Emissions from Alternative Fuels
Environmental Impact of “Clean” Fuels from Beginning of Life Cycle to Combustion
Emissions from alternative fuels may actually exceed those of fossil fuels. Though used synonymously, “alternative” fuels and “clean” fuels are not the same. The adjective clean — with respect to fossil fuels — is often a marketing tool. It does not always reflect the environmental impact of a fuel.
Clean combustion does not mean a fuel is a clean fuel. The release of low quantities of carbon dioxide into the air when burned is not the only standard. Combustion emissions are a cursory glance at a fuel’s carbon footprint. It is not sufficient. In order to determine the cleanliness of a fossil fuel, it is essential to consider the entire lifecycle of that fuel.
The entire lifecycle determines the carbon footprint of a fossil fuel.
Lifecycle: Cycle: AKA, “Well-to-Wheels” Analysis
Fuels come in three forms: gas, liquid, and solid. Overwhelmingly, the presumption is that gas fuels are innately cleaner than liquid fuels. It is assumed gas fuels are much, much cleaner than solid fuels like coal and wood. What may come as a surprise though, is the fact that these assumptions are not necessarily the case.
Still, liquid and solid fuel producers take great measures to develop clean fuels. The label for alternative solid fuels is biomass. Biofuels is the name for alternative liquid fuels. Biogas is the label for alternative gas fuels.
The prefix “bio” inclines consumers to believe an alternative fuel is cleaner than a traditional fuel. But, alternative fuels are not necessarily cleaner. Again, it is the entire lifecycle of an alternative fuel that is relevant. A complete analysis makes it clear, biofuels are not necessarily cleaner than fossil fuels.
Energy Spent in Production Versus Energy Gained During Combustion
Generally, biofuels have low energy production in relation to their fossil fuel counterparts. Low energy density is one of the biggest issues with biofuels, and biomass. Low energy density fuels produce less per unit of measure than high-density fuels.
But, it’s not just poor energy production that is an issue. It turns out that alternative and “clean” fuels are also big polluters. According to the International Civil Aviation Organization (ICAO), “From the feedstock extraction or production to the final use in an engine, the fuel goes through multiple steps constituting its life cycle. At each of these steps, GHG emissions are likely to be produced.”
Taking into account the energy density of an alternative fuel is the only legitimate means of determining carbon footprint. The environmental impact a fuel has throughout its entire lifecycle determines cleanliness. Without an entire lifecycle analysis, applying the label “clean” to an alternative fuel is inappropriate.
Two Types of Alternative Fuels
There are two types of alternative fuels: first generation and second generation. “First generation biofuels are made from sugar, starch, or vegetable oil,” according to Biofuel.org. “Second generation biofuels are “greener” in that they are made from sustainable feedstock.” But for the time being, only first generation alternative fuels are relevant. “At this point, most second-generation fuels are under development and not widely available for use.”
Two Types of Biofuel (Liquid Alternative Fuels)
There are two types of biofuels, petroleum alternatives, and diesel alternatives. There are three first-generation petroleum alternatives: ethanol, propanol, butanol. First generation biofuels are products of plant starch. Wheat, corn, sugar cane, molasses, potatoes, and fruits are the base for petroleum alternatives.
Biodiesel is a product of fats and oils. Biodiesel is a first generation alternative fuel, a product of animal fats, vegetable oils, nut oils, hemp, and algae. Green diesel is another first-generation biofuel. It is made by hydrocracking oils and fat and is, “chemically identical to fossil fuel diesel.”
Bio-methanol is the second generation petroleum alternative, but it has an extremely low energy density. Bio-methanol produces much higher emissions than other biofuels, so it is typically considered a clean alternative to traditional petroleum.
The name for second generation biodiesel is Fischer-Tropsch biodiesel. It is made from paper waste and pulp manufacturing.
Energy Density of Petroleum and Diesel Alternatives
Of the petroleum alternatives, butanol has an energy density of 36.6 megajoules/kilogram. Propanol has an energy density of 34 mj/kg. The lowest of any petroleum alternative, ethanol has an energy density of 30. The energy density of biodiesel is 37.8.
To put the energy densities of petroleum alternatives into perspective, olive oil has an energy density of 39 megajoules/kilogram. That of sunflower oil is 40.
Emissions During Lifecycle of Petroleum Alternatives Greater than that of Fossil Fuels
Biofuels — particularly those made of corn — are of no use. “Can we please stop pretending biofuel made from corn is helping the planet and the environment?” asks James Conca of Forbes Magazine. Two studies from The United Nations Intergovernmental Panel on Climate Change made it clear back in 2014 that, “corn ethanol is of no use.”
Scientists studied the amount of energy required to produce corn ethanol in contrast to how much it produces. They determined that there is less than a zero net gain. In other words, it costs more to produce corn ethanol than corn ethanol produces.
It gets worse though. The production of corn ethanol creates more emissions than the emissions reduction generated by adding ethanol to fossil fuels. “The IPCC was quite diplomatic in its discussion, saying,
‘Biofuels have direct, fuel‐cycle GHG emissions that are typically 30–90% lower than those for gasoline or diesel fuels. However, since for some biofuels indirect emissions—including from land use change—can lead to greater total emissions than when using petroleum products, policy support needs to be considered on a case by case basis.’”
Biofuels Maybe Accelerating Global Warming at Unprecedented Rates and Corn isn’t the only Culprit
But, corn isn’t alone with respect to alternative fuel emissions. In fact, almost all biofuel crops are of little to no value. Emissions from alternative fuels are much greater than previously thought. Taking the entire life cycle into account, according to The United Nations Intergovernmental Panel, “Most fuel crops, such as sugar cane, have problems similar to corn.”
Equally as relevant is the fact that biofuels actually produce more emissions than fossil fuels. “The net effect is about 50% more carbon emitted by using these biofuels than using petroleum fuels.”
Over the life of a biofuel, it will produce 1 ½ times more emissions than its fossil fuel counterparts.
An article published in 2013 by the Guardian goes so far as to call the European Union’s mandating of biofuel use a, “crime against humanity.” Talking about emissions from alternative fuels, according to the report, “environmentalists say biofuels made from some food crops contribute more greenhouse gases than the fossil fuels they are designed to replace, as well as causing deforestation and hunger.”
And emissions from alternative fuels are just one factor. The sustainability of biofuels also depends on its economic impact. The Gallagher Report is a document that was prepared in 2008 prior to the EU’s implementation of must-use alternative energy policy. In the summary of the Gallagher report, scientist concluded,
“There is growing concern about the role of biofuels in rising food prices, accelerating deforestation and doubts about the climate benefits. This has led to serious questions about their sustainability and extensive campaigns against higher targets.”
But, biofuels are not the only “clean” fuel that may be a farce. Biomass is quickly gaining the same kind of negative attention.
Types of Biomass (Solid Alternative Fuels)
Biomass fires furnaces, fuels boilers, and heats homes. Biomass is thought to be a less polluting alternative to coal and wood, so it is marketed as a “clean” fuel. However, like biofuels, biomass is manufactured and — therefore — its entire lifecycle contributes to its total environmental footprint. Again, the emissions from alternative fuels are under debate, especially biomass.
It turns out, biomass is, “dirtier than coal.” In a study conducted by, “A pre-eminent think tank in the United Kingdom, Chatham House,” biomass does less than nothing to reduce greenhouse gas emission when used to replace coal. “In most circumstances, comparing technologies of similar ages, the use of woody biomass for energy will release higher levels of emissions than coal and considerably higher levels than gas.”
Improving What We Have
Because of the emissions from alternative fuels, they — biofuels and biomass — are slowly but surely losing ground as a viable solution to greenhouse gases and global warming. Reducing the emissions of proven fuels is, on the other hand, something we need to begin taking far more seriously.