The authors omitted to cite a paper32 that introduces the SWITCH optimimization model.
32. Fripp, M. Switch: a planning tool for power systems with large shares of intermittent renewable energy. Environ. Sci. Technol. 46, 6371–6378 (2012).
Note: Owing to technical difficulties, this Addendum was published online on 2 March 2017, whereas the print version states 1 March 2017.