Pertinent facts of the kenetech fiasco

Regarding "Joint initiative on blade failures" (“uåX˜äŠÊ˜·³Ç, May 1997). The author writes that TPI built blades to Kenetech's design and to Kenetech's specifications. Abundant evidence demonstrates that the blades, when used within their designed limits, have performed well. Equally abundant evidence shows that many of the blade users pushed the blades to far greater revolutions than they were designed for in the pursuit of higher profits than heavier use can yield.

1 July 1997

In response to your article, "Joint initiative on blade failures" (“uåX˜äŠÊ˜·³Ç, May 1997), I take issue with the comment of the SMUD wind project manager that as Kenetech's blade vendor we "did not engage in the best business practices in the world."

TPI has been manufacturing composite products since 1966 and has built hundreds of cooling tower fan blades as well as 20,000 wind blades for Kenetech under an exclusive contract from 1979. We are one of the largest composite manufacturers in the US, employing 280 people building a variety of products. Our client list includes Otis Elevator, General Motors, Disney Imagineering, Raytheon, Sierra Technologies and Solectria. I have been building composite parts for over 40 years and understand all phases of composite manufacturing. We use the "SCRIMP" moulding process to manufacture our products. This patented system gives us a VOC free moulding operation, void free laminates, 70% fibre volume by weight, and weight variations of less than 1% between parts.

None of the above makes TPI immune to error, but we have an established reputation that has been carefully earned. The pertinent facts in the Kenetech fiasco are as follows.

TPI built blades to Kenetech's design and to Kenetech's specifications. There is abundant evidence demonstrating that these blades, when used within their designed limits, have performed well, and continue to do so. There is equally abundant evidence that many of the blade users, perhaps encouraged by over zealous Kenetech salesmen, pushed the blades to far greater revolutions than they were designed for in the pursuit of higher profits that heavier use can yield. Failures resulting from use beyond the designed specs cannot logically be attributed to the manufacturer.

A recent report of field failures at various Kenetech sites showed blades to be the least of the problems. The greatest number of failures started with the hydraulic power units, then came the pitch linkage, then cracked gear boxes, then cracked welds on the towers and finally the blades themselves. The point is that this chain of failures can be traced to the same problem of running these machines at loads far greater than what they were designed for. Since blades are the most highly visible element, it is easy to lay the blame there.

Numerous experts in the wind industry have seen our manufacturing process and I have not had a single negative comment on our quality control. We remain fully confident of the quality and cost competitiveness of the "SCRIMP" laminates. Once this issue has been properly investigated and the true facts revealed, TPI will once again be building the best blades in the business. I will say that the next time we will insist on a role in the design and specification process, and a hand in seeing that the prescribed performance limits are observed in the field.