There are various types of generators on the market at the moment. 
Solar and Battery
Solar and Battery have come along way with new Hybrid invertors able to be both on and off grid capabilities. We don’t specialise in this field as yet, but do recommend Dan the Solar Man, now known as ENERCO https://enerco.com.au/
Approvals with POWER AUTHORITY may also be required.
Wind Turbines
Wind turbines online between $250 AUD for small 800W kits up to several thousand dollars for larger 5kW–15kW setups, but they are generally inefficient and more expensive for standard suburban homes compared to solar panels.
Permits and Regulations: Local council approvals, zoning laws, and noise restrictions can make installing a tower or vertical turbine in a populated area difficult.
Moving parts: Require regular mechanical checks on bearings, blades, and braking systems.
Extra Components: You need a specialised wind charge controller, a battery bank, a grid-tie or off-grid inverter, and a dump load (resistor unloader) to safely burn off excess energy when your batteries are full and the wind keeps blowing. 
Diesel Petrol and Gas Generators
To help narrow down the selection, it is useful to consider:
Wattage requirements: Calculate the total watts needed to run essential items during an outage.
System type: Decide between a portable unit for flexibility or a fixed standby system for automatic power. 
Fuel type, Cost, Council approvals, etc.
Properly assessing these factors will assist in determining the most suitable fuel type and unit size for specific home backup needs.

Petrol Generators
Best for: Portable, short-term backup.
Pros: They are light, cheap to buy, and easy to refuel.
Cons: Petrol goes bad quickly in storage, and engines are louder. 
Diesel Generators
Best for: Long runtimes and heavy home use.
Pros: Diesel fuel lasts longer, and these engines are very tough. They use less fuel under heavy loads.
Cons: Units cost more and weigh more than petrol models. 
Gas (LPG and Natural Gas) Generators
Best for: Fixed home standby systems.
Pros: They burn clean, connect straight to home gas lines or large tanks, and require no manual refuelling during an outage.
Cons: Setup costs are higher, and they need professional installation.

Along side this, Earthing of generator, manual or automatic changeover switch, inlet and outlets to interconnect generator to line side of changeover switch, 2 or 4 pole circuit protection in switchboard to inlet for connection, and many other factors required.