Electricity: personal reflections

 This post follows on from a previous one about the cost of marginal electricity. I wanted to expand on a point I made there about a carbon tax.

          The problem is that some of us don’t have that much electricity to move. I use 4 energy-saving 60W bulbs, a PC and a laptop, a fridge and a microwave (to reheat food I usually cook on Sunday), all of which need to fit into my evening and can’t be moved. Over the course of the evening (5-10pm, peak period, assuming I’m home) that’s perhaps 3KWh, with my daily electricity usage not much bigger; no more than 3.5KWh in total. Average daily usage is maybe 12KWh per household, but since about 1/3 of households are unoccupied (26.7m households, 18m families, with some 330k households containing multiple families) daily usage in occupied homes is more like 16KWh per household.

          I do use more energy than just my electricity bill. I never use heating, but my shower uses hot water from the gas boiler, which I assume requires about as much energy as an electric shower, so that’s an extra 1.5KWH every day. In contrast, average households use four times as much energy from gas as from the mains electricity supply. The average consumption per year is 16MWh/household, or about 60 KWh/day for occupied homes.

          This is where the real savings are, which is why there has been a lot of focus on insulation and double-glazing, to cut heating bills.

          As we broaden our horizons beyond electricity to a more holistic view of energy usage, we see far more opportunities for savings and personal decisions. This is why a sensible carbon tax is so important. With a carbon tax that treats carbon dioxide emitted from beef production, car driving or lights treated the same, we can all prioritize our lives sensibly. We shouldn’t need to use complicated carbon calculators to guess whether our actions make sense or not by giving information on a myriad of different aspects of our lives. A sensible carbon tax, universally applies, would ensure that the markets deliver what we need, and that we can balance costs across our lives.

          Without this ability to compare and balance costs, we can get sidetracked by relatively unimportant concerns. For example, electricity, although important, is not as important as heating or transport. Turning lights off, or using energy-saving bulbs, is important because there is no significant cost in doing so, but is far less important a saving than some others, such as turning the heating down and wearing a jumper.

          Meaty diets emit more carbon than vegetarian diets (5.6 kg CO2/day compared to 3.8 kg/day. However, about 40% is from fertilizer use, and some figures add a large amount to account for deforestation. Organic home-grown meat avoids a lot of this cost. For example, the EU has an average CO2 emissions for beef of 12 kgCO2/Kg beef, but Brazil is more like 23. Beef is 10-11 times more carbon intensive than other meats, and the same source shows that North American crops can have carbon intensities of over 1 KgCo2/Kg food (because there are values over 1 of tonnes of CO2 per hectare, and example productivities of similar values of tonnes of grain per hectare). It is clear that the source of the food is very important, and simple divisions of meat or cereal are not sufficient. Emissions in the UK from agriculture are 9% of our total, of which over half is fertiliser and 30% from sheep and cow waste, including uncovered slurry pits.

          I eat meat, producing an extra few kg of Co2 a day. But that meat powers my bicycle and stops me needing to heat my home. Gas produces 0.203Kg CO2/KWh, so by saving all heating costs (let’s call it 2/3 of the heating bill, the remaining 1/3 going on the hot water I do use) I save 8.1 KgCO2/day.

          Estimates are that roughly 1/3 of national energy usage is on transport. Cars emit on average 14.3kg of CO2 per gallon of petrol, and cars, vans and motorbikes use about 12.6 million tonnes of petrol per year in the UK, and 12.4 million tonnes of diesel (all transport use is about 50 million tonnes, so personal transport is half of all usage; buses and coaches use about 1.2 million tonnes per year). If I return to the rough calculations, 1/3 of national energy use is transport, of which half is personal transport, giving us a national average of ½ our domestic energy use, or 30-40 KWh per day. I save all this in carbon by not driving to work, or even around after work. I don’t know how much the average person drives, but a vegan who saves no more than 3 Kg of CO2 per day over me on diet (and more like 2) would need to drive less than 10 miles a day (at 50mpg) in order not to destroy that carbon saving.

          My calculations show that it’s hard to track carbon. I’ve done quick and simple calculations using average figures, but these are only rough calculations. If I saw the cost to the world of my actions directly, through a carbon tax that directly affected by expenditure, I would be better able to live environmentally.