"Surplus energy" refers to having extra or unused energy beyond what is necessary for basic functions. It suggests having an excess amount of energy available, which can be used for additional activities or tasks. Full definition
The solar system is providing energy savings of 18 %, while producing 3,500 kWh of surplus energy per year. (interfaithpowerandlight.org)
As a result of the discoveries, researchers are closer to finding energy storage solutions for surplus energy generated from green technologies. (pnnl.gov)
If there is too much surplus energy then the power can also be used to create and store thermal energy to be used later. (scientificamerican.com)