A constant, year round, natural flow of water could be energy running past your door. Harness its free energy with a micro hydro generator and you could have the perfect complement to your solar setup. Even a small output can be a considerable benefit when it operates 24 hours per day, sunlight can't offer that advantage.
The Aqatek unit is a good mid range generator with outputs dependant on flow and head of water. Available in 12 and 24 Volt DC versions. Coupled with a good quality regulator and an appropriate heat dump load, micro hydro's offer a good realistic alternative to power generation.