California energy beet project gets $5 million for demo

By Susanne Retka Schill | February 28, 2013

Mendota Bioenergy LLC, a California energy beet-to-ethanol project, landed a $5 million grant from the California Energy Commission to build a demonstration plant in the Mendota area in Fresno County.

The project is slated to use advanced enzyme and microbial techniques to convert 10,000 tons of sugar beets harvested throughout the year into 285,000 gallons of advanced biofuel ethanol. The demo plant will help prove the technology and test agronomic enhancements and plans for year-round harvest. If successful, the full-scale project will be an integrated commercial-scale biorefinery, producing 40 MMgy ethanol. About 15 percent of that production is planned to be cellulosic ethanol.

“This could be an excellent re-establishment of an old crop to a new end—to make advanced biofuels,” said Jim Tischer, project manager with Mendota Bioenergy. “This is the first energy beet project to advance to the pilot and demonstration phase in the United States,” he added. With a year-round harvest schedule, the beet crop delivers ethanol yields that are greater per acre and have a lower carbon index than Brazilian sugar cane or North American corn.

The California project was launched in 2008 after the Spreckels sugar plant (owned by Southern Minnesota Beet Sugar Co-op) closed and growers created the Mendota Advanced Bioenergy Beet Cooperative to develop a new market for beets. A USDA-funded feasibility study came back favorable and in late 2010 the project received a $1.4 million CEC grant to move the project forward. Mendota Bioenergy LLC was created in 2011. With multiple partners in the private and public sector, the consortium did lab and pilot scale research, life cycle analysis, feedstock planning, agronomic work on energy beets, as well as technical work on the components of the proposed integrated refinery.

The proposed commercial project includes a 40 MMgy ethanol plant using about 1.4 million wet tons of energy beets annually. Process heat and about 40 percent of internal electricity demand will come from a biomass gasifier using wood chips from orchard prunings. The beet stillage plus food waste will feed an anaerobic digester capable of producing bioCNG that is the diesel equivalent of about 700,000 gallons annually. And a waste water treatment plant is expected to produce a surplus of about 400 acre-feet per year of treated water for irrigation. By recycling the water contained in the beets, the plant is expected to require little fresh water, Tischer added.

Project developers expect former sugar beet growers will be able to grow the energy beets year-round to supply the plant, and a grower payment system is being proposed that will incorporate the Btu used per acre and carbon intensity of growing practices. The use of biodiesel from salt-tolerant canola is also being planned to lower the carbon intensity in powering farm equipment and trucks.

In a presentation to the CEC in August, Tischer explained the energy beet project has several competitive advantages. Through the use of long-term contracts, it should have stable feedstock pricing. The technological risk will be low due to the use of well-known first-generation fermentation technologies. There will be room for improvement on the expected yields of 40 tons of beets per acre and 26 gallons of ethanol yield per ton of feedstock.

Perhaps the biggest competitive advantage in the California market is that the initial energy-beet-to-ethanol carbon intensity (CI) rating came in below 20 grams CO2 equivalent per megajoule. That compares with the 58.40 gCO2e/MJ rating for the best Brazilian sugarcane and a CI rating of 80.7 for California dry mills using natural gas and producing WDGS.

The demonstration project is expected to begin processing beets in late 2013 and operate for about a year. If those results are successful and financing is procured, construction of the biorefinery should proceed in 2016 with a fall 2017 startup.