Turbotricity

There is some really useful information on this on the ESB site here

PRESS RELEASE 26th Feb 2009
Minister Eamon Ryan today announced a substantial increase in the rate that the ESB is to pay for electricity purchased from householders with their own wind turbine or other renewable energy system. Last week the Commissioner for Energy Regulation had announced that such electricity would be purchased for 9c per KwHr, but the Minister has now effectively increased that rate to 19c for the first 4,000 turbines to be connected over the next three years.

The subsidy of an extra 10c applies only to the first 3,000KwHrs annually. This means that smaller turbines, or turbines on poorer sites will receive more support, while limiting the support for larger turbines. This may be fair enough because the intention of microgeneration is to meet a households own needs primarily, not just to install a large turbine for exporting to the grid.

We believe that the move will provide an enormous boost, not just for our business, but for many others trying to create Green Collar jobs. At a rate of 9c, we had estimated that our 2.5Kw turbine would be viable on very windy exposed sites – the new tariff substantially increases the number of sites on which domestic wind turbines become viable. The estimated payback time for a turbine on a site with an average wind speed of 6 m/sec is reduced from 17 years to 11 years by the change. For most householders, the change means an increase of over 50% in overall revenue from their turbine.

We have the best wind in Europe, and a high percentage us live in one-off houses built on good wind energy sites. Any turbine with a proven track record on our Atlantic coastline will find easy access to other EU markets, and this is exactly the sort of opportunity we should be developing here. Our business development had been hamstrung, because up to recently the ESB would not buy surplus electricity.

We are keen to ensure that turbines are only sold where they will work, and is critical of companies who, in the past, sold rooftop turbines in housing estates where they produced little or no electricity. The price increase will only make turbines viable in sites that have good wind conditions, and those in doubt should carefully assess their site. A turbine needs to be wide open to wind from any direction between south-west and north-west, and any turbulence from buildings or hedges upwind of it will decimate the productivity of any wind turbine.

Here are a few photos for media and other use;

Click on the link to see the photo. Right click on the link and select “save target as” to download it as a file.

Quentin Gargan and Dougie Blair of Turbotricity examine prototype turbines Click Here

Quentin Gargan with Turbotricity tower and blade set in West Cork. Click Here

Turbotricity’s Downwind Turbine Design Click Here

How not to fit a wind turbine – David Cameron’s house with a wind turbine which would mostg likely have been ineffective (had it not been in contravention of planning) Click Here (© Getty Images)

We sent out the following press release last night. INN took it up for their syndicated news service to local radio stations, and I’ve done two other interviews so far, as well as receiving heaps of enquires, so it seems to be welcome news!

ESB to purchase electricity from domestic wind turbines

The Commissioner for Energy Regulation has announced that the ESB is to buy electricity from so-called “micro generators” – householders who have their own wind generators or other renewable electricity systems. The price has been set at 9c per unit.

Turbotricity, an Irish company currently developing household wind turbines has welcomed the move. “Up to now, households with a wind turbine had to use a large bank of forklift batteries to store their power, involving additional costs and maintenance. It makes far more sense to sell surplus power to the grid and buy back extra energy when it is needed” said Quentin Gargan, MD of Turbotricity.

The company has argued that there is an opportunity for Ireland to become a world leader in the production of domestic wind turbines. “We have the best wind in Europe, and a high percentage us live in one-off houses in good wind energy sites” said Gargan. “A turbine which has established a reputation for survival on our Atlantic coastline will find easy access to other EU markets”.

Turbotricity, based in West Cork, is launching a rugged 2.5Kw turbine designed for Atlantic conditions. On most sites, the company expects to install these for between less than €12,000, including a free-standing tower and grid controller. The company’s development has been hamstrung because up to now, ESB would not pay for surplus electricity which was simply spilled onto the grid.

“We strongly argued for a higher feed-in tariff to support this industry”, said Gargan. “When it comes to wind energy, the large turbines are dominated by other countries, against whom Irish industry can never hope to compete. However, domestic wind turbines are made with smaller components, all of which could easily be manufactured here, and it is important that Ireland develops a strong industry in this growing market sector. It is our aim to mass produce turbines and bring prices down so that safe and effective wind turbines can have a sensible payback time, and the current offering from ESB will certainly help”.

The Commissioner for Energy Regulation has decided that the ESB offer is to stand as is. You can find their decision document by clicking here.

Its good news – at least we are getting paid something for the electricity we spill to the grid, though a higher feed in charge would have been a welcome boost. According to the CER document, it would require a shift in government policy for any subvention to encourage renewables. The document states that;

The development of a long term investment policy and any premium/support is a matter for Government policy and is outside the Commission’s remit. Additionally, the information gathered by the PES from the interim export tariff, will provide valuable information in terms of time and scale of export, which is critical if an enduring solution regarding export tariff structures is to be developed.

People selling electricity to the grid will have to accept an annual payment from ESB – however, much of the arrangement is temporary, so there is hope of improvements as more microgeneration gets onto the grid.

Also on the plus side, the Commission said that it might extend the number of free interval meters for people putting in their own microgeneration. At present the first 100 such meters are free of charge.

But all of this is beyond the wildest dreams we would have had when we first started developing our turbine – at that time we expected a zero feed in charge, so this quite a bonus and should give us a busy start when we launch our tubine.

Our Proven instructions insisted that the base of the turbine sit flat on the concrete, and be floated into place. We found that most other tower installers don’t do this – it is tricky getting the base level, and ensuring that you have no air under it, and even at that, the vibration over time can soften the concrete under the tower. I’ve seen two systems (including our own) which have slight movement in the base with water ingress under it.

It is essential that the hole for the foundation has vertical sides - a foundation that slopes in towards the bottom would allow rocking...

So we did what many other commercial tower installers do. You put in threaded bar, with a template top and bottom to ensure that the bars are properaly spaced and lined up. Pour the concrete, and then mount the turbine base a few millimeters above the concrete on the threaded bar. You can use nuts and washers under the base to level it.

Drop in threaded bar with plates top and bottom. Iron is optional if you use fibres in cement mix

The whole procedure should take about 4 hours from digger arriving on-site. We used a mini-digger to dig a hole 1.2m wide and 1.5m deep. It is important that the sides are vertical, not sloping in towards the bottom. A turbine foundation must never be shuttered and back-filled, so getting a hole in the ground with vertical sides is essential. In fact, we had trouble sticking to the 1.2m on the width and ended up with a slighly rectangular hole because the bucket on the digger couldn’t get a hole that deep with vertical sides.

Insert pipe for cable run in centre of frame. Cover pipe end and threaded bar to prevent cement getting in

We then set up shuttering around the top of the hole to allow the plinth rise slightly above ground. Because the ground isn’t level the shuttering was 9″ high at the bottom and 4″ high at the top. We set up the threaded bar with its templates top and bottom, and put ironwork at various heights along this. You don’t need iron if you use fibres in the cement mix.

We also dug a trench 1m deep for the armoured cable running from the house to the turbine. We ran a 2″ alkathene pipe from this trench into the centre of the template and the cable will run inside this pipe after the cement is cured.

We covered the end of the pipe with sileage tape, and covered the thraded bar with fingers off an old rubber glove to prevent cement blocking them up.

After pouring concrete, remove shuttering, clean off the threaded bar and leave the whole thing for two weeks to harden off

We needed 3 cubic metres of 40 newton concrete (because our hole was a wee bit on the wide side – normally about 2.25 cubic metres should have been enough).

We poured the concrete and used a vibratory poker to ensure that all air was removed. Then cleaned up our tools and called it a day.

The following morning, we removed the shuttering and cleaned off the threaded bar with a wirebrush. We now have to wait two weeks before mounting the turbine, but in the meantime, we can run the armoured cable to the fusebox and get the wiring done.

Most renewable energy systems have their expertise well developed in other countries. The wind farm turbines are cornered by Denmark, Germany and Spain, solar PV by China, USA, Spain and Germany. There are three renewable sectors in which Ireland could be a pre-eminent player; micro wind, wave and tidal power.

If we are to develop a micro-wind industry in Ireland, we need a favourable tariff in our home market so we can build and sell turbines to ourselves first, and for export second. For that reason, we have made a submission to CER calling for the proposed 9c feed-in tariff for microgenerators to be raised.

Even with the proposed ESB feed-in tariff of just 9c per KwHr, domestic wind turbines will be viable on good sites. You can get the power curve for a turbine and plot it on a calculator which will give you the annual output per annum. For a typical 2.5kw turbine on a site with a mean windspeed of 7m/sec, you will get about 7,850 KwHrs of power per year. Assuming you use half of that yourself, saving 16c and sell the other half to the grid for 9c, that will save you €980 per year.

If your turbine cost you €11,500 to install, the payback time will be 12 years. If your turbine cost €20K, that rises to over 20 years.

Of course, if electricity prices go up during that 12 year or 20 year period (and I’m pretty sure they will) then that payback time will come down. Your tower and foundation have a life of about 60 years, a turbine should last indefinitely but may need new blades after 10 years, and bearings after 20.

However, if your mean wind speed is 6m/sec, the payback time for a turbine costing €11,500 will rise to 16 years, and for a €20,000 turbine, to 27 years.

This is why our response to the Commissioner for Energy Regulation calls for a higher feed-in tariff. If we are going to get an industry moving in this area, it would be a great help to have a feed-in tariff similar to that in Northern Ireland. You can read our submission to the CER by clicking here.

Needless to say, we’ll have a post here when we get a response… In the meantime, the following quote from Hugh Piggott of Scoraig (who runs excellent courses on how to build your own wind turbine).

Why should it necessarily compete against cheap power from polluting engines? …The satisfaction of generating your own power, independently, from a clean endless source, is hard to quantify

Blade Design

Early wind turbines suffered from high levels of noise. In the case of large wind farms, this was partially caused by gearboxes rumbling, but modern domestic generators are designed to work without gears

That leaves the swish of air passing the blades as the only remaining source of noise. In a well designed turbine, this should not be audible above the normal sound of wind in the trees from more than 100m away.

Some Chinese models have straight-cut blades – the blade has the same pitch throughout its length. These are the worst offenders, and if you come across a wind turbine that whistles, poor blade design is the most likely cause. Whistling sounds are high pitched and can travel over a long distance. We once put up a Chinese 300W turbine on an experimental basis – until one day I was visiting a neighbour about half a mile away and heard the whistling…

A properly designed blade has a pitch that varies along the length of the blade. This is because the outside of the blade is travelling a lot faster than the area closer to the hub. The wind is blowing at right angle to the direction in which the blade is spinning. Thus the “apparent wind direction” seen by the blade at its edge, is totally different to the apparent wind direction seen by a part of the blade closer to the hub.

We are working with a blade which has been designed using the latest CAD software for optimising blade performance by having the best possible attack angle along the entire length of the blade.

A side-effect of this is that the blade also runs more quietly.

Planning exemptions only apply to wind turbines that have a sound level below 43db(A), when tested at the nearest dwelling. They also must be no more than 5db(A) above background noise.

For some systems, there will be noise during start up. This is because the inverter on many systems does not cut in for the first three minutes, and the turbine over-spins during this time. We are working to minimise this effect by using an inverter with a low cut-in voltage, so this three minute period will happen during low wind speeds, minimising the effect.

Ireland has probably the most liberal regulations in the EU for installing domestic wind turbines. Basically, small turbines are considered as an exempt development – in other words, you don’t need to look for planning subject to some conditions.

However it should be noted that recently An Bord Pleannala insisted in the removal of a wind turbine because it interfered with the character of the landscape and impacted on the archaeology of the area. Any general exemption from planning is still subject to certain restrictions which are outlined in the legislation (SI 600 of 2001). One of the key restrictions is that if the installation is deemed to interfere with the character of a landscape or a view of special amenity it would still require permission.

There are two sets of exemptions – domestic and agricultural/commercial.

For domestic houses, the total permitted height of the turbine from ground to blade tip is 13m. The distance from any boundary to the base of the turbine must be its height plus 1m. The rotor must be less than 6m in diameter, the turbine can’t be attached to a building, can’t carry advertising logos, and must quieter than 43 db at the nearest dwelling. The full list of exemptions can be downloaded by clicking here.

For commercial turbines, the total permitted height is 20m, the distance from any boundary is its height plus 5m, the rotor can be up to 8m in diameter. There are a few other restricitions in relation to proximity to power lines, airports etc., and you can find the full list of exemptions here

These are not limits on the turbine you can put up – simply exemptions to planning. Provided you are willing to put in a planning application (and are successful) you can go above these limits. There is a risk that by exempting a height of 13m, someone with a site that really needs a 20m tower won’t go to the trouble of putting in a planning application, and will end up with a severely compromised turbine that is inneffective.

As for the boundaries between what is an agricultural site, and what is a domestic site, there are no clear lines that I can see. Cabbage patch anyone?

Turbine cowlings and pinnacle

One problem with many downwind turbines is that because the tower is upwind of the blades, as each blade swings past its lowest point it suffers a shadow effect from the tower.

We are getting around this by setting the turbine on a lighter tubular pinnacle, and using cowlings to minimise the wind disturbance caused by this.

Despite costing about €20K, our old turbine at home has a crude cowling made from plastic sheeting held on with cable ties. The whole lot blew off last winter, and the cowling is shorter than the blades, so the tip of the blade has to pass through the shadow of a huge flange.

So today, we have settled on a design for the cowling and are starting on getting the mouldings done for this. We will have to get an original machined from CAD drawings and get a mould made from this. It’s a costly process, but a solid, well made cowling is essential to the smooth and quiet working of a downwind turbine, and without it, we would suffer a helicoptering sound as the blade passes the tower. Here’s hoping it all works out OK!