these into volume production, get people installing them and the energy equation will change rapidly.
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The complexity for the connection apparatus to the grid system are one of the killer's price wise. Corners cannot be cut as back feeding after a system fault, particularly from numerous sources could kill. Also one thing conveniently overlooked is that the ratings quoted for wind turbines are *always* without exception hopelessly overstated.
Unless you want to go completely off grid forever and all that entails then the planning implications of huge (or even less than huge) amounts of wind generation are immense, the consumer will still need to stump up the costs for conventional plant lying idle for the day the wind drops. If wind renewable's expand significantly more than the current renewable's target and compose a large percentage of that total (as they currently do) the shit would start hitting the fan as reality bit.
So no amount of windmill building, even up to and beyond T B Liar's targets will keep the lights on. Tidal barrages might have some future but again the environmentalists will moan. The ONLY possible future is nuclear. It will really upset the environmentalists but unless action is taken now (a firm decision to press the button for a new generation of multiple nukes in the next 12-24 months) the lights will go out in a couple of decades (or less).
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OLDTOWNGUY wrote:

thats nuts.

1kW peak perhaps. What do you really get?
Small windgens today dont pay back.

There are far more significant issues than that. Anyone who bases their argument on landscape is really missing it.

Yep, agreed. They would be much cheaper than dishwashers. But there are a number of issues to overcome.

much simpler, but it has to handle far higher powers.

The energy equation wont change greatly, house mounted mills wont contribute much percentage wise, but they can contribute some. They can save householders money if theyre cheaply mass produced, but not today. The block is the now point, no-one is buying so no-one is funding mass production. There are also blocks re planning, safety, legalities, noise, effects on house structures, and power feed issues. Hence no-one will invest.
Matt wrote:

Maybe someone else with more detailed knowledge can fill in, but is that not a case of suitable precautions not being in place on the supply companies side? IOW if mills became common, linesmen would never assume a circuit to be dead or stay dead, and working practices would need to change to deal with that. And could. If I've got this one right - if - its todays practices that are not safely compatible with the occasional backfeeding mill.
There may also be ways to automatically check for mill problems and isolate any such sources from the grid when needed for work.

not so sure about that. There is always wind blowing in some places, not in others. Its true that utilisation is not very good, but there will be some saving, though not as much as is reflected by nameplate figures or eevrn average output figs. As gennies go theyre the worst kind, intermittent and unpreditable individually, but less so in bulk. I forget the actual figs, but ISTR something like 20% of a nations electricity could come from windmills, and domestic ones wont produce that much.

Not really, simply a case of less utilisation. If wind made up too high a percentage, which IRL will never happen, there would be times at which some generated energy went unused. But price policies will take care of that. Domestic windgens arent going to be big on output after all. Even a biggish 1kW mill will average what, somewhere vaguely ITRO 100w out.

Just one part of the puzzle, it will add some.

I agree we need more nukes, theyre the most environmentally friendly option, and the one practical option for our ills.
Imho no lights will go out though, prices (and energy saving drives) will take care of that. Attitudes to energy may change as things get tighter and prices go up. There are various sources of energy not a whole lot above todays prices, those will come into play when prices rise. And most consumption will be much more efficient by then. And quite simply a lot of todays consumption just isnt needed.
NT
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On 17 Nov 2005 18:07:38 -0800, snipped-for-privacy@care2.com wrote:

As a "for instance" the electricity selling price (not the cost of generation) just dropped straight through the floor around five years ago. As a result a major power station (7% of the installed UK capacity) went bankrupt and was repossessed by the bankers, fortunately they had difficulty offloading it as scrap otherwise we really could be in the shit. That same power station is now on the market and in a bidding war attracting offers around GBP2bn. Until there is a coherent national energy policy and stable market conditions no investor (other than one who has been siphoning off IMF funds) will contemplate entering the market.
The Tories started this off in the 80's with the persecution of the miners at any cost increasing dependence on imported fossil fuels, the waste of North Sea oil revenues on unemployment benefit was deemed more acceptable than state funded/assisted construction projects that would provide real labour opportunities and provide something long lasting and of value to the nation (like a decent rail system or 4 lane M1 etc) The Tories then carried it on into the 90's with privatisation of the gas and electricity systems and the phoney sell off of the nuclear industry. The tosser Tory Clone T B Liar can't even get his head around the rapidly impending crisis after "eight glorious years"
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Matt wrote:

You're posing half the story only. Basic capitalist concepts tell us that if the power station were decommissioned and we reached the point where supply were insufficient, electricity prices would rise until investors would return to the market. IRL the moves are slow enough and preditable enough that a major station being decommissioned then another getting rebuilt would be pretty unlikely.
NT
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On 18 Nov 2005 08:20:45 -0800, snipped-for-privacy@care2.com wrote:

What I am saying is the price swings are so violent that one year the generation is very profitable, then the market evaporates *completely* because the market was manipulated by certain parties that have less than this countries interests at heart. More than one company just went to the wall (witness British Energy for instance) If scrap prices had been more favourable, and the banks had made the decision to go for stripping the site there is no way the "market forces" would have been able to react in time and build new generation. Witness the same thing happening in California a few years ago. No investment signals were flashing because the market didn't signal anything at all until it was too late. Those who did know what was happening and predicted it ahead of time were sidelined by know it all financiers. Some of the "informed" just took the severance money and retired to the woods up in Oregon and now live a comfortable existence "off grid". The UK market is identical. All the money, from all the tinpot dictators/football chairmen in the world doesn't give you the opportunity to jump the queue at the manufacturers and get what you want years early.
The centralised intelligent planning that went into the UK electricity market up until the late 70's disappeared forever to be replaced by almost total inaction throughout most of the 80's (except Sizewell) due mainly to government restraint and was replaced by the free market, sweet bugger all, head in the sand, couldn't give a shit approach post 1990 with the result that Postman Pat's cat half asleep has more idea of the UK's future power plant requirements than any slick suited inbred merchant banker making critical decisions for the future of the UK ever would.
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On Fri, 18 Nov 2005 17:39:02 +0000 someone who may be Matt

The problem with "basic capitalist concepts", as taught in O Grade economics, is that Adam Smith modelled the market of his time. Small family-owned companies, operating in a local agricultural market. As a result of this there were few barriers to changing product, everyone had much the same market intelligence and the interests of the owners and managers were the same. Markets are rather more complicated today, but party politicians appear unable to grasp this.

Well, there was centralised planning. How intelligent it was is a matter of debate. Two examples.
Scotland ended up with five large power stations (two nuclear, one gas/oil, two coal). There are others but these are all relatively small, apart from the oil fired one that has spent most of its life mothballed. This was the result of unintelligent planning. As well as the expense, it means that the system is less robust than it should be. The exception is the Highlands, which has a large number of small power stations, remotely/automatically controlled and remotely supervised.
The generators of the time were obliged to generate electricity as cheaply as possible, with the result that they built large centralised coal fired power stations that threw a lot of heat away without making any use of it. Had they been obliged to do the best for "UK plc" then they would have built smaller more local power stations, with the heat used for district heating. We would not now be facing a gas shortage if many homes had hot water piped in, instead of burning gas to produce it.
--
David Hansen, Edinburgh
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Agree 100%. The Merchant Wankers who run this country can't see beyond the next quarter's figures. A quick Google hasn't given the me an update on the current situation, but BNFL where looking to sell off their Westinghouse division... the one company with a modern approved reactor design, for sale to the highest bidder (probably be Far Eastern) just as the world moves into the next major phase of Nuclear build. Again the Bankers can see beyond the fast buck now to a potential bonanza 5-10-20 years down the line. Or maybe they've got the nod from Teflon Tone that he hasn't got the balls to order new nuclear.
Maybe a really long, hard winter with rolling blackouts would be the best hope for this country.
--
steve

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On Thu, 17 Nov 2005 23:36:23 +0000 someone who may be Matt

The report at http://www.eci.ox.ac.uk/renewables/ukwind disagrees with you.
On the myth of wind power being unavailable for long periods it has this to say:
"Low wind speed conditions affecting 90% or more of the UK would occur in around one hour every five years during winter; The chance of wind turbines shutting down due to high wind speed conditions is very rare - high winds affecting 40% or more of the UK would occur in around one hour every 10 years."
On the myth of wild fluctuations in wind output it has this to say:
"The most likely change in power output from a diversified wind power system from one hour to the next is less than plus or minus 2.5% of the total installed wind power capacity. Larger changes from one hour to the next do occur - a change in hourly output equal to around plus or minus 20% of the installed wind power capacity is likely to happen about once per year."
Note that wind forecasting for the next hour or two is highly accurate and hydro and gas turbine plants can start within a couple of minutes. The anti-wind claim that coal fired plant running constantly in reserve is necessary in case the wind suddenly stops blowing is a myth.
As Energy Minister Malcolm Wicks is reported as saying:
"The only sensible debate about energy is one based on the facts. This new research is a nail in the coffin of some of the exaggerated myths peddled by opponents of wind power."
http://www.bwea.com/media/news/141105.html
As for conventional plant lying idle, unless wind exceeds around 20% of total generation there is negligible extra plant than there would be if that 20% was generated by nuclear, coal or whatever.
http://www.sd-commission.org.uk/pages/media/list/wind.html and navigate down to the "Download our booklet 'Wind Power: Your Questions Answered', for householders" link then Section 5 of the booklet.
"Many people wonder what happens when the wind doesnt blow. The truth is that the national grid system is already designed to cope with large fluctuations in supply and demand. It must deal with rapid surges in demand such as during the breakfast period or at the end of a televised football match when millions of kettles are used at the same time.
"National Grid Company has confirmed that accommodating significant amounts of wind capacity on the electricity system is unlikely to pose any major operational challenges. Indeed theres no technical limit on the amount of wind that can be absorbed by the system the issue is simply one of cost.
"Wind power is becoming easier to predict. As it becomes more dispersed around the country it is increasingly unlikely that all the UKs wind farms will be out of action at the same time. To cover for any shortfall will require a small increase in the balancing services that are routinely used by the network operator. This, and issues such as grid reinforcement, will add a small amount to the cost of electricity, which is explained below.
"How will increased use of wind power affect my electricity bill?
"Lets assume that by 2020, we have achieved the Governments goal of generating 20% of our electricity by renewable means and this done solely via wind power. In this case, the extra cost to consumers of integrating wind power would be about 3.8% of the current domestic charge around 13 on the average annual UK bill. If the environmental benefit of reduced carbon dioxide emissions is calculated and included, the additional social cost of wind power will be less possibly zero."
Those who want further information can go to the "Download our full report 'Wind Power in the UK'" link. Section 3 of the report is the place that covers this issue.
For some information specifically on microgeneration http://www.sd-commission.org.uk/news/index.php?page=get_article&article_id=FK7OVZ8-BV9MRDZ-HKMFYS8-5OZZIS2 is a good start.
--
David Hansen, Edinburgh
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Never trust politicians statistics. It doesn't take anywhere near that extreme of wind conditions to cripple the power output from wind farms. And stationary highs with very light winds over most of the country (as at present) are a feature of the UK weather.

Rate of change in output is a red herring. What matters is the amount of conventional capacity that has to be kept on standby and/or used to produce the difference between wind farm capacity and actual output.
Has anybody got a figure for the actual average output of the current wind farms as compared with their theoretical maximum?
--
Roger Chapman

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On Fri, 18 Nov 2005 10:31:24 GMT someone who may be Roger
I don't.
Are you suggesting that the University of Oxford Environmental Change Institute are politicians?

In the full SDC report I referred to one will read:
"3.5 Capacity and flexibility of wind power
"The need for reserves
"It is commonly assumed that adding significant wind power capacity to the electricity system will lead to a large expansion in the need for balancing services, particularly reserves. This is due to an implicit assumption that the intermittent output of wind power results in the need for large amounts of reserves devoted entirely to providing standby power for wind output this is often referred to as backup plant. Therefore, if the average output of wind plant is 35% of its rated output (its capacity factor), the remaining 65% must be provided as reserve, or backup capacity.
"This reasoning is seriously flawed, for three key reasons:
" No generating plant is 100% reliable. Therefore, reserves are required to cover for unexpected outages on all plants.
" The rated capacity of the total installed wind plant is of minor interest to system operators, who make supply security assessments based on estimates of overall statistical probabilities for the complete generating mix. This leads to the concept of capacity values, described below.
" Wind power is often described as intermittent, which implies a high level uncertainty as to its actual output, but it can be quite accurately forecast in the appropriate timeframes for balancing electricity supply. A more precise term might be variable, especially when considering aggregate output, which benefits from the wide distribution of wind turbines across the country.
"Instead, system operators assign all generating plant a capacity value (often called capacity credit), which refers to the ability of that plant to contribute firm capacity to the overall system. High availability plant such as combined cycle gas turbine (CCGT) can have a capacity value of up to 90%, meaning 10 GW of gas plant would be treated as providing the system with 9 GW of firm capacity the remaining 1 GW allows for outages, both scheduled and unscheduled. Existing nuclear plant in the UK has recently shown lower capacity values of 75%, due to a number of problems at individual plants.
"No plant has a capacity value of 100%, because there will always be some statistical probability that it will not be available when required. When determining reserve requirements, system operators make an assessment of the needs of the system as a statistical whole rather than considering the needs of each individual plant. This leads to a treatment of wind output that is different than if it were the only generating source available.
"Capacity value of wind
"Due to the variability of wind power, its capacity value is more limited, as it will not be possible to displace conventional generation capacity on a megawatt for megawatt basis. The capacity value decreases as more wind is installed on the system; at low penetrations it has been put at roughly equal to the capacity factor for wind (30-35%), but at higher penetrations the value decreases. This is because with low penetrations wind output is hardly noticed on the system, but when this increases, the variability of wind becomes more noticeable and its ability to provide firm capacity is reduced. National Grid Company have stated that 8,000 MW of wind capacity would displace 3,000 MW of conventional plant, with 25,000 MW displacing the need for 5,000 MW. This means that wind power has a capacity value of around 35% at penetrations of around 6%, declining to around 20% at penetrations of 20%. These figures, along with other corroborating evidence, were accepted by the House of Lords Science & Technology Select Committee in their 2004 report into renewable energy.
"It is worth noting that the capacity value of wind is higher in the winter than in the summer, in line with seasonal changes in the capacity factor. This means there is a correlation between the capacity value and times of peak demand.
"Lower capacity values have been reported in other countries. For example, a recent report by E.on Netz, one of Germanys network operators, with 44% of that countrys wind capacity, quotes an average yearly capacity factor of just over 15%. However the UKs greater resource means that capacity factors and the associated capacity values tend to be higher than most other European countries and comparisons can therefore be difficult. In addition, the integrated nature of the GB electricity grid, differing trading rules (eg. gate closure times), and its wide geographical distribution, separates it from some of the other problems faced in Germany."
--
David Hansen, Edinburgh
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They could be and in any event even scientists are not always as impartial as circumstances should demand.
snip

It seems to me that this argument is based on the average output. No wind at all might be almost impossible but what about the presumably near 50% of the time when the output is below average? Sometimes it will be well below average.
--
Roger Chapman

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On Fri, 18 Nov 2005 16:28:02 GMT someone who may be Roger
No, it is based on understanding the performance of wind turbines. There is quite a lot of experience since Delabole opened in November 1991. http://www.bwea.com/ukwed/operational.asp lists the current position.
Like any other form of generation wind farms can be treated statistically, but that is not as crude as simply an average output.
--
David Hansen, Edinburgh
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>

25000MW is about 5000-10000 large wind turbines. To displace 5000MW, which is about one large or two medium conventional (or nuclear) plants.
Go figure.
--
steve

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On Fri, 18 Nov 2005 20:43:06 +0000 someone who may be Steven Briggs
If they were all built tomorrow then the largest turbine rating in use at the moment is 3MW, as at the recently commissioned Kentish Flats http://www.kentishflats.co.uk Assuming all were of this size that would be 8333 turbines, or 277 wind farms of that size.
To get that number into perspective the largest 200 cities, towns and districts are http://www.citymayors.com/gratis/uk_topcities.html If all the wind farms were built onshore then each of those cities, towns and districts would have 1.4 wind farms the size of Kentish Flats. It is more likely that say half the capacity will be offshore and half onshore.
That is a rather simplified analysis, but it certainly isn't "covering the whole of the UK with wind turbines", as some suggest.

5000MW is 20% of electricity generation (from the next sentence which you snipped). It would be delightful if 20% of electricity was generated by wind power, but it is not going to happen tomorrow. There is an aspiration for 20% of electricity by renewable means by 2020, but I doubt if that will all be from wind farms.

http://www.scottishpower.com/pages/aboutus_scottishpowerbusinesses_ukdivision_powergeneration_longannetpowerstation?nav outus_scottishpowerbusinesses_ukdivision_powergeneration_longannetpowerstation says that Longannet Power Station is the second largest coal-fired power station in the UK and one of the largest in Europe. It has an installed capacity of four, 600 MW units. In other words 5000MW is about two large conventional plants.
I know that Drax (3960MW) is the largest coal-fired power station in western Europe.
I couldn't rapidly find the largest gas turbine station, but couldn't find one above 1500MW.

http://www.british-energy.com/article.php?article# says that Sizewell B has an output of 1200MW. In other words 5000MW is about four nuclear plants.
--
David Hansen, Edinburgh
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A 2MW one was erected a week ago at M4 J11 (Reading). It seems to have caused quite some traffic congestion due to motorists slowing down to admire it. Ironically, there's been virtually no wind since it was finished, and mostly it's been barely managing 1 rev per minute.
--
Andrew Gabriel

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As is the new farm out near Friday Bridge in Cambs.
Mind you the turbine at the dogs home in Godmanchester every time I go past there its turning. Dorset seem to appear on any mill databases but suppose its privately owned.
Be glad when this bloody fine but cold weather breaks, give me a mild wind anytime:))...
--
Tony Sayer


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Arklow, Ireland, is built with GE 3.6MW turbines. Total capacity 25MW with 7 turbines. The largest turbines, in prototype testing at the moment, are 5MW (REpower Systems AG, prototype operating in Germany). Many sites may be limited to 2-3-4MW units, hence my estimate of 5000-10000 units for 25000MW. Reasonable?

I was taking the 20% that is the capacity factor of 25000MW of installed turbines, the figure given by National Grid at 20% market penetration. This allows for intermittent operation, periods like now, winter anticyclonic conditions when many sites would not be generating at all.

I was thinking of Drax as the large example.
I stand corrected on the Nuclear front, I looked up Torness (near you), at 1364MWe, assumed this was per reactor, it is in fact total for both. So 4 or 5 typical nuclear plants (current plants have a capacity factor of 75%, new build is expected to be 90%).
So to get to the point I was trying to make, let's take Torness again, an example close to home for you. 1364MWe at 75% capacity value = 1023MWe of useful capacity. To replace this with wind at 20% capacity value, thats 5115 MWe of turbines, or 1023 units of the current biggest (5MWe) turbines in operation.
So lets stick over 1000 turbines, at 450+ feet high, out in the Firth of Forth. How does that look? Expensive too, http://www.tsaugust.org/Wind%20Articles.htm#Nuclear
--
steve

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