How Much Would A Solar Panel To Power A Pretty Big School Be?
You’re probably looking in the neighborhood of a million dollars. The first thing you’ll do is audit the energy usage of the whole school. Let’s say you have a cheap PC that takes 300 watts. 300 watts of solar panel is several thousand dollars. For that, you could buy about 6 computers! Including one that’s only 20 watts. Now you only need a few hundred dollars worth of solar panel 
So you go through the whole school like that. Make it efficient. Now you’re buying a MUCH smaller solar panel than you would have otherwise.
How well is the building insulated? Does it need new doors or windows? Get em and save a fortune heating the place. How about earth sheltering the roof? Thermal masses? Go through it all.
Does it use electric heat? Nope not with solar panels! Put in a solar-thermal system that is 50 times cheaper. Air conditioning? Retrofit to ground loop heat pumps and save a lot more energy.
Then when you’ve squeezed every watt out of the school’s energy use, you put up a (much smaller) solar panel for a great deal less money.
Are you talking about size or cost?
If size, the entire parking lot and all athletic field would not be large enough. A large school has peak demand of about 500kw (before the students plug in their portable electronic devices for charging.Cost would be $5,286, 244. 35 . This is all with today’s technology.
You’re talking well into five figures in US$.