Tuesday, March 1, 2011

Global Power

This is not about political or metaphysical power. It is about energy sources and uses.  The world uses energy for transportation, heating, cooking, industry and generation of electricity, among other uses. Energy is measured in calories, BTUs, joules, kilowatt-hours (or barrels of oil).  Power is measured in watts, kilowatts, megawatts, horsepower, BTU/hr. Power is the rate at which energy is converted to work.  The laws of nature stipulate that you always have losses in converting energy to work and that there is no free lunch.

There are several sources with global energy use and power generation information.  One is the EIA, of the Department of Energy in the US, or you may try Wikipedia.  A useful graphical representation, slightly out of date, is from newscientist.com.  What might be worth observing in the context of this blog is that (i) electricity generation is only a subset of total energy use, (ii) coal is used primarily for electricity, (iii) nuclear is only used for electricity, (iv) transportation is a major user of energy and mostly oil and (v) the only visible renewable source of energy is hydropower.  On a global basis, other sources of renewable energy are too insignificant to even appear in graphical form.  Renewables are a higher percentage of total electricity generation (a subset of total energy consumption), but they are best reviewed on a country by country basis.

The US energy flows are best seen in the original  (or by clicking on the diagram).

Denmark, a major preacher of renewables, is basically an oil, gas and coal user. The source document may be found here.  Denmark has visible use of renewable energy sources, however it does not meet the Kyoto CO2 specs (for whatever that is worth) and has among the most expensive electricity rates in the EU.

Germany is quite interersting.   Their officiall 2010 figures indicate that 1,5% of their total energy requirements are from hydropower, wind and photovoltaics. Electricity percentages are higher and the diagrams for 2006, above and for 2008, below, indicate 10.6% of electrical power generated by hydro, wind and photovoltaics. 56% is from coal, lignite and natural gas, and 23% is nuclear.  I have seen, but have been unable to substantiate that renewable energy sources in Germany received a 13 billion euro subsidy in 2010.  A rather expensive hobby.

The bottom line is that a only a very rich and determined country may show a visible contribution in its energy consumption from wind and photovoltaics.  On a global basis, wind and photovoltaics cannot make any material difference. It is matter of orders of magnitude and cost. Good German export business, large use of taxpayers' and consumers' money but unclear energy or environmental impact. There is no free lunch and the renewable lunch is skimpy and outrageously expensive.