Several blog posts ago, Ann Pattison from Lufft USA introduced you to the new WindBridge™ smart device from Nor-Cal Controls Inc. solving communication barriers for wind farm operators. The device facilitates the connection of wind sensors such as VENTUS-UMB to the programmable logic controller (PLC). Through this, the turbines can run maintenance-free for a long time thanks to the robustness of the new wind sensor models. More about the cost benefit analysis of VENTUS used together with the WindBridge in the following post…
Project operators know that all wind turbines utilize a wind sensor to correctly orient the nacelle into the wind for optimum power production. If the sensor goes down or out of calibration, the wind turbine wind sensor failure mode is extremely costly, especially if the issue is not discovered immediately.
For example, a single GE 1.6MW turbine out of operation for 24 hours will mean energy losses of approximately $1000 or more. Revenue losses add up quickly if one multiplies these losses for the number of turbines down. In an icing event, when the most productive winds occur, up to 20% more can be lost due to the faults at the wind sensor. The replacement costs of the sensors themselves is also a large expense when it occurs too frequently.
It’s easy to see why reducing losses is paramount, but one must not discount costs of sensor maintenance and replacement when operating a wind farm. Skilled maintenance workers can solve a problem quickly, but costs of their time is valuable and no maintenance crew likes the idea of having to climb up-tower to fix a sensor, after driving an hour or two to the site, in freezing cold weather. Maintenance crews should be working on the daily task of increasing energy based availability for a project, not working to keeping wind sensors from failing.
In an effort to demonstrate cost savings and the long term reliability of making the switch to Lufft VENTUS with WindBridge™ from Nor-Cal Controls inc., the graph above shows an accumulated cost benefit over the course of three years of a project. Since projects live twenty years or more, its clear that benefits would only increase over time.
The data used in this graph was taken from a series of interviews with project maintenance personnel, where they informed us that on average 40% of mechanical wind sensors will need annual replacement due to failure and that at least 20% of the losses are due to icing on mechanical sensors. Graph also shows sensor replacement for mechanical sensors as once every 4 years for a single turbine.
Here some interesting figures about wind turbines at a glance:
- $40 per turbine per hour energy loss
- 1 GE 1.6MW turbine produces ~3500 mwh/year
- $0.10 per kwh energy price
- 5 hours down per replacement sensor
- $1,500 cost to obtain and install a typical replacement mechanical anemometer (approx)
- $5,000 cost to obtain and install a replacement ultrasonic sensor (approx)
- $2,500 additional workaround costs per year per project site
- $300 to calibrate a mechanical sensor per year
- At least one mechanical wind sensor per year replaced