Elon Musk's solar roof technology could help make personal sustainable energy sources more mainstream. In March, Musk announced on Twitter his solar roof technology would be available for order in April 2017. But only two or four styles of roof will be available this year.

During a TED Talk Friday, Musk clarified a bit. "We're starting off with two, two initially, and then the second two will be introduced early next year," he told the Chris Anderson in an on-stage interview.

Read: Tesla Solar Roof Tiles: New Panel Will Fit On Your Existing Roof, Save Renovation Costs

His company is working on four styles of tile. Each has its own look to ideally match a variety of home designs. Smooth glass, textured glass, slate glass and Tuscan glass are all in the works although Musk did not specify which two tile styles would be available this year. 

musk solar roof Textured glass solar tiles is one of the styles on which Tesla is working. Photo: Tesla

The way the roof is designed, the only tiles that will have solar cells behind them will be the ones that get enough sun exposure to create energy. What's so different about Musk's solar roof is that it looks like a normal roof. There are no big bulky panels, so from the street it, looks like a normal roof, but if you somehow got above the roof, you'd be able to see the solar cells behind the tiles.

Currently solar roofs involve affixing panels atop of a normal roof. It doesn't exactly blend in or look as sleek as what Musk has in mind for the future of solar. Additionally, his tiles are designed to last: They're made of toughened glass. "This is toughened glass, like well after the house has collapsed and there's nothing there the roof, the glass tiles will still be there," Musk said after explaining his company even considered making the warranty "infinity."

In addition to the longevity of the roof, he said he's confident it would be affordable and look good too. Essentially, he said the cost of the roof would be less than the cost of a normal roof plus the cost of electricity.

He said he thinks eventually most homes will have solar roofs. Traditional roofs last about 20-25 years. There are people who aren't looking to replace the roof on their homes quite yet, he said, but in 15-20 years, he said he thinks "it would be unusual to have a roof that does not have solar." That's because most homes in the United States have enough roof area to power the needs of the home although that depends on location. 

So while some of the tiles will be delayed, design and production are well underway. 

Anderson and Musk begin discussing the solar roof technology about 22 minutes into the talk.