@mark_m - definitely onto us. @ChrisBarnes was quoted in the ABC’s article
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Yes, I saw the reference when I read the news item. It was worth the read as 18 months back we stalled on committing to going off grid.
For our circumstances.
All the issues we found were covered in the article. Key is Batteries which as noted still need to come down to half their current cost relative to power costs.
Our demand is relatively low and mostly outside of peak sunshine. If off grid it still seems likely we will see enough cloudy days each year to need compromise. Staying on grid with batteries has a lower investment required, for half the benefit of off grid.
PV Generation only is of little benefit without a reasonable feedin tariff. 20c or better needed on peak daily export twice our daily usage.
Of interest is that we have all gas cooking and instantaneous HW which is not offset with solar PV, and helps limit our electrical demand to the fridge, water pump/treatment, all LED lighting, TV and all those intermittent needs over a day.
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For cloudy weather a small generator is the go. Avoiding standing charges by going off grid can pay for the generator in under 2 years, after that you are ahead. It’s best to oversize your PV array to minimise the need for generator use in cloudy periods of weather. Going larger on the PV makes more sense than going larger with a battery, as battery costs are still fairly high cf PV panels for commercially available batteries. DIY battery is another matter, with much lower cost.
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Generators and battery arrays (<40 db humming in the ‘right place’ w/hard surfaces and urban echoes can still become irritating) might be fine in some locales, but in cities they can be as antisocial as the neighbours pool pump or A/C re noise. It is reality and a price we pay and people get used to the pool pump, A/C sounds, train and tram and traffic out front, or the airplane approach path overhead, but while you might get used to them your neighbour might equate your off-grid system with a 24 x 7 party because the sounds are not commonplace like the others although one day they might be.
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Yes, in town they can be a problem, although the silenced ones should be ok if suitably located so as not to annoy the neighbours. Also, Mark is " in a mixed small rural residential and small farm area".
However, as mentioned above, oversizing the PV array can minimise or even eliminate generator use. Before I had 2 aquaponics systems running, I went for 2 years without using a generator (I didn’t even own one), with ~4kW of PV and a 21kWh LiFePO4 battery. I just cut household energy use right back in extended cloudy weather - flexibility in timing of loads is a must.
Don’t run the house on the generator, use it to charge the battery, just enough to get you back to the PV taking over. A LiFePO4 battery can safely be deeply discharged and not affect its longevity, unlike Lead-acid chemistry, which shouldn’t be deeply discharged, or kept in a discharged state for extended periods.
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Appreciate the suggestions here.
Our plan A is to locate any equipment in a stand alone existing garage/shed. So any background hum, fan noise etc is certainly not a concern. The Asian House Geckos will no doubt also not object. it would be good if they did and moved out!
From having spent some time in the city on and off, the background noise is ever present. Perhaps if you live on a large block in a leafy avenue suburb it is only aircons and pool pumps? The bigger concern with Solar PV in the city might be nothing to do with noise, but unwanted shading of panels. We don’t have any rights to the sunlight, however the local council and state governments can take it away with a s single planning approval.
p.s. Local Solar specialist sized consistent with Gordon’s suggestion an oversize array of panels. Also with varied orientations (we have lots of roof angles) to improve the early/late day generation. And a 20KWh battery pack for off grid. There was a need to allow for some increase in load through house extensions and an upgraded household treatment plant. At this scale if we were to choose panels only it would be a standard inverter, as their supplier of battery management provides an integrated inverter. The key consideration for the alternative of a two step installation was to leave enough spare cable length and space for the install. And to provide a 24x7 internet connection for remote monitoring! We can get long periods of continual wet and cloud in summer which is why the battery pack was sized so large. They have their own install in the shop with the data to back this up. Given you can charge from a small generator a much smaller battery would be viable. Of course the solar supplier does not like this thought. It also increases the cycle rate on the batteries compared to having more capacity. It would be great if you could top up the batteries from the grid off peak at night if needed, however with the poles and wires driving electricity prices the cost of keeping a connection kills any benefit.
We are also considering the needs of another property in the same region that does not have power connected.
Given the pain of dealing with multiple quotes I usually seek a reliable local vendor and work through all the known issues. Adding any online advice and info eg Choice it is then much simpler to seek other quotes for comparison and if need be negotiating the best deal locally. Some of the local suppliers/contractors are quick to pick up on this and always provide good service at competitive costs.
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