Day 18 of the Covid 19 lock-down. There is press speculation that home energy consumption could increase by 25% or more from enforced home working. We have seven people in the house for the duration, so I spent the day
analyzing our energy consumption and cost with some trepidation. But I needn’t have been concerned, we thought the Octopus Agile half hourly tariff combined with our PV generation/storage system would bring strong results, but the early results blew us away…this is a real winner !
Since the days of 120+ kWh consumption in February, we have made good progress reducing the net consumption: down by 54% per day through heating optimization and greater PV generation days (averaging 33kWh in March and 44 kWh at the start of April). Coupling this with Octopus’ Agile tariff has reduced the cost of energy from £ 18.8/day down to an unbelievable £ 3.21/day, a staggering 80%+ reduction !!
How is this possible ? In update 7 we reported that moving onto the Agile tariff had initially delivered 15% savings but, with this tariff, the majority of the cost comes between 4-7pm. I resisted the temptation to demand the family refrain from using power during this period and not cook tea until after 7pm !...nope no behavior change has occurred…frankly I would have been killed if I had !
Moving to British Summer Time lengthens the early evening generation and then using the 19kWh batteries to supplement the declining PV generation at that time has been the secret. We have reduced the % daily power consumed during this window from 20% down to 5%. There is a direct correlation between this factor and the daily saving.
And we still can go further: the complexity of the three phase supply means that we are still feeding back 15-20 kWh a day to the Grid and if we could reuse this power we would be very close to being off the grid. However, this is going to require a better load balance across the phases, a way of sharing the battery storage across the phases and a flexible additional battery storage. I am thinking this could come in the form of an electric car with a reversible flow battery that we could use for the house while not driving!
I am still trying to get going with the Octopus Outgoing tariff to sell the excess exported energy; it’s complicated ! .. they tell me that it is making their boffins’ brains hurt getting their heads around what we have done, no-one ever said the bleeding edge would be easy !...but their Agile product is a game changer.
