Thermoelectric energy storage system having two thermal baths and method for storing thermoelectric energy

A method for storing and retrieving energy in a thermoelectric energy storage system, comprising:

• a.) charging the system by heating a thermal storage medium, wherein the thermal storage medium circulates between at least one hot storage tank coupled to a cold storage tank via a first heat exchanger, wherein heat from a working fluid is discarded into the thermal storage medium in the first heat exchanger;
• b.) discharging the system by heating a working fluid in a working fluid circuit by transferring heat from the thermal storage medium to the working fluid in the first heat exchanger and expanding the working fluid through a thermodynamic machine;
• c.) connecting a first thermal bath to the working fluid circuit during charging to minimize the temperature difference between the first thermal bath and the hot storage tank;
• and
• d.) connecting a second thermal bath to the working fluid circuit during discharging to maximize the temperature difference between the second thermal bath and the hot storage tank.