Siemens Energy's wind turbine division Siemens Gamesa is planning to cut 4,100 jobs, or around 15% of its workforce, the unit's Chief Executive Jochen Eickholt said in an internal letter to staff seen by Reuters on Tuesday. "Our current situation demands adjustments that go beyond organizational changes. We have to adapt to lower business volumes, reduced activity in non-core markets, and a streamlined portfolio," Eickholt said in the letter.