Better late than never, I suppose. As you can see on the image below, solar panels were first installed on the White House a year before the world found out that Darth Vader was actually Luke's father (if you still haven't seen the original Star Wars trilogy, you deserve the spoiler). On June 20, 1979, President Carter had 32 solar thermal panels installed to generate hot water, but the panels were taken down (and not reinstalled intentionally) while the roof was being resurfaced in 1986 while Reagan was president.
While the White House's solar array was never big enough to make a huge difference by itself, the symbolism was quite important, so it was great news when in 2010 the Obama administration announced that it would re-installed solar panels on the roof of 1600 Pennsylvania Avenue! The completion date for the project was originally Spring 2011...
Well, you know how things are in the political sphere; everything takes time. In the time that it took Elon Musk to build an electric car factory, ramp up production of the then-new Model S, and send rockets to dock with the International Space Station, the White House has finally gotten around to installing the panels, a job that they've now just finished.
Unfortunately, the image at the top of this article is just a mockup done by a solar activist. The real system is more modest in size (6.3kW), though there are surely important security reasons for keeping the roof of the White House mostly clear (sniper nests?).
You can see the solar array in this video produced by the White House and published by the Washington Post: