Well into Autumn
Days are shortening quickly, especially noticeable since we went back onto NZ standard time. And although we’ve had a lot of lovely fine days, it is definitely cooler.
Our summer drought is well behind us, and although February was actually the third wettest since we started recording in 2013, most of that fell over a couple short but of quite intense rain events.
This autumn has seen more fungi appearing on Ulva than for many years, though not nearly as spectacular as exactly 20 years ago when the forest was alive with colour and shapes. What I know about fungi could be written on a post it, using a broad felt pen, but I do like seeing their colours and shapes in autumn.
Our solar system is working well, and we are getting better at managing it. Especially when we have guests in the house …… They seem to add around 10 to 15% of our overnight power consumption.
To recap :-
November 2021 System “live”, …… 7kw PV installed, with 24 kw hrs Lithium Ion batteries. Grid still available, but switched off. We did switch grid on on occasion.
February 2022 ….. Addition of 3 kw with second inverter.
March 2022 ….. Grid disconnected … we are off grid, with a 4.5Kw diesel gen set as back up.
November……… Installed 8kw air to water heat pump. This utilises excess electricity production, allowing us to minimise diesel furnace for domestic hot water and central heating. From October we reduced our furnace diesel consumption by 80%
Since August 2023 we have run our gen set 17 hrs to “top up” batteries….. so almost 9 months @ 2 hrs per month. This pretty much in line with usage since going off grid. The gen set is capable of 4.5kw, but for a variety of reasons we are limiting output to 3.5kw. Once these are addressed generator run time should be around 20% lower than above.
We have another 3 kw of panels to install, which will take our total potential to fractionally over 14kw. This may seem “over kill” but will significantly add to our generation on darker days. For example right now it is 1325 hrs and it is quite dull, with one inverter/array producing 972 watts, and the other at 448 watts. Battery is at 85%. With the extra panels we would have batteries at 100%.
Economics to Date
Since the system was commissioned we have produced/used 11906 kw hrs, which at $0.61 (SIESA Local power charges) totals $7272.66, add to this 12 months @ $95 per month line charge gives a total of $8402 saved. This does NOT include direct diesel savings from use of heat pump for hot water/central heating. Please note that the figure 11906 kwhrs is not our total production, but rather what we consumed. We have no way of knowing what we could have produced had we been able to store and use it.
It should be noted that Sails Ashore is almost fully electric. As well as the normal electric appliance we have all electric cooking, and produce a significant % of our domestic and central heating requirements from our solar power
Please note ……. SIESA charges indicated were at March 2022. Since then there has been significant increases due to the massive increases in diesel fuel.
What’s New in PV
There have been significant changes in the solar energy field since we started this project …..a simple Google search will show all sorts of interest free/low interest loans and grants now available.
In addition has come important advances in energy storage, which is of course the crux of the whole business. If starting now we would give serious consideration to mating Lithium Ion batteries with hydrogen cell technology see …..World-first home hydrogen battery stores 3x the energy of a Powerwall 2 (newatlas.com). At around 50% hydrogen cell tech is not at all efficient , but does have the advantage of being much more modular and able to store large amounts of energy when we have lots of excess. It would appear that a couple of cubic meters of storage would run us for well over 30 days, and with a low output generation cell of say 1 to 1.5 kw would act more or less as a trickle charger for our existing system when required.
We have links to all our Solar Power Posts etc on our “Solar Power & Environment” page
Sea Lions Abound
Our sealion population is increasing quite noticeably both on Ulva Island and around the village. This last summer we had a pup birthed on Ulva, and there are not many days we don’t see at least one, and often several. And we are really have to be aware, as I’m finding them occasionally some distance from the shore. In this case generally females … shades of the Irish song …. Tell me Ma, when I get home, the boys don’t leave the girls alone …..