"Which isn't a bad thing, I think on day one it's a lot better platform to work from than what we had this time last year.
"There wasn't any whiplash or anything like this... but I'm a bit happier and it's a good start, it's probably all we can ask for, for now.
He hopes more performance will come from the unit, either later in this week's test or during the second group of four days at the Catalunya track in March, when the focus moves away from reliability.
"We are still not on race trim, in terms of power, and we don't have all of the bolt-on bits on it at the moment
," he added.
"For now it is as expected.
"The team did say 'expect something similar to last year', for the first test at least
"It's pretty much that for now. I would say it's a decent start."
"There's a difference - it's obviously not as powerful as the Mercedes engine and you can feel that," he said.
"But there's benefits as well - the driveability is good, the Renault engine guys are working very well. We've been working with them over the winter and they've got a good handle on the procedures, the driveability of the engine.
"But, at the moment now, still definitely behind Mercedes on power."