Since there is no grid power, Off-Grid systems perform the function of being the “power provider”. No Grid power means there is no electricity lines coming onto your property from the outside. The system needs to provide all your power needs and be stable power under any circumstances rain or shine to users 24 hours a day 365 days a year for 20 to 30 years. It also needs to do this automatically without the user being required to “manipulate” the system or refrain from carrying on daily life as normal. A properly designed off-grid system should have several sources of power to draw from and manipulate those sources automatically to provide stable power. These should include renewables (solar, wind, water), generators (auto start), and battery banks. The inverter then chooses which sources to charge the batteries from and which source to us to provide power to the property and some cases use all power sources at once. A correctly designed off-grid system reduces generator fuel expense, extends battery life, and ensures batteries are not exposed to heavy depletion. It is essential that the system be robust enough to provide power for 3-5 days without any sunshine at all and in this case not deplete the batteries to empty. If designed incorrectly, the battery bank which is the most expensive component in your system could fail in as little as a couple of years and require expensive replacement. By automating the system, this is a mistake that can be avoided. As your power provider, off-grid systems must be designed by certified off-grid designers.
There are several types of battery storage now on the market. Lead Acid is the traditional staple for OFF grid systems. They range anywhere from 2 volt deep cycle, to 12 volt car batteries and many variations in between. Off-Grid typically can be 12v, 24v, 48v, 120v (v stands for volts) in domestic or small commercial situations. single phase up to 3 phase. 100 amp hours up to 3000 amp hours or more (special order). To put this into perspective a small vacation batch could use a 12 volt, 100 amp hour, single phase power system (and a generator) and do okay to provide the basics in a holiday batch for the odd visit. Whereas a house with a spa, pool, 300 sq meters, with A/c and Heat pumps and all the mods that come in a house that size, such as under floor heating, towel racks etc. Would potentially need 3 phase, 120 volt (using 2 volt deep cycle), 3000 amp hour batteries (using 2 volt deep cycle batteries, in other words 60 very large batteries per phase totaling 180 batteries or more if paralleled).
In an Off-Grid situation, generator, always always always. It also should be able to auto start and auto stop.
Solar, wind, and hydro generation-
Any of these sources can be combined to provide power to the system. Of course Sun (solar) should be the backbone. Wind power can be an assistant, but please do not think wind can be the sole provider at least in our discussion. While wind power is great as a contributor. I find Solar and wind combination works fantastic as usually when there is no sun it is due to a storm which has wind and usually when no wind it is because it is stinky hot and lots of sun. Of course these are generalities, but you get the point. Hydro is also a great tool, but it is very hard on the equipment and can be costly to upkeep which can affect your cost analysis and make green power not ideal due to costs.
Off-grid/Hybrid Inverters: While there are many companies offering off grid inverters, there are only 3 companies that are capable of true robust off-grid solutions. They are Schneider, Selectronic, and SMA and while we can offer all three we find Schneider and Selectronic to be leading the way in off-grid solutions. Schneider is a New Zealand premium company, heavily supported in engineering and product range. As the global specialist in energy management, Schneider Electric provides the technology and solutions needed to fully optimize energy usage through energy efficiency, energy management, renewable energy and new energy technologies. Selectronic is an Australian made product and specializes in providing energy to properties off the grid for over 30 years. The ability to draw energy from multiple sources including solar, wind, water, generators, and batteries makes Selectronic inverters the all-in-one solution. In addition, by using energy management software capable of over 300 programmable features to extend the battery life and to ensure stable power provision under any circumstances makes going off-grid a very economical, dependable option for the future.
Design and planning-
I guess the bottom line is to think this through before purchase. Build it right to make it last 20 years without buying anything as replacements. Spend a large chunk on good storage and robust sizing so you don’t deplete it everyday or cycle it as we call it in the solar industry, and a generator. If you pinch money on batteries you will end up paying later, and again ruining the costs analysis. I would much rather have people out there cheering solar because they are generating power and getting a good return on investment. It is possible you just need to think it through first, planning, then plan some more. I would advise it would be worth while in an OFF-Grid situation to either;
a) buy your whole system and installation together from a professional off-grid installer certified in off-grid (preferably a Selectronic or SMA or Connext certified Off-Grid designer). Do not use an On-Grid solar company for Off-Grid as they are completely different systems.
b) buy your system from a equipment supplier (like solar direct here) and then get some engineering work done by a professional off-grid installer certified in off-grid (preferably a Selectronic or SMA or Connext certified Off-Grid designer). Again, do not use an On-Grid solar company for Off-Grid as they are completely different systems. We can also provide you some guidance on who to use for this to ensure they are certified in Off-Grid solar design.