The following was contributed as an independent opinion article by Ethanol Europe.
By Zoltán Szabó, Climate Ethanol Alliance at COP23

Ethanol has existed as a motor fuel for over a century, but it is only in the last decade that its overall greenhouse gas (GHG) profile has been studied with any rigor to assess its role as a tool to reduce emissions.

The results show it is an effective fuel to mitigate emissions and displace fossil fuels when it is produced in line with responsible regulatory oversight that considers the whole spectrum of its production.

The large banks of data now available show that ethanol, on average, has 50% less emissions than petrol.  This trend is increasing annually and in the next decade emission reductions of close to 100% are expected.

A large body of empirical evidence is now readily available from the first decade of large-scale global ethanol production that allows actual impacts to be assessed.

For example, ten years ago, the total GHG emissions of maize ethanol were only somewhat better than fossil fuel. Under a standard carbon intensity measurement, it came in at around 60 gCO2e/MJ versus 85 grams for oil.

The gap has since widened.  In the past decade, GHG emissions of maize ethanol have decreased to about 45 grams on average, while, largely due to increasing extraction of  unconventional oil (including deep sea, shale, and tar sands, among others), fossil fuel has worsened. Both trends are expected to continue, resulting in an ever-widening difference in the climate profile.

The historical criticism of biofuel policies that they do not attempt to consider all emissions is also no longer true.  There is today no legally established regulatory framework that does not consider cultivation, transportation, processing, and indirect emissions.  There is also no industry promoted framework that ignores these sources of emissions. Such frameworks are essential to ensure the environmental integrity of the final fuel, which is why industry has not resisted them.

Current ethanol emission analysis is backed up by trend lines that reflect the most robust recent evidence. Many widely-referenced models use pre-2005 data and assumptions. Old data concludes that ethanol yields modest climate benefits; data on ethanol actually produced today paints a much better picture for the climate.

This is why the largest discrepancies in assessing ethanol GHG impacts from disparities between the projections of old models and current empirical evidence. 

As the purpose of biofuels is to displace oil, biofuel emissions must always be examined in parallel with those of the oil displaced.  The lifecycle GHG emissions of ethanol must be compared to the lifecycle GHG emissions of petrol. The analysis is similar for both commodities. 

Measurement of the emission performance of both oil and ethanol is done with broadly similar methodologies. In the case of ethanol important metrics are feedstock cultivation, production processes, co-products and indirect impacts. In the case of oil they are extraction, refining processes, indirect impacts and petrol combustion.

Following is a more detailed breakdown of this comparison.

Ethanol

In cultivation emissions, biofuel production has promoted higher yields, less waste, and lower unit applications of pesticides and fertilisers over the past decade.  The result has been a small decline in feedstock cultivation emissions (i.e. the carbon impact of growing corn) over this period.

But ethanol production processes today (the carbon impact of turning corn into ethanol and co-products) are not comparable to those of a decade ago.  Per unit energy use has plummeted by almost 50%, and yields per ton of feedstock have improved dramatically.  As a result, process emissions in ethanol are declining every year.

Ethanol now has many different and much more valuable co-products.  In the average corn ethanol plant nothing is discarded.  As a result, the co-product credit for ethanol facilities is increasing and will continue to increase. 

The most discussed indirect impact of ethanol has been indirect land use change (iLUC).  The substantial feedstock price increases some predicted have fallen far short of real impacts.  In most cases, crop prices in real terms are now lower than a decade ago. In addition, new calculations of iLUC using updated models yield ever lower estimates of iLUC. 

Oil

For oil, in contrast to ethanol, extraction emissions have been increasing and are expected to continue to increase.  Countervailing this trend, restrictions on flaring reduce oil extraction emissions slightly.  But as petrol refining is a mature technology, new technological breakthroughs that would lower refining emissions are not expected.

The indirect impacts of oil include wars, pollution from spills, inequality and other issues. Ironically, some proponents who want to include ethanol’s indirect impacts in lifecycle analysis do not argue for the same treatment of oil. 

The large banks of data now available show that ethanol, on average, has 50% less emissions than petrol.  This trend is increasing annually and in the next decade emission reductions of close to 100% are expected.

In some areas today, ethanol technology has already developed to the point where it achieves a 90% reduction. 

For oil, regulatory benchmarks such as the EU’s “fossil fuel comparator” show increased emission impacts from oil.

In conclusion, the contrast between climate performance of oil and ethanol is ever widening.

Climate Ethanol Alliance is supported by Ethanol Europe, Marquis Energy and Growth Energy.  Zoltan Szabo is Sustanability Consultant with Ethanol Europe. Quotations from this article may be attributed to him.

The reference base for this article is the EERL paper ’Corn Ethanol saves the climate – the only question is by how much’.