The “pump” will keep the electricity network stable in the event of faults, a job previously done by old power stations.
It will be housed in an agricultural-style shed, a steel frame building on farmland at East Grange Farm, near Sheraton village and the A19 and A179, on the outskirts of Hartlepool.
The “condenser” is a large motor which mimics heavy turbine generators in power stations, a Durham County Council planning committee meeting heard.
“The proposal is to help prevent blackouts occurring in the National Grid, which can occur when there is a fault on the transmission system,” said planning officer Lisa Morina.
“The chances of this happening are extremely low. But as electricity is increasingly being supplied by solar and wind, the chances of blackouts are increasing.
“Therefore, this proposal would offer a clear and effective solution to keep the National Grid moving in the event of a fault.”
No letters were sent to the council about the proposed facility, which would be connected to Hartmoor Substation.
Council departments and Natural England did not object although it was noted there could be “the potential to cause some harm to the landscape”.
Planning officers concluded the scheme was acceptable and made “a positive contribution to delivering renewable energy” in an appropriate location.
They said any visual impact could be eased through landscaping and planting.
Chartered town planner Dan Grierson, on behalf of developer Decerna, said: “Projects such as this are essential if we are going to continue to move to a low-carbon future.”