ELGIN, Ill. — Siemens is spending millions of dollars beefing up its manufacturing capacity in the U.S. and Germany in a bid to increase its market share of environmental products.

The Munich-based company unveiled plans Monday to spend $20 million expanding an existing plant in Elgin to build mechanical drives for wind turbines. Last week, Siemens said it would shell out nearly $280 million in Germany expanding production of items that serve the energy and resource processing sectors.

The company’s environmental portfolio is expected to generate nearly $39 billion in revenue by 2011, Siemens said Monday. In fiscal 2007, sales of Siemens’ environmental products exceeded $26 bllion, compared to $14 billion in sales for competitor General Electric. GE plans to sell $25 billion worth of ecomagination-related products annually by 2010.

“We’re significantly outpacing our competitors in this area,” company President and CEO Peter Löscher said Monday while speaking at the Siemens Media Summit in London.

Just about every Siemens division is producing products for its environmental portfolio, such as gas turbines, energy efficient lighting systems, eco-friendly trains and the modernization of aging power plants. Products in this portfolio must either reduce greenhouse gas emissions or address water and air pollution challenges.