Reducing maintenance cost for off shore Wind Turbines

A modern wind turbine is designed to work for 120,000 hours throughout their estimated life-span of 20 years. This would be the turbine operating for approximately 66% of the time for two decades. This is far more than modern car engine which is built to last for 4 000 to 6 000 hours of use. This equates to an average of 49 minutes driving a day over the same two decades

From experience, the maintenance costs of a new turbine will be very low but as the turbine ages these costs will increase and also with load demand.

Studies done in Denmark on the 5000 wind turbines installed in the country since 1975 has demonstrated that each new generations of turbines has had lower repair and maintenance costs than the previous generation.

Older wind turbines have an annual maintenance cost which are on average 3% of the original cost of the turbine. Because newer turbines are usually quite substantially larger in size and gives an economy of scale, so you get lower maintenance costs per kW of rated power. This is simply because you do not need to service a large turbine any more often than a small one. Couple this with the constant development of new materials and techniques and you will make savings on the maintenance costs. For modern machines the estimated maintenance costs are in the range of 1.5% to 2% of the original investment per annum.

It is known that the complete Operations and maintenance (O & M) services costs account for approximately 25% of the costs of offshore wind farms. This is relatively high. The cost of operations and maintenance for offshore wind farms is around EUR 0.03 per kilowatt hour of electricity. These costs can be reduced by a third in the space of ten years.” Achieving this calls for the use of innovative tools and processes. ECN is one company which has developed an Operations & Maintenance System which is now ready for launch and will enable the industry to run offshore wind farms at lower costs.

This is done through data collection.Wind farms produce large quantities of data: hundreds of sensors on the turbines collect and send data. Technicians and engineers also collect data. The data relates to areas such as breakdowns, repairs, spare parts that may be required, engineer reports as well as the loads placed on the turbines and how long different components will last. All of this is collected within the O&M system and organised for fast processing.

If it is possible to build up data over a long term and a smart database of operational data which enables fast analysis of it quickly and effectively, you have invaluable information for a sophisticated O&M strategy.”. This will enable wind farm operators to for example plan exactly how many working boats will be necessary, how many people need to be in the maintenance team, what components should be kept in stock and when maintenance must be scheduled. Most importantly it allows a long-term process of continuous cost saving improvements over the wind farms operating lifetime. “That knowledge can result in significant cost savings and prevent turbines breaking down unexpectedly and failing to supply energy.”

Reducing the costs of offshore wind is an essential condition for achieving the ambitions of generating power. The target is based on a cost price that decreases consistently over time. The O&M program with a directed system will an important contributor to enabling cost price reduction and innovation in the same.

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