Recently, I was reading Paul Roberts' book, 'The End of Oil' when I came across this paragraph:
More broadly, this trend helps us see why energy experts get so anxious when they begin calculating how the world is going to power itself over the next century. By most estimates, assuming that projections for future energy demand and population growth hold true - and that we maintain our current disdain for energy efficiency - by the year 2100, the world's ten billion people will need something on the order of fifty terawatts of electricity, or around four times what we produce today. That is a staggering amount of power. Generating it would require an energy infrastructure far larger and costlier than any that exists today, and it raises questions about not only the adequacy of our energy supplies, but the quality of that energy. By some estimates, given the slow success and low power densities of nonhydrocarbon energy technologies, we would not be able to meet all this new demand without using a lot of fossil fuels, which we've no way to ensure that we can burn cleanly. In other words, our unwillingness to take energy efficiency seriously enough to reduce demand may make it flat-out impossible to stay within any sort of reasonable carbon budget. The End of Oil, Paul Roberts, Mariner Books 2005, p 223
In this single paragraph Roberts uses the word, 'energy' 8 times, and the word 'power' 3 times. Each time he used either of these words, I had to stop reading to decide whether he used these words correctly or, as is so common in everyday media stories, as though energy and power were interchangeable words with the same meaning.
To a metrologist, a physicist, or an engineer energy and power are quite different quantities altogether and they shouldn't be muddled. As these folk know:
energy is the ability to do work and it is measured in joules, and
power is the rate at which energy is used and it is measured in watts.
My concern over this apparently simple matter is that books like Paul Roberts' are beginning to be debated all around the world and many commentators are not at all clear what energy and power are and how they differ from each other.
Can anyone tell me how they approach this measurement dilemma?
Cheers and thanks,
Pat Naughtin
Geelong, Australia
