The media always report statistics of oil production, reserves etc in “barrels”. But how many people know how big a “barrel” is?* Indeed is it an appropriate unit of measurement to use in the context of world energy policy?
The oil industry used to be dominated by American companies, and as with aviation and computers, American units have largely been adopted as the industry standard.
This might not matter since the only people who trade in oil are industry insiders, and arguably the general public do not need to know how big a “barrel” is. They will understand that if OPEC reduces output by x million barrels per day, that’s a lot of oil, and price rises can therefore be expected. In any case, outside the USA, they will still buy the end product in litres.
Yet although it is not a consumer protection issue, there is a problem. Any departure from the International System of Units should be discouraged, as it results in dual labelling, conversion errors, the need to know two systems when one will suffice – and of course general incomprehension.
More particularly, the “barrel of oil equivalent” is used as a
measure of global energy production and consumption. For this, all energy sources (m3 of gas, tonnes of coal, etc.) are converted by energy content into the equivalent energy available in a barrel of crude oil.
BP produces an annual report of world energy consumption and has just produced this year’s. See www.bp.com/statisticalreview
I notice that they are now using the tonne of oil equivalent alongside, or sometimes in place of the barrel. Whilst this is clearly an improvement, it doesn’t really give you what you’re looking for. If you’re talking about world energy consumption, rather than just oil, then surely joules (or gigajoules – GJ) are the unit they should be working with? I can see some logic in using a quantity of oil to measure reserves, and refinery throughput, but if you’re comparing nuclear and gas, for example, what has oil got to do with it? The joule only gets a mention in the conversion tables – 1 tonne oil equivalent ~= 42 GJ.
*A “barrel” is 42 US gallons (equivalent to approximately 159 litres)