A daring plot to pave roadways with solar panels has raised over $2 million despite questions about the costs and effectiveness of such a network. Scott and Julie Brusaw have received more than 40,000 donations — the most ever on the crowdfunding platform Indiegogo — and they’ve come from all 50 states and 42 countries.

“It’s very humbling that people all around the world are getting behind this,” said Scott Brusaw, an electrical engineer, who launched the campaign with his wife. “We’ve had people call from all over the world to tell us, ‘When you build the first parking lots, let us know because we’ll fly there just to say we’ve walked on it.’ It’ll bring a crowd to town.”

The campaign launched to little fanfare on April 21, but interest picked up as celebrities weighed in on social media, and an attention-grabbing YouTube video went viral. Since being published May 18, the seven-minute video has been viewed more than 15 million times.

Canadian Michael Naphan reached out to the Brusaws and offered to do the video for free. “If you can give me footage of the prototype, I think I can make you a video that can go viral,” Brusaw recalls being told.

The Brusaws actually extended the Indiegogo campaign past its initial deadline. Overworked and anxious, they had been ready for the campaign to wrap up. But they received a call from Indiegogo’s chief executive, who persuaded them to keep it going, according to Brusaw. With donations coming in at over $10,000 an hour at that point, why turn off a money spigot?

So they continue to work 18-hour days between managing the campaign on social media and doing media interviews.

With the influx of cash, they say they will hire a staff of at least six engineers. The Brusaws live in Sandpoint, Idaho, where they plan to install their first public solar panels. Sandpoint is applying for grants to cover the costs of installing the panels in sidewalks and the parking lot of a welcome center, according to Brusaw.

He expects to have a product ready by the end of the year. Brusaw wants to begin installation next spring, and then watch for a year to see how the panels do. Only then would the team branch out and try the panels in actual roadways.

While the $2 million in donations indicates that plenty of people are thrilled about solar roadways, it remains to be seen whether Brusaw’s vision can work on a broad scale. Brusaw said he has no estimate of how much these roadways will cost. Maybe Brusaw is on to something big, or maybe 40,000 people helped fund what will end up as just a tourist attraction for a small town in Idaho.