Biofuels Could Reduce Greenhouse Gas Emissions By 96%

by Steve Hanley (Clean Technica) There is nothing inherently wrong with internal combustion engines. The problem is the fuels we use to run them emit billions of tons of greenhouse gases every year, gases which cause the Earth to get hotter. The byproducts from burning gasoline or diesel fuel account for almost a third of all US greenhouse gas emissions according to the EPA.

It’s true that internal combustion engines are less efficient than electric motors. In a perfect world, we would take the billions of them in use in the world today and replace them with motors powered by sunlight or wind or ocean waves. And someday we will, but it will take many generations to make that happen. What do we do in the meantime?

A new report published by the National Academy of Sciences is based on a joint research project by the Argonne National Laboratory, the National Renewable Energy Laboratory, and Oak Ridge National Laboratory. It offers a cost effective way to make biofuels that can be directly substituted for gasoline, diesel fuel, or jet fuel with few if any changes to the engines. Depending on the source of those biofuels, greenhouse gas emissions would be reduced from as little as 40% all the way up to 96%.

Just think for a minute what slashing exhaust emissions by 96% might mean. The world is on a trajectory that will see renewable energy replace fossil fuels eventually. But there may not be time enough for the transition to be completed before an existential crisis for most living things on Earth occurs.

What if while we are waiting for renewables to become the norm we eliminated the vast majority of tailpipe emissions? The only people who could possibly object are fossil fuel companies, but why should they be allowed to continue poisoning the environment just so their stock prices don’t plummet? What if instead of spending trillions of dollars on carbon capture or geo-engineering, we simply burned something else instead?

The one-step process is known as Consolidated Alcohol Dehydration and Oligomerization, or CADO. But what does it mean for emissions? To find out, the researchers enlisted the aid of scientists at the Argonne National Laboratory. They have created a computer analysis tool known at GREET, which stands for Greenhouse Gases, Regulated Emissions, and Energy use in Transportation.

The program simulates energy use and environmental outputs of various vehicle and fuel systems and has been used 40,000 times by researchers around the world. It can analyze multiple vehicle and/or fuel systems, taking into account where raw materials are mined or extracted to when they are disposed of or emitted. It is a well to wheel analysis which calculates the energy use and emission levels throughout.

The analysis showed that hydrocarbon blends made using the CADO conversion process reduced greenhouse gas emissions anywhere from between 40% up to 96% depending on the feedstock and the conversion pathway. GHG emissions fell by 40% with corn grain, 70% with sugar cane juice and 70-96% with cellulosic biomass such as sugar cane straw and corn stover.

How will people and governments react to this news, which could turn trillions of dollars worth of extraction and refining equipment into worthless junk overnight and decimate the value of energy companies? We will know soon enough. If you hear about this in the mainstream press anytime soon, that will be one thing. If you don’t, that means the fix is in and the fossil fuel companies have been busy burying this news under a mountain of fear, uncertainty, and doubt. And buying politicians to keep the gravy train going for those companies.

Not every discovery in the lab results in commercially viable solutions, of course. Whether this research ever makes it into the mainstream of commerce, no one can predict. But compared to the time and energy that will be consumed trying to geo-engineer the atmosphere or capture carbon dioxide from the atmosphere and bury deep beneath the oceans — both of which will cost trillions of dollars — investing in further exploration of the CADO process seems like a no-brainer. READ MORE

Excerpt from Proceedings of the National Academy of Sciences: Technoeconomic and life-cycle analyses are presented for catalytic conversion of ethanol to fungible hydrocarbon fuel blendstocks, informed by advances in catalyst and process development. Whereas prior work toward this end focused on 3-step processes featuring dehydration, oligomerization, and hydrogenation, the consolidated alcohol dehydration and oligomerization (CADO) approach described here results in 1-step conversion of wet ethanol vapor (40 wt% in water) to hydrocarbons and water over a metal-modified zeolite catalyst. A development project increased liquid hydrocarbon yields from 36% of theoretical to >80%, reduced catalyst cost by an order of magnitude, scaled up the process by 300-fold, and reduced projected costs of ethanol conversion 12-fold.

Current CADO products conform most closely to gasoline blendstocks, but can be blended with jet fuel at low levels today, and could potentially be blended at higher levels in the future. Operating plus annualized capital costs for conversion of wet ethanol to fungible blendstocks are estimated at $2.00/GJ for CADO today and $1.44/GJ in the future, similar to the unit energy cost of producing anhydrous ethanol from wet ethanol ($1.46/GJ). Including the cost of ethanol from either corn or future cellulosic biomass but not production incentives, projected minimum selling prices for fungible blendstocks produced via CADO are competitive with conventional jet fuel when oil is $100 per barrel but not at $60 per barrel. However, with existing production incentives, the projected minimum blendstock selling price is competitive with oil at $60 per barrel. Life-cycle greenhouse gas emission reductions for CADO-derived hydrocarbon blendstocks closely follow those for the ethanol feedstock. READ MORE