Humans, despite having originated in hot parts of the world, have long looked for ways to make buildings more comfortable in hot weather. The first attempts in the 19th century involved circulating air over blocks of ice, but modern air conditioning first had to await the invention of mechanical refrigeration.

Liquids absorb heat from their surroundings when they evaporate or boil, and you can control the temperature at which that happens by controlling the pressure: the higher the pressure, the higher the boiling point.

William Cullen first demonstrated refrigeration using this principle in Glasgow in1748, but it was 86 years before Jacob Perkins of London patented the first practical ice-making machine, and it wasn’t until 1911 that Willis Carrier invented a practical air-conditioning system.

In both a refrigerator and an air conditioner, a liquid is boiled in an evaporator. It absorbs heat as it expands, and the warmed vapour is then compressed (which makes it even hotter) and run through pipes that allow it to radiate that heat away (which is why the back of your refrigerator is so hot). In other words, both refrigeration and air-conditioning boil down to (sorry) transferring heat from whatever you want cooled to a place where you don’t mind that heat being released.

The most common refrigerants for the last 80 years have been chlorofluorocarbons. Although later implicated in the erosion of the ozone layer, they were actually developed as a safe alternative to the much nastier refrigerants that preceded them, such as sulfur dioxide. Stable, incombustible and non-toxic, CFCs made air conditioning practical in office buildings, hospitals, apartments, trains and buses, and, by 1950, automobiles.

There are new ozone-friendly refrigerants in use today, but refrigeration-based air conditioning still has its problems. For one thing, it’s energy-intensive, as those with central air conditioning well-know from their sky-high electricity bills in hot weather.

But now comes word that the U.S. Department of Energy’s National Renewable Energy Laboratory (NREL) has invented a new kind of air conditioner that could potentially use anywhere from half to a whopping 90-percent less energy than standard systems.

The new system, called DEVap, is based on evaporative cooling rather than refrigeration. In a really dry climate that doesn’t get too hot or too humid (say, Denver), you can cool and humidify air simply by flowing water over a mesh and then blowing air through the mesh.

Unfortunately, evaporative coolers don’t work well enough to cool really hot air to a pleasant temperature, and in a humid climate they actually make things more unpleasant by increasing humidity while hardly cooling the air at all.

DEVap combines an evaporative cooler with desiccants, chemicals that absorb water from the air (you know, like those “Do Not Eat” packages you find in electronics packaging). It uses highly concentrated syrupy solutions of salts such as lithium chloride and calcium chloride that can create very dry air.

One challenge with desiccant-based cooling systems has been their complexity. DEVap has simplified things immensely by using thin membranes that are hydrophobic–water beads on them instead of soaking through them. This allows the membranes to control the flow of liquid within the cooling core, keeping the water and the desiccant separated from the air stream.

What that means in practice: hot, humid air flows into the core and in a fraction of a second becomes cool, dry air that can then be directed into the space to be cooled.

The NREL has patented the DEVap process, and will be refining it over the next couple of years with the goal of eventually licensing it to manufacturers.

It won’t help this season. But in a few years, you may be able to enjoy a cool, comfortable house without any heart-stopping power bills, all summer long.

But there’s an obvious problem with this. That stuff we’re turning into fuel is also food for humans and feed for animals.

(And as an aside, how come we always call it “animal feed” as opposed to “animal food”? And why don’t we ever refer to “human feed”? Hmm?)

A lot of the plant is wasted when you grow crops for fuel or food. The leaves and stems, with their tough cell walls made of cellulose, hemicellulose and lignin, are more of a nuisance than anything else. Wouldn’t it be great if there were a use for what is now plowed under or burned?

There is, or there soon will be, thanks to research aimed at using bacteria to convert this “lignocellulosic biomass” into fuel in its own right.

A just-published article in Nature reveals the state of the art. Titled “Microbial production of fatty-acid-derived fuels and chemicals from plant biomass,” it describes the successful engineering of the common bacterium Excherichia coli–better known as E. coli and generally in the news when it contaminates water or meat and makes people sick–into a producer of biodiesel.

One of the co-authors of the research study is Jay Keasling, chief executive officer for the U.S. Department of Energy’s Joint BioEnergy Institute (JBEI). “We’ve got a billion tons of biomass every year that goes unused,” he says, adding that fuel produced from that biomass could make up for as much as half of U.S. oil imports, turning “the U.S. Midwest into the new ‘Mideast’.”

That’s not hyperbole: by one estimate, lignicellulosic biomass could produce more than 7,500 litres of renewable petroleum per acre.

The researchers modified the E. coli genome, inserting genetic code for the production of an enzyme called hemicellulase, which can break down hemicellulose into smaller sugar molecules which E. coli can then turn into fatty acids.

E. coli normally produces only as much of the fatty acids as it needs for its own cell membranes. But the researchers’ E. coli were further modified so that the fatty acids just kept coming, turning each bacterium into a microscopic biodiesel factory.

The process takes place in fermentation vats, into which the bacteria expel little drops of oil. Turn off the impellers, and the oil floats to the top, where it can be skimmed off.

Even better, by tweaking the process, chemical products ranging from solvents to lubricants to jet fuel could conceivably be produced.

Of course, it’s important to note that the research reported in Nature is just a proof of concept. There’s no commercially viable process for doing any of this yet–but Keasling hopes there will be within a very few years. Work will continue as the researchers search for ways to make use of even more of what’s in the feedstock–not just the hemicellulose.

There’s already a company standing ready to market fuels and other microbe-produced chemicals. Based in California, LS9, founded by a geneticist and a plant biologist, helped fund the research reported in Nature. LS9 points out that the crude oil produced by bioengineered bacteria has none of the contaminating sulfur of regular crude oil, so it’s cleaner. And despite its unorthodox origins, it can be refined like any other crude oil in a standard refinery.

There are other companies pursuing their own paths. Amyris Biotechnologies, for example, says it has also created bacteria capable of providing renewable hydrocarbon-based fuels. There are many more.

Why would this be preferable to ethanol production as it is currently carried out? Aside from the aforementioned fact that we’re presently turning food into fuel, hydrocarbon fuels are more efficient than ethanol, packing about 30 percent more energy into any given quantity. And even better, they take less energy to produce: ethanol production, which involves distilling, requires 65 percent more energy than hydrocarbon production does.

Perhaps the oil industry will slowly evolve away from the purview of drilling companies and into the realm of agriculture.

As for the marketing slogan for this new germ-produced form of fuel, I think I’ve come up with a winner: “E. coli. It’s not just for food poisoning anymore.”

What do you think?

Fermenting the sugars found in corn or other grains into ethanol has been around for a long time, of course, and it’s pretty much a proven technology. On the other hand, do we really want to be turning food into fuel?

More promising have been recent advances in turning lignocellulose, the stuff that makes up the cell walls in plants, into ethanol and other fuels: that would allow us to use grasses, wood chips, straw and other non-food as biomass.

Now comes word of a fuel-producing technology that doesn’t require biomass of any sort: just carbon dioxide and sunlight. And no, I’m not talking about trees.

On Monday, a Massachussetts company called Joule Biotechnologies announced that it has the technology to convert carbon dioxide directly into transportation fuels and chemicals. Not only that, they say, “this eco-friendly, direct-to-fuel conversion requires no agricultural land or fresh water.”

The company was founded in 2007, and relies on something it calls “Helioculture” technology, mixing, as the New York Times’s article on the announcement puts it, “CO2, Slime and Sunshine.”

More specifically, the company grows genetically engineered microorganisms in specially designed bioreactors. The microorganisms are photosynthetic, able to use energy from the sun to convert carbon dioxide and water into ethanol or hydrocarbon fuels.

The process works well in the laboratory, so the real question is if it can be scaled up to an industrial-sized plant. To find out, Joule plans to break ground on a modular pilot plant early in 2010 that will produce ethanol (trademarked as SolarEthanol), and the following year hopes to begin construction on a commercial-scale operation that can also produce hydrocarbons and associated chemicals, “several of which have already been demonstrated at laboratory scale.

It’s looking for sites near CO2 producers such as coal-fired power plants and cement kilns, with locations in Texas, Arizona, Nevada and New Mexico, places with lots of sun and lots of space, under consideration

Open spaces are needed because a large plant would look a lot like a solar array: a huge field covered with panels, except these panels, rather than producing electricity, would produce liquid fuels

The company estimates that a single acre covered with its “SolarConverter” panels (flat, transparent, and about the size of a sheet of plywood) could produce 20,000 gallons of ethanol at a cost of $50 a barrel. (That makes it competitive with oil, although it’s worth noting that that price includes existing subsidies: what the unsubsidized cost would be, I don’t know.)

At that level of production, if you built enough plants to cover, in total, an area the size of the Texas panhandle, you could meet all of the United States’ transportation fuel needs.

In Technology Review, writer Kevin Bullis notes that the company’s technology sounds similar to that of biofuels produced by algae—but the company says it is not using algae, and its stated production estimates are an order of magnitude greater than algae-based biofuels, which are estimated to have potential yields of only 2,000 to 6,000 gallons per acre.

Its estimated cost of production is also only a fraction of that of algae-based biofuels, which currently would require crude oil to rise to $800 a barrel in order to be competitive.

Besides, algae produces oils that have to be refined, whereas Joule says its microorganisms will produce ethanol or hydrocarbons directly. The Joule microorganisms also excrete the fuels, whereas algae has to be harvested and processed to extract oil.

Too good to be true? Maybe. But there are other companies in the race to develop the same kinds of technology. And with the push to reduce carbon dioxide emissions and move away from fossil fuels, that race is only going to get hotter.

So remember the name: Joule Biotechnologies.

Someday, its genetically modified critters could be cheerfully churning out the fuel that powers your car.

Naturally occurring oil comes from one-celled plants and animals that died in the oceans, settled to the floor, decomposed, and were eventually crushed underneath the planet’s sliding tectonic plates. The pressure and heat far underground broke down the creatures’ long chains of hydrogen, oxygen and carbon-bearing molecules, called polymers, turning them into petroleum hydrocarbons, which have much shorter molecular chains.

Scientists have tried to recreate this process for years. The usual approach has been to superheat organic feedstock in an attempt to drive off any water it contains and break down the molecular chains at the same time. This takes so much energy that you almost burn a barrel of oil for every barrel produced.

In the late 1980s Paul Baskis, an Illinois microbiologist and inventor, suddenly realized how to improve the process. TDP doesn’t drive off water; it uses it. In fact, it adds more. The water conveys heat throughout the feedstock, causing its molecules to begin to break down at a much lower temperature (about 260 degrees C) and pressure (about 45 atmospheres) than with previous methods. Then the slurry is quickly dropped to a lower pressure, causing 90 percent of its free water to flash off as steam (which is then used to heat the incoming feedstock).

Minerals settle out and are shunted to storage tanks, while the remaining liquid pours into a reactor similar to that used in an ordinary refinery. The liquid is heated up to 480 degrees C to further break down the long molecular chains, and the resulting hot vapour rises up into a tall distillation column. Different substances condense at different heights: gas is captured at the top, light oil flows out of the upper middle, heavier oil out of the middle, water out of the lower middle part, and powdered carbon collects at the bottom.

With a little tweaking, the process can turn waste into other things besides oil. Polyvinal chloride (PVC) can be turned into the valuable chemical hydrochloric acid, for example. TDP can also destroy hazardous waste such as PCBs, dioxins, heavy metals and medical infectious waste, process agricultural waste and human sewage, process the noxious discharges from pulp and paper making, and recycle tires, among other things.

TDP is being championed by Changing World Technologies (www.changingworldtech.com) which has been running a pilot plant at the Philadelphia Naval Yard in partnership with the Gas Research Institute since 1996. Now a $20 million commercial facility is coming online in Carthage, Missouri, where every day it will turn 200 tons of turkey-processing waste–feathers, organs, blood, etc.–from a Butterball Turkey plant into 600 barrels of high-quality oil, 21,000 gallons of water, and 11 tons of minerals, mostly from bones, which make excellent fertilizer.

The oil should cost only $15 U.S. a barrel to make; in three to five years, that’s expected to drop to a very competitive $10 a barrel; it should get even cheaper after that. The U.S. government provided some funding for the Butterball plant and has also provided grants for demonstration plants to process chicken offal and manure in Alabama and crop residuals and grease in Nevada. There are also plans for plants to process turkey waste and manure in Colorado and pork and cheese waste in Italy.

Oil companies, despite the potential competition, like TDP too: it can convert heavy crude oil, shale and tar sands into light oils, gases and carbon, and convert the heavy solid waste produced by refining petroleum into natural gas, oil and carbon. TDP can also clean up coal, extracting stuff like sulfur and mercury–which are valuable, but bad for the environment when burned–leaving coal that burns hotter and cleaner and can be more easily crushed for use in electricity-generating plants.

Turning the U.S.’s annual production of agricultural waste into oil and gas via TDP would yield the energy equivalent of 4 billion barrels of oil–within spitting distance of the amount of oil the U.S. imports every year. Or imagine a local plant that turns your garbage into the fuel that eats your home. The possibilities are mind-boggling.

As more and more TDP plants come on line, we’ll soon know if this technology is really too good to be true–or maybe, this time, both good and true.

An article in the November 1 issue of Science sets out the challenges. Entitled “Advanced Technology Paths to Global Climate Stability: Energy for a Greenhouse Planet,” it was written by a team of 18 scientists and engineers from major universities (including McGill), U.S. government laboratories and agencies, and even Exxon Mobil. The U.S. Department of Energy funded the project.

The level of carbon dioxide in the atmosphere has increased from 275 to 370 parts per million in the past century. Unchecked, it will pass 550 parts per million this century. Climate models and the study of past climate changes indicate that that could warm Earth’s climate as much as it cooled during the last Ice Age. Stabilizing the level of CO2 lower than that will require “Herculean efforts,” the authors conclude.

The world today requires 12 terawatts (12 trillion watts) of power generating capacity, of which 85 percent is fossil-fueled. Power requirements continue to soar as the world’s economy continues to grow. Stabilizing the level of CO2 in the atmosphere by mid-century while permitting the current level of economic growth will require 30 terawatts of carbon-free power production, the study estimates–and we don’t have the technology to achieve that.

Possible sources of carbon-free power include hydrogen, biomass, solar thermal and photovoltaic, wind, hydropower, ocean thermal, geothermal and tidal.

Hydrogen sounds good, but doesn’t exist in geological reservoirs, which means it is usually extracted from hydrocarbons–and per unit of heat generated, more CO2 is produced by making hydrogen from fossil fuel than by burning the fossil fuel directly.

The other sources mentioned currently provide less than one percent of the world’s power, and all suffer from the same problem: low power production per area. For example, producing 10 terawatts of energy using biomass would require more than 10 percent of the Earth’s surface, roughly equivalent to the area covered by all of human agriculture, and a solar array that could produce 10 terawatts would cover a square 470 kilometres on a side. (All the photovoltaic cells shipped from 1982 to 1998 would cover a square only three kilometers on a side.)

Even if we could scale up solar arrays and windmill farms to meet our needs, existing power grids, designed for centralized power plants, couldn’t manage the loads. So another challenge we face this century may be the complete reengineering of our electrical distribution systems.

Another way to harness solar energy is the space solar power satellite, a huge solar array in space that transmits power to Earth by microwave. But getting 10 terawatts of power to Earth by this method would require 660 orbiting solar arrays, each the size of the island of Manhattan. Launch costs, note the study’s authors with admirable understatement, are likely to be “high.”

What about nuclear power? Well, fission, our current method of nuclear energy generation, not only creates radioactive waste and lends itself to the proliferation of nuclear weapons, it’s based on a non-renewable resource, uranium. Meeting the mid-century power needs using fission, the study’s authors estimate, would use up the world’s known reserves in just six to 30 years.

The best hope for a long-term energy solution remains fusion. Fission releases energy through by splitting a large atom (that of uranium); fusion, which powers the sun, releases energy by fusing two small atoms (of forms of hydrogen) together. Fusion powers the sun. Current research has brought fusion power close to the break-even point, at which the amount of energy produced by the fusion reaction is equal to the amount of energy required to bring about the fusion reaction. But fusion power plants are still years away.

The study’s authors believe a massive Apollo-style research and development program will be required to ready new power sources for the world in time to stabilize the CO2 levels in the atmosphere at a reasonable level…and time’s a-wasting.

“Combating global warming by radical restructuring of the global energy system could be the technology challenge of the century,” the authors conclude. “…Stabilizing climate is not easy. At the very least, it requires political will, targeted research and development and international cooperation. Most of all, it requires the recognition that…the fossil fuel greenhouse effect is an energy problem that cannot be simply regulated away.”

Primitive, industrial-revolution technology has gotten us into this mess; it will take advanced, futuristic technology to get us out.

Considering that everybody living in the northern hemisphere 13 years ago was the unwilling recipient of at least a few radioactive particles from Chernobyl, we all have good reason to hope they’re correct.

Nuclear reactors split uranium atoms by bombarding them with neutrons. A small portion of the atoms’ mass becomes energy, and they release more neutrons, which in turn bombard other nearby atoms, splitting them and beginning a chain reaction. If the material is packed together tightly enough, this chain reaction is uncontrolled, and you get an atomic explosion. In nuclear reactors, a material called the moderator controls the chain reaction by slowing the nuetrons.

In Chernobyl-style reactors, the reaction is moderated by graphite. Ordinary water is piped through the core of the reactor and heated into steam. This both cools the reactor core and drives the power turbines. Chernobyl-style reactors don’t have a containment vessel–the steel-and-concrete tower familiar from North American reactors–and become unstable at low power, liable to sudden surges of power.

On April 25, 1986, the Number 4 reactor at Chernobyl was to be shut down for routine maintenance, and it was decided to take advantage of that to run a test of emergency power systems. Due to poor communication, a series of actions was taken that led to a dangerous situation: the reactor’s power output fell to the point where it became unstable, certain safety systems were disabled, and most of the control rods, used to damp neutron output and thus shut down the reactor in a hurry, had been withdrawn.

At 1:23 a.m. on Saturday, April 26, 1986, the unstable reactor suffered a power surge estimated to be 100 times greater than normal. The fuel ruptured. Hot fuel particles hit the water system, causing a steam explosion that destroyed the reactor core. A second explosion ripped the roof off the reactor building, exposing the reactor core and sending a shower of hot, highly radioactive debris into the air.

The building caught fire, giving rise to more clouds of radioactive steam and dust. More than 100 fire-fighters fought the blaze, many of them suffering fatal radiation doses; the building fires were extinguished within a few hours, but by then the reactor’s graphite had caught fire. It burned for 10 days, hurling a constant stream of radioactive material high into the atmosphere. Radioactive emissions continued in total for 20 days.

After the accident, the reactor was encased in a steel-and-concrete sarcophagus that is currently being re-fortified. Two of the other four reactors were permanently shut down. Ukraine was supposed to close all of them by 2000, but because the government can’t afford to build the two new reactors it needs to replace the power it draws from Chernobyl, reactor Number 3 is now up and running again.

Immediately after the accident, 134 people showed signs of acute radiation sickness, of whom 28 died. 135,000 people were evacuated from the area; most received significant doses of radiation. Approximately 800,000 workers were brought in to try to decontaminate the area, and received varying doses of radiation. Around 270,000 people continue to live in contaminated areas.

Large portions of agricultural land were contaminated, including almost a quarter of the agricultural land in Belarus. A swath of forest near the site received so much radiation the trees died and had to be destroyed as radioactive waste. Interestingly, wildlife now abounds in the area, and although rodents are so contaminated you wouldn’t want to handle them, researchers have yet to find any malformed individuals.

There has been a substantial increase in reported cases of thyroid cancer in Belarus, Ukraine and some parts of Russia. An increase in leukemia was expected, but hasn’t shown up yet. Nor have there been perceived increases in other cancers–but that could be simply because enough time has not yet elapsed. Nevertheless, it’s estimated that, when all the health consequences are taken into account, 3,756 people have now died from the accident.

Harder to measure have been the psychosocial effects, caused by the fear of disease, the stress of being exiled from their homes, a distrust of authorities, and economic and social hardship.

Not to mention insomnia. With a nuclear reactor once again operating at Chernobyl, it’s a safe bet a lot of people aren’t sleeping well these days.

Well, believe it or not, nowadays you can farm the wind. In fact, windfarms are cropping up all over, with the newest one recently announced for two of the windiest places in Canada (neither of which, believe it or not, is the Scarth Street mall). Unlike other farms, however, windfarms don’t produce food. Instead, they produce energy.

The two new Canadian windfarms are both in Quebec; one is located near Cap-Chat in the Gaspé and the other near Matane in the Lower St. Lawrence region, where the wind velocities average 28 kilometres an hour. Together they will boast 133 55-metre (15-story) towers, each topped with an enormous propellor-like turbine 48 metres in diameter. When fully operational, the two windfarms will produce about 100 megawatts of power, enough to supply the needs of a 16,000 households, which will be sold to Hydro-Québec.

The Le Nordais Wind Farm, the largest development of its kind in Canada and one of the largest in the world, is being built by a unique consortium of Quebec, Danish, Japanese and Toronto companies. The consortium hopes the new Wind Farm will provide a major boost to the commercialization of wind power in Canada. So do a host of other people, ranging from environmentalists to companies that have been longing for years to attempt similar developments in places where the wind blows almost constantly–like the Prairies, for instance.

It’s sad but true that, though Canada has lots of windy places, it’s lagged behind other countries in developing wind power. There have been a few commercial efforts in Alberta, and that’s about it. Wind power did make the news in Saskatchewan a few years ago, but that was because SaskPower decided to pull the plug on a wind power demonstration project proposed for southwestern Saskatchewan because it was too expensive.

Humans have been harnessing the power of the wind in a variety of ways for millennia, beginning with the development of sailing vessels more than 5,000 years ago. As early as 200 B.C., windmills were being used to grind grain. In the 14th century, the Dutch used windmills to drain the marshes and lakes of the Rhone River delta and create new land. In North America, windmills have been used to grind wheat and corn, pump water and cut wood. It was only natural that, as electricity came into use, windmills were also used to generate electricity.

Generating electricity from wind in many ways is simplicity itself. As the wind blows, it causes the blades of a turbine to turn (because, as the wind flows around the blades, it moves faster on one side of each blade than the other, creating an area of low pressure. The higher pressure on the other side of the blade pushes it in that direction.) The turbine spins a tight coil of copper wire inside a magnetic field, which generates an electrical current in the wire. The turbine is typically placed on a high tower because wind speed is more consistent high above the ground.

As is true of almost every other form of energy, wind power really originates with the sun, because it’s the uneven heating of the Earth’s surface by the sun’s rays that causes the wind to blow.

Wind power got a boost in the 1970s when the price of oil increased, spurring governments all over the world to institute research and development programs. Fossil fuel prices fell again, however, and wind power suffered from technical problems and cost difficulties that caused interest in it to taper off for a while. The foremost technical problem has always been that wind speed is variable, which means the amount of energy produced is variable, which makes it hard to integrate wind power into a conventional power grid. (For that reason, most wind-power generating systems include banks of batteries that store excess energy production when the wind blows hard and feed it into the system when the wind dies away.) The foremost cost problem has been that windmills are expensive to build. Recent technical breakthroughs by European researchers, however, have reduced the cost of wind power to the point that it is competitive with other forms of energy. Last year, the world’s total wind-power generating capability reached 7,200 megawatts–enough energy to supply 1.1 million households. That’s four times the generating capacity of just six years ago, and in another four years, it’s expected to almost triple, to more than 20,000 megawatts.

The benefits of wind power are obvious: the wind itself is free, and a spinning turbine doesn’t pollute (although, of course, manufacturing the turbines and towers in the first place does generate some pollution). The biggest environmental downside is that windfarms take up large amounts of space. However, the towers are quite thin and the turbines are high above the ground, which means that the land surrounding them can be used for other purposes, such as farming or ranching (once the cattle get used to the whirring high above their heads). In fact, a typical windfarm only occupies about five percent of the land it’s installed on.

The U.S. Department of Energy estimates that the world’s winds could potentially supply as much as 10 times the current total world energy demand each year. A more realistic figure of what we might eventually achieve is 20 percent of the current demand. Even that would represent an enormous reduction in global pollution.

Hosea’s prophesy of reaping the wind and sowing the whirlwind was one of doom and despair; but today, farming the wind actually holds great promise for a brighter, cleaner future.

We use fossil fuels primarily for power generation and transportation. Huge strides have been made in reducing emissions, but scrubbers and catalytic converters don’t change the fact that fossil fuels are non-renewable, or get rid of carbon dioxide, the main culprit in the projected global warming. This has spurred the search for alternatives.

Fast-flowing rivers can be harnessed to spin turbines and generate electricity. Hydroelectricity doesn’t pollute, but its dams and river diversions can flood habitats.

Nuclear fission splits the large uranium nucleus into two smaller nuclei, releasing huge amounts of energy which can make steam to spin turbines. Nuclear energy is also emissions-free, but reactors are expensive to build and waste disposal remains a concern.

The “ultimate” alternative is fusion, in which two light nuclei are fused to form a heavier one, releasing even more energy than fission, but it won’t be practical for decades.

Fusion powers the sun, whose energy can be tapped either through photovoltaic cells, which turn sunlight directly into electricity, or through mirrors, which focus the sun’s heat. On the plus side, solar energy is inexhaustible and emits no pollutants; on the down side, it requires huge tracts of land covered with solar cells or mirrors.

Wind power is the other major alternative; California, the world leader, has 15,000 wind turbines producing about one percent of its electricity– enough for all the homes in San Francisco. The technology is simple: the wind spins a windmill which drives a turbine. Windmills don’t pollute, but again, they take up huge amounts of land.

When you talk about replacing fossil fuels in automobiles, most people think of electric cars. Changing to electric cars without changing to alternative forms of power generation simply shifts fossil fuel use from automobile to power plant. (Some studies indicate that could actually increase pollution.) But if you could combine alternative power generation with an electric car, you’d have a true emissions-free vehicle.

Electric cars have been around since the early 1900s, when they were as fast as any other car. They were abandoned because existing batteries were heavy and had to be recharged frequently. Things haven’t changed much: although today’s high-tech electric cars look great and can go from zero to 100 kph in eight seconds, they have a range of only a couple of hundred kilometres and then have to be recharged for several hours.

There’s still no miracle battery on the horizon, but there could be a better alternative: a fuel cell. A fuel cell uses an on-going chemical reaction to generate electricity; it’s different from a battery in that it has to be supplied with fuel from an external source. Theoretically, a fuel cell can convert fuel to electricity with nearly 100 percent efficiency. (The internal combustion engine is only 10 to 20 percent efficient.)

Fuel cells work with almost any hydrocarbon fuel, including gasoline, while producing little pollution and maintaining high efficiency, but the best fuel of all, in a fuel cell or straight up, would be hydrogen, because burning hydrogen produces only one by-product: water. Unfortunately, hydrogen is also very expensive to produce and store, which means that for now hydrogen-powered cars aren’t practical.

Today’s solar-powered cars are fragile, expensive and slow. Barring some huge advance in solar cell technology, they’ll stay that way.

The only non-fossil fuel that’s being used on a large scale is ethanol, or grain alcohol, created through fermenting plant material. Its cousin is methanol, or wood alcohol, originally made from wood but now produced from carbon monoxide and hydrogen or processed from natural gas.

Both can be used directly in car engines modified to resist their corrosiveness, and both burn very cleanly. Added to gasoline, they produce gasohol, which can be burned in unmodified engines. Gasohol burns more slowly, coolly and cleanly than gasoline, providing greater octane and fewer pollutants.

The “alternative fuels” most in use today, however, are still fossil fuels. Propane (a component of natural gas) is one; another is natural gas itself. They both burn cleaner than gasoline and produce only about half as much carbon dioxide.

Of course, we’ve got a huge infrastructure built up around our existing use of fossil fuels, and that means any changeover to alternatives will be gradual. But it will happen.

Check back in 50 years: you’ll hardly know the place.

A coal bed starts out (we think–very few people have the patience to directly observe a process that takes millions of years) as a silted-over peat bog. As the layer of sediment over the bog increases, it forces water out of the peat. The peat becomes richer in carbon and deficient in oxygen, until eventually hydrogen stops combining with oxygen to form water and instead starts combining with carbon to form hydrocarbons. Spongy, fibrous peat becomes hard, brittle coal: vegetable matter turns into rock.

Similarly, petroleum (Latin for “rock oil”) starts out as layers of marine plankton–microscopic plants and animals–at the bottom of the sea. Sediments build up over these layers, and as in coal, the pressure and heat force out water and oxygen, leading to the formation of a variety of hydrocarbons, from tar to gas.

Humans used coal as a fuel as early as 1100 B.C. in China. Petroleum has also been used for millenia, but not as a fuel. Though usually found deep underground, in some places it seeps to the surface, which enabled our ancestors to use it to caulk boats, to mend roads, as a medicine and liniment, in torches and lamps, and, people being what they are, as an incendiary weapon of war.

The modern age of petroleum began in the 1850s, when overhunting of whales caused the price of the whale oil used in lamps to skyrocket. Starting in Romania, people turned to kerosene, refined from petroleum collected from surface seeps. It quickly became the illuminant of choice (to the relief of whales), which made petroleum valuable, which led to the first oil well, completed on August 27, 1859, in Titusville, Pennsylvania.

All those first oil-drillers wanted was kerosene: they burned off “useless by-products” like gasoline. But then along came the internal combustion engine, and Henry Ford. Today, gasoline accounts for 30 percent of all oil use.

The fact you can get both kerosene and gasoline out of petroleum is what makes it so valuable. Crude oil is made up of many different hydrocarbons, and through the skillful use of heat, technology and chemistry, you can convert any hydrocarbon into any other.

The basic method of separating the various hydrocarbons is to pump hot crude oil into the bottom of a tall steel tower. The lighter (and most valuable) compounds, those with the smallest molecules and the lowest ratio of carbon to hydrogen, vaporize and rise to the top of the tower, where they condense and drop back down to be vaporized again. Since the different compounds condense at different heights, you can draw off what you want: gasoline from the top, kerosene from the middle, and fuel oil from the bottom.

Further refining techniques involving vacuum, heat and catalysts, collectively called “cracking,” can break the big molecules of the less valuable hydrocarbons into small, more valuable molecules: valuable not only as fuel, but as raw material for plastics, synthetic fibers, paints, fertilizers, insecticides, soaps, synthetic rubber and more. Without petroleum, modern industry couldn’t function–more’s the pity, because the use of fossil fuels carries a pretty high cost, starting with the degradation of land during the creation and operation of coal mines and oil fields.

But that’s small potatoes compared to the pollution caused by actually burning the stuff. Coal smoke is an unpleasant pollutant in its own right–the source of London’s infamous 19th-century pea-soup fogs–and the sulfur compounds in coal are the direct cause of acid rain. Burning petroleum, particularly in automobiles, contributes to low-level ozone pollution: smog. Then there are oil spills, from minor losses from truck and car accidents to the Exxon Valdez and oil-well blowouts in the Gulf of Mexico. And finally, there’s the concern about global warming due to the heat-trapping effect of the carbon dioxide produced by burning fossil fuels.

These concerns have sparked research into cleaner ways of using fossil fuels (and ways to avoid using them at all), but don’t dump your oil company shares just yet.

We’re addicted to the stuff, and it’s going to be a hard habit to break.

Actually, that’s not a very fair comparison, because nuclear fusion really does seem to be on the way, while most people will never get rich in a lottery. On the other hand, a lot of lottery winners will have come and gone before fusion finally becomes a viable energy source.

However, on still another hand (hmm, that makes three), almost all of our present energy sources are ultimately derived from nuclear fusion, because nuclear fusion is, literally, the power of the sun.

Fission, as you may recall from last week’s column, is the splitting of a very large atomic nucleus into two smaller nuclei. The two smaller nuclei mass less, even put together, than the large nucleus did. That missing mass turns into energy–lots of

energy.

Fusion is the opposite process. In nuclear fusion, two small nuclei are combined to form one larger nucleus. Oddly enough, when you’re dealing with very light elements like hydrogen and helium, two small nuclei actually have more mass than a single nucleus of twice the size. Once again, after fusion, there’s a missing mass, and it’s that mass that turns into energy.

How much energy? Well, ever hear of the hydrogen bomb?

Fusion is a lot harder to achieve than fission, because, as a little experimentation with magnets will show you, like charges repel. If you try to shove two hydrogen nuclei together–each consisting of a single positively charged proton–they’re not going to like it. The sun overcomes this mutual distaste by the simple procedure of cramming everything together to a density 100 times that of water, then heating it up to 15 or 20 million degrees. At that temperature the particles get quite excited, rush around frantically and run into each other with great force. But even in the centre of the sun, it’s estimated that a proton will exist on the average for 10 billion years before it’s finally fused with another. (And I thought I’ve been single a long time…)

So in order to initiate fusion on Earth, physicists have to not only match conditions at the centre of the sun, they have to improve on them. One way is to use deuterium or tritium, both isotopes of hydrogen–that is, they both have a single proton in their nucleus, like hydrogen, but they have one and two extra neutrons, respectively. Fusion of these nuclei occurs millions of times faster than the Sun’s basic proton-proton reaction.

In order to create the high temperatures required for fusion, physicists must turn the deuterium and tritium into a plasma. This is the fourth state of matter, above the familiar three of solid, liquid and gas; it’s a “soup” in which electrons and nuclei are completely separated from each other. Trouble is, this plasma is at a temperature of 100 million degrees Celsius. Obviously you can’t let this touch the walls of the container you’re trying to keep it in.

One solution to keep the plasma from vaporizing the machinery that created it is to contain it in a magnetic field, or “bottle,” shaped like a doughnut. (Well, scientists call it a “torus,” but it looks like a doughnut to me.) This kind of fusion reactor is called a tokamak, and it’s been the most popular over the years.

A newer kind of fusion reactor uses what is called “inertial confinement.” Basically this relies on the inertia of the fuel to keep it together after it has been compressed to the high density necessary to achieve fusion, which is accomplished by focusing extremely powerful lasers on glass-walled pellets containing the fuel. The beams evaporate the outer layers of the pellets and cause the rest to implode, compressing the fuel.

Still, it’s the tokamak that has had the most support, and the tokamak which has so far had the most success. In fact, just a year or so ago physicists at Princeton University announced they have developed a fusion reactor capable of producing as much energy as it consumes. This point, called “break-even” is an important stepping stone toward the development of a commercial fusion reactor.

Fusion is an immensely attractive energy source for a number of reasons. For one thing, its basic fuel can be obtained from one of the most plentiful substances on earth, ordinary seawater. (Deuterium exists naturally in seawater; although tritium does not, it can be produced from relatively common lithium during normal operation of the reactor.)

For another, fusion would be a very clean form of energy, producing far fewer and far less dangerous wastes than fission. (Fission reactors produce plutonium; fusion reactors produce helium. Which would you rather have in your back yard?)

The trouble is, energy-producing fusion is proving to be an immensely tough technology to develop. The Princeton project has been underway for 15 years and has cost $1 billion, and scientists caution fusion could still be decades away from commercial use. That was why the flap a couple of years back over so-called “cold fusion” was so great.

It would certainly be convenient if fusion could be induced in a test-tube instead of requiring duplication of conditions at the centre of the sun, wouldn’t it? Unfortunately, while something may have been happening in that test tube, fusion apparently wasn’t it–at least not in any exploitable form.

Still, the race is on, and it really does appear that it will only be a matter of time before fusion is the energy choice of a “new generation.”

Considering the environmental and economic costs of our present methods of energy production, it can’t come a moment too soon.