Contact Energy has heard it risks becoming a dinosaur company like New Zealand Post, who did not predict what email was going to do to its business.
That warning shot was fired by an investor, Robert Murray, during the power firm's annual general meeting in Wellington on Tuesday.
He said self-generation, such as solar, could render electricity companies redundant in a couple of decades.
Contact Energy chairman Grant King suggested his business was relaxed about alternative energy, because there was little state support for solar.
He said there were not significant subsidies for some of these technologies in New Zealand.
Mr King said overseas some of these technologies have been heavily subsidised, although some of the subsidies have now been withdrawn as the economies of those countries come under pressure.
The shareholder also accused Contact Energy of a lack of vision around technology.
But chief executive Dennis Barnes said the company was up to speed to with how power generation was changing around the world.