Warwick Wind Trial Results (to date 11 Dec 2007)
The WWT trial has had a difficult two years to get to where it is, namely the world’s first public domain trial of multiple models of grid connected small wind turbines on different sites especially urban sites. Just getting to this point has obviously been a mammoth task for the WWT team given the very limited resources they have had. All credit to them, especially to Mathew Rhodes and David Hailes. But they are now only one third of the way through (turbines up, data coming in) and they have the other two thirds still to come (capture one year of data, analyse data, write up and clean up). At this point they have only got one month of data (for Nov 2007) from all 24 sites (they have longer data runs from some sites) including the following manufacturers and products:
- Ampair (Ampair 600)
- Eclectic (Stealthgen D400)
- Renewable Devices Swift (Swift Mk2)
- Windsave (WS1000 c/w Plug’n’Save)
- Zephyr (AirDolphin)
There were going to be FuturEnergy turbines installed but they have failed to deliver as far as I gather. In fact an important learning point from the trial is that originally it was going to be of just Windsaves and Swifts but they both pulled out (as manufacturers). To date the only manufacturer that was prepared to commit to public datalogging was Ampair. All the other turbines have been ‘volunteered’ for the trial by clients. A list of the turbines that ought to be in the trial but are not yet (i.e. ones that are being marketed for building mounted including steel frame buildings) would include:
- Quiet Revolution (QR6 or QR5)
- FuturEnergy (1kW)
- SouthWestWindpower (various)
- Ropatec (various)
- Samrey (Wren)
- Aerovironment (Architectural Wind)
The results as presented at the 11 December 07 seminar are on the WWT site here except for the picture of the RD Swift that shed blades at BRE.
Quick advert: Yes we are very pleased with the relative performance of the Ampair 600. But we are not perfect and we have a lot to learn.
The context of the WWT trial is that several manufacturers have recently (last 5 years) entered the small wind turbine market with the initial marketing vision of low cost wind power for everyone (which by definition has to mean 0.5-1.5kW turbines; urban locations; grid connected; often building mounted). This is exemplified by Windsave and all credit to them for their laudable marketing ambitions. The industry incumbents then spent a few years trying to ignore the newcomers and then started to get serious about a response. From now on I’ll use Windsave as the exemplar of the newcomers since they’re the first to try breaking into the mass market with B+Q.
Quick advert: The media are trying to set us Ampair as being the 'rivals' of Windsave in a sort of mirror image way that media like to do. This is absolutely not what we are.
The main industry issue is the potential reputational threat to the industry arising from the over ambitious marketing claims of the newcomers. So as an industry we have become very serious about standards and testing, and in both the BWEA and the AWEA there are responsible manufacturers doing serious work in this respect (the AWEA effort seems to be mostly SouthWest and Bergy as manufacturers; the BWEA effort includes the following manufacturers: Ampair, Proven, Iskra, Gaia, Marlec, Quiet Revolution, and Windsave – I’m listing the ones I have seen taking standards committees seriously and yes that includes Windsave who are being very supportive in that respect). So the new entrants have done us all a favour in forcing us to take testing etc seriously and this is where Ampair have been putting its emphasis.
Soon people will be able to start publishing results in accordance with the new standards and that will be a dramatic step forwards. In the meantime there are already changes arising as a result of this - for example several manufacturers now have test sites in a way they did not have until recently. Also the new Ampair catalogue contains information we did not previously give.
Similarly the whole resource issue is being studied much more rationally than before. I think that within a year we will be able to predict actual windspeeds in post code grids (i.e. 10 house packets) to a fair degree of accuracy (much much better than NOABL). This work is being triggered by the new entrants but in truth it will be most use for people in the 5-15kW range. Early results are coming out in the form of adjustment factors in MIS 3003, the BRE assessment FB17, and the Loughborough CREST work and within a year these and the Warwick trial and EST trial and some other stuff in the pipeline will all be integrated.
Now coming to the particular commercial business case implicit in Windsave 'a wind turbine for every home' yes I would agree that these results objectively illustrate that this is not a good idea on electricity production grounds. The reason why we as Ampair agreed to participate in the Warwick trials when Windsave pulled out was because we felt intuitively that it was a bad thing for the industry to rush headlong into this in the way Windsave were (at the time they had just started their B+Q marketing campaign). Also at the time both Paul Gipe and Hugh Piggott were quite correctly raising serious concerns on both product performance and resource availability grounds with both of them doing useful work in informing the debate. At Ampair we decided to put our effort into the whole standards business and hoped that others would run the trials and expose their turbines to the reputational risk involved. But when Windsave pulled out of the WWT (by not supplying turbines) we felt that it was vital that somebody filled the gap and we stepped forwards. We'd only just got our grid-tie system working on the Ampair 600 so this was a huge risk to us. Also we were not exactly keen on house mounting (and still aren't) and definitely did not have the resources to actually go and do installs (and still don't – installation is what our distributors are supposed to do). So we were risking our reputation to disprove something we didn't in any case agree in and doing so on behalf of the wider industry.
Because of this we pushed to get the tower block sites included in the Warwick trial. As we expected the wind on these is very different than the suburban roofscape wind. In fact we are probably seeing more wind up there than at 5m height on Lands End. So far we cannot usefully convert all that wind into energy (because we are limited by our inverter, and because we are limited by noise production) and so we cannot yet reach any firm conclusions about the power production utility on these sites. But it is obviously a dramatically different prospect than suburban roofs.
So far the Warwick results only represent one month of data so it is simply too early to start doing much statistical crunching. And even when there is a year of data we can only crunch it so far as it is deliberately quite poor resolution data (to keep instrumentation costs down) and so the WWT team themselves are very sensibly trying not to over-analyse the data. In due course a higher resolution data set will become available from the EST trial which will include about 100 turbines but that is running about a year behind the WWT (there is some overlap) and then more analysis can be done.
Quick advert: The results to date for Ampair are that:
- The Ampair 600 appears to be at least as powerful as the Windsave WS 1000 and the Zephyr AirDolphin, i.e. Ampair's 0.6kW turbine is at least as powerful as the so-called 1.0kW turbines of the competitors.
- The Ampair 600 is yielding a much better import:export ratio than the competitors.
- The Ampair 600 has a much wider range of mounting systems than the competitors.
- The Ampair 600 is proving noisy in very high winds (on top of three exposed tower blocks - we are fixing this pretty quickly and already have workarounds in place).
In an Ampair context almost all our building mounted turbines have been included in the WWT, i.e. we're not hiding anything. In fact we've encouraged WWT to deliberately put turbines at very poor locations and it has been Ampairs that have ended up in the bad locations so we are certainly not cherry picking sites. Anyway we regard building mounted or urban microwind as being very much for R+D or for early adopters at present.Overall the results so far are that at current energy prices there is not an economic case to be made for grid connecting at typical suburban roofline. There may be a rational economic case for grid connecting at tower block roofs. And of course there is always an irrational case (the green statement thing) or the rational case on non-power production grounds (e.g. for education). Already this crucifies many of the new entrants’ original business case but they are adapting and are now trying to persuade their backers that they will be mega rich at 2% of the UK housing stock. There is a prospect of some sites being suitable and I can see some sites yielding 1000kWh over the course of a year (i.e. 25% of a typical on-gas semi's electricity use; or 20 year payback from a £2k turbine not that the current £2k turbines models will last 20 years). Bear in mind that the UK has about 20 million dwellings.
Quickly we should put to bed the CO2 content issue. The BRE assessment FB17 analyses this in conjunction with the Bath Life Cycle Assessment work (we assisted both projects, see my earlier commentary) and the results are that for a wind turbine that has the design choices of an Ampair (think 'right' weight - too much or too little weight are both bad, as bad as weight in the wrong place) and is in a moderately windy location will have CO2 paybacks of less than 5 years. In a poor wind location CO2 payback for an Ampair is more than 10 years. In good wind CO2 payback on the Ampair 600 is less than 1 year. These paybacks are very sensitive to design choices and so the RD Swift and the Windsave are both much worse than the Ampair (which now gives you the three anonymous turbines in the BRE assessment FB17) which is a function of their poor weight ratios. This would be even worse for Windsave if the actual location of the manufacture of the Windsave were taken into account. It would also be bad for Windsave and for RD Swift if the actual performance of their units were taken into account (BRE have assumed the manufacturers' power curves are believable and only adjusted for wind resource: a fair assumption for Ampair but as is becoming evident this is not a good assumption fr everyone). So on CO2 payback turbines can vary from good to bad depending on wind resource and on model chosen.
Then returning again to the 'futility of using wind turbines in urban locations' question I would say that right now for most premises it is futile. But I think it is premature to write off the whole area in the way we were doing 2-3 years ago. As with other small wind turbine markets we will find that there are niches that are viable and slowly we will build successively better performing generations of turbines that compete in those niches. If I was a guessing man I would guess at seaside locations (so they must be marine grade) and high rise buildings (so they must be safe) and right weight designs and 20 year lifetimes for microwind which sounds like a fair description of an Ampair turbine. For small wind (5-15kW) it will mean a different set of clients (those with large plots of land). And the jury is still out on the Darrieus rotor crew (i.e. VAWT designs).
So if we can get 0.01% of the UK habitable stock to take a sub 1kW turbine each year that represents a market of 2000 units/yr which would be a useful contribution to greater volume manufacturing. Can we do that - I don't know. Are we taking it seriously ? Yes we are now which is not what we would have said two years ago. Are we betting the business on it ? No as we see it as just one of the many niches we have to compete in. Will we change our mind ? Probably, we must be rational technical/economic decision makers and we must be guided by the science in all this and as more facts emerge we will rethink things. If we can make a small wind turbine that can be affordabe and be building mounted and meet the criteria then we can progress towards the economies of scale. But we would be doing that in any case so it's not too great a distraction from our other markets which obviously look very different from a user perspective.
The initial results from WWT have triggered a substantial series of articles in Powerhouse News under the headline "Micro-wind manufacturers cry foul at trial humiliation” which I can't post for obvious copyright reasons. Well at Ampair we are not crying foul and nor do we feel humiliated. We have plenty of problems but we will fix the issues we are seeing because they are learning experience. I would encourage any other manufacturer or importer to step forwards, volunteer more sites for datalogging, and get on with learning. Ideally that could include small wind manufacturers in the 5-15kW bracket out in open terrain because now that WWT have a decent instrumentation package and data analysis process they can start to cost effectively deliver results to the public.
So to summarise the Warwick Wind Trial is a huge step forwards and the team behind it are to be congratulated. They are simply putting the data out and are letting it speak for itself. As ever more data is welcome and inevitably there will be comparisons made, some valid and some not but that’s life.