Let’s get straight to it: 50 cents per day.
That is what I paid for electricity over the 350 days of billing I have since the Powerwall was installed, and my electricity provider changed over.
This is important to note, as the two weeks up to change of provider meant I wasn’t getting any export benefits from my solar panels. Mugged!
The saving is over the $2000 mark, but for the sake of round numbers, let’s call it $2000.
To put in perspective what money means to my family: our recent road trip, to central and southern NSW, cost almost exactly that. Essentially, I got my little summer break for free.
Facts And Figures
According to the billing received by Diamond Energy over the 350 day period:
- Import total was 1349.830kWh (or 3.857kWh / day)
- Export total was 3807.403kWh (or 10.878kWh / day)
Not quite the 1:3 ratio I was looking for, but that figure is probably no longer simple to calculate, which I’ll explain below.
From the SolarEdge web portal, I have the following factoids:
- Lifetime energy: 9.1MWh
- CO2 emissions saved: ~3400kg
- Equivalent trees planted: 11
- Light bulbs powered for a day: ~26,200
That is kind of the feelgood stuff, despite the Powerwall not necessarily being “green” as people might imagine.
As with anything, there is a carbon cost associated with production. The early iterations of any battery product are going to be a little bit on the dirty side.
As one example: Lithium ore needs to be shipped from the mine to the refining facility. The refined lithium is then shipped to the cell production facility, which may or may not need shipping to the final place the Powerwall was built.
Tesla are addressing this with “vertical integration” of production, particularly for their cars, but also batteries in general. This means more processes can be done at one site, reducing shipping costs (and therefore carbon c0st) of transporting components.
Other Factors Considered
Keen observers will remember that in October I got more solar panels. That took my total system size to 6.5kW of panels. I just heard a bunch of critics trumpet “AHA!” but keep in mind, I still only have a 5kW inverter.
Therefore the maximum power I can generate is limited to 5kW, though the peak time lasts a bit longer on a sunny day.
It is hard to quantify what effect this has on the system, beyond saying “there is more solar capacity”. As the new panels are oriented WSW they’re not always going to be ruling the roost in terms of efficiency.
Its also a smaller factor than it otherwise would be, having been installed four months out of the year. Granted, they were the sunnier months.
Another consideration is my move to Time Of Use tariffs in the first week of August. This has an effect on two areas of my billing.
If I’m smart enough to “game” the tariffs, and avoid doing anything during peak time, I can save a lot. Unfortunately peak time coincides with oven and air conditioner use, so that’s not always possible.
The billing and the import numbers above will be affected by Reposit Power managing tariff arbitrage. When I import power now, it might be a result of my needs being bigger than the system output, the battery being empty, or because Reposit sees a cloudy day and wants to import some at a cheaper rate.
Putting together the new panels and move to TOU, a better time to revisit this might be October this year. That way, I’d have a true idea of what I can really save with all components working together.
The Vagaries Of Billing
Those out for a bargain will know to shop around with their electricity companies, and see how best to maximise their savings.
Whether that is through generous sign-up rebates, or big discounts for paying on time or via direct debit. It all adds up, and people without solar or batteries can benefit if they do their research.
As I pay such low amounts anyway, discounts don’t add up to much. Pay-on-time discount across the year was $20, and paying by Direct Debit discount was $17.62.
The bigger benefit was referring people on to Diamond Energy, which netted me $105 across the year. Against that, I paid $22 (inc GST) application fee with Diamond, so the benefit was more like $83.
If we add that $83 back onto the billing, it goes from 50 cents per day to 75 cents per day.
I pay about $1 a day to connect to the electricity network, so its still good. There are even a few dollars in GridCredits unaccounted for at this point.
Year Of The Powerwall
When I say “Year Of The Powerwall” I’m not speaking only to the year I’ve had. This year, 2017, marks the landing of Powerwall version 2 in Australia, and overseas.
I’ll level with you: I haven’t really spoken much about PW2 since the launch, because I’m still experiencing some angst.
I thought I’d done OK with my battery, then in the same year, Tesla brings out one TWICE as good.
C’mon Elon… I thought we were mates!
Overall though, this is a good thing. I think we’re about to see the domestic battery market kick off in 2017, with Tesla in front. That is quite amazing, given the prediction was market maturation in 2020. We’re three years ahead!
Talking to a few people getting quotes and installing them, right now there are very few people price-competitive per kWh.
As the manufacturers in Korea and China start their own uplift via vertical integration, prices are going to keep sliding, and competition increase.
This can only be a good thing for the consumer, for the grid, and for energy security and stability moving forward.
And any consumer who is getting a Powerwall 2: I think a zero electricity bill is well within reach.
If you factored in selling power back to the Grid out of the battery, which I think will replace solar feed-in tariffs eventually, you could even turn a small profit.
As always, user experience may vary. Its up to you to make the most out of your investment.
As I wrote earlier in the month, we have had some heat wave conditions here in Sydney, with outside temperatures getting into the high 40s (120oF). That was kind of insane, but it kicked off some GridCredits for me, which is also a good thing.
As we’re moving toward more extreme weather events, having a flexible and robust grid, with user storage available for emergencies, will be important.