An international feel to this month’s blog and the chance to make some interesting comparisons. It wasn’t quite Salzburg, (I was skiing in the Austrian Alps) but it was Prague which is (though Lyds may beg to differ) the capital of the Czech Republic. Both showers were thermostatically controlled, supplied from an electrically heated centralised hot water store making the comparisons more valid.
The Austrian shower was state of the art, aerated head, 7 litres/minute flow rate, in a brand new skiing chalet in a large, matt black tiled, walk- in shower with a surrounding air temperature of 25 degrees C. The Czech shower dated from the communist era, was in an unheated area in a very small flat in a plastic shower cubicle with a broken door. And the flow rate? Well it was either 4 litres/minute or 12 litres/minute with nothing in between, (and only once was I able to get it to work at the lower rate). The one thing they both had in common was no bath anywhere to be seen (ahh the bath, such a quaint British custom!).
And the carbon comparisons? Well this is where it gets really interesting… The carbon intensity of gas doesn’t change markedly between one country to the other but the carbon intensity of electricity certainly does.
The IPCC rates the carbon intensity of Austrian electricity (including imports) as 0.187 kgCO2/kWh. Almost 70% of all electricity in Austria is generated from hydro, and about 28% from fossil fuels (mostly oil). Austria has one nuclear power station – mothballed before it generated any electricity! Construction of the plant started in 1972, and protests gathered momentum as the build progressed. In 1978, just before it was ready to go live, the Austrian Government decided to hold a referendum, secure in the assumption they would win it. However, 50.47% of the votes were against and so (despite its 1 billion Euro price tag) it was never activated. The Austrians joke that they have the only 1:1 scale working model of a nuclear power plant in the world!
During the summer months theoretically all consumption comes from hydro. But in practice, some of it is exported and some of the base load covered by thermal power plants. In winter, when less water is flowing, the country relies on imports, ironically a lot from the Czech Republic, who do have nuclear. (In fact, 10% of all electricity consumed in Austria comes from the Czech Republic).
The Czech Republic produces its electricity predominately from coal fired power stations (67%) and nuclear (32%), resulting in a far higher carbon intensity of 0.606kgCO2/kWh. (Again, an IPCC figure). This means that using electricity in the Czech Republic is 3.2 times as carbon intensive as using electricity in Austria.
So what effect does all of the above have on my three minute shower in each country? Working from first principles, with a temperature lift of 28 degrees (incoming 10 degrees, 38 degrees required at outlet), the electricity required to heat 1 m3 (1000 litres) of hot water is 33kWh. My Austrian shower used 21 litres of water, required 0.68kWh of electricity and produced 0.13kg of CO2. My Czech shower used 36 litres of water, required 1.17kWh of electricity and produced 0.71kg of CO2. Over a year, with a shower a day, the Austrian shower would produce just 47kgCO2, whereas the Czech shower would emit 259kgCO2.