Solar PV and Tesla Powerwall 2 performance June 2020 in the UK

In this video I’m going to take you through our solar PV and Tesla Powerwall 2 performance and stats as well as our electric car costs usage for the month of June 2020. So stay tuned Hi John here, and welcome to my channel If you’re new here, then all the details of my system that I’m going to be talking about are down below in the description. So have a ganders down there if you want to know the details of our setup, our individual components, and the configuration. I’m going to start with a highlight. We had our Feed-in Tariff (FiT) payment arrived. Hurrah! So I’m going to talk you through that, and how that’s made up So on June 1st I submitted our FiT generation reading which covered the last three months and we’ve been credited with a princely sum of £956.83 This was the highest quarterly payment and basically only made possible for the awesome months of April and May, which phenomenal. So this payment is calculated from the generation from our original 4kW array. We don’t have a fit payment on our new array. The payment is made up in two parts; so we’ve got the generation payment and the deemed export. The generation payment is calculated by taking a total generation figure at the end of the period away from the previously submitted one, from the previous quarter Much like how an electricity bill is calculated, you know, the difference between the two readings gives you your consumption. In this case it’s our generation. The second part of the payment is the Deemed Export the term Deemed Export is an industry term for an estimated export. 50% of what we generate is our Deemed Export figure. So if we generate 100 kilowatts our Deemed Export would be 50 kilowatts. They assumed we’re going to use 50% of what we generate. So these two values are combined to one quarterly payment. And for this payment the deemed payment, deemed export payment was £32.88 and the generation payment was £932.95 Making the total of £965.83 Our FiT scheme dates back to September 2011, when the PV system was commissioned. And we get 55.36 pence for every kilowatt we generate. Now these payments are index-linked and they’re index-linked the Retail Prices Index. So for example last year the generation value was 54.17 pence. This year as I’ve just said is 55.36 pence which is a rise of 2% The value of changes on the 1st of April each year. And the deemed export has also changed. The deemed export payment was 3.82pence and that was risen to 3.90 pence. And that rose on the 1st April this year So there you go. That’s the jolly news, so let’s get into the detail of the month of June 2020. Overall the month was not wall-to-wall sunshine unlike May Many people think that June is hot and sunny. However I have many recollections are the first couple of weeks of June is always wet and rainy. I often used to go to Le Mans in the Cobra at the beginning of June. With no wet weather gear and I always remember getting wet, soaked, there and back whilst we were there. So yeah June is typically I’m a bit moist. At one point during the month I didn’t think we were actually going to be March’s total. Let alone come anywhere close to April or May. However, we didn’t manage to creep past that on the 26th of June. So yeah the month has really been a mix of cloudy skies, rain and then the odd clear blue days where we’ve done really good in generation, and you’ll see that when we look at day-to-day later on. So our first chart is our monthly solar generation in June 2020. We generated 803kWh from our two systems combined. And that

worked as an average daily generation over the month of 26.8kWh And as you can see from the chart it’s nowhere near May’s total and sitting somewhere between March and April Regular viewers will know that we have two systems. A 2.34kW of additional solar panels that was fitted in October 2019, and before that we had a 4kW array which was fitted back in September 2011 So I always split those two figures out across the two systems because I know quite a few of you would like to compare the 4kW system against your own 4kW system. So I’ve made it easier, well for me, and hopefully for you and I’ve created a new chart which has the totals for the two systems, in a stacked column chart. Are you ready for the big reveal? So as you can see here our original 4kW array produced 504kWh over the month and the new 2.34kW array produced 299kWh The smaller array is 60% of the size of the larger one. And if you work out the percentage difference between those two figures it’s actually 59%. So fairly close in terms of its performance. Let’s scroll down and look at the contribution of the Tesla Powerwall and our solar panels to our overall self power for the house. The Tesla Powerwall is set on Self-Powered mode. I did swap it back to Cost Saving mode for one day in the month The forecast for Friday the 12th of June looked like a scene from Lord of the Rings looking towards the dark menacing skies of Saran’s castle in Mordor. So I decided to stick the Tesla on for one night and what it meant was of the Powerwall charged overnight on the cheap rate to carry us through that Friday. And it did very well in fact. The downside is because I’m on the original Tesla Gateway 1, there’s no option to save a percentage of the battery for backup purposes. It’s sort of all full or empty There’s no reserve that can be saved for the use in the event of a power cut, or power outage, or for manually triggering it when you decide to run off grid. So hey ho. So for the month of June we are looking at 91% self-powered looking at the split you can see that the bulk of that was supplied by so the solar panels at 57% and 33% was provided by the Tesla Powerwall. The Powerwall contributed more this month because of the reduced amount of sunshine. If you look at May 2020 solar accounted for 69% of our total self-power. Every day was sunny from almost dawn to dusk, which meant the percentage of power provided by solar panels to power house was much much higher. Because June was not so sunny and then the Powerwall had to be used more and often picked up the delta between what the panels could provide and what the house required. The remaining 8% of our 93% self-power was pulled from the grid. And you’ll see that later and when you look at me the day-to-day. In terms of our overall totals we generated a 803kWh as you know from our solar and the house used 841kWh so slightly more usage than solar power generation Let’s have a look at the year-on-year. I like to have a look at this chart. It tracks our solar production since day one, basically when we have the system installed. And as you can see we track back to 2012 for the month of June. Unsurprisingly June, current June, or 2020 June, towers head and shoulders above the historic data. If we just look at our original 4kW configuration that produced 504kWh in June 2020. and the newer one if you remember was 299kWh So that puts the June totally into a bit more context, or perspective for you. And it means that June just gone is our fourth worst year over the nine years for the month of June. So yeah it wasn’t particularly brilliant June for us

Okay let’s move along and look at the Powerwall. This is the Powerwall in and out chart. It tracks what we put into the Powerwall and what we pull out the Powerwall over the month. The Powerwall had a round trip efficiency of 90% for the month. We put 282kW in and took 251kW out Self-explanatory on that on not much more to say. So let’s skip merrily along and have a look at the day-by-day in a little bit more detail. And the idea of this is really just to pick up on the trends. And you can drill into the granularity of the detail if you wanted to. I don’t go into a day-by-day detailed analysis however, if that is of interest to you then by all means pause the video and/or download a copy of my spreadsheet which is linked in the description below. So all of the spreadsheet basically has been used for all the underlying data which I’m using to bring up these charts for you. So yeah have a look down there if that’s of interest to you. It’s sitting in my Dropbox. The key for the chart is blue represents our house usage Yellow is solar production, orange is what we sent to the grid, and red is what we pulled from the grid. A couple of highs and lows that are worth picking out. Grid usage which is shown in red there’s a couple of days where we took benefit of our cheap off-peak rate electricity as the solar forecast looked really bad So we use the off-peak timer to run the glass kiln and charge the Tesla. And that happen to the 7th & 8th June. You can see the peaks there for those two days. On the 12th that was the day I swapped the Powerwall to Cost-Saving mode so that charged up overnight on the cheap rate as well. And it charged 100% so 13.5kW. And on the 20th the Kona was charged overnight on off-peak rates as well. I’ll cover in more detail the Tesla and the Kona mileage, how much we put in charging, the costs etc later in this video So that’s the red stuff. Look at the yellow stuff, that’s the solar. You can see there there are 7 days where we peaked around 40kW for the day over the course of the month. So not a brilliant month, certainly if you compare it to May. We also had 12 days we where we generated between 20kW – 30kW a day. Our house, and our typical usage, we need about 25kW each day to break even. So you can see there that some days we were on song and other days we were behind the curve. Let’s move along and have a look at our daily average grid usage. So this chart looks as our average over the month of what the house used versus what we actually pulled from the grid Blue is a house and red is what we pulled from the grid on the chart. So our daily average grid usage has risen from 0.7kW in May to 4.3 in June. That’s our daily average. And our daily average house usage was 28.6kW in May and now it’s 28.kW so very similar to May’s usage Let’s have a look at the next chart. So this covers what we sent to the grid which was 113kW in June. If I was an Elvis fan at this point I would say ‘Way on Down…’ so be thankful though I’m not Basically a lot less than half of what we sent back to the grid in May Obviously as a result of that we did less solar production as well so it is sort of swings and roundabout If we scroll down to look at what we actually pulled from the grid over the month Which was 130kWs and as mentioned earlier we when we looked in the day by day the vast majority of that total would have been off peak at our 5 pence a kilowatt rate. So £6.50 for the month. 130kW x 5p = £6.50 For the month that’s fine Moving on let’s have a look at the eddi How’s that been performing The eddi heats our hot water from the excess solar. The priority order for

our system is to power the house first, then fill up the Tesla Powerwall, then the eddi, and then the zappi in that order. Once the Powerwall is a 100% fully charged then the eddi and zappi move up the order So it’s house, eddi then zappi In June the eddi has diverted 45kWh of solar energy to heat our hot water. And we don’t use any other heat source purely the eddi to heat our hot water. Which we have got set to 65C For the year the eddi has diverted 208kWh to heat hot water. With a cumulative total of 281kWh. I’m actually not a hundred percent sure that figure of 45kWh is correct. The reason I say that is because I’m part of the beta testing group for the myenergi products and it basically means I regularly update the firmware with the newly released beta releases that they send out. And silly me I always forget to record the stats before I do the firmware update. I have a nagging doubt in the back of my mind that some of the data may have been lost when I’ve done a firmware update. However, I say that when I look at April’s total it’s sort of in keeping with June’s total so you know I may be wrong. As you’ll see in a little while when we look at the zappi I definitely I know this or 20kW adrift there. Which is why I feel that maybe there might be some data missing there when I’ve been a firmware update and it’s been been lost. Anyway we will see In terms of what is recorded, and what that means in savings, and using our off peak tariff of 5 pence per kilowatt The monthly saving is £2.25 With a year today saving of £10.40, again in the 5 pence per unit rate. And a cumulative saving of £14.05. And the eddi turns one year old on the 22nd of July this yea. So we will be holding a small ceremony in airing cupboard to celebrate. It will be a small ceremony as well because not much room in the airing cupboard Let’s move along then. Let’s have a look at the zappi which covers our Model 3 and our Kon.a So lockdown has eased a little in June in the UK which meant we’ve used the car a little more. So let’s look at the Tesla first. So the Tesla has covered 575 miles during the month of June which is 444 more than it covered in May. We now has a total mileage of 4,248 miles I’ve also I recorded quite a few YouTube videos on autopilot during the month of June which is why the Tesla mileage is up quite so high. And within that I also did two public charging sessions both at superchargers, Tesla supercharges and I generally used the Newport Pagnell services Junction 14 on the M1 southbound. That’s nearest one to me. And both of those charges were 20 minutes, splash and dash type charges. Just about enough to get me a toilet break and a cup of takeout coffee. The supercharging was free as I’ve had people used my Tesla referral code when they ordered their cars. So thank you very much to those people who have made use of that And what that means is we both get a thousand, a thousand each, for free supercharging miles. So the cost to run the Tesla for the month was purely down to home charging. It cost £3.83 for the 575 miles covered. And that was putting 76kW in at 5 pence off rate which works out at £3.83. The Kona we used that even less in June. We did 108 miles. It now as a total mileage of 9,849 miles And that’s actually booked in for its first annual service on the 17th of July, which actually was the earliest the dealer had for a service while you wait appointment slot. It’s a year

old today actually, the 1st July. Happy birthday Kona I will be doing a separate video on our 12 months ownership You know, the highs, and the lows, the good the bad. All that kind of thing. So watch out for that should be coming out soon. I mentioned earlier about the monthly totals not being what I believe to be totally accurate for the eddi due to the updates of the firmware. I updated the zappy twice over the course of the month and I’m sure it’s about 20kW light in terms of its total amount for the stats. So I’ve used the data from my spreadsheet which I know is accurate and included that 20kW of the Kona charge because I don’t believe that’s included in the figures So the 108 miles covered by the Kona Cost a £1 to charge it for the month, basically. And that’s calculated by that 20kW on the 20th of June It’s a 20kW x 5 pence is £1 So the cost to do the miles for each car over the course of the month was, for the Tesla Model 3 £0.007 pounds per mile over those 575 miles. For the Kona it was £0.009 pounds per mile for the 108 miles covered in the Kona. So there you go. Do let me know in the comments down below what you ended up for the month of June and what your system is and your setup, just so we can compare apples for apples. People like to see that and a lot of people comment on the how useful that data is So please make your comments down below also if you have any questions then please drop those down in the comments below as well and I’ll do my best to pick them up in an answer them. So yeah until next time. Thanks for watching. Take care and I shall see you on the next one Alright stay safe. Bye