Siemens Gamesa said the change of chairman was the "logical next step" in the potential merger and integration within Siemens Energy, one that unions oppose due to planned job cuts.

The appointment comes a week after the company missed its full-year core earnings margin target as revenue declined, mostly due to project delays and supply chain disruptions that stalled wind turbine generator production.

Bruch succeeds Miguel Angel Lopez, who had chaired Siemens Gamesa's board since December 2017 and tendered his resignation shortly before the announcement.

Earlier on Thursday, Siemens Gamesa said its board had issued a favourable opinion on Siemens Energy's offer of 18.05 euros ($18.65) per share in cash for the remaining third it does not already own in the Spanish company.

Four independent directors voted unanimously to recommend the deal and the remaining board members adhered to their decision, it added.

Last week, Siemens Energy formally launched its 4.05 billion euro bid after clearance from Spanish stock market regulator CNMV.

Trade unions oppose the takeover and seek to prevent the company planned 2,900 job cuts in its "Mistral" strategy programme.

The offer's employment conditions are "clearly insufficient, if not non-existent, as they do not provide any guarantee of employment protection or working conditions for the staff," the unions said in a report.

During the board meeting to evaluate the takeover offer, union representatives demanded that Siemens Energy maintain the wind turbine maker's current workforce over a five-year period.

They also asked the German company not to outsource activities that could affect employment volumes and to present a comprehensive plan detailing expected synergies and concrete implementation deadlines.

COVID-19 pandemic-related supply chain problems, competition and skyrocketing steel and aluminium prices - exacerbated by the war in Ukraine - have made manufacturing wind turbine components a tough business in recent years, despite strong demand from governments banking on wind energy to wean themselves off fossil fuels.

($1 = 0.9682 euros)

(Reporting by David Latona; Editing by Andrei Khalip and Josie Kao)

By David Latona