Solar roof, the new Tesla business idea

Electric car maker Tesla has added another product to its lineup: Solar roof tiles. As of Wednesday, customers worldwide could order a solar roof on Tesla's web site. Installations will begin next month in the U.S., starting with California. Musk took to Twitter to confirm the delivery and installation of the tiles. According to his tweet, the first two styles will be in 2017 in the United States, and in 2018 for overseas orders.

The glass tiles were unveiled by Tesla last fall just before the company merged with solar panel maker SolarCity Corp. They're designed to look like a traditional roof, with options that replicate slate or terracotta tiles. The solar tiles contain photovoltaic cells that are invisible from the street.

Pricing and availability have been the biggest questions surrounding the shingle-based system. In a company blog post Wednesday, Tesla said its system will cost roughly $21.85 per square foot, citing Consumer Reports figures that said Tesla's system would need to beat $24.50 to be affordable. The roof is guaranteed for the life of the home. Tesla said it can't cover an entire roof in solar shingles, partly due to the presence of obstructions like chimneys and skylights and to local codes. It will use a mix of active and regular tiles based on data gathered from Google's Project Sunroof about the energy generation potential, product cost, available tax credits and other variables for a given address.

Tesla CEO Elon Musk wouldn't say how many orders the company expects to get this year. "It will be very difficult and it will take a long time, and there will be some stumbles along the way. But it's the only sensible vision of the future," Musk said.

Tesla’s long-term goal is to offer solar panels to its customers. In November 2016, Tesla completed the $2.6 billion acquisition of SolarCity Corp., which was founded by Musk’s cousins Peter and Lyndon Rive.