In this guest blog Marjon and Greg Martin describe the costs and benefits of their new battery system in Adelaide, South Australia. A fascinating and informative story - thank you both, M.
Greg and I are not off-grid but we have made changes to reduce our environmental impact significantly in the five years we’ve lived in our 1880s blue-stone cottage in inner-city Adelaide.
By the way, we enjoyed the Skype session you did in Adelaide and agree that once people make a change they’ll continue to make more changes. That’s been true for us in each of the houses we have lived.
In this cottage we have double-glazed the windows, put insulation under the roof, adding a pergola at the back of the house and external blinds at front and back of house to reduce the effect of Adelaide’s long hot summers. We installed six water tanks in a very small backyard to capture all the water that runs off our cottage and back shed. Two of these tanks, some 3,000 litres, are plumbed into the house to the laundry and bathroom.
We now have 16 solar panels with a system capacity of 4kW and a WattGrid 10 battery system, using POzV Deep Cycle Gel batteries. This offers us storage capacity of 10kWh, but we limit ourselves to use 60 per cent of this capacity to ensure longer battery life. The battery unit is situated behind the house, under a pergola with pull-down shade blinds. It’s important to bear in mind that this particular battery system is not designed to go off-grid.
AllGrid, the Brisbane company who designed our battery system, were looking for a trial site in Adelaide to promote their product, ideally in the Adelaide City Council area, and where the household were not receiving any government-subsidised feed-in tariff. They wanted a household in Adelaide city as the local council offered an energy storage rebate scheme – and were willing to help promote the launch – and AllGrid research said that battery storage units such as theirs would be more appealing to households who weren’t getting much of a subsided feed-in tariff.
Fortunately, we fitted the bill. We were only receiving eight cents from AGL as a feed-in tariff, and we were eligible for Adelaide City Council’s rebate scheme.
The cost of the WattGrid 10 battery system is $11,990, and the rebate from Adelaide City Council was $5,000.
While we are low energy users we naturally jumped at the chance to include batteries in our attempts to reduce our energy use and contribute to supplying green energy.
We have changed the way we use energy, even though we still use gas for hot water, cooking and heating. In the limited space of a small cottage, an instant gas hot water service makes sense. We did investigate an electric hot water system but found it would be heating too much water for our limited needs. We now run the washing machine overnight and recharge IT items overnight, to use the energy stored in the batteries, and we bought an induction hot plate. On the latter we cook and boil most of our hot water. We time our activities according to the best energy use for us. We do our washing and ironing at night but rarely vacuuming – somehow changing that habit has been too hard.
So far our electricity bills have shown a small rebate, even with only an 8 cent feed-in tariff. However, we expect to pay something this winter quarter as it has been very overcast and our energy production has halved.
In this house we will never be off the grid, but what has been extremely satisfying to us both is that we have reduced our reliance on the utilities, contribute to providing green energy and use our rain water not only at home and in our backyard veggie garden but also to water our street gardens.
Marjon and Greg Martin
30 June 2016