WEBVTT NOTE Transcript 2024-04-12 from FLAC by https://elvery.net/prototypes/transcribe/ on my MacBook Air M1 on maximum quality setting. NOTE Body edited. 00:00.000 --> 00:13.720 Statscast. Hi, I'm Damon Hart-Davis, and welcome to Earth Notes podcast on all things 00:13.720 --> 00:22.760 eco and green and efficient at home! 5th July 2020 for June's Stats. Turn-of-the-month 00:22.760 --> 00:28.940 update of home energy and related stats, and poking at data from 16WW. Here's a mystery 00:28.940 --> 00:47.640 sound to keep you guessing until later. [...] As the UK's Met Office said, the "very sunny 00:47.640 --> 00:51.980 and warm weather of late May continued into the start of June," but then petered out into 00:51.980 --> 00:57.440 a more typical mixed bag. Old joke: "If you don't like the weather in the UK, wait 10 00:57.440 --> 01:04.239 minutes." Thus, for example, 16WW PV generation was a pretty normal 19kWh per day and close to the original PVGIS prediction. Weather and life are clearly nowhere near normal in 01:09.520 --> 01:14.600 all sorts of other ways, from much more rain than average across the UK in June, to pandemic 01:14.600 --> 01:20.920 infection relapses requiring new lockdowns into July from Leicester to Lubbock, Texas. 01:20.920 --> 01:26.200 Back here in slightly less sunny 16WW, gross electricity and gas consumption are still 01:26.200 --> 01:30.860 elevated, though maybe a bit less so with the younger Xboxing child back in school two 01:30.860 --> 01:36.400 days each week. Because the sunshine has been less consistent and predictable, timing loads 01:36.400 --> 01:42.680 to match the sun being out (e.g. when should we run the dishwasher?) is harder. So self-consumption 01:42.680 --> 01:48.640 dropped a bit since May even though we continue to export heavily overall. Another local stat... 01:48.640 --> 01:53.000 By an advanced scientific process known as "counting", which I seem not to be very good 01:53.000 --> 01:58.600 at, mid-month I estimated that my normal lockdown exercise jaunt, to and around the edge of the 01:58.600 --> 02:04.920 cemetery, seems to be about 2,000 steps so maybe 20% of what should be my daily target! 02:04.920 --> 02:10.120 And my Captain Caveman look isn't going away anytime soon given the catch-up pressure on 02:10.120 --> 02:13.400 local barbers. 02:13.400 --> 02:14.400 Visualisation. 02:14.400 --> 02:18.300 Today's visualisation came about because I'm trying to better understand some heating-related 02:18.300 --> 02:23.700 stats, and prodded my own data to get there. In the building physics world there is a simple 02:23.700 --> 02:28.880 model that says, for heating climates such as the UK, that above a certain 'base' temperature 02:28.880 --> 02:34.200 the building won't need heating. That may be because outside is warm enough generally, 02:34.200 --> 02:38.760 or because even if it's a little cooler outside than would be comfortable inside, heat gains 02:38.760 --> 02:44.760 from people and appliances make up the difference. The default base temperature assumed for UK 02:44.760 --> 02:50.040 buildings is 15.5 degrees C. Though it makes sense to try to compute a more accurate value 02:50.040 --> 02:57.040 by observing how a particular building works. For 16WW I use 12 degrees C as the base. 02:57.040 --> 03:02.200 For every degree below that base temperature the heat demand is assumed to go up linearly, 03:02.200 --> 03:08.520 so that a day with two HDD (two "Heating Degree Days") should require about twice as much space 03:08.520 --> 03:14.920 heat energy as a day with one HDD. The fewer kilowatt hours of heat needed per additional 03:14.920 --> 03:19.760 HDD of demand to keep the building comfortable, the more efficient the building is. Low is 03:19.760 --> 03:25.480 good! (You can read more about how all this works at my favourite degree days dot net.) 03:25.480 --> 03:30.400 One assumption is that the kilowatt hour per heating degree day figure should be roughly 03:30.400 --> 03:35.360 constant, at least when there is space heat demand. The kilowatt hour per day figure often 03:35.360 --> 03:39.800 won't drop to zero even when there is no heat demand, such as in summer, where the 03:39.800 --> 03:46.240 same energy or fuel is used for other things such as cooking or DHW (Domestic Hot Water) 03:46.240 --> 03:53.720 as it often is in the UK. I plotted 16WW daily gas consumption against HDD with 12 degrees 03:53.720 --> 04:01.440 C base for 2016 up to the end of June 2020. Although it's messy, I think it's true. 04:01.440 --> 04:07.080 Heat demand, kilowatt hours, rises massively mid-winter as you'd expect, but the kilowatt 04:07.080 --> 04:12.320 hour per heating degree day shape seems much flatter, which is what I wanted to check. Note 04:12.320 --> 04:16.399 that we generally only have the heating on November to March. The pattern recognition built into our brains is pretty good. For those of you looking at 04:20.120 --> 04:23.880 this episode's page and show notes, you can see if you agree with my interpretation 04:23.880 --> 04:31.840 or not! For 16WW, kilowatt hours per heating degree day is now around 2.5. Before conserving, 04:31.840 --> 04:39.720 it was over 4. For 2019, the metrics were 2.3 kilowatt hours per heating degree day, 04:39.720 --> 04:45.360 and a base load of 2.7 kilowatt hours per day. Those are about right, extracted from 04:45.360 --> 04:54.360 our messy, real-world data. The years 2016 through to 2019 show similar values. For 2020, 04:54.360 --> 04:58.400 for the first six months including a record warm spring and lockdown, the figures are 04:58.400 --> 05:04.640 1.7 kilowatt hours per heating degree day, and a base load of 4.8 kilowatt hours per 05:04.640 --> 05:11.120 day. The latter up (and the former down) likely due to unusually high occupancy. (As of this 05:11.120 --> 05:16.600 episode, only half the data for 2020 exists, but the dataset and grassroots should update 05:16.600 --> 05:22.240 as more comes in.) Have a look, in the show notes, to see all the graphs and the raw data 05:22.240 --> 05:26.200 and see what you think. I'd like to go back and do the same for previous years, though 05:26.200 --> 05:30.720 instead of daily data from Loop for gas Demand, I have manual meter readings already captured 05:30.720 --> 05:35.800 electronically at about weekly cadence. I have more detail that I could transcribe from 05:35.800 --> 05:38.120 paper records if needed. 05:38.120 --> 05:43.000 Bonus soundscape and number. Though I didn't audify any numbers this time, I didn't want 05:43.000 --> 05:47.600 to leave noiselessly. Over the last couple of days I've been enjoying the field recordings 05:47.600 --> 05:54.640 at Cathartic Audio. So I made another of my own, a 'daytime' 16WW capture to go with previous 05:54.640 --> 06:01.640 dawn and dusk. Here's little of it with birds and cars and DIY oh my! 06:01.640 --> 08:48.640 [suburban noises and birds chirping] 08:48.640 --> 08:52.640 The full raw track is available from the show notes. 08:52.640 --> 09:00.640 And since you asked, that (mystery) repository revision number as of preparing these words, is 35359, 09:00.640 --> 09:05.640 up 675 from the last statscast, so just over 20 revisions per day. 09:11.640 --> 09:17.640 There's more on my Earth Notes Web site at Earth.Org.UK.