The airline industry is considered one of the hardest to decarbonize. Renewable aviation fuel accounted for less than 0.1% of current global jet fuel demand of about 330 million tonnes in 2019, investment bank Jefferies said last year. Governments and investors are trying to boost incentives to produce lower-carbon emitting jet fuel.
After just more than 100 years of history of industrial acetone–butanol–ethanol (ABE) fermentation, patented by Weizmann in the UK in 1915, butanol is again today considered a promising biofuel alternative based on several advantages compared to the more established biofuels ethanol and methanol. Large-scale fermentative production of butanol, however, still suffers from high substrate cost and low product titers and selectivity. There have been great advances the last decades to tackle these problems.
When you ride the bus to school in the morning, your journey is probably powered by diesel or gasoline, which is both made from petroleum. Petroleum is a fossil fuelFossil fuels are formed underground over millions of years, and are composed of organic matter from the tissues of ancient plants and animals. Fossil fuels include coal, natural gas, and petroleum. Petroleum can be refined into other fuels, such as diesel and gasoline., which means that it is made from decomposed, fossilized organisms – such as ancient plants, plankton, and algae – that have been buried under the Earth’s surface for millions of years.
This work assessed the economics and carbon footprint of alcohol (ethanol vs. n-butanol)-to-jet fuel production using eucalyptus for feedstock. Considering a risk-mitigating strategy of investing first in the alcohol plant (organosolv pretreatment, enzymatic hydrolysis, fermentation) and waiting five years until the second investment (alcohol-to-jet plant), the minimum jet fuel selling price was similar in both ethanol and butanol cases (2.10 and 2.08 US$/l for 20% Internal Rate of Return, IRR). In contrast, according to a stochastic decision-making framework that had carbon footprint as one of the criteria, the ethanol pathway is more promising. Nevertheless, even optimistic assumptions (regarding e.g. lignin price, and the interval between project phases) were ineffective to prevent eucalyptus jet fuel from depending on price premium (>1.00 US$/l), which is needed for better returns than those from eucalyptus ethanol plants. Therefore, the feasibility of alcohol-to-jet fuel production in eucalyptus pulp mills depends on long-term, stable premium and subsidy.
A lot of fuel is required to keep our country running. Americans consume an average of 390 million gallons of motor gasoline and 197 million gallons of aviation gasoline, per day, to fuel planes, trains, and automobiles. Most of the fuel that we currently consume is fossil fuel formed from the fossilized, buried remains of plants and animals that lived millions of years ago. One such fossil fuel, petroleum, is refined into other fuels, such as diesel and gasoline.
Because of their origins, fossil fuels have a high carbon content, meaning they produce a lot of energy when they are burned. However, burning fossil fuels can have negative impacts on our environment through air and water pollution and the release of carbon dioxide, a known greenhouse gas thought to contribute to global warming. Another limitation of fossil fuel is that they are an exhaustible resource that will eventually run out. Our growing fuel needs compounded with the risks and limitations of fossil fuels have led to a renewable energy movement aimed at reducing the production and use of fossil fuels in favor of cleaner, more sustainable fuel sources.
Butanol, a 4-carbon alcohol (butyl alcohol), is produced from the same feedstocks as ethanol, including corn grain and other biomass. The term biobutanol refers to butanol made from biomass feedstocks. The benefits of biobutanol, when compared with ethanol, are that biobutanol is immiscible in water, has a higher energy content, and has a lower Reid vapor pressure. Under the Renewable Fuel Standard, corn grain butanol meets the renewable fuel 20% greenhouse gas emission reduction threshold.
On an otherwise normal flight from Chicago's O'Hare International Airport to Washington, D.C.'s Reagan National Airport on Wednesday, a United 737 Max 8 passenger flight operated with 100% sustainable aviation fuel -- a first, and monumental, step for the aviation industry.
Boeing, CFM International, Virent, World Energy, and United partnered on the 612-mile demonstration flight, which emitted an estimated 75% less CO2 than a flight using traditional jet fuel, the companies said. The flight used 500 gallons of SAF in one engine and an equal amount of traditional jet fuel in the other.
All of the food we eat contains chemical energy initially derived
from sunlight. We know that it is photosynthesis that transfers
energy from light into chemical energy, and we are used to
talking about ‘calories’ in our food. You may have estimated
the amount of chemical energy in a foodstuff or a plant using
a calorimeter (see Figure 1). This instrument measures the heat
released when a sample is burnt. The greater the amount of
heat energy released, the higher the calorific (chemical energy)
content of the material. Combustion of fossil fuels to provide us
with heat relies on the chemical energy stored in plants when
they were alive (see Figure 2). With an ever-decreasing supply
of fossil fuels, however, we are constantly on the lookout for
alternative sources of energy.
