Photovoltaic panels use direct or indirect sunlight to generate electricity. Panels are most effective in direct sunlight but still work even when the light is reflected or partially blocked by clouds.
You will never pay more and you could pay a lot less. It depends on the plan you choose. If you choose the 5% Discount plan you will save 5% on what your utility would have charged you for the electricity that is allocated to you, each and every month.
If you choose the Rate Cap plan, you will never pay more than the utility rate the day you enroll. If utility rates go up, you will save. If utility rates go down, your rate also goes down.