Small wind turbines are turbines with a maximum blade-height of 49 feet (15 meter) and generate relative low power. Their purpose is to use them in urban areas, but can be placed in any location. They claim to (partially) provide power for peoples own household.
Little is known about the real performance of these small wind turbines. So 4 Dutch groups decided to start a project to test these small wind-turbines. Recently the first test results were published on the internet. After some calculations by OliNo we got some interesting results. The results show that a photovoltaic (PV) system is more cost effective than the best performing small wind turbine….
In 2005 four Dutch groups started together the project (Dutch website) to test the real performance of small wind-turbines. The groups are: DELTA N.V. (power-company), Provincie Zeeland (local government), Gemeente Sluis (local government) and stichting Zeeuwind (wind-power cooperative). Some time later Greenlab, a joint venture between ENECO and Greenchoice (both power companies), joined the project. The project is run by this unique co-operation of these five groups.
They found a good location for the tests in the Technopark in Schoondijke (Netherlands). The location is near the Dutch coast. There are several reasons why this location is suited: The average wind-speed is high compared with a location inland and it is an open field with no obstructions. Electricity production in urban areas which are less windy and have more obstructions will therefore be lower compared with the test field.
Location of the Test Field
The test field is part of a unique experiment. This is the first time that several wind turbines are tested at the same time, in the same test field with the same wind conditions. This makes it possible to easily compare the wind turbines with each other on efficiency, reliability, cost of ownership, impact on the environment and sound pollution.
This test shows if these small wind turbines are economical / technical feasible and fit into geographical planning. It is important to have renewable energy generation and if this test has positive results this may stimulate more renewable power installations.
On 7 November 2007 the test field was officially opened by Marten Wiersma, the deputy of the Province Zeeland. After the start signal the test started.
During the first period of the test some some wind turbines have some start-up problems and needed to some adjustments to generate good test results. In an agreement with the participants it was decided to not include the test results of this first period (until March 2008) and give the participants the opportunity to adjust their wind turbines where necessary.
The first test results (Dutch report) do not look to good. The amount of electricity produced by the wind turbines in the period between April 2008 an September 2008 is shown in the table below. To get a better insight in the cost efficiency of these small turbines I have extrapolated the numbers. I assume that the expected life-time of these wind-turbines is at least 20 years and that they will operate with the same efficiency as during the test period. I do not take into account the additional costs like maintenance. With these assumptions I can now calculate the price of the generated electricity per kWh.
Images of the website Kleine Windmolens Testveld Zeeland are used with the explicit permission of the photographer
The calculations show that there are big differences between the cost efficiency of the turbines. The cost vary between € 0,35 / kWh for the best performing wind turbine and €12,44 kWh for the worst performer. This is more than a factor of 35! These numbers also show a huge difference for the cost per kWh between these small wind turbines and big wind turbines. Here is an example:
An 2MW wind turbine like the Amstelvogel of wind cooperative the Windvogel cost € 2.104.600. The yearly production is 4.4 GWh. With an expected life-time of minimum 15 years the price is € 0,032 per kWh.
I did not take into account, as with the small wind turbines, the maintenance costs of the turbine to make a fair comparison. I also did use a Net Present Value calculation to keep it simple. Future cash-flow like maintenance and changing price of electricity are not included in the calculations.
Compare with PV System
Lets compare the price per kWh with a photovoltaic (PV) system. I assume that the PV system has a minimum life-cycle of 25 years. Let take a 2500 Wp PV installation with a cost price of € 5,- per Wp. The yearly production is around 2250 kWh. This results in a price of € 0,22 / kWh using a life-cycle of 25 years.
The production results of the small wind-turbines in the first test period are disappointing. The results show that a PV system is more cost effective than the best performing small wind turbine.