The marketplace has developed several strategies for the operation and maintenance (O&M) of wind turbines. The O&M programs available cover scheduled maintenance, which includes routine, semi-annual maintenance activities. The programs can also cover unscheduled maintenance, which is usually related to drivetrain component failures and blade failures.
The management of risk related to maintenance costs is the driving force in selecting the O&M program that best fits the needs of the owner. The average gearbox life is approximately seven years. The other major components – main shaft bearings, generators and blades – also have average life expectancies below the original 20- to 30-year service life given to wind turbines. So, the inevitable risk is not if, but when the failure occurs, who is going to pay? Therefore, you will see a shift in risk as you look at the available O&M strategies. I will focus on four popular variations of the O&M strategies available at this time.
OEMs. Original equipment manufacturers (OEMs) provide a full-service program, including both scheduled and unscheduled maintenance activities. This allows the OEM to employ permanent technicians at the site for ongoing, continuous services. This is usually the most expensive option, as it shifts all of the risk onto the OEM and allows the owner to have a very stable expected cashflow.
ISPs. Independent service providers (ISPs) provide a similar service to what was previously described in the OEM choice, with one main exception: Major component parts are charged additionally when needed. Although some ISP programs include a minimum of major components, this can also be expensive but does shift some of the risk back to the owner, as there would not be an unlimited supply of spare parts included.
Self-performers. The owner provides all services, as it self-performs all scheduled and unscheduled maintenance activities. This is, on the surface, the lowest-cost solution, as the cost does not reflect the risk that must be budgeted for major component failures. Basically, this strategy puts 100% of the risk on the owner. This can be offset by the purchase of an insurance program but would drive the cost for this strategy up because it would shift the risk from the owner to the insurance company.
Hybrid strategy. A popular strategy, a hybrid, involves the owner either self-performing or hiring an ISP to perform the scheduled semi-annual maintenance, but it has the option of utilizing the OEM or the ISP to perform the major maintenance, including drivetrain and blade maintenance and replacements. This cost is sensibly in the middle of the choices, as this becomes a shared risk between the owner and the third party.
Each owner has to manage its risk as it relates to the possibility of major component failures. The urban legend that began in this industry that wind turbines last 20 years without maintenance has proven to be false. The owners are now faced with the harsh reality that major failures are real and do happen.
Some owners can mitigate their risk by installing aftermarket equipment that will monitor the conditions of wind turbines. The monitoring systems provide feedback and can indicate when a component is reaching the end of its useful life. The result can give the owner the opportunity to make lower-cost repairs to its turbines and avoid the larger catastrophic component failures. Examples of these systems are vibration monitoring and real-time oil monitoring.
Additionally, when replacement components are installed, the owner can limit its risk by utilizing improved materials in the gears and bearings. The owner can implement improved lubrication programs. These aftermarket improvements extend component life and further limit the risk.
There are many choices in the marketplace. You cannot simply run a wind farm like driving a modern automobile – just put gas in it and occasionally remember to change the oil and forget about it. Maybe wind turbines will get there someday, but for now, the owner needs to be smart about it. You must have an understanding of O&M costs and major component failure costs to guide you in your strategy selection. You must pay attention to innovations in the market, always looking for that better mousetrap that limits your risk and improves your production.
Unfortunately, this industry was described as a 20- to 30-year maintenance-free system. This is wrong. It’s just the opposite. It will take continuous improvements, just like in the auto industry. One day, wind turbines may be maintenance-free, but until then, pay attention, and manage your risk. – Judah Moseson
Judah Moseson is vice president of business development at Cooke Power Services. He can be reached at firstname.lastname@example.org.