The Hummer, king of SUVs and preeminent symbol of extravagant energy consumption, is properly vilified for the prodigious amount of carbon dioxide that blows out of its tailpipe as it roars about town. Carbon dioxide, the main contributor to global warming,1 is now about as popular as ants at a picnic.
Yet, we humans breathe out an average of about two pounds (one kilogram) of carbon dioxide a day. That adds up. With six billion of us, our breathing accounts for more than 4.4 trillion pounds (two trillion kilograms) of C02 a year!
The more effort we exert, the more carbon dioxide we exhale. That means America’s favorite high-calorie burner, Michael Phelps,2 is exhaling vast quantities compared to a couch potato who sits watching reruns of Jerry Springer all day. Does this make Phelps the equivalent of a horrible Hummer, and the couch potato a pious Prius? Should we curtail our exercise and hit the couch to become stewards of our planet?
Absolutely not! Human exhalations aren’t the same as a car’s exhaust, and there’s a good reason for that: The carbon dioxide we breathe out has been captured from the atmosphere by the food we eat. It’s a closed circle. The Hummer, on the other hand, releases carbon dioxide that was locked away long ago in fossil fuels. It’s not the same thing as far as our atmosphere is concerned. Our breathing is carbon neutral; the Hummer’s exhaust is not.
Could we make the Hummer more like us? Could we make cars breathe carbon dioxide like we do? There’s already a similarity – we both combust our fuel. The energy we get from food is stored sunlight. When sunlight hits a plant, it is stored as chemical energy in the form of sugars – think of the plant as a chemical battery. When we eat it (or eat the animal that eats it), those sugars react with oxygen – they get oxidized – releasing the energy.4 The fuel the Hummer burns is being oxidized as well, releasing solar energy that was stored up millions of years ago.
Humans and Hummers are both oxidizing something, both combusting or burning fuel. The answer to the problem of the Hummer lies in biofuels – fuels that are derived from plants. Biofuels can produce both heat and electricity, but their unique promise is as a replacement for liquid fuels – petrol, gasoline and diesel – powering the engines of our cars, trucks, trains and planes. Biofuels are a sunlight battery for the common engine. It’s not quite that easy, though-two problems must be resolved.
First, where does biofuel come from? We can eat almost anything – from pizza to pop to liver and onions – and convert it to energy. Engines can’t. We need to convert “predigest” – plants (biomass) before they can go in the tank. But the easiest plants to convert happen to be the ones that we eat, too. The last thing we want in a crowded world is to be competing with our engines for food. Driving a Hummer with biodiesel in the tank is not so virtuous if someone in the developing world goes hungry as a result.
Second, do we get more energy out of the biofuel than we put in? It takes energy and often fossil fuel-based fertilizers to produce the biomass and transform it into fuel. Biofuels only make sense if we get more out than we put in.
Existing biofuels – the first generation come from waste and easy-to-convert crops like corn, sugar and soy beans. None of these will ever contribute much to long-term energy supply, since they don’t solve either of these two problems. Ethanol from corn, for example, is a bad idea. Not only does it eat up a food crop, but it can take more energy to make than it produces.
Future-generation biofuels hold more promise. The biotech industry is racing to engineer microbes that will predigest wood chips and the inedible parts of our crops. Strange fungi are being discovered that actually breathe out diesel fuel. Scientists are engineering plants that digest themselves, along with strange machines that can rip apart material and put it back together in new forms. New kinds of plants that grow in the desert and drink saltwater will replace the crops we need to feed our kids, and algae factories will pump out fuel for our jets.
When I first became aware of the climate change problem, I had an immediate (and quite selfish) reaction: Can’t I enjoy a campfire under the stars anymore? Perhaps, if the wood comes from a forest that isn’t being degraded, there’s no real carbon problem.
Just like that campfire, one way to use biomass is to burn it and use the heat directly. Wood for cooking and heating is renewable biomass – as long as the forest isn’t stripped bare. In developing countries, this basic form of energy is still a big contributor: about 20% in China and 40% in India.1 In developed countries like Sweden and the UK, there are crops grown for this purpose, like fast-growing willow.
Wood pellets can, in theory, be used to replace coal in coal-fired electrical plants. Ontario Power Generation, in Canada, has fired the massive Atikokan Generating Station with wood pellets and is studying what’s involved in converting all of the province’s coal-fired plants.
Incinerating municipal, industrial and farm waste is another potential source of heat. Municipal waste is just a fancy word for garbage. Industrial waste is stuff like wood chips, and farm waste is crop residue, like inedible stalks. These aren’t exactly renewable, but if we’re producing it anyway, we might as well use it. Denmark gets almost 5% of its electricity from burning municipal waste, and Sweden and Finland get about 20% of their energy from basic biomass.
President Ronald Reagan once derisively dismissed global warming as just a “bunch of cow farts” (he was referring, of course, to methane). Ironically, methane is a greenhouse gas,6 and capturing any form of it to use for energy is a win-win. It’s easy – let wastes naturally decompose into methane (called anaerobic digestion) and use it for heat or electricity. Landfills – great big piles of garbage buried under a layer of dirt – leak methane over many years.
Animal waste is a perfect candidate for so-called biogas. Decomposition is sped up by adding water and controlling the temperature. There’s a farm in Ontario, Canada, doing just that. Each cow in the herd produces enough energy to keep three 50-watt light bulbs lit constantly.7
What’s the potential? Not much – there’s enough animal waste in the UK, for example, to power about 400,000 homes. That’s less than 1% of capacity.8 And it would be about the same in other countries.
We’re producing these wastes anyway, so we might as well use them. But there’s not enough to really change the game.
Brewmasters everywhere know how to make fuel: Start with a starchy (sugar-filled) food and ferment it to produce alcohol.9 The same idea runs through the winemaker’s art, the finest Scotch whisky and ethanol from corn. While wine and whisky are great ideas, ethanol from corn is not.
Our cars can certainly run on ethanol. But corn is something we need to eat. Converting all the corn grown in the US to ethanol would barely make a dent in energy consumption – but it would surely cripple the food supply. Even worse, it takes almost as much energy to produce ethanol as we get from the fuel10 – its “energy balance” is low. Energy is needed to produce and transport the corn, and fossil fuel-based fertilizers are required to grow it. We need to drop “corn-to-ethanol” – it’s a pipe dream.
Brazil has a slightly better idea. Sugar cane has a higher energy content than corn, so that’s what they convert to ethanol. Their PRO-ALCOOL program is the biggest commercial biofuel project in the world, and it’s estimated to have saved over $40 billion in imported energy over its first 25 years. Many cars in Brazil are modified to run on 100% ethanol, and those that aren’t can run on an ethanol blend. “Flexifuel” is the real deal in Brazil.
Diesel engines are more efficient than gasoline engines, and it’s diesel that powers our trucks, ships and trains. Finding a replacement for diesel would be a real coup. Well, look no further than your local supermarket or deep fryer. When Dr. Rudolph Diesel invented his engine back in the 1890s, he envisioned it running on vegetable oil, which almost any diesel engine can do. Biodiesel is easy to make – just squeeze the right seed. Many seeds, like soy or mustard, contain oils that can be readily converted to biodiesel. The question is, what’s the best seed?
Just like corn-based ethanol, many biodiesels compete with our food supply. There’s only so much that existing cropland and deep fryers can contribute. In the US, waste grease could replace less than 1%11 of US diesel use. If all current US soy production were used to make biodiesel – and we’d be giving up a huge slice of our food production to do that – it would replace less than 5% of US diesel. 12 There are slightly better choices – like mustard seed and rapeseed (also known as canola) that produce more oil per acre13 – but the general lesson remains: There is nowhere near enough land to make both food and fuel using existing crops.
According to Canadian historian Gwynne Dyer, “The world food supply is heading into a perfect storm, and the key element that is pushing the system into crisis is biofuels … To be more precise, it is the first-generation biofuels, based on converting corn or sugar cane into ethanol, and soy or palm oil into biodiesel.” 14 The long-term solution to biodiesel lies in next-generation sources15 – like cellulose, algae and halophytes that don’t compete with our food sources.
“The fuel of the future is going to come from fruit like that sumach out by the road, or from apples, weeds, sawdust almost anything … There is fuel in every bit of vegetable matter that can be fermented.” That was Henry Ford way back in 1925 – and he was right.
Forget food sources – the next generation of liquid fuels will come from inedible things like wood chips, the stalks and leaves of corn, switchgrass, and other indigestible goodies. To make this switch, we need to figure out how to produce ethanol from something called cellulose. Cellulose is the most abundant organic molecule on Earth, since it’s found in nearly all plant life. It’s the fibrous stuff that forms 5O% to 90% of a plant’s structure. But locked away in that hard-to-digest material is sugar. Converting cellulose to ethanol is “considered by many as the Holy Grail of biofuel production,”16 according to Phil McKenna of New Scientist magazine.
The key? Finding a way to break down the cellulose. Companies around the world are in a race to genetically engineer new proteins and bugs that do the job, plants that digest themselves, and even a fungus that breathes out diesel fumes. Cutting-edge science is designing new ways to break down the complex molecules, rip apart the material and put it back together in new ways.
One way to get at those sugars is to build an “enzyme” to do the job. That’s a complicated molecule made by living organisms like bacteria. Enzymes are usually proteins, and they act as a catalyst – meaning they speed up a chemical reaction. The trick is to find an enzyme that speeds up the breakdown of cellulose into sugars.
How do we find (or engineer17) the right bacteria? That’s the hard work done in labs run by companies like Iogen, based in Ottawa, Canada. Once they’ve found the right bacteria, the idea is to mass-produce it in a giant “bioreactor,” unleash the enzymes on the cellulose and voila – out pop the sugars. The next step is to add yeast to brew a kind of beer. That “beer” is refined into ethanol. logen has a demonstration plant up and running, and it’s working to overcome at least two problems – energy and money. The company can’t use much of either if the plant is to go commercial.
Other companies, like Qteros, based in Hadley, Massachusetts, are skipping the enzyme altogether. Qteros wants to develop a bacteria than does the job directly. Its bacterium is called the Q microbe.18 Shaped like a lollipop, the tiny bug can be engineered for different plant sources, producing the “beer” for refinement to ethanol. The Q microbe is, according to the company, like the “yeast…plus the enzyme … all in one.”
One of Qteros’s competitors, Boston based Mascoma, has produced a similar bacterium. Founded by professors from Dartmouth College at the University of California, Mascoma has a pilot plant up and running that converts wood chips and other cellulose sources into almost 250,000 gallons of ethanol a year. A full-scale commercial plant in Michigan is expected to be operational by 2012.
Lurking in a tree in Patagonia is a fungus that grows on cellulose and breathes out the components of diesel. Forget the enzymes, forget the bacteria, forget the yeast. This little fungus goes straight to the juice – cellulose to diesel! Not only can it skip the steps from cellulose to fuel, but its discovery also means that microbial agents may be able to produce oil directly – even though conventional wisdom says that oil is only produced by geological processes involving intense heat and pressure over long periods of time.
Gary Strobel, of Montana State University, discovered the fungus. “There’s no other known organism on the planet that does this,” he says. “We’ll do some scale-up and fermentation, then get enough to run a little engine.”19 Transforming this fungus into a large-scale commercial operation will come with a host of problems, but it’s an elegant concept.
Here’s a wacky idea: Build a corn stalk that produces enzymes that can break down its own cellulose. Make sure it only does it to stems and stalks, and only when you tell it to – by grinding it up, not when it’s growing in the field. A corn stalk that turns itself, on demand, into the goop that others work so hard to produce – sound far-fetched?
At Michigan State University, researchers have spliced three new genes into a corn called Spartan Corn, which in turn produces three enzymes that break down cellulose. Each gene produces an enzyme to perform a step in the process. 20 Further tweaking limits enzyme production to leaves and stalks, and only within a sort of storage area in each cell. That means that the enzymes aren’t released until the stalks are ground up into little pieces. Pretty crazy stuff.
What the Michigan State team has built is corn that acts as its own breakdown bacteria. “This is basically a shortcut; you don’t need to put this gene in other microbes,” says MSU researcher Mariam Sticklen. “Our corn is a green bioreactor using free energy from the sun.”21 It’s early days, however, and the corn needs to demonstrate productivity and resistance. ln other words, that clever bioreactor must also show that it’s good at being regular old corn.
Lego – kids love it because they can put all those bits and pieces together in so many ways. Take apart a spaceship and build a robot. Could the same principle apply to cellulose? Could you take it apart and put it back together again in a different form – just like making a robot from a spaceship? Range Fuels, based in Colorado, makes a device that does just that. The company’s converter breaks biomass into little bits, and then puts those bits back together in a more useful form – like ethanol.
Range Fuels has fed more than 30 different kinds of non-food feedstock into its demonstration plant, including switchgrass, hog manure and lots of Colorado pine killed by the ubiquitous Pine Beetle. The converters are designed to be small and modular, so you can bring the plant to the feedstock, rather than shipping the feedstock to the plant. Smart.
Why go to third-generation? Second-generation sounds pretty good, as long as it doesn’t compete with our food supply. Is there really a need to go further? Sure there is. According to Dennis Bushnell, chief scientist at NASA Langley Research, “there’s just not enough fresh water and arable land to produce enough biofuels to replace the petroleum.”22
If we were to replace all US petroleum with first – or second – generation biofuels from conventional crops like soy, it would require the use of more23 than the entire US land mass. Even palm oil, which generates 20 times the amount of biofuel per acre than other biofuel-based crops, would require more than one-third of the arable land – and palms don’t even grow in Kansas!
When the European Union first mandated that a percentage of all diesel fuel be biodiesel, it ignited a surge of deforestation in Indonesia. Rain forests were being hacked down to make room for plantations of palm for palm oil production. Needless to say, the plan backfired. The net result was an increase in carbon emissions, not a reduction, since deforestation causes a massive spike in greenhouse gases.
In early 2008, billionaire adventurer Richard Branson, the founder of Virgin Atlantic, flew one of his planes on a mix of regular fuel and the oil from 150,000 coconuts. It was touted as a sustainable flight. The problem comes when you count the coconuts. Analysts pointed out that there aren’t enough coconuts in the world to fuel all the planes flying in and out of Heathrow alone. To be fair, though, Branson did demonstrate the possibility of alternative fuels, and he’s now looking into something even more far out: producing fuel from algae.
Algae is one of three new sources of biofuel that look promising. Algae can be cultivated in tanks and farmed from seaweed in our oceans. Halophytes – plants that drink saltwater and can grow in unproductive deserts like the Sahara – won’t compete with food. Jatropha, a plant that can grow on marginal land and on top of regular crops without reducing yields, also holds promise.
Pond scum, seaweed, green goop – the unappetizing slippery stuff is one of the most promising sources of biofuel. It’s possible to squeeze the oil out of algae to produce biodiesel, and break down the rest to produce ethanol. John Sheehan, at the US National Renewable Energy Laboratory, says: “There is no other resource that comes even close in magnitude to the potential for making oil.”24
Harvested from the ocean or grown in tanks on non-fertile land, algae can be fed wastewater or even the emissions from smokestacks. These little balls of25 oil are harvested on a continual basis, and can produce more than 40 times more fuel per acre than any other plant – up to 20,000 gallons per acre, per year. In the right conditions, algae can double its volume overnight. The trick is to get the growing conditions just right, and to do it on a big scale.
How big? Salix, in Fort Collins, Colorado, has been dabbling in algae-based fuels for years. The company’s CEO, Douglas Henston, says: “If we were to replace all of the diesel that we use in the United States with an algae derivative, we could do it on an area of land that’s about one-half of 1% of the current farm land that we use now.” No doubt it’s promising, but that’s one big pond – and we’re not talking about a regular old turtle-and-tadpole pond here. These are high-tech, triangular-shaped aquariums called “photobioreactors.”
Algae can pack a double punch: Since it can eat high concentrations of carbon dioxide, it can be fed straight from a conventional power plant. You can create one of these bioreactors by fine-tuning the algae to the CO2 and the surrounding environment using selective culture growth. By feeding in water and emissions samples, you can grow just the right algae to optimize production. The idea is to surround power plants with thousands of bioreactors that gobble up C02 and produce oil at the same time.
Algae can also be grown in the dark. California-based Solazyme feeds its algae plant sugars like wood chips, rather than sunlight. Solazyme’s challenge will be the same as other biomass users: securing a big enough supply of plant sugars to produce fuel on a commercial scale.
Algae-based fuels are just beginning to hit the big-time, and we don’t yet know who the winners will be. One thing is certain: Big money is starting to flow to algae, much of it in California. San Diego-based Sapphire Energy has raised more than $100 million for algae production. Another San Diego company, Prize Capital, has announced a $10-million “X-prize” to encourage critical breakthroughs.
Halophytes are plants that love saltwater. So here’s an idea: Irrigate vast swaths of desert with saltwater, and grow plants for biofuel. This may not be happening on a commercial scale yet, but the idea is sound, and some high-powered “This is a revolution for agriculture as well as for energy.”26
What’s the potential of halophytes? Well, according to Bushnell, the Sahara Desert alone could provide 94% of the world’s power27 if it were converted to halophyte biofuel production. This may sound crazy – but these are the sorts of ideas that we need to take a really close look at. It was once thought absurd to cross the ocean or split the atom or go to the moon!
Jatropha is a plant that grows an inedible seed that’s ideal for producing biodiesel. What makes the plant really promising is that it can be grown on crummy land that’s no good for crops, or nestled among existing crops, without lowering the yield. That means it’s a kind of “fuel for free” when mixed with other crops. It’s promising enough that the government of India has singled the plant out for a national biofuels push.
Clearly, biofuel has a role to play in the clean-energy future. Some European countries already generate up to 20% of their energy needs from biomass, mainly from burning waste for heat and electricity. Its biggest contribution will be to replace our liquid fuels, primarily those used for transportation. To replace more than a small fraction of our petroleum use, biofuels must stop competing with our food crops for arable land, water and fertilizer. To get really serious, we have to get more sophisticated than using wood, inedible farm waste and other cellulosic sources.
The problems associated with cellulosic ethanol are twofold: limited biomass supply and the dangers associated with the required genetic engineering. There just aren’t enough wood chips and plant stalks, and even if there were, engineering those tiny little self-reproducing microbes, like bacteria, is risky. There’s always the danger of introducing new bugs that upset our delicately balanced ecology.
To completely eradicate the need for petroleum, biofuels must come from the sorts of third-generation fuels outlined above mainly algae and halophytes. Biofuel is no magic bullet. Biofuels will only change the game if we spend as much money building vast fields of bioreactors and irrigating deserts with saltwater as we do finding and defending our sources of oil.