Wind Turbine

current turbine performance


The Wind Turbine was installed in 2011.

The various sections of the wind turbine completed the journey from Lyness to Ore Brae and were assembled in situ.

Here are some photographs showing the various stages.

In order to take the left-hand turn from Lyness to Ore Brae required making a circular tour of the Hoy Hotel! Once up the hill and at the site the sections had to be lifted off the trucks and then be lifted on top of each other and secured into position.

Update Nov 2020

As this project has recently slipped into its tenth year of operation we thought it might be a good time to circulate an update as to the story so far, whilst also providing some insight as to some of the challenges that lay ahead. An amount of the information will already be well known to some community members, but has been included / repeated to benefit those who have joined us more recently.

The Island of Hoy Development Trust (IoHDT) started the project in 2008 and after early feasibility studies, and having identified a site, it obtained funding for initial project development alongside very similar projects on Eday, Shapinsay, Rousay and Stronsay.

The IoHDT immediately formed a trading subsidiary, Hoy Energy Ltd (HEL) and charged them with the task of obtaining capital funding and developing / completing the turbine project as modelled and allowing the targeted outcomes to be achieved.

In March 2011 HEL achieved closure on a £1.74m financial package with 90% funding from the Co-op Bank – repayable over 15 years. The €900k Enercon turbine was ordered from Germany and the £800k civil engineering works started in early May. The turbine went live and started generating to the Orkney distribution grid on October 20th 2011.

The turbine is an Enercon E44 which stands on a 45m tower, has a rotor blade diameter of 44m and measures 67m at its highest point. When generating at full power it produces 900kW and exports to grid at 11,000 volts.

In order to produce 900kW the turbine requires a steady wind speed of minimum 14m/s (32mph) which will allow it to spin at 33rpm under full blade pitch. If the wind speed exceeds 28m/s then the turbine automatically feathers its blades to a neutral angle and shuts down into storm mode. The relationship between wind speed and generation is more cubic than linear, so sadly if the wind speed drops 10% then output will drop nearer to 30%. Whilst the turbine does an excellent job of adapting to all wind speeds the days where a continuous 900kW output is achieved are indeed quite rare, often a brisk day will see the turbine churning merrily at 30rpm but will likely be only be producing around 500kW.

The annual production target in the financial model (used to obtain the bank loan) is 2,294,000 kW/h. To date we have managed to hit this target every year except for two, 2015 and 2019.

As the project qualified for a feed-in-tariff in 2011, a government generation subsidy, the income it obtains is proportionally higher than any current wind farm project could obtain as the FiT is now closed to new applications.

Our project sells all of its generated energy to the national grid via a power purchase agreement (PPA), currently with NPower, which generally achieves between 3p and 5p per kW/h dependent on market prices and seasonal trends. In addition we claim a FiT of 12.7p per kW/h, so total income is currently around 17p per unit, roughly the same as most of us pay for our domestic electricity.

Annually the project will generally gross between £370k and £450k, of course dependent entirely on wind levels as well as other factors such as breakdowns and export limitations from grid constraints. Due to the high levels of bank funding the project is subject to tight financial controls, managed quarterly by the Co-op Bank with formal accounting audits being completed annually by Scholes Accountants in Kirkwall.

HEL only receives money earned by the turbine from the bank (quarterly waterfall payments) when all pending loan payments have been made and various financial covenant tests have been passed.

HEL employs part time staff to operate and monitor the turbine on a 24/7 basis, as well as conducting the administrative tasks, covering everything from risk assessments and health and safety management through to organising maintenance and of course the all-important monthly energy sale and FiT claims.

The HEL management team consists of five directors, two of which are common to the IoHDT board. The team as a whole benefits from a wide range of experience in the social, commercial and technical arenas coupled with professional legal and financial expertise.

HEL does not pay bonuses or share dividends, with 100% of taxable profits being formally targeted for donation to the IoHDT, using the trusts charitable status to minimise corporation tax. Any amount of trading surplus not transferred to the trust is retained in HEL and formally accounted as an operational reserve in readiness to fund future repairs such as turbine blade replacement, the current operational reserve is £525k

All HEL and IoHDT audited accounts and financial statements are available in the public domain.

Income from HEL to the IoHDT was originally modelled to be around £75k pa starting in 2013, transfers actually started in 2012 and to date have averaged out at £90k pa. This money has been managed by the trust to achieve and maintain the initial project outcomes, which include the community bus service, refurbishment and support of the islands community centres and provision of a community benefit fund.

Information on the community benefit fund, including how it is managed and how awards are made is available from the IoHDT.

HEL have faced many challenges over the past 9 years, including extensive lightning damage on two occasions, extended periods of grid exclusion due to data communication issues and generator winding failures through salt corrosion being amongst the worst. Sub-sea cable failures have also been responsible for reduced income in the last 2 years, an issue that sadly has yet to be fully resolved.

More recently the HEL board are looking at strategies for the post year 12 period, when a prepaid / pre-budgeted service and repair contract (EPK) from Enercon will no longer be available – additionally worrying as Enercon are now looking to diversify their business away from on-shore wind turbines.

Financial provision is also required due to the expectation of blade replacement being required in the next few years, with a set of new blades currently sitting on the Enercon price list at circa €400k ex works, the final cost with shipping, crane mobilisation and engineers would likely see a final figure close to £500k. At the outset we were informed by Enercon that operational life expectancy for an E44 turbine was 18 years, but this could be less in Orkney due to high wind levels.

We are currently in year 10 and so in the not too distant future, probably after the post EPK year 12 situation is clear, the HEL board will be looking at options to hopefully replace the existing project and or exit in such a manner as to maximise community benefit. Hopefully the more recent IoHDT Legacy Project will make some headway towards that goal.

Should anyone want additional information please feel free to contact the IoHDT or any of the HEL Directors, or send an email to

Turbine performance since it was commissioned:

The project has a targeted level of performance based on the turbine site wind yield report. Project financing from the main project funder was modelled using this report and target.

Achieving 100% of this target should comfortably allow projected operational costs to be met as well as provide a surplus for the community benefit fund.

Summer months will likely be below the mean target, hopefully winter months will be above!

Financial Year 2012/13

Yearly Summary: Turbine performance was 95% of target

Turbine performance
Financial Year 2013/14:

Yearly Summary: Turbine performance was 118% of target

Turbine performance
Monthly 2013/14

April 2013

May 2013

June 2013

July 2013

Aug 2013

Sep 2013

Oct 2013

Nov 2013

Dec 2013

Jan 2014

Feb 2014

Mar 2014

Turbine performance

105% of target

75% of target

49% of target

56% of target

63% of target

99% of target

120% of target

167% of target

182% of target

193% of target

166% of target

143% of target

Financial Year 2014/15:

Yearly Summary: Turbine performance was 70% of target (prior to loss adjustment)

Turbine performance
Monthly 2014/15

April 2014

May 2014

June 2014

July 2014

Aug 2014

Sep 2014

Oct 2014

Nov 2014

Dec 2014

Jan 2015

Feb 2015

Mar 2015

Turbine performance

84% of target

28% of target

34% of target

45% of target

88% of target

49% of target

119% of target

121% of target

29% of target *

59% of target *

39% of target *

143% of target

*  Storm damage

Financial Year 2015/16:

Yearly Summary: Turbine performance was 105% of target

Turbine performance
Monthly 2015/16

April 2015

May 2015

June 2015

July 2015

Aug 2015

Sep 2015

Oct 2015

Nov 2015

Dec 2015

Jan 2016

Feb 2016

Mar 2016

Turbine performance

96% of target

121% of target

82% of target

64% of target

52% of target

78% of target

100% of target

140% of target

174% of target

153% of target

120% of target

77% of target

Financial Year 2016/17:

Yearly Summary: Turbine performance was 98% of target.

Turbine performance
Monthly 2016/17

April 2016

May 2016

June 2016

July 2016

Aug 2016

Sep 2016

Oct 2016

Nov 2016

Dec 2016

Jan 2017

Feb 2017

Mar 2017

Turbine performance

101% of target

67% of target

50% of target

62% of target

70% of target

92% of target

105% of target

112% of target

115% of target

140% of target

139% of target

119% of target

Financial Year 2017/18:

Yearly Summary: Turbine performance was 111% of target.

Turbine performance
Monthly 2017/18

April 2017

May 2017

June 2017

July 2017

Aug 2017

Sept 2017

Oct 2017

Nov 2017

Dec 2017

Jan 2018

Feb 2018

March 2018

Turbine performance

144% of target

58% of target

62% of target

61% of target

69% of target

98% of target

144% of target

175% of target

127% of target

130% of target

122% of target

136% of target

Financial Year 2018/19:

Yearly Summary: Turbine performance was 97% of target.

Turbine performance
Monthly 2018/19

April 2018

May 2018

June 2018

July 2018

Aug 2018

Sept 2018

Oct 2018

Nov 2018

Dec 2018

Jan 2019

Feb 2019

March 2019

Turbine performance

69% of target

50% of target

71% of target

44% of target

56% of target

136% of target

151% of target

130% of target

133% of target

119% of target

89% of target

111% of target

Financial Year 2019/20:

Yearly Summary: Turbine performance was 98% of target.

Turbine performance
Monthly 2019/20

April 2019

May 2019

June 2019

July 2019

August 2019

September 2019

October 2019

November 2019

December 2019

January 2020

February 2020

March 2020

Turbine performance

63% of target

54% of target

40% of target

24% of target

39% of target

108% of target

120% of target

110% of target

112% of target

197% of target

173% of target

132% of target

Financial Year 2020/21:

Yearly Summary: Turbine performance was 89% of target.

Turbine performance
Monthly 2020/21

April 2020

May 2020

June 2020

July 2020

August 2020

September 2020

October 2020

November 2020

December 2020

January 2021

February 2021

March 2021

Turbine performance

64% of target

87% of target

49% of target

74% of target

33% of target

85% of target

87% of target

133% of target

140% of target

81% of target

116% of target

120% of target

Financial Year 2021/22:

Yearly Summary: Turbine performance was 86% of target.

Turbine performance
Monthly 2021/22

April 2021

May 2021

June 2021

July 2021

Aug 2021

Sept 2021

Oct 2021

Nov 2021

Dec 2021

Jan 2022

Feb 2022

March 2022

Turbine performance

78% of target

57% of target

29% of target

37% of target

39% of target

59% of target

117% of target

125% of target

116% of target

85% of target

178% of target

117% of target

Financial Year 2022/23:

Yearly Summary: Turbine performance was 97% of target.

Turbine performance
Monthly 2022/23

April 2022

May 2022

June 2022

July 2022

Aug 2022

Sept 2022

Oct 2022

Nov 2022

Dec 2022

Jan 2023

Feb 2023

March 2023

Turbine performance

76% of target

75% of target

80% of target

89% of target

47% of target

97% of target

131% of target

152% of target

120% of target

140% of target

82% of target

72% of target

Financial Year 2023/24:

Yearly Summary: Turbine performance was 96% of target.

Turbine performance
Monthly 2023/24

April 2023

May 2023

June 2023

July 2023

August 2023

September 2023

October 2023

November 2023

December 2023

January 2024

February 2024

March 2024

Turbine performance

70% of target

79% of target

25% of target

55% of target

82% of target

82% of target

132% of target

88% of target

134% of target

163% of target

133% of target

110% of target


Financial Year 2024/25:

Yearly Summary: Turbine performance is currently 80% of target.

Turbine performance
Monthly 2024/25

April 2024

May 2024

Turbine performance

130% of target

80% of target


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