Offshore Wind Turbines T2-T6, municipal

Fig. 1. The municipality owns wind turbines T2-T6
(framed, Bonus/Siemens 2.3 MW). Picture by Sweco,
who did the environmental assessment.

In 2002 the Samso municipality bought five offshore wind turbines. The municipality created a municipal energy company Samsø Vedvarende Energi Aps (Samso Renewable Energy) which takes care of the investment. The surplus from the company is re-invested in energy activities.



The Samso municipality participated from the very beginning in the renewable energy island project (Samso a Renewable Energy Island(external link)). The municipality participated in the steering group for the erection of the offshore wind park.


The municipal board decided to borrow funds and buy five offshore wind turbines. The board had difficulties making the decision, because it was a risky investment to be made on behalf of the tax payers.

Eventually the decision was approved by the authority that supervises the operation of all the municipalities (da: tilsynsstyrelsen), on the condition that the purpose of the company is not business, but to support sustainability or renewable energy projects within the municipality.

According to law the municipal ownership must be via a company with limited liability. The energy company that was established, Samsø Vedvarende Energi Aps, is thus a limited shareholder company with a single shareholder, and the shares cannot be sold publically. The equity capital is 125 million DKK (17 million EUR). The profit cannot be used to cover the daily operation of the municipality, but only for energy related purposes.

Pre-Calculation Based on Sales Material

The price of each wind turbine is the same as the other wind turbines in the park, and the five municipal wind turbines are also operated by the company Samso Havvind. Therefore the simple project balance is similar (see Offshore Wind Turbine T1(external link)).

The price of one turbine is almost 25 million DKK (3.3 million EUR) which explains why the equity of the limited company is five times larger. The annual income depends on the selling price of the electricity. The first ten years the price is guaranteed by the government (feed-in tariff) at 0.43 DKK/kWh (0.057 EUR/kWh).

With an optimistic selling price the internal rate of return (IRR) is 9.1% and a payback period of 10 years.

But the municipality borrowed the investment capital in Kommunekredit which is the funding agency for local governments (municipalities). The interest rate of such a loan is perhaps 3-4%. There are therefore some financial costs that prolong the payback period and diminish the internal rate of return (IRR). Furthermore, the limited company must pay tax on the surplus.

It is an uncertain investment in the sense that the selling price of the electricity was not known at the time of investment. Also, if some of the equipment breaks the repair costs are higher for an offshore turbine than for an onshore turbine.

The electricity selling price is guaranteed by the government, but only for the first ten years (0.43 DKK/kWh or 0.057 EUR/kWh). Thereafter the electricity price is the spotprice on the Nordpool electricity exchange plus a governmental add-on.

Post-Calculation of Actual Project

Fig. 2. Long-term debt in the project company.

Data are not readily available, but we have some of the annual financial statements. It is quite difficult to see how the project balance evolves, because there are many accounting lines that disturb the picture. But, concentrating on the long-term debt, Figure 2 plots the debt.

Apparently the debt decreases reassuringly. After six years of operation, the debt is reduced to almost one third (the initial investment was in 2002, and the wind turbines were commissioned in 2003). In 2006 almost 2 million DKK (267 000 EUR) of the surplus was passed on to finance an energy project instead of reducing the debt.

By extrapolation the debt should be paid back at the end of year 2013, after 11 years.

Turning to the technical side, where the data material is better, the five turbines run as expected. Figure 3 shows the annual production of energy relative to the nominal production. The first year is low, because the turbines were only just installed and did not run a full calendar year. Otherwise they produce a little more than nominal, except for the year 2006, which was a poor wind year nationally. In fact 2006 was the worst year in 27 years of recording.

Fig. 3. Annual production index. The nominal
production is index 100. The average over the whole
period is 99.


Power rating 5 turbines at 2.3 MW = 11.5 MW
Nominal energy production 5 x 7 765 MWh/year = 38 825 MWh/yr (= index 100)
Nominal capacity factor 39% of full capacity
Production to date (31 Dec 2010) 61 500 MWh (all production data are from Energistyrelsen)
Average production per turbine (until 31 Dec 2010) 7 663 MWh/year per turbine (index 99)
Production 2003 29 633 MWh (index 76)
Production 2004 40 227 MWh (index 104)
Production 2005 39 643 MWh (index 102)
Production 2006 35 842 MWh (index 92)
Production 2007 41 682 MWh (index 107)
Production 2008 39 990 MWh (index 103)
Production 2009 40 324 MWh (index 104)
Production 2010 39 164 MWh (index 101)
Production 2011 43 823 MWh (index 113)
Producer Bonus Energy (now Siemens)
Dimensions Hub height 61.2 m, rotor diameter 84.6 m, height from sea level to wing tip 103.5 m.
Foundation Monopile, steel, diameter 4.5 m, length 45 m, 300 tonnes, hammered into the sea bed.
Savings SO2 113 tons, NOx 112 tons, CO2 34 000 tons, particles 2 100 tons
Economy (2002 prices)
Owner Samso municipality through the Samsø Vedvarende Energi Aps limited company.
Start-up date 8 Feb 2003
Nominal lifetime 20 years
Total construction costs 5 times 24 459 750 DKK = 122 mill DKK (16.3 mill EUR)
Original feed-in tariff 0.43 DKK/kWh (0.05733 EUR/kWh)
Turn-key Contractor Deme
Foundation Bladt

  1. %Bladt%
  2. %DanishWindTurbine%
  3. %Deme%
  4. %EnerginetDKTheDanishWindcase%
  5. %EnergistyrelsenStamdata%, T2 has turbine ID 570715000000062933
  6. %LORCKnowledge%
  7. %PaludansFlakOnAMap%
  8. %PaludansFlakProduction%
  9. %SamsoHavvind%
  10. %SiemensWind%
  11. %Vindinfo%
  12. %WindEnergyTheFacts%

Created by system. Last Modification: Thursday 04 April 2013 22:09:21 CEST by jj.