Great sunshine, shame about the virus.

With a superb 223.5 hours of sunshine, April generously bestowed lots of free kWh on the solar panels. But coronavirus ungenerously killed tens of thousands in the UK. Which meant lockdown. Which meant very little driving in the EVs. Which meant the vast majority of our stored energy went into domestic load via the Powerwall.

On the upside, “one permitted exercise a day” meant around 500 miles in early April on the eBike, through the beautiful countryside around home.

River North Tyne, near Wark
eBike on 14th Century byway in Northumberland

All was going brilliantly, until 14 April, when Alan got hit from behind on the back of the helmet by the wing mirror of a delivery van doing that COVID-driving thing; assuming there’ll be nothing else on the road. Long story short: two spinal fractures, two broken hands and face mashed up a bit. And the van driver didn’t stop. Alan found some minutes later unconscious on the road. On the upside: had the odd experience of being the only non-COVID patient in the A&E hospital. 2 consultants and an entire nursing team. On the downside: bike knackered. On the really big upside: one of the A&E consultants said that 8 out of ten cyclists who have that accident end up under the wheels of the vehicle which knocked them off. So, really glad to be alive!

So that’s why April’s performance report is a bit late getting to you folks. Apologies; better late than never.

Key results:

  • 833.3 kWh solar generation; of which
  • 307.3 kWh charged into Powerwall storage battery for domestic use;
  • 526.0 kWh used at time of generation for domestic load or charging EVs.
  • 184.3 kWh off-peak grid electricity consumed; of which
  • 116.7 kWh was charged into Powerwall storage battery.
  • 41.2 kWh peak electricity consumed.
  • Total cost of grid electricity purchased: £22.04
  • Total Government payments for solar generation: £40.63
  • Net overall cost of electricity in month £-18.59 (i.e. negative 1.5p/kWh).
  • Total consumption in month: 1,175 kWh
  • Cost of 1,175 kWh at UK average cost per unit: £182.20
  • Actual cost of electricity, including standing charge, net of Government payments: £-18.59
  • Total savings on electricity costs alone vs UK average: £200.79
  • Total savings, including the cost of petrol saved by driving EVs: £271.26

However, lockdown and injury meant very little driving in month. Only 424 miles. Hence a lower than normal emissions saving of only 297kg carbon dioxide avoided, compared to roughly 3/4 tonne in a typical month. Basically, we didn’t do very much green-powered driving, for which hydrocarbon fuel would otherwise have to be burned. So less planet-saving by us. But there was a huge amount of planet-saving by the coronavirus: kept billions of cars off the road worldwide and grounded global aviation. Silver lining or what?

Now, Mr Corona, thanks for coming in to HR for your performance review. Let’s start with the positives. No question about it, you’ve made the biggest contribution in modern history to solving the climate crisis. So an outstanding A+ on that score. And you might even put Ryanair out of business, so maybe humanity will have another reason to thank you. But, I’m afraid I am going to have to issue you with a formal warning about this global zombie apocalypse megadeath thing you’ve been doing. It’s just not acceptable and you’ll have to stop…

Back in locked down Northumberland, only a tiny fraction of our EV mileage was ‘fuelled’ with overnight cheap rate electricity, for a total cost of £2.29 in the month. The rest was solar, costing £0. So that gave us an overall average fuel cost of £0.005 (half a penny!) per mile.

Overall that’s a saving of £70.46, versus the £72.75 cost of fuel to drive an internal combustion engine (ICE) car for the same 424 miles. On that basis, ICE fuel costs would be around £0.17 per mile.

That makes our largely solar-powered miles around 34x cheaper than petrol! So feeling super-smug this month. Will aim for absolute zero fuel costs in May.

As usual, click the image below to download the full monthly report. Payback economics are here.

Tesla preparing Vehicle To Grid bidirectional charging and registering as a UK Generator. What does it all mean?

Some really important news broke in mid-May 2020.

Tesla is apparently enabling Vehicle To Grid (V2G) charging capabilities on its vehicles. 

V2G is super-important.  This basically completes the jigsaw which enables Tesla to become a major player as a wholesale participant in energy markets by leveraging:

a) its fleet of stationary batteries, Powerwall and Powerpacks;

b) its fleet of mobile batteries, in owners’ cars;

c) its fleet of solar installed on owners’ roof spaces;

d) Tesla’s Autobidder platform to enable grid market participation; and

e) the company’s Edge Computing capability to enable it to route electricity intelligently (and profitably) between solar generation, stationary batteries, any V2G-equipped Tesla car and superchargers.

The addition of V2G is a game-changer, in that it allows Tesla to use the entire fleet of cars and Powerwalls in a given country to offer (highly lucrative) grid services such as peak shifting, demand spike mitigation, and Rate Of Change Of Frequency (ROCOF) response.  Some of these grid services require response within seconds, which only battery storage, some pumped storage hydro, and Compressed Air Energy Storage (CAES) can deliver.

In countries with a functional dynamic electricity market and an increasing proportion of generation coming from (inherently intermittent) renewables, any wholesale player who is able to offer near-instant-response storage on a significant scale is in a very strong position.  And Governments/Grid Operators love it too, because the combination of renewables plus large scale storage enables a massively faster transition to net zero carbon.

So I’d expect Tesla to be using its unique app-enabled access to a highly distributed fleet of huge numbers of (relatively small) batteries and, in lesser number, domestic-scale solar installations to aggregate this distributed storage and micro-generation capacity up to the industrial scale which enables it to play in the wholesale electricity market.  

At the wholesale scale, it will then use Autobidder to dynamically route the surpluses it has aggregated to wherever it will make the most money.

The UK is probably the most advanced dynamic-priced electricity market in the world.  So it’s no surprise that Tesla recently lodged its formal application with the regulator to operate as a generator supplying the UK grid.  

This will not be about Tesla building a large fixed-plant power station.  Instead this will involve:

  1. Tesla dynamically supplying the grid from the distributed storage, into which its IOT platform gives it access and insight, to make money from the lucrative peak-mitigation and ROCOF services the grid requires;
  2. plus using the trading rights a grid-connected generator enjoys to purchase energy at low-cost (or even negative cost) super off peak periods when the grid has a surplus; and
  3. pump that super-cheap energy to its customers’ cars and Powerwalls so that those end users home and cars are optimally charged, at the cheapest possible rate, with enough energy to power each user’s intelligently-predicted home load or next car trip.

Off course, I’m expecting Tesla’s algorithms, using the company’s fleet-wide data and predictive analytics, to be able to make all the necessary choices, in real time.  I’m also expecting that there will be zero requirement for the individual end customer to make any input.  Apart, perhaps, from telling ‘the system’ via the Tesla App that she/he wants to go to a specific destination tomorrow morning (when that’s different from a regular commute pattern, which Tesla already knows about anyway).  In that case, I’d expect the battery to be optimally charged overnight to reach the desired destination, taking into account time-optimised supercharger stops where necessary. 

So what’s the killer advantage from Tesla’s POV as a grid-connected generator with wholesale trading rights?  It’s all about capital cost. 

A.N. Other generator would have to stump up the cash to build or buy the power station before they can sell the electricity it producers.  In Tesla’s case, it’s their customers who have paid the capital cost of ‘building the power station’, because they paid Tesla when they took ownership of their car or Powerwall.  The difference of course is that, whilst each Tesla customer owns only a tiny fraction of the overall capacity, collectively they own 100% of it. This shifts 100% of the risk off Tesla’s accounts.

Things are moving pretty rapidly.  Tesla have already quietly partnered with, Octopus, probably the UK’s most innovative domestic electricity supplier, to offer the “Tesla Energy Plan”.  This is marketed as “an energy tariff specifically designed for Tesla vehicle owners who have solar panels and Powerwall installed in their home.”  Note the solar panels bit.  This is important, because anybody with a solar inverter is already technically enabled and legally allowed to export surplus energy to the grid.

Clearly, there has to be a compelling answer to the question from the customer’s perspective: ‘what’s in it for me?’  And that’s as follows.  

  • In the UK, typical average domestic electricity costs 15p/kWh.  
  • Under the Octopus Tesla Energy Plan you pay only 8p/kWh for the energy you buy from the grid.
  • And, super-importantly, you also get paid 8p/kWh for any energy Tesla export to the grid on your behalf.  

The Octopus/Tesla collaboration also clearly shows the direction of travel commercially too.  “It offers customers 100% clean electricity and savings of up to 75% compared to Big 6 tariffs. This is achieved through giving you the lowest flat electricity tariffs in the UK, combined with smart management of your home’s energy and electric vehicle (EV) charging.”  

The key detail is in the FAQs.

Q: “What happens if I already have another electric vehicle charger installed, do I still need to have a Tesla Wall Connector?”

A: “No, although we do need you to disable any smart charging features if your charger has those capabilities. Doing this will allow you to use your existing charger for the Tesla Energy Plan.”

This couldn’t be clearer. 

  • As the end-user you’re being asked give up the right to route your solar generation intelligently to your Powerwall and your Tesla car. In our case, this would mean switching off the intelligent functions in the myenergi ‘zappi’ smart charger, which routes any surplus solar production into our Model X, net of domestic consumption and Powerwall charge up.  
  • In return, intelligent energy and storage management done by Tesla, on your behalf, will ‘typically save you 75%’ compared to Big 6 suppliers.

From our own perspective, it will be interesting to do the numbers at the end of a full year to find out which approach saves most money.

  • Our own plan, which is essentially as follows. Install the smart tech on-site, maximise self-consumption, make maximum use of 5p/kWh super-super-cheapo Octopus electricity in the 4 hour window between 00:30 and 04:30 every morning, and minimise use of 13p/kWh energy during other 20 hours. Try to get exports to grid as close to zero as possible.
  • Or just hand the whole process over to Tesla, pay 3p more per kWh than our super-off-peak consumption, and let Tesla pay us 8p/kWh for exporting as much of our solar generation as possible whilst still leaving us enough to drive the cars when and where we want and power the house from the Powerwall when the sun’s not shining.

Watch this space!

Elektrek broke the V2G story here.

You can sign up with Octopus Energy here. This referral link will save you, and us, £50 off an Octopus electricity bill.

March 2020 Performance Update

The big news in March 2020 was, of course ‘Black Death 2.0’ (aka COVID-19), bringing death, fear and economic implosion on a worldwide scale.

On the upside, it was an exceptional sunny month! Only March 1929, 1995 and 2003 have produced more hours of sunshine in the North East of England since MetOffice records began (in 1929). So a juicy 521 kWh of free electricity fell out of the sky and into our house, domestic storage battery and two EVs.

And lockdown meant that, in the latter part of the month, we hardly did any mileage in the cars, so we used less off-peak electricity on the exceptionally good value Octopus Go tariff.

Headline summary data (rounded to nearest whole number) is listed below. Click the image at the end of this post for the usual detailed PDF of the month’s performance. And click the banner here for a referral link that will save you (and us) an additional £50 on their dirt-cheap overnight energy.

  • Solar generation: 522 kWh, of which 177 kWh was stored in the Tesla Powerwall domestic battery and discharged during peak hours.
  • Tesla Powerwall discharge of stored electricity: 546 kWh, of which 177 kWh came from solar and 369 kWh from off-peak electricity.
  • Octopus Go off-peak grid supply: 802 kWh, of which 369 kWh went to Powerwall and 433 kWh went to charging the two cars.
  • Peak grid energy consumed: 180 kWh.
  • Total financial benefits in month: £421 including motor fuel saving.
  • Total CO2 emissions savings in month: 570 kg.

This rather helpful month has helped keep the whole system on track for a rapid payback. Running totals are here. However, if the COVID-19 lockdown persists for a prolonged period over the summer months, a rather counter-intuitive effect will become apparent. If we drive very few miles in our EVs, then it is likely that they can be entirely ‘refuelled’ from completely free solar energy. The payback equation subtly alters:

  • Payback to date has been on the basis of reasonably high mileage, which is refuelled using a blend of solar and (quite a lot of) off-peak electricity. There is massive delta between the cost of that electricity blend and the cost of petrol to propel a conventional car over the same mileage.
  • In lockdown, far less miles will be driven, which will mean that this delta does not come into play, as the vast majority of charging is likely to be solar, at £0 cost.
  • Our savings, versus petrol for a given distance, are likely to be less overall. In short driving “a few miles at absolute zero energy cost” is likely to deliver less of an overall benefit than “many miles at a very low blended energy cost.” The effects will play out over the next few months.

During this month, Alan also published an article analysing the major upgrade to the package of tax breaks and other incentives the UK Government is introducing on 6th April 2020 to encourage the uptake of electric vehicles.

Major UK Government incentives for EVs

At the start of the new tax year on 6 April 2020, a major uprating of UK Government tax breaks and incentives for EVs comes into force.

When employer and employee tax breaks are combined with other hard cash savings of EV ownership, the total financial benefits of owning and driving and EV for business use, compared to a old-tech car, could amount to 100% or more of the sticker price a new EV over three years and 45,000 miles of use.

Document updated 27 May 2020 to reflect the elimination of the “luxury supplement” of £320 Road Tax from Year 2 onwards, but only for all battery electric vehicles. More expensive ICE cars still have this penalty.

The full report is is here.

Thanks to CleanTechnica for featuring this report. Link here.

February 2020 Performance Report

February 2020 was a month of severe storms (Ciara, Dennis and Jorge) which brought widespread flooding and general misery to much of the North of England. Fortunately, all the solar panels stayed firmly attached to the roof and even managed to generate a bit of electricity on the few sunnier days between the downpours.

So, once again, the bulk of the emissions-reducing and cost-saving contributions came from the Octopus Go tariff, providing dirt cheap, green-sourced, electrons to the two EVs and the Powerwall between 00:30 and 04:30 every night. Click the button below if you’d also like to sign for 5p/kWh electricity sluiced into your EV or domestic storage battery in the small hours.

As usual, the detailed monthly performance report is available by clicking the image at the end of this post. The headlines are as follows.

  • £460 financial benefit in the month. This saving compares the cost we actually paid for all the electricity we used (overwhelmingly during the night on the Octopus Go tariff to charge the cars and the domestic storage battery) versus the cost we would have paid at the UK average rate per kWh. It includes a saving of £232 for the petrol we did not have to buy to drive the 1,545 miles charged to our EVs during the month.
  • 404 kg of CO2 emissions avoided by using only 100% renewably-sourced electricity versus the emissions that would be caused by using electricity produced at the UK average generation mix of renewable and carbon-based sources.
  • 311 kg of CO2 emissions avoided by using only 100% renewably-sourced electricity to power 1,545 miles of motoring in EVs, versus the emissions that would have been caused by covering the same distance at the UK average g/km CO2 emissions rate.

January 2020 Performance Report

January in Northumberland is never a good month for solar panels. The earth does the tilting on its axis thing, which means the sun barely creeps above the horizon, except for a couple of hours around midday. In short, one does not feel particularly illuminated in January.

And, speaking of a lack of enlightenment, January 2020 finally inflicted Brexit upon the UK. It remains to be seen what the effects will be in GreenTech and sustainability. So far, the Government is making all the right noises about pressing ahead towards Net Zero by 2050. Time will tell.

Meanwhile, on the much smaller scale of photons hitting our roof and electrons getting stored in the domestic battery, the two EVs and the eBike, only 67.3 hours of sunshine in January 2020 meant that we were once again, as in December, heavily reliant on the Octopus Energy Time Of Use Tariff to fill up the various batteries with cheapo energy in the dead of night. Click the button below if you’d also like to sign for 5p/kWh electricity sluiced into your EV or domestic storage battery in the small hours.

The detailed report (PDF) can be downloaded by clicking the image at the end of this page. Headline figures for the month are.

  • £217 in the month saving on electricity purchase costs, compared to UK average kWh price.
  • £256 fuel cost avoid by not having to buy petrol or diesel for 1,712 miles of motoring.
  • 770 kg of CO2 emissions avoided in total including domestic electricity sourced from zero emissions supplier and zero emissions motoring.
January 2020 Monthly Performance Report

December 2019 Performance Report

The last month of 2019 was very dull in North East England for the first three weeks, before a sunny period between Christmas and the New Year rounded things off. Overall, the Met Office recorded 60.9 hours of sunshine in the month.

Given the generally murkiness of the winter, the bulk of the savings and benefits this month again come from using the Octopus Go tariff. This supplies heavily discounted (5p/kWh) electricity between 00:30 and 04:30, which we use to pour dirt cheap electrons into the 14 kWh Tesla Powerwall domestic storage battery + 100 kWh Tesla Model X and 30 kWh Nissan Lead + (new this month) 1 kWh Riese & Müller eBike.

In overview, December 2019 produced £502.45 in financial savings and benefits. And 796 kg of CO2 emissions avoided. The detailed monthly performance report can be downloaded by clicking the image at the end of this page.

The detailed monthly report can be downloaded by clicking on the image at the bottom of this page. Before that, here’s the link to Octopus Energy if you’d like to get your hands, or (more accurately) your meter, on to all that lovely super-cheap electricity.

November 2019 Performance Report

November was another very dull month with little consistent sunshine until the last two days. When the Met Office publish the sunshine hours stats, we’ll update this post with that information. But it wouldn’t be a massive surprise if this turned out to be one of the dullest November in North East England.

With the lack of sunshine in mind, only just over 100 kWh of solar energy was generated, so most of our savings this month came from the Octopus Go super-cheap off-peak electricity we charged into the combine 144 kWh batteries of the Tesla Model X, the Nissan Leaf and the Tesla Powerwall domestic energy storage. As usual, the petrol we didn’t have to buy to cover the mileage we drove in the EVs was a major contribution.

In headline summary, the headline performance result in November 2019 was a saving of £506, and 759 kg of CO2 emissions avoided. the detailed monthly performance report can be downloaded by clicking the image at the end of this page. The key numbers were as follows.

  • £228 cost of electricity savings versus UK average cost on total consumption of 2,252 kWh.
  • £278 saved versus cost of petrol, to cover the 1,756 miles we charged to our cars using 100% renewably-generated electricity.
  • 405 kg CO2 emissions avoided by using 100% renewably-generated electricity.
  • 354 kg CO2 emissions avoided by charging 1,756 miles of motoring using 100% renewably-generated electricity.

Also as usual, here are the referral links to Octopus Energy and Tesla if you want to start making these kind of savings yourself. See the links page for details about how the referral links work and the benefits both you and we receive.

November 2019 System Performance Report

October 2019 Performance Report

October 2019 was a pretty dull month, with the Met Office reporting only a miserable 90.1 hours of sunshine in our region, so it wasn’t great for solar generation. The 308 kWh produced are more or less in line with our expectations for the solar 24 panels we currently have in service, pending the installation of the final 8 panels when the ceramics studio is built in the next few months. Obviously, we expect significantly better production in the brighter months (roughly March to September), further enhanced by the final solar panels being commissioned.

Nevertheless, the system did an efficient job of using super-cheap electricity to charge the domestic storage battery (Tesla Powerwall) and the two electric cars (Tesla Model X and Nissan Leaf) in the off peak hours, and then using the stored energy, both around the house during peak hours and for powering 1,095 miles of EV driving. Taking into account both our own solar generation and peak-shifting (using stored cheap electricity during expensive peak hours) and motor fuel cost avoided, we saved £369.71 in October 2019.

All the electricity we consume, both from our own solar generation and our grid imports from Octopus, is 100% generated from renewable sources. This enabled us to save 526 kg of CO2 emissions in October 2019, taking into account both domestic electricity usage (versus UK average CO2/kWh for generation at power stations), and in EV driving versus the CO2 petrol/diesel cars would have emitted when covering the same distance. Details are in the downloadable monthly report at the bottom of this page.

We use the ‘Octopus Go’ tariff to make much of the financial saving and their 100% renewable sourcing policy enables us to make significant emissions reductions, even in a dull month with not much sunshine. Disclosure: If you sign up to any Octopus Energy tariff via the link provided, both you and we will each get £50 off our electricity bills.

Our total consumption in the month of October was 1,899 kWh, of which:

  • 215 kWh (11% of 1,889) was solar, generated in peak hours, and consumed immediately, also in peak hours, generally around the house, or for charging the batteries in our two EVs.
    • A further 93 kWh of solar generation went into charging the Powerwall battery (see below).
    • This portion of the solar power we generated was therefore ‘delayed’ consumption. To avoid double-counting, we account it under the next item, only when it is discharged from the Powerwall at a later point and consumed.
  • 514 kWh (27% of 1,889) was the stored energy discharged from the Powerwall, which was all used during peak hours. The stored energy came from the following sources:
    • 93 kWh from solar (18% of 514);
    • 421 kWh from off-peak grid electricity (82% of 514). The Powerwall is configured to avoid any consumption of peak electricity.
  • 878 kWh (46% of 1,889) was off-peak grid energy, from 100% renewable generation. It was used as follows.
    • 421 kWh of the off-peak grid energy (48% of 878) were used to charge the Powerwall at a cost of 5.00p/kWh. The Powerwall then discharged the stored energy for use in the house during peak hours, avoiding a cost of 12.93p/kWh, for a net saving of 7.93p/kWh. The month’s saving from this ‘peak shifting’ alone accounted for £45.42.
    • 449 kWh of the off-peak grid energy (51% of 878) were used to charge the batteries on our two EVs. This equates to 1,049 miles of motoring.
    • 8 kWh of off-peak grid energy (1% of 878) were consumed by other loads which were running during off-peak hours.
  • 283 kWh (15% 1,889) was peak grid energy, from 100% renewable generation.

Our total bill from Octopus for imported grid energy was £88.21 including VAT. This was made up of £7.75 standing charge (31 x 25p) and £80.46 actual energy costs.

£88.21 was our total cost covering all of our domestic electricity use and 1,049 miles of EV driving. That’s a total of only £2.84 a day (£19.88 a week) for domestic electricity AND motor ‘fuel’.

The combined benefits of zero-cost solar generation, plus using the two car batteries and the Powerwall domestic battery to fill up with electricity during the dirt cheap 5p/kWh Octopus Go off-peak period, meant that our average cost of electricity overall was only 4.67p per kWh. This compares very strongly to the UK average cost of 15.5p/kWh.

Please note. Anne fired the pottery kiln eight times in the month. Each firing uses approximately 50 kWh of electricity. So roughly 8 x 50 = 400 kWh (21%) of our 1,889 kWh total consumption was for the ceramics business. It’s worth noting that this additional consumption would not apply in normal domestic premises which do not run an energy-intensive business on the same site.

The full monthly report is below. Please click on it to download a PDF from our cloud storage.