Separately, NRG today reported it swung to a quarterly net profit of $47m, or $0.24 per share, from a $136m loss, or $0.37 per share a year earlier.

New Jersey-based NRG will now originate solar system contracts with its residential electricity customers and then sell them to Sunrun and Spruce Finance, who will provide support over the contract life.

California-based Sunrun is one of the largest residential solar installers in the US.