By Alan Baldwin
SPIELBERG, Austria (Reuters) - Triple world champion Lewis Hamilton fears he may have to start two of the Formula One season's remaining 13 races from the back of the grid, handing Mercedes team mate Nico Rosberg a significant advantage in the title battle.
The Briton will have a fresh power unit for Sunday's Austrian Grand Prix but he told reporters that meant he had reached the limit on some components.
Each unit has six elements, of which the engine is one, and using more than five of each in a season incurs automatic grid penalties.
"I’m starting with my last (power unit) this weekend, I will have at least one race where I start dead last, most likely two," said Hamilton, who is currently 24 points behind championship leader Rosberg.
"The worst thing is that I’m the only Mercedes driver to have had that (unreliability).
"Considering that we are THE Mercedes team, if there are 40 engines you would hope we have the best of the 40 but that’s just the way it goes," he added.
"I just have to do the best I can with the one I have now and the one or two I get beyond that."
Mercedes supply three other teams -- Williams, Force India and Manor -- apart from their own but Hamilton has suffered more reliability problems than any of the eight drivers using the same engines.
Mercedes said the champion was on his fifth turbocharger and fifth motor generator unit (heat), but only his third engine.
"I think it's inevitable he will get a penalty at a certain stage," said Mercedes boss Toto Wolff, while adding that the team hoped to limit the damage to one extra unit.
"I wouldn't say two. The guys are so revved up around (engine head) Andy Cowell, so motivated to sort it out, that I have zero doubt they will sort it out."
Hamilton said he would aim to take any penalty at circuits -- such as Monza or Spa -- with the most chances of overtaking and making up ground.
"I have to go into it thinking I can still win it. There could be safety cars, could be all sorts of things. I try to have an optimistic view on it but it's not that easy to overtake in some places," he said.
"So essentially the chances of Nico winning and me finishing second or further back are obviously higher."
(Editing by Ed Osmond)