It’s now been almost three months since I installed rooftop solar and battery storage on the 30-yar-old home I bought early last year, and there is absolutely no doubt it has made a huge difference to the nature of my bills, the source of my energy. and the way I use it.
As I wrote in October, I had 5kW of LG 315 Neon2 solar modules installed – half facing east and half facing west, along with two 1.2kWh Enphase lithium ion battery storage units. Those $50/week bills are now a thing of the past, and I expect to pay no more than $50 a month essentially my network fee. The bills may turn out to be even lower.
Here are the five things I have learned about solar and storage:
Know your consumption:
It’s great to have an idea of how much electricity you use, and also when you use it. The quarterly bill only gives you a bulk reading that tells just a small part of the story. The real interest is in which appliances you use and when they are being used. The best way to do that is with a monitoring device. I used Solar Analytics, which are primarily for solar and storage monitoring but also give minute by minute usage data. They cost around $500 but may be worth it because it could deliver savings on what size system of solar and storage you choose.
Small is good for battery storage
I’ve only got two storage devices, and I could have installed more. But to what purpose? The 2.4kWh do not cover the oven or the kettle, for instance, but they keep most things in the house going for most of the evening, often powering the house until 2am or even 5am in the morning, and react quickly if household use jumps above solar supply during the day,
My daily draw down from the grid used to range from 15kWh to more than 30kWh. Now it ranges from around 0.2kWh to around 4kWh. The average since I replaced the electric hot water with an evacuated tube solar hot water system is just 2.2kWh.
As this graph below illustrates, I now use an average of just overt 8kWh a day from the solar array, and export around twice that much.
That means that – courtesy of the 10c/kWh feed in tariff i get from community-owned and renewable energy focused Enova Energy (soon to rise to 12c/kW), I’m getting about $1.60 a day from solar exports, and paying around 60c/day from grid imports.
And I’m paying $1.50 a day for the use of the grid to buy and sell energy. that works out to be a net bill of around 50c/day – although I bet that rises in winter, as the days shorten and the solar production falls. So I’m figuring $1 a day on average.
Which is not to say that bigger batteries aren’t good. But right now, I don’t need one, and probably won’t unless I want to go off-grid, or provide back-up power in case of an outage. (Enphase won’t ride through a blackout, but the house came with a generator that I have yet to need).
Solar hot water is a must:
I chose evacuated tubes from Apricus for two reasons. One, they are local, two, they work, and three, I wanted to leave enough excess solar PV output to help fill my electric vehicle, if I ever get it.
This means that I went from this – the big block on the left is the electric hot water ….
two this …
There are a bunch of alternatives for electric hot water- using the excess solar PV f your electric tanks, using the various solar thermal offerings (such as fixed plate or evacuated tubes), or getting a heat pump, which also uses the sun. they are all better than using the grid (which basically means you are boiling the water twice – once in the coal plant, and another in your tank), and it’s good to know it will still deliver when the grid fails.
Battery storage prices are coming down:
Many installers report a lot of interest in battery storage, but not a lot of buying. That is starting to change, if the battery storage developers are to be believed, but it seems pretty clear the battery storage costs will come down quickly in the new year. Tesla’s Powerwall 2 effectively shaved 50 per cent off the costs per used kilowatt and that means that the combination of solar and storage can come pretty close, or even beat, grid power in most states. The Powerwall 2 won’t be delivered until February, March, so most competitors will hold their pricing levels until then.
The price of rooftop solar panels are also coming down – thanks mostly to a big increase in Chinese manufacturing capacity that has not yet been matched by demand, and ever improving efficiencies. Offsetting this is the slight reduction in the upfront rebate – from 15 years “deemed”: output to 14 years – but the reality is the good quality solar modules can be bought and installed for less than $2/watt. Unfortunately, too many consumers in Australia are going for the “bucket shop” variety, installing the cheapest panels they can find. Avoid it. These are important pieces of equipment.