INTRODUCTION TO CELLULOSIC ETHANOL
Cellulosic ethanol is chemically identical to first generation bioethanol (i.e. CH3CH2OH). However, it is produced from different raw materials via a more complex process (cellulose hydrolysis).
Conventional ethanol production utilizes a fermentation process to convert starches or simple sugars to ethanol. The vast majority of the world's ethanol is produced from either corn or sugarcane.
In contrast to first generation bioethanol, which is derived from sugar or starch produced by food crops (e.g. wheat, corn, sugar beet, sugar cane, etc), cellulosic ethanol may be produced from agricultural residues (e.g. straw, corn stover), other lignocellulosic raw materials (e.g. wood chips) or energy crops (miscanthus, switchgrass, etc).
These lignocellulosic raw materials are more abundant and generally considered to be more sustainable, however they need to be broken down (hydrolysed) into simple sugars prior to distillation. This may be achieved using either acid or enzyme hydrolysis. Both approaches have been the subject of continuing research interest since the 1970s, and large investments driven by biofuel mandates have made in the US and Europe to speed up development of this route to bioethanol.
PRODUCTION OF CELLULOSIC ETHANOL
First commercial scale cellulosic ethanol facilities went online in 2012 to 2016 in the USA, the largest facilities currently are :
DuPont, Iowa, USA, 83,000 tons per year capacity, start-up in 2016, currently idle.
POET-DSM Advanced Biofuels, Iowa, USA, 75,000 tons per year capacity, start-up in 2014, operational.
Abengoa Bioenergy Biomass of Kansas, Kansas, USA, 75,000 tons per year capacity, start-up in 2014, currently idle.
GranBio, Alagoas, Brazil, 65,000 tons per year capacity, start-up in 2014, operational
Longlive Bio-technology Co. Ltd, Shandong, China, 60,000 tons per year capacity, start-up in 2012, operational.
A number of smaller demostration plants for production of cellulosic ethanol are operational or under development. In addition, a number of pilot plants are developing thermochemical/biochemical routes to create bioethanol from commercial waste and MSW.
In the USA, the Energy Policy Act of 2005 created a Renewable Fuel Standard (RFS) for the U.S. that required 7.5 billion gallons of renewable fuel -- primarily corn ethanol -- to be blended into the fuel supply by 2012. The RFS also called for 100 million gallons of cellulosic ethanol production in 2010. In 2015, the annual cellulosic ethanol production crossed the one million gallon threshold. For the entire year, 2.2 million gallons were produced. In 2016, another 3.8 million gallons of cellulosic ethanol was added. Then 2017 saw the biggest jump in cellulosic ethanol production to date, with production reaching 10.0 million gallons, still far away from the 100 million gallon target.
Crescentino (Italy). The Beta Renewables commercial scale cellulosic ethanol plant at Crescentino was officially opened on 9th October 2013. It is currently the world's largest advanced biofuels refinery with a production capacity of 75 million litres of cellulosic ethanol annually. The shareholders of Beta Renewables are Biochemtex, a company of the Mossi & Ghisolfi Group (M&G), TPG Capital, and Novozymes.