Entrepreneurs fight global warming

Pebblecounters and politicians are among the many non-technical people who tend to go for what they call ‘market solutions’ to technical problems. Emissions trading markets are good examples of their ideas. Extraordinary turbulence occurred in the European CO2 emissions market at the end of its first trading period and was widely reported in the press (including MPS, June 2006, pp3, 8 and 48).

Myself, as a horny-handed son of toil, I prefer technical solutions to what I regard as primarily technical problems: but I do see that finding technical solutions and spreading their application may be tougher than exploiting commercial instincts and business people’s ingenuity.

One sort of emissions trading that may appeal to you, as it does in its way to me, is the sale of greenhouse gas credits by a certain Irish company that taps methane from livestock (such as pigs, cows and poultry) so that the farmer can burn the gas to generate heat or power for his premises, and thus provide the enterprising Irish business with emissions reduction certificates for sale to customers such as Electricité de France.

Methane greatly outdoes CO2 as a greenhouse gas, and its emission reduction certificates must carry a corresponding cachet.

Here is one good turn from our planet

Not every power engineer has been lucky, or unlucky, enough to have met, somewhere in the course of his education and training, something called the Coriolis effect. You may recall it vividly and need no reminding, but I have had to cheat a bit. The source I have tapped tells me that Newton’s second law does not hold in a rotating frame of reference unless the body being considered is supposed to be acted upon not only by its complement of ‘real’ forces but also by a ‘Coriolis’ force.*

The effect of this force on the moving body is diversion. Thus a freely falling body (ie a body impelled by gravity alone in vacuo) hits the earth slightly away from the point vertically under the release point. Thus also, and more complicatedly, the trade winds take the directions that they do in equatorial parts.

All of which is fun for physicists, meteorologists, yachtsmen (knowing sailors use the effect to help them get the better of less knowing competitors in races) and others. However, studies of coastal wind movements have shown them to be influenced by the Coriolis force in a way beneficial not only to crafty yachtsmen but, potentially, to offshore wind farmers. British, French and German research has reportedly shown that, thanks to the Coriolis effect, what may be aeoliculturally useful gusts and jets are created parallel to coastlines.

I expect offshore wind farmers to beat paths to the door of Andrew Orr at The European Medium Range Weather Forecasting Centre, Reading, UK. He is master of the mathematical modelling that could enable them to do as well out of Coriolis calculations as yachtsmen have done. And also, incidentally, enable them to foresee any coastal flooding problems that might come their way.

Our rotating planet does not always turn so benignly, even for those – the wind power buffs prominent among them – who yearn to save it. Moreover, modellers of the physical kind, as distinct from the mathematical, can play pivotal roles in the furtherance of wind-power-related technology. Physical modelling can indeed be of literally fundamental importance to some people in the field.

I have in mind the aspiring offshore turbineers lured by apparently rich prospects among the many coastal shallows around such places as the British Isles. These waters are attractive because their wind regimes are not weakened by land barriers. Unfortunately, however, the seabeds may be treacherous in that the sediments supporting turbine-tower foundation-caissons may be shifted by waves and currents if the structure designers have not understood them and taken them properly into account: and the necessary knowledge is still being acquired.

For instance, at H R Wallingford Ltd’s research station in Wallingford, UK, model tests in a large basin have revealed that the speed with which sedimental holes are scoured around turbine-tower caissons by waves and currents can vary greatly with the shapes of the foundations where they are joined at their tops to the tower bases. That speed can in fact vary by as much as 80%.

As a publication of the UK’s Institution of Civil Engineers points out in reporting this work, “any hoped-for expansion of green energy from wind-farms cannot take place unless investors can be reassured about the stability of the system over the duration of the wind-farm’s life”. So I expect that H R Wallingford Ltd and the European Medium Range Weather Forecasting Centre will both draw the aeolicultural cognoscenti.