Government Goals for Wind Power Create Opportunities for Repair Companies
Wind power is good for the composites industry and offers profitable opportunities even for companies not directly involved in wind blade production, said Greg Rose, technical product manager for ITW Plexus.
The U.S. government has big plans for wind energy and that means big business for manufacturers and especially for repair services. By 2030, the goal is to have 20 percent of the energy needed for domestic use produced by wind. That means existing generators, as well as the thousands not yet built, will have to be repaired.
“To meet the energy goal, rotors will have to get bigger,” Rose said. “Doubling the size of a rotor blade increases the power generated four times. Towers will also have to be higher since winds are faster at higher elevations. Higher towers and bigger blades along with the sheer numbers of generators needed mean more and more off-shore wind farms. All those statistics signify on-site repairs will become more economically viable as the cost of removing, transporting and replacing parts goes astronomical.
“The causes of blade failure are many and complex,” Rose said. “The most common problems are caused by manufacturing flaws causing many blades to need repair from day one. Some problems are purely cosmetic but some are basic engineering problems including poor selection of materials or poorly designed joints.” The environment in which the turbines operate lends itself to damages from lightening, ice, erosion, fatigue and even birds. These diverse problems require a diverse tool kit of materials and knowledge of the right repair medium for the job depending on the size of the blade, the access to the damage and the ambient conditions.
Acrylics or methacrylates, for example, require additives that make them more flexible and can be customized for use even in areas that can’t be prepared or cleaned properly. Epoxies are reliable and are good at highs temperatures and are able to self clean a surface but require surface preparation and a dry bonding area. The bonding of urethanes however can be improved by a slightly damp environment, Rose said.
Polyesters can be used to fill in gaps or holes and are good for modifying poor joint design. They can also be weighed and mixed on site to adjust the cure rate for each situation. These are just a few of the factors that impact the repair job and each repair must be considered on a case-by-case basis.
Rose stated that one of the problems facing the wind blade repair industry is a lack of best practices or industry standards. As a new industry, wind generator manufacturing is learning as it goes about what works and what doesn’t. Each failure and repair is now being studied to help develop new procedures and guidelines for the future.
“When somebody’s blade breaks, everybody gets hurt. There is an urgent need for industry standards.” Rose said.
