The 33-year-old staked his claim for the seat after topping the time-sheet in southern Spain on his first day of testing with the Enstone-based team.
The veteran of 172 race starts has been unattached since leaving Sauber at the end of the 2010 season, after replacing Pedro de la Rosa for the final six races following spells as Mercedes reserve driver and then Pirelli test driver.
Ã¢â‚¬Å“I would have liked to come back to Formula One in different circumstances, but IÃ¢â‚¬â„¢m proud to have been given this chance,Ã¢â‚¬Â Heidfeld said.
Ã¢â‚¬Å“Everything has happened so quickly, but IÃ¢â‚¬â„¢ve been very impressed by what I have seen so far in terms of the facilities and the dedication of the people at Enstone.
Ã¢â‚¬Å“I really enjoyed the test last week in Jerez and IÃ¢â‚¬â„¢ve already settled in well with the guys at the track.
Ã¢â‚¬Å“I have a good feeling for the car, which is quite innovative. IÃ¢â‚¬â„¢m extremely motivated and canÃ¢â‚¬â„¢t wait for the season to begin.Ã¢â‚¬Â
Heidfeld was always the favourite to replace Kubica as the most experienced driver not contracted for 2011, and his experience from 11 years in the sport will allow the team to fully develop the R31 once the season gets under way.
Bruno Senna also got an opportunity to drive the car at Jerez, but with just one season in F1 at struggling Hispania in 2010, the Brazilian was never really in contention for the drive.
Ã¢â‚¬Å“The team has been through a very difficult couple of weeks and we had to react quickly,Ã¢â‚¬Â said Renault team principal Eric Boullier.
Ã¢â‚¬Å“We gave Nick a chance in Jerez last week and he really impressed us. HeÃ¢â‚¬â„¢s quick, experienced and is very strong technically with his feedback and understanding of the car.
Ã¢â‚¬Å“We always said the priority was to have an experienced driver in the car and we feel he is the ideal man for the job. We are pleased to welcome Nick to the team and look forward to a strong start to the season with him and Vitaly in Bahrain.Ã¢â‚¬Â
Heidfeld will make his second appearance for the team on Friday morning for pit-stop practice at the start of the Barcelona test, as well full days of running in the car on Saturday and Monday.
Confirmation of HeidfeldÃ¢â‚¬â„¢s appointment comes on the same day Kubica underwent a final operation on his elbow, with the Pole expected to remain at the Santa Corona Hospital for a further two weeks to allow doctors to monitor his progress before beginning his rehabilitation.
Despite KubicaÃ¢â‚¬â„¢s determination to return before the end of the season in November, Renault could stick with Heidfeld for the entire season to ensure Kubica undergoes a complete rehabilitation and to limit any problems being out of the car could cause.
Should Kubica return before the end of the season the team would have to request special dispensation for him to experience some mileage in the current car, with a ban on in-season testing still in place.
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