For your specific situation, you can reuse panels, inverters, and most wiring etc between roofs or depending on things like a HOA install them elsewhere for less. A solar gazebo or car port for example can directly use the panels as a roofing material. Some people are even using them as fences.
The actual calculations get involved including things like permits and your weather etc. But don’t assume your only option is spending 15+k for some contractor to show up and slap a bunch of panels on your roof.
PS: 30k is overkill for your usage, and you don’t need a battery unless you are particularly worried about power outages.
And don’t forget about inflation when doing your ROI and invest returns calculation. US electricity prices averaged 16.04c/kWh March 2023 to March 2024, but 15.50c/kWh March 2022 to March 2023. https://www.eia.gov/electricity/monthly/epm_table_grapher.ph...
As to liquidity, the stock market may be a better long term investment but it’s quite risky even over surprisingly long periods.
Can you elaborate on how you arrived at that conclusion? At least where I live, the math didn’t work out. It seemed like smarter conservation was a much better alternative. A couple portable/window A/C units that pay for themselves within a year or two made a heck of a lot more sense than $30k of solar on a roof already at half it’s life. Maybe when it’s time to replace my roof I’ll reconsider, but the payback didn’t seem there. (FWIW, I probably average < $100/mo in electricity.) I know conservation can go against human nature, but it sure seems like the better option for me.