Yes, this is true, though its not clear how hard the Wachowskis fought to keep their original idea.

The only "official statement" I know of is an off-hand comment from one of the Wachowskis on the DVD commentary for one of the director's cuts (I forget which but I think its on the Ultimate Matrix Collection.) They discussed the whole setup for the Matrix and mentions that they "originally had a different idea" before dismissing the question as irrelevant to the story. (e.g. it doesn't matter to them why the machines did what they did, as its just a plot device to get the story started.)

More details about what that original plan was come from some written material based on early pre-release information from the movie. Specifically, Neil Gaiman's short story "Goliath" is set in the Matrix universe and includes this alternate view. I have also heard that the "novelization" of the Matrix included this idea but there's no such novel that I know of; its possible that a novelized version of an early script exists (there's a published version of the shooting script for sale but that includes the story as filmed.)