If I'm generating 2x as much solar power as I need, what's the best way to utilize the excess energy?

Connect to the grid, and store any excess as a credit with your power company. That's like having a 100% efficient battery. Any other kind of storage is lossy.

Also, be sure to look at a map of "peak equivalent sun" such as this http://rredc.nrel.gov/solar/old_data/nsrdb/1961-1990/redbook/atlas/ when sizing your system. There is no way anywhere in Canada would get 2450 hours per year of peak sun. That's probably a figure for any sunlight at all, including weak morning and afternoon sun, and winter sun at a low angle. The usable sun for generating electricity may be half that.

Usually whatever you don't use is credited back to you from your local power authority.....In other words it will be taken off the following bill prior to you making the payment.

1

I would install half the number of electrical panels and install thermal panels in the other half's place. That will let you heat water or air much more efficiently than using electricity or hydrogen. PV panels are only maybe 15% efficient, while thermal panels can be 60-70%.

DK