Formula One newcomers Renault are confident their engines will be in better shape in 2016 compared to 2015's offering.

Renault will start the 2016 Formula One season in a better position than in 2015 after learning from their mistakes 12 months ago, says director of operations Remi Taffin.

The French constructor will return to the sport with their own team next year after agreeing a deal to take over Lotus, having spent the last five years as engine suppliers.

Renault struggled in 2015 as their power units failed to provide the power and reliability to compete with Mercedes, Ferrari and Williams.

Their customers Red Bull and Toro Rosso only scored 254 points between them, with 15 retirements across the four drivers.

However, Taffin believes they are making big strides as the new F1 seasons looms large and he is confident Renault will benefit massively.

"We arrived at the first winter test [of 2015] believing that we had made a big step forward between seasons. We genuinely thought that we had done a good job," Taffin said.

"It was the case in certain areas, but we were caught out in three principal ways. The first was a significant reliability problem with the pistons. We had another part inside the PU electronics that we could not put our finger on and it continued to be a source of problems.

"The final element is that we braked so late for 2015, taking decisions until the last possible moment. The specification of PU for the first race was determined very late in the day and quite simply we braked too late, and we weren't ready.

"We wanted to make up the gap so badly that we pulled the rug out from under our own feet, but this particular cocktail of problems did allow us to learn a lot and make sure that the same issues will not reoccur in the future.

"We end the season much more knowledgeable and information-rich - unfortunately we did not get the results we wanted, but everything has allowed us to prepare in the short term for 2016 and longer term beyond that.

"We are in much better shape now than we were at this point last year, for sure."