For a while there, there was a chance that solar expansion was in trouble. In the US, the federal Investment Tax Credit is set to end in 2016, which many believe will slow adoption, even as technology gets better than ever. Without an outside funder forcing solar to make good financial sense, the only way the tech could survive is if it started making that same sense all on its own. Now, Elon Musk‘s solar power venture SolarCity has taken another major step toward that goal,announcing a new solar panel product that can produce power for about $0.55 per watt.

The efficiency of the panels themselves can reach 22.5%, which makes them the most efficient residential panels ever created. On the surface, this seems to only mildly outpace the 21.5% efficiency achieved by the prior leader, SunPower. However, the whole appeal of this new SolarCity panel is its affordability, and the venerable SunPower solar cells are much more expensive than the average. We don’t yet have final pricing for these new SolarCity panels, but with the price of solar plummeting in recent years they’ve got to be fairly cheap to compete.

The announcement comes as a result of SolarCity’s acquisition of Silevo, a solar manufacturing startup that boasted a new, high efficiency panel architecture. The company calls it Triex technology, and it incorporates crystalline silicon with thin films and complex tunneling junctions for electron management. What’s important is that the technology is not physically all that different from existing silicon semiconductor structures, meaning that Silevo did not have to reinvent the wheel in order to revolutionize it.

With the acquisition of Silevo, SolarCity also became one of only four “vertically integrated” solar companies in the US, meaning that it can now handle its own business all the way from manufacturing through sales on to and installation. That will help them keep costs down as well, especially if this new technology ends up being its core, best-selling home product. SolarCity is already the largest installer in the US, and with Musk’s penchant for enormous manufacturing plants like the Gigafactory, it could make a run for manufacturing as well.

These new solar panels will be manufactured in Buffalo, NY, at a facility called Riverbend. They’re entirely products of the US (minus the raw materials), just like Tesla‘s car batteries, The company hopes that Riverbend can produce up to 10,000 panels per day, and employ something like 2,000 people in the process.

Of course, affordability is just a relative term, and whether the panels are comparatively cheap doesn’t necessarily mean you can afford them, especially without government subsidies. In that spirit, SolarCity actually wrote a blog post advising that we need to move past the idea of solar power existing only on residential rooftops. It advocates for a more diverse set of installations, like including community solar for powering modest clusters of homes.

Solar power still isn’t right for everybody, everywhere, and that will only become more true if federal subsidies dry up. But it’s becoming right for a larger and larger proportion of the country, and fairly quickly, too. With full control of the process, SolarCity can now start to control the cost per kilowatt hour directly, and SpaceXhas made it clear what happens when you let Elon Musk muck with the status quo.