LONDON, July 15 (Reuters Breakingviews) - Another year, another profit warning from Siemens Gamesa Renewable Energy (SGREN.MC). Shares in the wind-turbine maker plunged 17% on Thursday morning, wiping nearly 3 billion euros off its market value, after it admitted soaring raw material costs might propel it to an operating loss this financial year read more . After a similar goof in 2019, investors can be forgiven for questioning its ability to hit a 10% operating margin target. Chief Executive Andreas Nauen’s admission is particularly striking given the money pouring into renewable energy and – until recently at least - the sector’s rapidly shrinking costs. His recent complaints about competitive pressures also invite unflattering comparisons. Shares in rival Vestas Wind Systems (VWS.CO), which suffers the same cost pressures, fell 6% on Thursday morning. Yet over the last two years, the Danish company’s shares have outperformed Siemens Gamesa by 23% and at $36 billion, it is now twice as big. Nauen needs to turn things around in more ways than one. (By Ed Cropley) On Twitter http://twitter.com/breakingviews Capital Calls - More concise insights on global finance: Mastercard’s India slip is not too badly timed read more Bargaining like Beckham produces a solid strike read more EU lights slow-burning fire under carbon prices read more Bank of America makes little hay as sun shines read more Guy Hands tries late entry to housebuilder party read more