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I want to pull the plug!

20th September 2011   9:37AM  

The two big questions about Off-the-Grid Power Systems.

By Ben Stanton -

Have you ever held a power bill in your hand and dreamed of just walking out your gate and chopping down the nearest power pole with a large axe… or even a blunt rock?


Hi, my name is Ben. I install Solar Power Systems and have started this blog to answer some of the common questions that our customers raise in the early days. Most of this stuff is the very basics but occasionally I may wax lyrical about something I am passionate about. Either way I hope you will find this informative and maybe slightly entertaining (and maybe even a wee bit strange).


I’m sure we have all had moments where the long haired, live-off-the-land, hippie lifestyle has suddenly made more sense than the bill-laden eat-sleep-work life we find ourselves in – from time to time! (If it’s been that way for as long as you can remember then you might be reading the wrong blog!)

Solar Power Generation has gone from a pipe dream for many to an affordable reality in less than 5 years. In just one of those years (2010) the global manufacturing of PV solar panels has doubled, in a single year! During a global recession!

Affordability is no longer an issue for most

- the question has now become one of Return on Investment (ROI) and then answering the, what I call the “Yestertech hangover” questions. Questions like “can it run my TV without blowing it up?” and “will I suddenly run out of power while sewing?” (ok, I made that one up – but if you think about it, that would be a good question!) These questions have been answered by the huge advances made in the technology of off grid system electronics, PV and battery technology.



So on to price.

The biggest question people have when they think about going “off-grid” is the simple “HOW?” then soon followed by “how much?”




So Straight into it:

FIRST – Question number TWO: Price.


The smallest off grid system for a home we have installed was around $18k (NZ).

This is an absolute minimal system capable of delivering about 1.5kWh per day (that’s about enough to keep a small refrigerator running)

The more power you use the larger the system will have to be to support it.


There are a lot of things to consider like how energy efficient your appliances are eg: will you buy a new super efficient refrigerator? Will you want to have a dishwasher? Do you have a plasma or a LED/LCD TV? Will you design your house for maximum energy efficiency (right down to having the refrigerator ventilated on a south facing outside wall and using as much natural light as possible)


These are all factors that add up to two things:

1. How much energy will you use on average each week and
2:what time of the day you will be likely to use this energy.

Point 2 will be mainly determined by the age and habits of people living in the home eg: A school aged family will use energy differently and a different times of the day than a retired or working couple.

I will talk about some of this a bit more in future blogs.

By the way, the reason these things are not important for a grid-tied system is because the grid acts as your battery and generator (which are large cost portions of the off-grid system) and the grid-tied system just takes whatever sunshine is available and you either use it or you feed it back – it’s simple.


At the other end of the price scale (for a domestic home) I did a system for a family in Manukau that was 2KM off the road and 750Msq and they didn’t want to worry about having super efficient appliances AND they have four kids! Their system cost around $100k – Sounds crazy but when you compare that to $140k for mains power down the driveway it looks quite attractive!

750M2 off the grid

Their system cost around $100k – Sounds crazy but when you compare that to $140k for mains power down the driveway it looks quite attractive!  More on that in a later post…


So it’s easy to see that price varies with the requirements – what ever you do don’t let someone just sell you an off the grid system without them first asking you a few questions about how you use electricity.

Everybody uses electricity differently – that’s why some only have a power bill of $80 and others are over $1000  – so as you can imagine a big part of my job is actually giving people ideas about how to save electricity. I do this well, so well in fact that I have lost the odd sale, but hey, that’s ok, they are better off and I’m happy to have helped.


I the interests of being interesting I will sign off on this blog (and it’s getting late too!) I will leave you with a few photos of the system I installed in Raglan for Sue:


My Daughter having fun on the Trampoline with the Solar Array behind her - and the perfect catch phrase!



The Inverter, Charger and Display unit on the wall. Sue wanted it out in the open so she could show it off to people!



This is the battery bank - perfect size for the minimal loads that Sue runs (Just a few lights, a jug, toaster and big screen TV)

A closer look at the inverter (Left) PV Charge Controller (Right, Bottom) Mate Display Unit (Right, Mid) and the Hub (Top) This is all equipment from Outback Power Systems - Very high quality and reliable.

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