Earth Notes: Saving Electricity and Gas (2014)Updated 2022-05-15 21:27 GMT.
By Damon Hart-Davis.
2014 data (kWh: e used 1678, e gen -3944, g 2997).
|Month||Consumed kWh (/d)||Generated -kWh (/d)||Consumed kWh (/d)||Period||Notes|
|2014-01||190 (6.1/d)||-76 (-2.4/d)||532 (17/d)||20131231T19:25Z to 20140131T19:02Z (31d)||Meter readings: electricity generation 75.9kWh, export 48.5kWh, import 162.6kWh (thus net consumption (I+G-E) 190.0kWh); gas ~47.9m^3 (so 532kWh @ 11.1kWh/m^3).
Imports passed 5MWh. Very mild and wet this month.
HDD12=156 vs 231 last January (implying gas 2.8kWh/HDD12 at 3kWh/d baseload).
|2014-02||131 (4.7/d)||-145 (-5.2/d)||461 (16/d)||20140131T19:02Z to 20140228T18:17Z (28d)||Meter readings: electricity generation 144.8kWh, export 117.5kWh, import 103.5kWh (thus net consumption (I+G-E) 130.8kWh); gas ~41.5m^3 (so 461kWh @ 11.1kWh/m^3).
Boiler/CH problems this month: internal bypass in ~10-year-old boiler apparently inadequate following (furred-up) primary heat-exchanger replacement mid-month, so had to leave one rad on permanently which wastes energy. External bypass fitted 2014-03-14.
Mildest February (lowest HDD12) in my records.
HDD12=127 vs 230 last February.
|2014-03||162 (5.2/d)||-341 (-11/d)||365 (12/d)||20140228T18:17Z to 20140331T18:08Z (31d)||Meter readings: electricity generation 340.9kWh, export 286.3kWh, import 107.0kWh (thus net consumption (I+G-E) 161.6kWh); gas ~32.9m^3 (so 365kWh @ 11.1kWh/m^3).
HDD12=112 vs 254 last March.
|2014-04||123 (4.1/d)||-437 (-15/d)||137 (4.6/d)||20140331T18:08Z to 20140430T17:48Z (30d)||Meter readings: electricity generation 436.7kWh, export 387.4kWh, import 73.6kWh (thus net consumption (I+G-E) 123.1kWh); gas ~12.3m^3 (so 137kWh @ 11.1kWh/m^3).
Passed 14MWh exports.
Heating officially off at the boiler 25th, though only operating intermittently before then.
HDD12=44 vs 121 last April.
|2014-05||136 (4.4/d)||-528 (-17/d)||132 (4.2/d)||20140430T17:48Z to 20140531T17:30Z (31d)||Meter readings: electricity generation 527.5kWh, export 458.2kWh, import 66.6kWh (thus net consumption (I+G-E) 135.9kWh); gas ~11.9m^3 (so 132kWh @ 11.1kWh/m^3).
Passed 4MWh generation on the newest 1.29kWp string, and passed 20MWh generation for entire system according to the Sunny Beam.
HDD12=19 vs 50 last May.
|2014-06||135 (4.5/d)||-631 (-21/d)||116 (3.9/d)||20140531T17:30Z to 20140630-18:00-BST (30d)||Meter readings: electricity generation 631.2kWh, export 552.7kWh, import 56.7kWh (thus net consumption (I+G-E) 135.2kWh); gas ~10.5m^3 (so 116kWh @ 11.1kWh/m^3).
Savings from automatically switching the ADSL modem off-grid ~62% of the month when the batteries were full amounts to perhaps (7.7W*24*30*.62) or ~3.4kWh, ie 2.5% of gross consumption.
HDD12=2 vs 8 last June.
|2014 running total (Jan--Jun)||877 (4.8/d)||-2157 (-12/d)||1742 (9.6/d)||20131231T19:25Z to 20140630T18:00Z (181d)||Implies total footprint to date -227kgCO2: electricity (average 202W gross) -558kgCO2e @ 0.43kgCO2/kWh (netted), gas 330kgCO2e @ 0.19kgCO2/kWh.|
|2014-07||100 (4.1/d)||-496 (-20/d)||85 (3.5/d)||20140630-18:00-BST to 20140725T06:38Z (24.5)||Meter readings: electricity generation 496.3kWh, export 441.0kWh, import 44.9kWh (thus net consumption (I+G-E) 100.2kWh); gas ~7.7m^3 (so 85kWh @ 11.1kWh/m^3).
Short measurement month due to fortnight holiday starting in last week of July.
Import of ~9.5kWh vs gross consumption of 23kWh (1.7kWh/d) over the fortnight (well, 13.5d!) that we were away (with most things turned off other than the fridge/freezer (est ~60%/40W), security lighting / clocks / phones / etc, ADSL Internet modem (~10%/8W), and MHRV fans (~5%/4W) as ~70W baseload total vs ~200W 6M average), is consistent with the average daylight hours that the PV will have covered load. (1.8kWh of gas use was recorded between the last reading on the holiday morning and the first reading on return, which is likely a bit of DHW for washing!)
Passed 17MWh generation on the first generation meter/FiT (75% of the roof).
HDD12=0 for whole of calendar July vs 0 last July.
|2014-08||114 (3.0/d)||-650 (-17/d)||83 (2.2/d)||20140725T06:38Z to 20140831T17:07Z (37.5)||Meter readings: electricity generation 650.1kWh, export 595.9kWh, import 60.0kWh (thus net consumption (I+G-E) 114.2kWh); gas ~7.5m^3 (so 83kWh @ 11.1kWh/m^3).
Long measurement month due to fortnight holiday starting in last week of July.
Passed 16MWh exported, of which nearly 600kWh this (extended) month alone.
HDD12=5 for whole of calendar August vs 0 last August.
|2014-09||130 (4.3/d)||-326 (-11/d)||99 (3.3/d)||20140831T17:07Z to 20140930T18:43Z (30)||Meter readings: electricity generation 325.7kWh, export 276.5kWh, import 80.4kWh (thus net consumption (I+G-E) 129.6kWh); gas ~8.9m^3 (so 99kWh @ 11.1kWh/m^3).
HDD12=5 vs 10 last September.
|2014-10||143 (4.6/d)||-175 (-5.6/d)||121 (3.9/d)||20140930T18:43Z to 20141031T17:51Z (31)||Meter readings: electricity generation 174.6kWh, export 141.4kWh, import 110.2kWh (thus net consumption (I+G-E) 143.4kWh); gas ~10.9m^3 (so 121kWh @ 11.1kWh/m^3).
Passed cumulative 18MWh generation on the first meter (3 strings).
HDD12=15 vs 23 last October.
|2014-11||155 (5.2/d)||-86 (-2.9/d)||282 (9.4/d)||20141031T17:51Z to 20141130T18:29Z (30)||Meter readings: electricity generation 85.9kWh, export 61.6kWh, import 131.0kWh (thus net consumption (I+G-E) 155.3kWh); gas ~25.4m^3 (so 282kWh @ 11.1kWh/m^3).
Heating tested 6th, see graph and notes, and on properly after the 11th roughly.
Expecting daily electricity consumption in Nov/Dev/Jan to be very roughly: 1kWh each for cooking, washing m/c, dishwasher, fridge/freezer, boiler, with about 0.5kWh for other things mainly TV and lighting.
HDD12=79 vs 139 last November (ending the third warmest autumn on record).
|2014-12||159 (5.1/d)||-54 (-1.8/d)||585 (19/d)||20141130T18:29Z to 20141231T19:25Z (31)||Meter readings: electricity generation 54.4kWh, export 34.8kWh, import 139.4kWh (thus net consumption (I+G-E) 159.0kWh); gas ~62.7m^3 (so 585kWh @ 11.1kWh/m^3).
Rolled 6MWh imports over New Year's night.
Christmas at home and lots of OpenTRV testing may have bumped up gas use!
HDD12=183 vs 152 last December (ending the warmest UK year on record)
|2014 total (Jan--Dec)||1678 (4.60/d)||-3944 (-10.8/d)||2997 (8.21/d)||20131231T19:25Z to 20141231T19:25Z (365d)||
Gas consumption an all-time low of just under 3MWh, probably because 2014 was a record warm year (HDD12 of 747 vs 1218 for 2013).
Ecotricity estimates our annual electricity imports at just under 1.1MWh (and our bill was a bit over £10 less than this time last year), and annual gas use at ~2.8MWh (and our bill was a bit over £8 more than this time last year), with an estimated total not much over £400 per year. Mean gross electricity consumption ~200W, import ~125W.
|kgCO2||722kg (2.0/d)||-1696kg (-4.6/d)||569kg (1.6/d)||~-0.41tCO2 (~-1.1kgCO2/d) gas/electricity emissions total for 4 people, based on 0.43kgCO2/kWh for electricity (netted) and 0.19kgCO2/kWh for gas, ie slightly carbon negative.|
Note that we haven't flown this year again, we still don't own a car and travel almost entirely by (usually-electrified) public transport.