Words Matter

I don’t watch many ads on TV, but I happened to see this one near the end of a football game last week. It was one of those public relations ads from Exxon Mobile telling what a wonderful job they were doing developing biofuel from algae. Someday this fuel will be used to power planes, ships and trucks “and cut their emissions in half.”

Wait a minute; something is not right here! Biofuels are carbon-based. When they burn, they emit mostly carbon dioxide. The only way to cut emissions in half is for the same amount of fuel to produce twice the energy as traditional diesel or jet fuel. That involves a factor called energy density.

Now biofuel is generally good. It comes from plants that extract CO₂ from the atmosphere. When biofuel burns it releases the same CO₂ back into the atmosphere, so it is considered to be carbon neutral. 

The downside is that first generation biofuels, such as ethanol, are produced from edible crops. They require a lot of space to grow and a lot of energy to plant, harvest and transport.

Biofuels processed from algae are a second-generation biofuel, similar to fuel made from the inedible and discarded part of a food crop, such as cornhusks or switch grass. The advantage is that food and fuel do not compete with each other, as when ethanol is made from corn.  And the production consumes “small amounts of energy while producing considerable fuel output.”

Other advantages are that algae production is efficient, in that, it can be grown “in almost any climate thanks to the open- or closed-tank approaches that are available today. As long as we can provide this natural product with enough sunlight to create photosynthesis, then it has the capability to grow quickly.” It is a renewable energy source that can be refined into a variety of products, and it can yield almost five times more fuel per acre than sugar cane or corn.

Two major disadvantages according to the same source are that it currently requires about 20% more energy to grow than it yields and production cost is still higher than the alternatives.

Exxon Mobile confronts the skeptics by citing partnerships with several major universities and a private firm to use gene technology and other research to build on the advantages and overcome many of the disadvantages. It looks promising, but they still “face some significant technical hurdles before biofuels production from algae will be possible at a significant commercial scale.”

The question remains about the claim of half the emissions. All fuel from wood and manure to jet fuel has a characteristic called energy density. “Energy density is the amount of energy stored in a given system or region of space per unit volume or mass.”  Gasoline has an energy density of about 45 megajoules per kilogram (MJ/kg). “Ethanol produces 30 megajoules/kilogram.” For that reason, a car will go farther on a gallon of pure gasoline than it will on a gallon of ethanol or any mix of ethanol and gasoline. Adding ethanol at the pump reduces MPG.

This 2011 paper from Stanford gives the energy density of algae-based biofuel at 20-25 MJ/kg, about half that of gasoline. Even if the research at Exxon Mobile’s partners could double it to equal that of gasoline or diesel, it would still be far short of their claim of cutting the emission of planes, ships and trucks in half. 

Deeper reading at the Exxon Mobile site gives the answer: “If key research hurdles are overcome, algal biofuels will have about 50 percent lower life cycle greenhouse gas emissions than petroleum-derived fuel.” The saving is not in emissions but in the energy expended during the entire production and delivery process.

The claim in the ad is inconsistent with that explanation thus is really inaccurate. Perhaps the advertising firm misunderstood, or the company just dumbed it down for football fans. In either case, I love it when I’m right!

Environmentally Friendly?

Most people don’t know where most of our products come from – what raw materials are used, how they are manufactured, etc.   That makes it very hard to judge what is and is not environmentally friendly.

A few years ago some analysis revealed that a holistic assessment of ethanol’s environmental footprint from planting and harvesting through the point of burning it as a fuel in automobiles might be worse than the same consideration for gasoline. The farming, refining and transportation end of the businesses are also relevant. And as it burns it releases the same CO₂ into the atmosphere at almost the same levels on a per-mile basis.

The same is true of many other products. That’s why I wasn’t surprised by the news that plastic grocery bags could be better for the environment than organic cotton ones.

That news came last spring from a study conducted by the Danish Environmental Protection Agency (DEPA). They measured the environmental impact of the standard plastic bag against “the organic lifecycle of seven common materials used for shopping bags…along 16 different environmental parameters, including climate impact, ozone impact, human and environmental toxicity and water use.”

According to the DEPA spokesperson, “The results showed that plastic bags made out of ‘LDPE plastic’, like the ones found in grocery stores, have by far the lowest impact on the environment. The biggest environmental impact was assigned to the organic cotton bag; it has to be used at least 149 times to offset its climate impact, compared to 43 times for a regular paper bag.” Note that people often buy the “organic” cotton believing they are doing the environment a favor.

At the end of the report, they recommended that any bag should be reused as many times as possible, for example, using the plastic grocery bags to line small trash cans. Note that if they were reused even once, would they be almost 300 times environmentally friendlier than an organic cotton bag? 

But it doesn’t end there!  Remember those reports earlier this month about the researchers at the Helsinki-Vantaa Airport, the main airport in Finland, finding that the place most filled with germs and bacteria was not the toilet seats but the trays used in the pre-flight screening process? They were teeming with disease-causing viruses. The same can be true of reusable cloth grocery bags and shoppers don’t realize that danger or guard against it.

As the Chicago Tribune reports: “Most shoppers -- 97%, in fact -- reported that they do not regularly, if ever, wash the bags.” About 75% report that they do not use separate bags for meats and for vegetables, while almost one-third use the same bags for other non-food items.

When they tested a sample of the bags (84) for bacteria, they found some contamination in all but one.  The full report can be found at Assessment of the Potential for Cross Contamination of Food Products by Reusable Shopping Bags.

"It is estimated that there are about 76,000,000 cases of foodborne illness in the United States every year. Most of these illnesses originate in the home from improper cooking or handling of foods. Reusable bags, if not properly washed between uses, create the potential for cross-contamination of foods.” And if they must be washed between uses, that further adds to their environmental impact by water use, and it shortens their life.

  

So while some cities and states are moving to ban the bags, they are not considering all the diverse factors that go into the problem. It’s pretty typical of legislators to pass laws that address a surface problem to make them and their constituents feel good, while ignoring many details that might lead to an opposite conclusion.

Biofuels and Butterflies

Perspective teaches us that life is about tradeoffs.  Here is one that is not so obvious.

Any Master Gardener (or third grader) can tell you that pollinators are vital to our food supply. So when I hear people fuss about monarch butterflies, I always wonder if it’s because they are superior pollinators. It turns out they probably are not.  The National Wildlife Foundation tells us:  “Bees are well-known pollinators, but over 100,000 invertebrates—including butterflies, moths, wasps, flies, and beetles—and over 1,000 mammals, birds, reptiles and amphibians, act as pollinators.”  All pollinators are struggling, but why the emphasis on monarchs?

This website describes monarch butterflies as charismatic mini-fauna, small animals that stir positive feelings in us when we see them. They are pretty and easily identifiable, so we feel a special bond with these butterflies, hence the fascination with them and the handwringing over their gradual disappearance.

Reasons for their decline include logging in the Mexican overwintering zone and the uses of broad-spectrum insecticides on farms and in personal gardens. Inability to adapt to some factors of climate change may also contribute.  But that particular site puts the bulk of the blame on the disappearance of their breeding habitat. “The caterpillars eat only one plant: Milkweed. And milkweed has been vanishing from the landscape.”

Especially corn farmers are tilling every last inch of soil available, thereby eliminating milkweed that once grew around the edges of their fields.  The site links this to our demand for the cheapest food possible, which they say leads farmers to “keep their fields weed free, kill milkweed, and – by extension – kill monarchs.”

But that’s not exactly correct. Farmers do not grow more corn because we insist on low food prices any more than Saudi Arabia pumps more oil because we like low gasoline prices.  The problem is not on the supply side; it’s the high demand for corn brought about by rules requiring that ethanol be mixed with gasoline to reduce our dependence on foreign oil.

Some argue that the ethanol rules are also designed to reduce the amount of carbon dioxide released into the atmosphere.  Burning ethanol or other biofuels is “cleaner” than burning gasoline on a gallon-for-gallon basis, but they are not as efficient. Burning a gallon of gasoline provides more energy than a gallon of ethanol, so when everything is accounted for the mpg-to-mpg difference is insignificant in terms of CO₂ emissions. Foreign oil is the primary reason.

Now we get to the trade off.  Most think: monarchs are good, and biofuels are good, but drilling for more oil off shore or in Alaska is bad. But doing so could eliminate our dependence on foreign oil resulting in less pressure on the farmers to till every available square foot leaving more milkweeds as a breeding habitat for monarch butterflies.

Perspective reminds us that we can’t have everything exactly the way we want it – butterflies and biofuels.  Compromises are sometimes necessary.

Note:  Near where I live (that evil) Monsanto promotes planting milkweed in highway medians.

Ethanol Does Pollute

I recently attended a lecture by a college professor about the dangers of climate change.  During the presentation he praised the mechanic of the university airplane for converting it to use ethanol-based fuel.  (He uses this airplane to fly to Alaska and back for his research.)  Since the thrust of his presentation was reduction of CO2 in the atmosphere, it seemed strange that he should commend a switch to ethanol which is a hydrocarbon and also emits CO2 when burned.  Using ethanol is about reducing dependence on foreign oil, not reducing CO2 in the atmosphere.

This may come as a surprise to some, but in this black-and-white world of environmental slogans many are led to believe that ethanol = good and gasoline = bad, as this presenter implied.  After reviewing a number of sources, I found the below table on CO2 emissions and the energy per gallon for various substances.  There is a more detailed explanation on the source website.  The conclusion is that ethanol emits less CO2 per gallon, but also produces less energy per gallon.  When you go through the calculations, it comes out that it emits at least 95% of CO2 as gasoline for an equivalent amount of energy to power your car or this airplane.  Ethanol is not really a “cleaner” fuel in terms of CO2 for climate change modeling.

Now consider how much land area an oil well takes up compared to a cornfield and that use of gasoline does not affect the food supply.  Is this another instance where we have not applied sufficient critical thinking before promoting a politically correct solution?