The Call, Column 56 – The Right and Wrong Way to Do Biofuels

13 11 2016

(September 25, 2016)

The Urban Farmer

The Right and Wrong Way to Do Biofuels

In today’s installment of Renewable Energy 101, we’ll talk about some of my personal favorite energy technologies (I may have said that about every technology we’ve discussed). These are energy sources that come right from the Earth, and are some of the coolest, most democratic sources, accessible to anyone who cares to implement them. Enter: biofuels.

As promoted by the US Federal government, biofuels are not a good idea. They have sunk large amounts of research time and tax dollars into corn-ethanol biofuels, wherein heavily-subsidized commodity corn is turned into a sugar-rich syrup, and from there into ethanol, which can be burned. That’s great and all, but the majority of commodity corn is grown using a lot of fossil fuels, between the pesticides, herbicides, fertilizers, agricultural machinery, storage, and transportation. Estimates have it that one Calorie – a unit of energy, both in food and other situations – of “corn energy” requires around TEN CALORIES of fossil fuel energy to produce. When you look at the full lifecycle carbon emissions of that gallon of ethanol mixed into your gasoline, the picture you get is much bleaker. From seed-to-sparkplug, that gallon of ethanol created something like 10 times as much carbon dioxide as would have been created by just burning the gas. That’s hardly a win for the environment. No matter how good it makes us feel that we aren’t burning gas directly.

(This mockery of the name of environmental sustainability is only possible because of how much money the federal government invests in order to keep commodity crops cheap. By subsidizing commodity field corn heavily enough over the past few decades, the market has been flooded, and its wholesale price is next to nothing. This gives our population the illusion that we, in the United States, are incapable of suffering food shortages; but it has made farmers dependent on the federal subsidies to make a living and filled our diets with a rather unhealthy crop. That also answers the question: Why are grains at the base of the food pyramid? What’s more, this unholy subsidization hides the true costs, both in dollars and environmental destruction, of the products of commodity corn. Hence, biofuels are made to seem like a sustainable, financially-viable idea!)

Now that we have that out of the way, let’s talk real biofuels. First off, what exactly are they? As you know, plants and photosynthetic microorganisms capture the energy from the sunlight, and turn it into energy-rich chemicals like fats, carbohydrates, proteins, and fibers, which are sometimes eaten by other organisms, like animals. A “biofuel” is the general term for one of many different setups which allow us to turn this not-directly-useful chemical energy, stored in plants, bacteria, algae, and even things like animal waste – into useful forms, like heat, electricity, and substances that can be easily burned.

As you can probably guess, the biofuels that are actually in line with the goals of environmental sustainability do not come from corn, for the most part. Rather, they come from either 1) an organic waste stream – manure, yard waste, or agricultural byproducts; or 2) something grown for this particular purpose, whose lifecycle emissions are very low.

The most basic example of biofuel is probably the oldest human utilization of stored energy, other than by eating things: burning wood! Trees store a lot of energy in their long fiber molecules. Using this type of “biofuel” is as simple as burning logs in your fire pit or fireplace, extracting renewable solar energy from the contained fibers and using it to heat your house or, if you’re the next-level homesteader that I aspire to be, even to cook your food.

There are certain problems associated with wood-burning, but they aren’t inherent to it. First off, yes, it is absolutely a renewable resource if done correctly. A tree takes in x pounds of carbon dioxide during its lifetime, and burning it releases no more than x pounds of carbon dioxide back into the atmosphere. This is over a very short overall lifecycle (unlike fossil fuels, which release carbon dioxide that’s been sequestered for millions of years), meaning that it has no net effect on global warming. But the full assessment of its sustainability comes down to how it’s farmed.

It is imperative that, as ecologically-conscious human beings, we maintain and grow our Earth’s environmentally- and economically-valuable forestland. It is customary in Western nations to clear-cut forests, logging all of the trees and destroying the entire forest ecosystem, and giving the land 20 or 30 years to grow back before cutting again. That’s ridiculous. Instead, we can log forests at a rate defined by what’s called the “Maximum Sustainable Yield” – take a fraction of the trees every few months or every year, focusing on the dead, dying, and diseased. In any forest area, there is a specific rate of extraction – a number of trees harvested per month or per year – that maximizes the speed at which the forest produces usable wood. By harvesting at this rate, and taking the trees that, while perfectly usable for firewood (or lumber), contribute very little to the ecosystem, we make the forests better instead of worse. That is a sustainable harvest of a renewable source of energy.

The next type of biofuel that I want to talk about is biodiesel. Without getting into too much detail, there is a specific chemical process which turns oils – typically, used frying oils from restaurants or those extracted from algae – into hydrocarbon fuels that very closely resemble petroleum. This biodiesel can then be burned in much the same way as gas.

This is an example of a renewable biofuel energy that taps into a waste stream. By using frying oil, which is no longer valuable as food, and would otherwise just be dumped in a landfill, the biodiesel process reclaims a dense source of stored energy. But even this isn’t truly sustainable, because restaurants rely on oils extracted from soybeans, canola seeds, or corn, which all have huge carbon footprints. With that said, it is still a disruption to the waste stream and, depending on how you look at it, does create energy without using any additional resources. As long as restaurants continue frying food in gallons of oil, this type of biodiesel has its place in the renewable energy arena.

One special type of biodiesel is that made with algae oil. You see, there are certain types of algae – both wild species and the products of human breeding – which contain large amounts of long-chain fats. Like frying oil, these fats can be converted to biodiesel and used as a combustible energy resource. But algae can be grown nearly anywhere there is sunlight, is more efficient than plants at capturing solar energy, and is very easy to grow using 100% sustainable methods. It is even relatively simple to set up a system of clear tanks (i.e. plastic water bottles), and raise biodiesel-quality algae along a sunny exterior wall of your house!

Algae biofuels are an infant concept, but they’re picking up speed. And while some species can be used for biodiesel production because of their high fat content, there is promising research being done on algae with vastly different chemical composition, used instead for direct combustion or in other chemical reaction processes that yield usable energy.

Finally, we’ve gotten to anaerobic, or “methane” digestion. From a very high level, an anaerobic digester is a single tank, or set of 2 or 3 tanks in series, which convert a slurry of organic materials – animal manure, yard waste, agricultural byproducts – into carbon-neutral natural gas. That’s a pretty awesome idea!

This is done by taking advantage of a long list of chemical reactions, that already occur in nature but are catalyzed by a variety of bacteria. These bacteria can turn fiber, fat, carbohydrate, and protein molecules into methane, a purified form of natural gas which, like I described about wood above, adds no net carbon dioxide into the atmosphere. The process is called anaerobic digestion because the tanks are maintained as low-oxygen (“anaerobic”) environments, and the methane they produce can be burned just as natural gas is, to heat homes or drive electricity-producing turbines.

I believe this to be one of the most useful renewable energy technologies within its own niche, because it doesn’t require a lot of special equipment (there are countless stories of conservation-minded individuals building methane digesters in their backyards), and can take such a wide variety of inputs that it is hugely effective at interrupting the organic waste stream. And guess what? As I write this, two digesters are being built in Rhode Island!

My column appears every other Sunday in The Woonsocket Call (also in areas where The Pawtucket Times is available). The above article is the property of The Woonsocket Call and The Pawtucket Times, and is reprinted here with permission from these publications. These are excellent newspapers, covering important local news topics with voices out of our own communities, and skillfully addressing statewide and national news. Click these links to subscribe to The Woonsocket Call or to The Pawtucket Times. To subscribe to the online editions, click here for The Call and here for The Times. They can also be found on Twitter, @WoonsocketCall and @Pawtuckettimes.

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