Before revision:  The availability of an analytical solution paves the way to an efficient market calibration of model parameters . As case studies, EEX German electricity and TTF Dutch gas markets were considered. Two different single-factor models and a two-factor one were calibrated against market prices: out-of-sample validation showed that a two-factor model outperforms the other two approaches .
After revision:  The availability of an analytical solution paves the way to an efficient market calibration of model parameters is performed. It is shown that the availability of an analytical formula for the variance makes the calibration 14 times faster, thus proving the practical value of tractable and general methods to derive it .