It’s been estimated that the average person’s lifestyle consumed a power of 20 kWh per day

It matters where the energy is: lots of heat just 100km under our feet doesn't help much although manufacturing earthquakes might, just a bit. We're not Iceland which can rely on geothermal heat closer to the surface to operate huge aluminium smelting plants. So we can (almost) forget geothermal. Public "services" like a well-equipped army or well-heated academics also consume. Maybe some demand should be counted as production if it can be sustainably avoided by our efforts? Next week is the first chapter looking at the overall balance of demand to potential renewable supply.

Tide farms, tide barriers and two-way tide pools sound very attractive. And they won't make the world stop turning. Unfortunately, even for the rather tide-rich British Isles, we can only really hope to cover something about equivalent to our lighting and gadget energy consumption this way. And the economics of building large installations are not yet clear. Stuff, on the other hand, is much less attractive. Just making and transporting it -- TVs, food, drink, packaging, cans, computers ... -- is our biggest single consumption category. Reducing the stuff-intensity of well-being seems like a good goal.

To summarize all these forms of stuff and stuff-transport, I will put on the consumption stack 48 kWh per day per person for the making of stuff (made up of at least 40 for imports, 2 for a daily newspaper, 2 for road- making, 1 for house-making, and 3 for packaging); and another 12 kWh per day per person for the transport of the stuff by sea, by road, and by pipe, and the storing of food in supermarkets.

Dieter Helm and his colleagues in Oxford estimate that under a correct account, allowing for imports and exports, Britain’s carbon foot- print is nearly doubled from the official “11 tons CO2e per person” to about 21 tons. This implies that the biggest item in the average British person’s energy footprint is the energy cost of making imported stuff.

Figure 15.8. Energy requirements of different forms of freight-transport. The vertical coordinate shows the energy consumed in kWh per net ton-km, (that is, the energy per t-km of freight moved, not including the weight of the vehicle). See also figure 20.23 (energy requirements of passenger transport).

This river of reading material and advertising junk pouring through our letterboxes contains energy. It also costs energy to make and deliver. Paper has an embodied energy of 10 kWh per kg. So the energy embodied in a typical personal flow of junk mail, magazines, and newspapers, amounting to 200 g of paper per day (that’s equivalent to one Independent per day for example) is about 2 kWh per day.

As for a 500 ml water bottle made of PET (which weighs 25 g), the embodied energy is 0.7 kWh – just as bad as an aluminium can!

Computers Making a personal computer costs 1800 kWh of energy. So if you buy a new computer every two years, that corresponds to a power consumption of 2.5 kWh per day.

In which we learn that to get by on wave power you need to be very very insular -- that is, have a small number of people per unit length of exposed coastline (sounds like a nice place to me, but the British Isles don't fit the description) -- and also that our food habits, especially for red-blooded carnivores with meat-eating pets -- amount to more than half our driving habit in energy. There is a real energy case to be made for vegetarianism (approximately twice as efficient) and even more for veganism (another doubling).

The typical diet has an embodied energy of roughly 6 kWh per kWh eaten. Coley (2001) estimates the embodied energy in a typical diet is 5.75 times the derived energy. Walking has a CO2 footprint of 42 g/km; cycling, 30 g/km. For comparison, driving an average car emits 183 g/km.

Eating meat requires extra power because we have to feed the queue of animals lining up to be eaten by the human.

Modern agriculture is the use of land to convert petroleum into food. Albert Bartlett

While wave power may be useful for small commu- nities on remote islands, I suspect it can’t play a significant role in the solution to Britain’s sustainable energy problem.

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I think that it’s a good idea to switch off such a charger – it will save you three pounds per year. But don’t kid yourself that you’ve “done your bit” by so doing.

All the energy saved in switching off your charger for one day is used up in one second of car-driving. The energy saved in switching off the charger for one year is equal to the energy in a single hot bath.

We also learn, moreover, that traffic kills one million birds per year in Den- mark. Thirty-times-greater horror! Thirty-times-greater incentive to ban cars! And in Britain, 55 million birds per year are killed by cats (figure 10.6).

We use about as much to heat and cool ourselves (in Britain) as we use to move around in our cars, while lighting uses onlu a graction of that energy - especially using low energy fluorescent bulbs or the new generation of LED lights. Hydro-electric power in Britain, however, even with generosity from the wet Highlands, will only deliver about one third of the small amount of energy we use to light ourselves. How unfortunate that such accidental power-concentrators as mountains and streams are not more plentiful, and not just, maybe, for the energy benefits.

Loch Sloy’s surface area is about 1.5 km2, so the hydroelectric facility itself has a per unit lake area of 11 W/m2. So the hillsides, aqueducts, and tunnels bringing water to Loch Sloy act like a 55-fold power concentrator.

A more modest luxury is an electric blanket. An electric blanket for a double bed uses 140 W; switching it on for one hour uses 0.14 kWh.