Toyota is launching a solar panel roof on the plug-in version of the Prius hybrid in global markets. The solar power will flow directly to the Prius’ battery pack when the car is parked. When powered up, the panel will power the air conditioner and accessories to enhance fuel efficiency by upwards of 10-percent, according to Toyota.

Europe and Japan are the only markets getting the solar power thus far on the Prius Prime. Toyota would like to launch the technology on the car in North America and may do so at a later date. The problem is that the solar panel utilizes a reinforced glass that does not live up to U.S. rollover standards. Toyota claims they are working on a new version that would rectify that issue.

“We would like to introduce this, at least in the lifetime of the current model. It should be possible to do a lot of charging this way in places like California or Arizona,” explained Koji Toyoshima, the chief engineer of the Prius, in an interview with Automotive News.

This isn’t the first time the Prius has utilized solar panels on its roof. Toyota offered it on the last-generation Prius. However, the old one was not nearly as large and apparently did not impact rollover testing like the new one.