Can I use solar panels to power an outdoor router?

I want to expand my wireless network out into my garden so I can run my laptop when I am sitting out there. I have bought a specialist outdoor router which says it only needs 12 watts to run.

I am wondering if I can make a solar power set up hidden away in my garden somewhere that will power the router all the time so I don't ever have to think about it I can just pick up my laptop and go sit in the yard and enjoy my wireless connection.