Wednesday, December 16, 2009
Engineering for Clean air
Climate change is a hot topic. It's the talk of Copenhagen town. The great and green are flying in from all over the world, to declare on this grand-stand their determination to save the planet, preferably at someone else's expense. Copenhagen must also host an army of official and unofficial delegates, and a swarm of private individuals, many using climate change as a lever to promote minority political or social views.
So I was not surprised to read that the carbon footprint of the conference will be in excess of 40 kilotonnes.
Our politicians have accepted the conclusions of one group of climate scientists, notably that human combustion of carbon-based fuels is polluting the atmosphere, and consequent heat trapping is changing earth's climate in ways which are damaging or dangerous. Ice-caps and glaciers are melting, extreme climate events are increasing, human populations are threatened. Action now is imperative.
The problem is that action means nothing short of a revolution in the global economy, with sharp reductions in the living standards of wealthier countries.
A smaller and less influential group of climate scientists dismisses this theory of AGW - Anthropogenic Global Warming. They dispute the data, the analyses, the conclusions, and the warnings. Their position strengthened after recent evidence of dubious practices in the AGW group. Some have suffered personal criticism or vilification for expressing opinions counter to the prevailing dogma: always a danger sign.
Any scientific theory is open to refutation or rebuttal: those responding with outrage thereby admit they lack data or arguments sufficient to convince.
So what is my position in this spectrum of noisy opinions?
The one thing beyond dispute is human pollution of the atmosphere. It needs very special pleading to attribute the increasing atmospheric carbon dioxide concentration to factors other than human combustion. Other pollutants include smokes and dusts, oxides of nitrogen and sulphur, dioxins, and halogenated hydrocarbons, notoriously destructive to the ozone layer.
Of course volcanoes discharge huge quantities of dust and gases, and a warming ocean releases carbon dioxide, but these natural processes do not explain the increase in pollutants in the past century.
The critical question is whether this pollution is causing our planet to heat, and our climate to change. The answer, at present, is a definite maybe.
But that is sufficient for determined action, given the possible consequences of continued pollution. In any case, pollution reduction must improve living conditions for all life on this our only planet.
So, what are the main sources of pollution - and what can we do?
Forest burning is the human activity which causes the most pollution. Brazil, Indonesia, the Phillipines and Malaysia are current offenders, causing smogs sufficient to disrupt transport and damage health over wide areas.
Coal burning for power generation and industrial effluents create the 'Asian Brown Clouds', notably affecting much of China, India and South-East Asia. These signs of human activity are easily visible from space. Remember that Beijing had to take drastic action to improve air quality for the Olympics.
Taken together, forest and coal burning must be the most damaging anthropogenic impact on the atmosphere. The 'greenhouse' effect of released gases is combined with acidifying compounds, while water vapour and particulates increase strongly the capacity of air to absorb and retain heat. The loss of forest exposes soils to warming and dessication, and reduces the fixation of carbon dioxide by photosynthesis.
And much of this pollution is in the zones where solar irradiation is most intense.
It is absurd to clear forest to ranch cattle, to provide cheap meat for hamburgers; it is bad to clear forest to plant oil-palms. It is bad to clear forest.
In my judgement these are the pollution sources which need the most urgent attention.
Let us do our bit. Let us start tomorrow a long-term policy to recreate the Caledonian and Pennine forests.
Hydrocarbon combustion must be the next largest source of pollution. These are cleaner fuels than coal or wood, releasing less sulphur oxides and particulates, and delivering more energy per unit release of carbon dioxide [hydrogen is oxidised as well as carbon when hydrocarbons are burnt]. But the quantities used annually are vast, and the carbon is released from underground reservoirs, previously sealed from the atmosphere.
Shipping is a major oil consumer, using heavier grades of oil, more likely to be sulphurous. Globalisation depends on shipping, so globalisation is an important factor in pollution accounting.
Apologists for air-travel protest that aircraft effluents are a small percentage of total emissions. But aircraft discharge pollutants high in the atmosphere, and especially in the stratosphere. The thin air at altitude means aircraft exhaust gases are slow to dilute, and atmospheric layering means slow circulation of pollutants to low altitudes, where the various processes removing them are found. Watch contrails, and see how long they take to disperse.
Contrail haze absorbs heat, and shades the ground below. I understand that after the 9/11 atrocity all aircraft in the United States were grounded for several days. The consequent clearing of contrail haze caused a measurable increase in air temperature in New York. Much of that temperature increase was caused by the heat otherwise absorbed by contrail fogs and gases, warming the stratosphere.
Strangely, politicians are protective of air travel. Proposals to tax aircraft fuel are resisted; new runways are planned; growth in air travel is promoted.
The planet cannot carry air travel at its present level. The issue must be addressed: the costs of air travel must be increased sharply, and aircraft fleets reduced.
Cement manufacture pollutes as much as aviation. Coal or oil fuels furnaces to drive carbon dioxide from limestone, and pump dust-laden gases from smoke stacks, unless expensive filter plant is installed.
Private automobile use is fiercely criticised by AGW campaigners, and there is no disputing its serious effects in cities. This factor is already much reduced by modern efficient cars: my VW Golf returns more than 60 mpg, as a good example. Battery cars reduce local pollution, but are not efficient if hydrocarbons or coal are burnt to deliver electrical power for charging. The Toyota Prius, so beloved of the greens, is unlikely to return much above 40 mpg. Battery production and disposal has serious environmental impacts too.
A strict and enforced national speed limit of, say, 100 kph or 60 mph would cause a substantial fall in fuel consumption, but I shall be surprised if this is in the manifesto of any major party.
Heavy goods vehicles are heavy polluters, 5 or 6 mpg is a usual figure. Again the message is simple: foster local production. It is absurd to transport to Britain French bottled water, Bavarian dairy products, and Polish coal.
Yet another issue our politicians prefer to avoid. "Get loads off the roads" ought to be a popular electioneering slogan.
An ambitious programme to create fast efficient rail services is needed urgently, especially for freight, and especially in overcrowded Britain. Let this be accompanied by an equally ambitious redevelopment of nuclear and hydro electricity generation, reducing greatly our dependence on imported hydrocarbons for transport, industry, and domestic energy.
Domestic power and heat is the last big item on the list of atmospheric polluters. So much more can easily be done: insulation, low consumption lighting and appliances, solar water heating and electrical generation. So many people prefer to turn up the heating instead of wearing warmer clothes.
I am impressed by the potential of small local hydro-power units in mountainous districts. Quite a small stream with sufficient fall can power an entire village, with surplus sold to the grid. Put the money currently subsidising wind-power into small and large scale hydro-electricity, so much more efficient, so much more reliable.
Last summer I watched the tidal flow through the Ballachulish strait, and wondered how many kilowatts a line of turbines would deliver. In Britain we have so many opportunities for such development.
Wind-farms are my bugbear. Wind-farms are curiously symbolic of New Labour: very expensive, obtrusively visible, contemptuous of landscape, and hopelessly inefficient and unreliable. In the best position a wind turbine may deliver its rated output for one third of the time, and most of those installed achieve less than that. I wonder how long a wind turbine needs to offset the considerable carbon footprints of its manufacture, transport, installation and servicing.
Wind turbines are the triumph of green fantasy over engineering reality.
I have little fear of nuclear power, especially modern fuel-efficient systems. I would insist they be nationally sponsored; not run for profit, but pricing to cover all costs of construction, running, and disposal; and internationally supervised.
Fusion power is within sight. ITER is already in construction, the first demonstration fusion power plant. The cost may reach 10 gigabucks, a third of the cost of the 'troop surge' in Afghanistan.
Why has Britain lost its leading position in this most vital technology?
Efficient large scale energy storage remains an unsolved problem. Hydrogen offers a solution. We should be investing urgently in technologies for hydrogen generation, storage, distribution and use.
Why are we not doing these things? I despair.
Oh dear. This blog-post is banging on a bit. Bear with me while I make three more important points.
The first is that investment in Britain's power supplies and infrastructure should have begun a quarter century ago, when we had North Sea oil wealth. Unfortunately those were the Thatcher years, when that awful, remarkable woman chose to squander money on unemployment and the destruction of our industrial and engineering base, in obedience to economic theory long discredited.
When the New Labour era began TB-GB were deaf to warnings of the growing urgency of new power generating capacity. Now at last a French company mostly owned by the French government will build new nuclear power stations in Britain, for French profit at Britain's risk. It is probable there will be serious power shortages before this new capacity starts up.
I recall the huge bill-boards when I was a teenager in the 50's. "Britain leads the world in nuclear power. British achievements speak for Britain."
Second, every person in Britain consumes, on average, 4 kilowatts total - electricity, heating, car engines etc. New Labour's mass immigration has increased the population, officially by 3 millions, in reality probably 4 millions, maybe 5. That's at least a 12 gigawatt increase in power demand, which supply will struggle to provide. And rapid population growth is expected to continue. Britain's population is already too large: further rapid growth must be detrimental, environmentally, economically and socially.
New Labour has delivered a broken, bankrupt, balkanised Britain, a poor base from which to begin major programmes of reconstruction and change.
Third, I have a growing suspicion that events may overtake our fears of global warming. Evidence is mounting that the sun is entering another 'Maunder Minimum', like that which began some 380 years ago, soon after the discovery of sunspots.
After a period of high solar activity in the late 20th century the last solar cycle was notably quiet, with substantial reductions in sunspot number and other measures of solar activity. We are well past the end of the predicted solar minimum, and so far solar activity has remained low or very low. Sunspots may be rare during the 21st. century.
We know that the last Maunder Minimum was accompanied by global cooling - a little ice age - which lasted some 70 years. We also have reason to believe its onset was abrupt.
The disputed failure of predictions of global temperature to rise this century may prove to be real. Arguments about solar variation driving climate change may shortly be put to the test.