Williams are testing a flywheel kinetic energy recovery system
Williams have ruled out using Formula One's new Kinetic Energy Recovery System (Kers) at the season-opening Australian Grand Prix.
Kers stores energy that would normally be lost during braking and converts it into power that drivers can then use.
It is not yet mandatory and so far no team has committed to using it in the race in Melbourne on 29 March.
"We're clear that we're not going to be using it in Australia, but not clear when we will use it," said a spokesman.
Williams are testing a flywheel kinetic energy recovery system - the device that stores energy under braking - and have set up a company to develop the technology both for Formula One and further applications outside the sport.
Everything related to Kers has been designed with safety in mind so I'm happy that our car will be safe
McLaren's world champion Lewis Hamilton
They added that they will be focusing on the development of slick tyres and will introduce Kers as and when they have a system that can improve performance.
The Kers system gives drivers a burst of extra power at the push of a button in the cockpit.
Most teams have said they will wait until after the final pre-season test next month before deciding whether to take the system to Melbourne.
Although some drivers have already announced they would prefer to run without Kers and others have voiced safety concerns, world champion Lewis Hamilton said earlier this week he was happy with the system in his McLaren car.
"I can tell you everything related to Kers has been designed with safety in mind, so I'm happy that our car will be safe," he said.
"And the way you use it will vary from track to track. Maybe some teams won't run it at every race. But I like it - it's something else to play with in the cockpit, and that's not a bad thing.
"Of course, unlike the engines, which are frozen, Kers development will continue throughout the whole season so it's an area where the teams will be making advances on a regular basis."