Take what is given to you, Freely.
Off-Grid power supplies are the new world trend as they are less offensive to our environment and cheaper than power supplied by the cities power stations.
Power delivered through photo-voltaic solar panels or wind turbines is dramatically cheaper as well as more reliable. Using the resources given to us at the dawn of man has become our way to live sustainably. This energy can be stored in many ways, either hydro electrically or through 21st century battery technology.
Energy, by definition cannot be created or destroyed, it simply is changed from one state to another state. Energy consists of many states, heat, potential energy (batteries), Kinetic energy (movement), electrical energy, solar energy and the one we have yet to understand, "Children's energy" or "Youth" (nobody knows where it comes from).
Inverters have come a far way since the modified or square wave units back in the 90's. The introduction of IGBT (Integrated bipolar transistor) technology has allowed us to introduce computed sine-waves from DC (Direct current) power in sample rates that bedazzle the human mind. Inverters can also learn how they are being used and adapt accordingly.
Latent energy is one of the simple truths in life that is very easily overlooked. Heating a home is not always a case of heat it while it's cold. Heat energy stored in the walls and floor can quite comfortably keep a house warm during evening hours. A well-insulated solar geyser will stay hot through the night. A well-insulated fridge or freezer will stay cold or frozen for many hours. Taking example from the definition of a battery, "A series of cells intended to provide energy".
Battery technology, the ever-evolving industry! Since the auto mobile industry has climbed on the bus, battery technology has become quite the focus of renewable energy. Swinging words like "Super capacitors", "Regenerative energy" and "fast charging". Destroying the planet seems to be the key focus here since the emission laws on vehicles prohibit the fact that any vehicle may cause more damage than it does good. Battery technology improves daily, this being said, we are already in a very good space when it come to longevity, reliability and price. In 10 years from today, we will be even better off. This is not to say that Solar power is not viable NOW! In fact, this is probably the best time to invest in going off the grid, things will only get better from here.