High Efficiency Operational Reserve by SOFC for the Effective Grid Integration of Variable Renewable EnergiesFumihiko Yoshiba, Tohru Yamamoto, Hiroshi Morita, Yuji Hanai, Isamu Watanabe and Yoshihiro MugikuraE3S Web Conf., 113 (2019) 02015DOI: https://doi.org/10.1051/e3sconf/201911302015