In this video I'm going to take you through our 2021 year roundup for our solar PV,
Tesla Powerwall and two electric cars.
I'll also incorporate the monthly update for December in the mix. So stay tuned!
Hi John here thanks for tuning in. If you're watching this in early January well and Happy New
Year to you. If you're not then perhaps it's happy Spring, happy Summer, happy Autumn, happy Winter
whatever. I've split this video down into chapters and you can see that in the description down below
under the video if you want to skip to a particular section. Also in the description
and now on screen are the details of our system for those who aren't familiar with our setup.
I'm going to start off doing the overall totals for the year 2021. It's worth stating actually
at this point that there's a 6% variance in favour of what the Tesla app reports
against what my two solar PV generation meters report. The generation meters are more accurate
however where applicable I've included the figures from both sources to allow me to show
all the data sets as the generation meters are only going to show PV solar generation.
For 2021 we had the following figures according to the Tesla Powerwall app. House usage for
the year was 12,410kWh or 12.4MW. I'll refer to everything as units from now on it's a lot easier.
Solar generation was 6,660 units. From the Powerwall we used 3,440 units
and to the Powerwall was sent 3,892 units. That works out at a round trip of 88% efficiency over
the 12 months. From the grid we pulled 6,210 units and to the grid we sent back 600 units. Which
averages 1.6 units per day. Moving on to look at our self-powered performance from our solar
panels and battery. Our solar generated 53% of our total house energy usage shown here
on the solar energy offset column. We were self-powered from solar for 32% of the time.
We were self-powered from the Tesla Powerwall for 27% of the time. During our peak rate time
slot 81% of the time we were self-powered either by solar or the Tesla Powerwall battery. During
the off-peak rate time slot 9% of the time we were self-powered by solar / Tesla Powerwall.
Remember the off-peak time start is during the night time which means no solar activity and
frequently the Powerwall would have been charging during this time slot so hence the low 9%.
The difference between the 2021 self-power percentage during peak and off-peak from
those in 2019 and 2020 can be explained thus. We were on the Octopus Agile tariff from July 2020
through to the beginning of August 2021. This has a 4 hour peak slot with a 20 hour off-peak slot.
From August 2021 onwards we moved on to the Go tariff which has a 5 hour off-peak time slot
and a 19 hour peak period. This explains the variance between the 2021 figures
and those for 2019 and 2020. We're basically not comparing apples with apples.
FiT (Feed in Tariff) payments for the year total £2,294. This was almost bang on the average yearly
payment over the past 10 years. We have another 15 years of payments to come as we've signed up to
the 25 year FiT scheme when we initially got our panels. Let's balance this against what our system
has cost us to date. Our 4kW array installed in 2011 cost us £15, 225. The Tesla Powerwall
and the myenergy zappi installed in 2018 cost £7,141. The myenergi eddi installed in 2019 was
£375. The 2.34kW array installed in 2019 was a £5,795. Which gives a grand total of £28,536.66.
Our FiT payments to date are £22,392. The difference is actually £6,144 adrift.
And I've worked out that will break even in 2 years and 7 months
based on the current rate. And remember that the FiT payment is paid just on the generation
total for the 4kW array. We receive no payments for the later additional array that was added.
This chart is the annual FiT payments for the previous years. As you can see it varies
between £2,000 and £2,500 depending on how much solar is generated from that 4kW array.
Our FiT payment is paid quarterly and actually very promptly I might add by EDF. And here
is the 4 quarterly payments over the years from 2020... 2012 trouble with dates today!
Okay that's our yearly data. I don't have a total of how much we spent on
electricity although I do have it on gas. Although it's not 100%
accurate! Let's just bring up on screen so you can have a look see what I'm talking
about. Gas... gas... gas... there it is and the reason it's difficult to work out
year on year because my last bill also my first bill starts on the 30th of November
2020 and runs through till April 2021 and then the other bill is right at the end of the year runs up
to the 4th of January. So it's not too bad just a few days into the new year but our total gas usage
over that billing period is £740.51. It's probably at least £150 less than that because we've got
the whole of December 2020 included in that first bill total of £412.85. So it's near enough And as
you can see on screen it's... you could probably work it out if you really wanted to. In terms of
electricity. I can't give you that unfortunately because I haven't been billed up to date.
Currently the last bill from Octopus energy is on the 4th of August 2021.
And that's where we moved from Agile to Go Faster. And there's some meter swapped and all that
malarkey if you remember. But it means that we're missing some meter readings so waiting for those
bills to come through for the last 4 months. So I can't really give you a sensible figure on that.
So that's the yearly data. Before I move into December's data if you have any questions then
drop them down in the comments below. And let me know how you got on for the year.
I guess I was impressed with the fact that solar offset our energy from the grid by
53%. Our electricity bills would have been 53% higher without solar and if we just let that sink
in for a minute with the current situation with the escalating energy bills that we were seeing
couple that with a home battery which also added a further 27% to our self power over the year
you can clearly see that solar and a home storage battery works in the UK over the course of a year.
Let's have a look at the December figures shall we. These are very poor.
It's yeah, see how everyone else got on but I think it's a similar story. Let's bring up the
first chart. Our 2 solar arrays produced 112 units during December. Only just beating December 2018
which was 108 units. However, in December 2018 we only had a 4kW array of panels on
the roof and not 6.34 as we have now. So yes it's even worse when you look at it that way.
In terms of the split between the 2 arrays 70 units came from the 4kW array and 42
units came from the 2.34kW array. And then you can clearly see if you skip across to December
2018 where it says 108 that was all from the 4kW array whereas 70 from
the 4kW array December just gone. Solar and the Tesla Powerwall provided 38% of the power during
the month for self power and as you can see the lion share of that came from the battery.
This would have been charging overnight on cheap rate electricity as there was very little,
in fact probably no surplus sunshine to charge the battery and power the house.
This year-on-year chart bring that up on screen so you have a look at that. Looks at the past
Decembers and it's really telling. From 2019 onwards that's for both arrays. Before was just
the 4kW array. December 2015 just creeps into the lead as being the worst December on record however
if you were comparing light for like system sizes then 2021 would be the worst and sprint passed
it to the finish line claiming the crown of the worst month ever at 70 units for the 4kW array!
The day by day for the month is a sea of red and blue. It really visually demonstrates how little
solar activity we had. 1 day at just under 20 units for the day. 4 days between 5 and 15 units.
We did actually manage to generate something every day and I know that's not been the case with other
solar watches that I follow. We did have 7 days where we generated less than 1kWh for the whole
day. Our worst day was actually December the 25th where we generated 100watts on that day!
We started generating at 10:25am in the morning and it was all done and finished by 13:05pm in
the afternoon. When we had a peak of 500watts at 13:00pm. That was a really grey December
Christmas day. So not surprisingly our grid usage was up in December and this chart shows our
average grid usage and house usage over the course of the month. Average daily house usage was 45
units with 43 of those units coming from the grid. We sent 13 units back to the grid in December and
which is good. It's really low so that's a little ray of sunshine in a sea of gloom.
We pulled 1,345 units from the grid in December which is a bit of a record.
Not one I particularly want to celebrate to be fair however you know no sunshine means
more grid pull if one's daily lifestyle and pattern remains the same. Look at the eddi,
the myenergi eddi heats our hot water from surplus sunshine. So it had a bit of a rest in December.
3.2 units over the month bringing its yearly total to 353 and its running accumulated total to 820.
The Tesla Model 3 covered 1,099 miles during the month bringing its total year-end mileage to
16,991 miles. Almost 17,000 miles. The Kona covered a massive 133 miles during the month
and its total mileage was 13,715. We no longer own the Kona as of early January. That's a video
I've actually just uploaded on the Hyundai buyback process for the Kona. So if you want to see that
go and have a look at that because it gives a lot more information than I'm going to share here.
You can also see the yearly totals for the cars so
8,821 miles covered in the Tesla versus 3,013 in the Kona and based on these yearly mileage
figures we decided to get a much smaller second hand EV to replace the Kona with a smaller range
rather than have 2 expensive 300+ mile range EVs sitting on the driveway. We'll use the small EV
for frequent short trips to the shops, post office, drop into town that kind of thing and
we've actually already purchased it. I'll reveal what it is once it arrives in the next week or so.
28% of our annual home EV charging came from sunshine which equates to 775 units saved
of electricity. And if you took a UK average unit rate of electricity and 19 pence per unit
and that's saving £150 in electricity costs over the course of the year. Yeah that's it! I don't
want to take this too long and to rambling. So that's our 2021 roundup and our December stats
as well. Thanks for watching as always and I'll see you on the next video. Alright take care bye.