The Wonder of Wind
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The Wonder of Wind

by Joel Gilbert
Many people have thought about having their home or work-place at least partly powered by renewable energy. Whether through altruistic visions of ‘doing our bit’ or the hard-nosed dreams of the potential money to be made then having our own sustainable energy supply can be a very attractive proposition. However, whilst much has been written on the experiences of installing and maintaining solar PV panels, comparatively little has been written on its handsome cousin: wind power.

There’s plenty to think about when it comes to installing a wind turbine. From the initial outlay, through the bureaucracies associated with planning permission and getting the system ‘live’, to the level of maintenance the system may require. There are also questions concerning how much carbon dioxide and money really is to be saved from going up into the proverbial smoke once your turbine’s operational. After all, many sellers and web-sites are willing to predict how much money you will make per year, how much electricity you will generate, and what the payback time of your investment is going to be, but how much of this is to be believed?

Rafe Staples, partner at consultancy firm Powis-Hughes, decided to install a wind turbine next to the company’s Berkshire office. The decision to go for wind power was aided by the office’s rural location, which provides better quality and consistency of wind than urban sites, and helps find in wind’s favour when compared to the electrical output of solar pv panels. Furthermore with the government’s Feed-in Tariff (FIT) scheme guaranteeing good rates of pay for every unit of wind electricity generated for 20 years, the time seemed right to invest.

To try to get an accurate picture of the likely financial return and carbon reduction for a wind-turbine, Rafe used the site planning tool of the renewable energy website RenSMART (see table below). Equipped with this knowledge, and with predictions looking favourable to both pocket and planet, Rafe took the plunge.

Indicative Price£28,164 Ex. VAT
Pay back time7 years (2017)
Return on Investment170%
Feed-In Tariff Rate26.7 p/kWh
CO2 Avoided112,744 kg
Yearly Generated10,325 kWh
Exported1,705 kWh
Total Generated206,492 kWh
Table 1: Table of predictions for 6kw wind turbine made on RenSMART website based on office location and yearly energy use.

The initial outlay to Powis-Hughes for the 6kw indicative price of £28,164 + VAT given on the RenSMART website (Please note: All prices are not inclusive of VAT as the rate is dependent on whether the turbine is a domestic or commercial installation). However, despite the total cost still coming in under the estimate, £3,500 is more than someone should reasonably expect to pay to get a wind turbine system live, so what was this extra money spent on, and can these ‘extras’ be avoided?

The bulk of the additional outlay became necessary when Rafe found out late on from his electricity supplier that the local network would be unable to handle the additional output the turbine was to (hopefully) produce. This left Rafe with three options to solve the problem, that is: a) to downsize the turbine thereby generating less electricity, b) to upgrade the office to a three-phase power supply, or c) to upgrade the electricity company’s local network! Rafe decided option b) to be the most suitable, as it would allow for both the smooth running of the larger 6kw turbine and cost less than a local network upgrade.

Rafe’s decision to upgrade the office power supply to a three-phase system did present an unforeseen increase in cost and an unwelcome headache for Rafe. However,for those considering whether to invest in a wind turbine it is possible for this stress to be minimised or even avoided. One of the key problems for Powis-Hughes was that the local electricity company only let them know fairly late during the installation process that an upgrade would be required at all. This delayed the whole project by two weeks. Yet the majority of homes and offices wishing to install a wind-turbine will not need an upgrade as most local energy supplies will be able to cope with the extra output. Despite this, it is worth checking with your supplier first to make sure that they are able to cope with additional output, it may save you a lot of hassle!

Planning permission and the installation of an export meter also became areas of difficulty. The planning regulators of Berkshire County Council were not initially receptive to the idea of a renewable capability blotting the agricultural landscape, but the proposal was approved on appeal. Unlike with the supply difficulties mentioned above, there appears to be no easy way getting through the planning permission process should you find yourself based in an obstinate council. However, there are set regulatory guidelines which should normally find in a wind turbine’s favour.

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Similarly Rafe found that the installation of an export meter was also hindered by the conflicting interests and responsibilities of different organisations. Again the only option for Rafe seemed to be to ‘grin and bear it’, there being no way to fast-track himself through the process. Rafe did however mention that just remembering the meter was his way of billing the electricity company (and exacting some sort of revenge) managed to help him through the ordeal. Once installed, the meter shows how much electricity is being supplied to the national grid and thus how much you are owed (albeit at a miserly rate of 3p/kWh). Similar problems may arise for other purchasers of an export meter but it is worth noting that once local renewable energy generation becomes more common, and electricity companies become used to the installation processes, having an export meter installed should become less of an issue. Yet there are no guarantees!

Once these obstacles were overcome Rafe was finally ready to have his wind-turbine, and Powis-Hughes were primed to be the masters of their own energy-generating destiny.

The 6kW Proven 11 wind turbine was installed by Industrial Maintenance Services on April 20th. It has a maximum electrical output of 6kW, achieved by three downwind, self- regulating blades with a rotor diameter of 5.5m, and has three Windy Boy inverters to transform the wind into electricity. The predicted figures shown in the table above for the turbine’s carbon reduction and profitability were obtained by entering the office’s post-code, terrain and available space, and estimated electricity usage onto the RenSMART website (note: a less accurate prediction can be obtained by just entering your potential site’s post-code on the home page). It was these figures that encouraged the company to have a turbine installed, but eight months since the installation, how accurate have they proved so far? And is Rafe getting value for money?

Once these obstacles were overcome Rafe was finally ready to have his wind-turbine, and Powis-Hughes were primed to be the masters of their own energy-generating destiny.

The 6kW Proven 11 wind turbine was installed by Industrial Maintenance Services on April 20th. It has a maximum electrical output of 6kW, achieved by three downwind, self- regulating blades with a rotor diameter of 5.5m, and has three Windy Boy inverters to transform the wind into electricity. The predicted figures shown in the table above for the turbine’s carbon reduction and profitability were obtained by entering the office’s post-code, terrain and available space, and estimated electricity usage onto the RenSMART website (note: a less accurate prediction can be obtained by just entering your potential site’s post-code on the home page). It was these figures that encouraged the company to have a turbine installed, but eight months since the installation, how accurate have they proved so far? And is Rafe getting value for money?

In terms of raw data the Powis-Hughes office has used 6,800kWh of electricity since the wind turbine was installed in March. During this period the turbine has generated 5,090kWh, leaving an approximate difference of 1,700 kWh between use and generation. However, the amount of electricity imported from the national grid will exceed this figure as not all of the generated electricity will be used as the office’s power supply. On stormy days when the turbine is generating at capacity electricity will be exported to the national grid. Likewise on calm days electrical use will exceed generation meaning electricity will have to be imported. This is generally bad news for renewable producers as import price is approximately four times the amount you receive for exporting it! However the website does make allowances for this and some importation from the grid should not affect payback time or return on investment.

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So from these first eight months, and assuming that output is maintained, the RenSMART system is able to give more accurate predictions for the full year. That is, approximately 9,080kWh electricity will have been generated and 11,090kWh will have been used by the office. What does this mean for the company’s investment?

The first thing we can tell is that the extrapolated figure for micro-generation of 9,080kWh per year is 88% of the original predicted figure made on the RenSMART website of 10,325kWh. If the turbine continues to generate at this level then the reduction in CO2 emissions will be a considerable 99,240 kg. This is less than the initial prediction of over 112,000kg of CO2 yet it is still substantial enough to be considered worthwhile, 1000,000 kg is a large weight by most people’s reckoning!

The website also originally predicted for the payback time to be 7 years and the RoI to be an impressive 170%. This can now be adjusted to 8 years and 157% respectively. Although slightly down on the original estimate the figures still strong. Further to this once the savings made on the initial cost price are accounted, the payback time and RoI are closer to those predictions originally made. Therefore it seems to be so far so good for the Powis-Hughes and Rafe’s investment.

Actual Price£27,000 Ex. VAT
Pay back time7 years (2017)
Return on Investment168%
Feed-In Tariff Rate26.7 p/kWh
CO2 Avoided99,240 kg
Yearly Generated9,080 kWh
Exported1,705 kWh
Total Generated181,600 kWh
Table 2: Table of predictions for 6kw wind turbine made on RenSMART website based on first eight months performance.

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This just leaves us with the question of maintenance. Within the deal provided by IMS the turbine has a standard 3-month service, followed by a free maintenance check annually for two years. After then the system will need to be annually checked by a professional as the mast needs to be lowered and re-hoisted. This is estimated to cost in the region of £200 per year. However, the cost is included within the predictions made on the RenSMART website so shouldn’t impact upon the payback time or the return on your investment barring a spectacular breakdown in the generating ability of the turbine. Maintenance of the turbine is usually limited to lubricating the rollers and bearings.

There have been worries for Rafe along the way and these have mainly centred on getting the turbine up and running. The difficulties in getting planning permission and an export meter installed have already been touched upon, but Rafe has also admitted to being worried by the turbine not spinning as much as he’d hoped on a number of days. There can be nothing worse than investing so much in something only for it to sit idle in your back garden! However this is countered to some extent, when Rafe describes his the favourite aspect of his turbine is “seeing it spin like ‘Billy-O’ in stormy weather”. His fears should be laid to rest when he sees the figures for how the turbine is actually performing (that and the first cheque from the electricity company!).

Having a wind turbine installed will not be the answer to everybody’s energy needs, much will depend upon the location and space available to have a worthwhile system put in. In addition many will rightly worry about having to shell out such a large figure to begin with. However, a number of private companies now offer to cover the initial cost of the investment in return for the FITs and electricity company payments. This obviously takes away your profit but will appeal to those wanting to reduce their carbon footprint and reduce energy bills. Now may just be the perfect time to find out how worthwhile it is for you.

Joel is a freelance journalist covering political and ‘green’ issues. If you would like him to write an article for you or your organisation please contact him at joeldbgilbert@gmail.com

You can access the RenSMART estimation tool for free at www.rensmart.com/Tools/SitePlanner