Can I go off grid with solar?
Absolutely you can and we do have a lot of customers who are already doing so, you do have to be more conscious of what you are using and what the weather is doing but this is not a hard process and is very rewarding. Here I have a comprehensive guide with a case study to show it is indeed possible for you to off-grid.
Okay, the case study I have for you is based on a household consuming 15kWh per day which is a reasonable and average consumption. I know that the main question that is on everyone’s lips is what does it cost so here goes?
The system for this study
SMA solar inverter
SMA inverter charger
21 x Longi 315 watt Mono Perc split cell solar panels (total array 6.615kW)
1 x BYD 13.8kWh Lithium battery bank
This solar system has the installation included for the area we operate installing solar which is the Sunshine Coast and the greater south-east Queensland area with total costs as follows.
Total system cost $28919.00 inc GST
STC rebate 109 STC’s @ $36.00 = $3924
Total customer outlay $24995.00 inc GST
The STC rebate system price can fluctuate and does reduce each year here in Australia but at the time of writing this, June 2019, that is what you will get and after the end of the year that will be reduced. This system can on average in this part of the world (Brisbane Australia) produce around 27.5kWh per day so in the summer you will get more and in the winter a reduction on that figure. What you have to understand with going off grid once your batteries are full up and you are not using any power the system will take a break on your roof and wait until you need its assistance with more power required.
Off-grid solar v On-grid solar, how does it work out?
Grid connected system
15kw per day @ .25c per kWh = $3.75 per day + grid daily charge of $1.00 totalling $4.75 per day.
So total charge per year $1733.75 now let’s think about how much do you think electricity prices will rise by each year, let’s say 3%. If we work with a period of 20 years then the total cost using the 15kWh per day works out to $46586.51 lets now work with the off-grid system.
Total original outlay $24995.00
Other costs $10000.00 (additional battery or inverter)
Total cost $40995.00 which works out at a saving of $5591.51 which is amazing when you consider only a few years back off grid would always have been a loser when doing a comparison.
The battery with this system is a Lithium iron phosphate which is considered one of the safer battery chemistries in use at the moment and is made by BYD who if you do some research do make a lot of batteries. The total battery bank is 13.8kWh and they do say that it is all usable but we would set your system so it does not go below the 15% threshold so leaving you 11.73kWh to use. The industry standard when designing off grid solar systems is for 3 days autonomy and you should design for this and we do but we do have a lot of systems out there that once you have explained to customers, when you go off grid with solar you need to live and breathe off grid solar, meaning that when the sun doesn’t shine adjust your usage it really is not that hard. This has been made easier with the new Lithium batteries as you can easily add another battery which is fantastic, that is of course if you choose the right battery system!
Do I need a generator?
You really must also have a generator backup with any off-grid system and you would be a fool not too, then in the event of the battery dropping to low or there has been really bad sunlight for days (doesn’t happen often here I know) and you couldn’t adjust your 1st world power usage down enough then you can, with regret I know switch on the fossil fuel munching planet destroyer that is your generator. When you purchase a generator please make sure you get quality as the biggest problem we find is that with the solar system working so well the generator will most often sit there so long without being required, when you do need it the battery is flat. Regular testing with a quick run should alleviate any problems here.
Can I charge my electric car if I go off grid with solar?
Absolutely, now electric cars at the moment consume approximately 1 kWh of electricity to 5 kilometres of driving this, of course, does depend on the type of driving you are doing but we need a base to work on. Now you will find that most people only normally travel 50kms per day which equates to 10kWh of power required which is easily achievable. We do have customers that are in exactly this position at the moment and yes we have the system programmed so that when the solar batteries are full and the car needs charging it automatically starts charging the car.
You will notice that the title of this page is “can I go off grid with solar” well as you can see the answer is a resounding yes with prices that are comparable and as you have seen better than the grid. I do though have to say if you have a grid connection and you do not have any power outage issues, then why would you. If you invest in an on-grid system the investment is a lot less and the returns are almost immediate (see my guide to on-grid solar page here). If on the other hand, you like the independence that going off-grid solar offers and you don’t like being left in the hands of the grid operators and retailers, or as is often the case getting the grid to your property is just too expensive then go for it I say.
Now I feel I have to add that when you are buying any solar system but even more so with an off-grid solar system you must do your research on the company you are going to buy from. I know the temptation is to just go for the cheapest system but trust me this will not go well for you if you do this. You must find a company that has a good reputation within the industry and who actually know what they are doing when it comes to off-grid solar. Do you really want to be stuck trying to get help from a salesman who sold you the system and a sub-contractor who has since moved on? Look for a solar company who are electrical contractors and who have their own in house employed electricians as the company will normally be run by people who actually know these systems and are not just a sales team.
About the Author
Andy Hall has been providing solar energy to homeowners in Queensland for over 10 years. Starting his electrical contracting career in the UK over 30 years ago, Andy has a focus on on-going training and innovation.