Technology enabling the UK power grid to control the charging of electric cars could correct only 6 percent of the additional imbalance in supply and demand by 2020 caused by rising use of the cars, a study said on Tuesday.
The technology could also provide a vehicle owner with a modest annual financial return of 50 pounds, National Grid estimated in a report published together with engineering company Ricardo.
Utilities and grid operators fear that the large-scale introduction of electrical cars could cause supply problems when millions of car users charge their vehicles during peak demand hours after returning from work.
With a system in place, the grid operator would be able to interrupt or vary the charging of an electric vehicle according to grid imbalances during peak and off-peak times
The UK government said on Monday that it expected 60 percent of all new cars registered in 2030 to be electric.
Another option considered by the industry is to invest in vehicle-to-grid (V2G) technology that also enables transfers from cars back to the grid, known as reverse charging.
The study said vehicle owners with V2G technology could reap annual revenues of 600-8,000 pounds, depending on the vehicle's size.
But it also said that "very significant capital cost and balancing limitations ... would serve to render the fleet scale roll-out of the V2G balancing service uneconomic" if extended to owners of single cars.
V2G operation "may be attractive for owners of captive vehicle fleets such as industrial or local delivery vehicles ... where interface costs might be shared across multiple vehicles or battery packs," the report said.