Grown in Marin
University of California
Grown in Marin

Power to the dairy

Marin and North Bay dairy farmers are leaders in producing local pasture-based organic and conventional milk.  They also are the critical mass behind the artisan and farmstead cheese movement, with nearly half of California’s small scale on-farm and specialty cheese creameries located in the North Bay.  In addition to delivering these high quality dairy products, they have been at the forefront of renewable energy production - energy to meet their dairy and creamery needs, with the potential to produce surplus energy for sale on the grid.

The Giacomini Dairy receives recognition as an AgSTAR Partner from Cara Peck of U.S. Environmental Protection Agency for the farm's methane digester.
The Giacomini Dairy receives recognition as an AgSTAR Partner from Cara Peck of U.S. Environmental Protection Agency for the farm's methane digester.

All of this comes from recognizing that the manure generated on working dairies has power potential through the generation of methane gas.  Since the late 1960s dairies have been capturing and storing manure in holding lagoons for application to the land during the growing season.  These manure management systems were installed to protect water quality.  Now, through the installation of covers and gas collection systems these lagoons are being converted to “methane digesters” that capture methane and use it to run electrical generators that power the dairy.

Setting the trend as early as 1980, the Grossi Family Dairy of Novato installed the first dairy digester in the western United States.  Ralph Grossi explained that the family's “motivation was high cost of power and need to have a more efficient waste management system.”  The capital costs were covered by a grant from the Buck Trust, through the Landal Institute, and a California Department of Energy loan.  Through a contract with Pacific Gas & Electric they were able to repay the loan.  “Since operational cost was relatively low and electrical rates were high, we were able to pay off the loan in less than 5 years,”  Ralph shared.  This digester was shutdown in 1987 when the dairy herd was sold, removing the manure feedstock source for the system.   

Currently in California there are at least 18 digesters on dairies.  This includes two in Marin County.  The latest one to be installed in Marin is on the Giacomini Dairy in Point Reyes Station.   It became fully operational in 2009 and provides all the electricity that the dairy and Point Reyes Farmstead Cheese creamery need.  

On June 6, 2012, Western United Dairymen hosted a celebration of the digester and their partnership with California Energy Commission, Sustainable Conservation, Pacific Gas & Electric, and the California Department of Food and Agriculture to bring 18 methane digesters online since 2002 and the inception of the Dairy Power Production Program (DPPP). 

Electricity is not the only benefit that comes from dairy manure and the use of a methane digester.  Digesters recommended for use on the size of North Bay dairies include the use of a solids separator.  The resulting solids are the perfect source for high quality bedding material and compost.  In the case of the Giacomini Dairy, Teddy Stray seized the opportunity to grow Point Reyes Compost Co.  As “Purveyors of Premium Poop” Teddy and his team have created a successful line of compost and potting soils from the separated solids.

Teddy Stray explains how separated solids are composted.
Teddy Stray explains how separated solids are composted.
Another added benefit from the Giacomini dairy digester is the hot water resulting from cooling the generator engine.  By using the hot water coming off the generator to heat milk to cheese making temperatures, the creamery has entirely replaced its use of propane for that purpose.  The result is reduced energy costs.

Similar benefits are being realized on Blake’s Landing Farm in Marshall.  The Strauss family installed its digester in 2000 through a partnership with the Marin Resource Conservation District and Natural Resources Conservation Service.  Upgrades for tying into the grid and replacing the generator were made in 2010 with support from DPPP.  “We are offsetting almost 100% of our electrical needs for the farm and about 50 to 70% of our propane needs,” explained Albert.  He also shared as benefits that “we keep methane gas out of the atmosphere and odors are greatly reduced,” while at the same time “we are able to keep rain water out of our manure system,” making managing manure even easier.  
    
Installing and operating a methane digester has considerable obstacles.  Most notable is the initial capital requirement.  For the Giacomini Dairy costs were approximately $600,000.  Total costs on Blake’s Landing Farm were approximately $500,000.   Estimated periods for return on investment are as much as 12 years at today’s rates for power and propane.   This level of capital in the face of that return on investment is a tall order for a small dairy to consider on their own.  

In addition to entry costs, other obstacles can include air quality regulations and restrictions, impacts of lower electricity rates to generating revenue from selling surplus power, and system maintenance requirements.  These obstacles have been made a priority by Governor Brown.  Sandra Schubert, Undersecretary for California Department of Food and Agriculture, participated in the June 6th celebration and relayed to participants that “future funding opportunities” are being developed and that through a partnership with U.S. Environmental Protection Agency and the U.S. Department of Agriculture “we are addressing the obstacles to implementation” that dairies face in California and nationally.  

Marin’s dairy farmers have been leaders and partners in overcoming these barriers.  And the continued and renewed support from state and federal partners will be welcome by more of Marin’s farmers looking to seize the power of methane on their dairies.

(For more details about DPPP and dairy digesters in California read Western United Resource Development’s Program Evaluation Report.)

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