Study of an HTGR and renewable energy hybrid system for grid stability

Sato, Hiroyuki  ; Yan, X. 

A hybrid system combining HTGR and renewable energy is investigated to compensate intermittent renewable energy power generation. A new proposal of using the inventory and bypass control devices already built in the gas turbine, is found to be effective to compensate hourly to daily variation of renewable energy. The reactor thermal power remains at constant full power while the heat output is increased or decreased subject to the need of reactor power generation. On the other hand, the massive heat capacity in the graphite core is shown to be sufficient to compensate renewable energy on a time scale of seconds to minutes and up to about 20% of the rated power output of the nuclear plant. Similarly, no additional control devices are required to perform this control operation. These findings demonstrate the technical and economic potential of the HTGR system to maintain the stability of a grid being incorporated with significant portfolios of renewable energy power generation.