What's the size of your grid connection? If it can handle twice the amount of power (actually a bit more) than you'd need when running on the grid for 24 h, you could store the energy as LoyceV suggested. Storage solutions are always expensive, though. Hydro storage only works in certain topographies. You might try a sodium sulphur battery (once of the cheapest chemical battery solutions for your power to capacity ratio).

If that doesn't work, your own generation is the way to go. Are you sure solar panels are too expensive?
Is there running water near your place? Could a small running water plant work?
Is your region a good place for geothermal power?

Sorry to say it's also quite possible that there is no economic solution for your problem.