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.

This PDF has all the detail.

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.