The story
RESOL was founded in Hattingen in 1977, where the founder produced the first solar controllers in his own private flat. A few years later, the enterprise moved to the neighboring town of Sprockhövel, but moved back to Hattingen into a new building in 1998. In 2007, another new building was added, and currently (April 2009) an annexe to the first plant is being built. It will be inaugurated in summer, increasing the total plant and office space to 6,600 m².
In 2009, RESOL employed 160 people, and in 2008, turnover of 29 million euros was generated.
From Wikipedia’s article on RESOL, shared under CC BY-SA 4.0.4