The Energy we need

This week's theme is the hot topic of energy - where we get it, what we use it for, how much of it we are using, and what the future holds for energy security.....oh yes, and what this all might be doing to our environment!

Sample any of the daily press and you'd be forgiven for thinking there is an underlying sense of panic around about how we are going to feed the ever increasing demand for energy. And on the flip-side, concern about what this panic seems to be creating in the energy industry in terms of the risks being taken in extracting energy from the earth in ever-more ingenious, and some might say, dubious, ways.

Where we get our electricity from in the U.K. and the balance between sources is interesting from an environmental point of view. At the moment the proportions go roughly like this:

gas 41%
coal 33%
nuclear 19%
renewables 3%
oil 1%

Electricity on it's own has a sense of magic about it. Faraday was indeed a genius, but he could not have possibly foreseen how much of our current everyday infrastructure now depends on it - from heating and lighting homes and businesses, driving trains, to powering the computer I am writing this on. Unlike other commodities we buy, it cannot be stored and then picked off a shelf or ordered over the internet - it has to be produced at the moment it is needed. Apart from its invisibility, this is also part of its magic - or rather the amazing power-generating infrastructure that is needed to ensure we get it when we need it.

In the U.K. that demand can vary enormously with time of year and time of day, and what's on the TV. On a U.K. summer evening, typically the power demand - always measured in multiples of Watts - is around 15 - 20 gigawatts. A gigawatt is a billion watts. In the winter, around 6.00 p.m., the demand can be in excess of 60 gigawatts. So demand has obvious peaks - although the cause of them has some interesting features. The most important feature in any large power station, or more accurately power distribution centre, amongst all the banks of computer monitors, is the humble TV. Why? Because what is being shown on it has a large bearing on what the power demand is going to be, minute by minute. The largest peaks in demand happen toward the time when the credits for 'East Enders' appear, or at the end of a penalty shoot-out in the World Cup. Immediately afterward is when households go straight to the kettle, and nationwide demand for electricity can go so high as actually to exceed the total capacity of generation in the country - at such times the distribution centres usually make a discreet telephone call to France and say, "more power please".


But what of the consequences of using all this power? Our current burning of coal in particular, and its planned increase by our government, is a big cause for concern. Burning anything that releases carbon into the atmosphere is bad news, but coal releases about 40% more CO2 than gas, when it is burnt. Even worse, a coal-fired power station runs at about 40% efficiency, compared to a gas-fired one on 52%. The coal advocates of course point to carbon capture and storage (CCS) as the way forward here, but even such conservative institutions as the International Energy Agency have said that ..." large scale (CCS) is probably 10 years off (development), and is a real potential emission mitigation tool from 2030..." Apart from the UK, the US and China both have enormous coal reserves they are only too keen to exploit.

So later in the week we will be hearing more about CCS and so-called 'gas-fracking', the humble elm tree, how local development plans affect our demand for energy.... and more.

I'll now think about lighting the woodburner. Anybody got any spare wood?