It can be baffling but this process can be smoothed out. But there are a lot of details. Here's how I go about designing systems:
- Create an energy budget and understand how many kWh per day of energy you need. This is a key process, a tedious task, but of critical importance. If you are generating your own power, you should know how much you need. This is all easier said than done. Firstly, no appliance label actually tells you how much power it _really_ uses; it focuses on the theoretical and is usually overstated by 30%. Ideally you take a power meter like the kill-a-watt and find out how much power something really uses. Bit of a pain, but good data means good system design. There's a template for this here: http://www.energyalternatives.ca/SystemDesign/default.html
- you will learn that phantom loads are absolutely deadly and unless you have lots of money and a big system are best avoided at all costs. That clock radio, persistently sucking energy can use more daily power than a microwave or kettle.
- then I figure out what nature offers you for energy. Solar, wind, microhydro and what it will take to generate that power, keeping in mind seasonal variations. That's a whole topic unto itself.
- it sounds like your plan is to use a generator to cycle charge batteries, so that you have 24hr power, and the generator runs as needed to charge batteries. There is a science to doing this efficiently. I've seen so many people wasting so much time and energy they'd be better off just running the generator 24x7 and use less fuel. There are losses and inefficiencies during the charge/discharge cycle so yes it's really possible to burn more fuel by cycle charging if not done right. To the subject line of Nickel Iron that's the wrong technology for cycle charging for sure. I've done a lot of these systems and currently building a 180 kW system to power an entire off-grid community.
- I can't speak directly to gasification; great if you can make it work, it's certainly doable and established knowledge. It is a significant effort for sure though unless you can somehow store the gas for later use. I'm not a fan of propane - very expensive fuel to burn, fussy engines and hard to find mechanics in some areas. Diesel is lowest cost fuel to burn / highest cost engine. Good for biodiesel options.
- common, true deep cycle motive power batteries like L16's or golf carts work well for cycle charging. I've got entire remote wilderness resorts running on L16's. Sizing of this will depend on your loads and how often you want to run the gen.
- You will want a good sized 24 or 48V inverter (12V is a real pain and best skipped) with a big robust battery charger integrated (called and inverter/charger - way better than two separate devices), so you can charge the batteries up as fast as possible by running the generator, and then the inverter will provide power when no generator.
- A system status meter tells you where your system is at capacity wise.
- as more renewables come online, your reliance on the generator is less and less.
- solar is very cheap these days and last forever. Fossil fuels are expensive and one time use. So it's a balance of how much fuel now vs solar later - but the sooner you can stop spending money on fossils and redirect to renewables the better.
Hope that helps.