Fuel cells and PV power California brewery

A California craft brewery aims high when it comes to corporate citizenship and its carbon footprint ” to the extent that it has installed both a substantial fuel cell energy system and two large-scale photovoltaic arrays. It now generates around 80% of its power needs on-site, and aims to increase this to 100%, as Cheri Chastain reports

In a small town in Northern California, a craft brewery is taking big strides in the energy world. Sierra Nevada Brewing Co. sits at the north end of the Sacramento Valley in the small town of Chico, California and has become a world-class brewery in a short 28 years. The brewery has grown into the second largest craft brewery and seventh largest brewing company in the United States.

Sierra Nevada Brewing Co.’s primary mission is to produce the finest quality ales and lagers. Sierra Nevada Brewing Co (SNBC) believes this mission can be accomplished without compromising its role as a good corporate citizen and environmental steward. Founded in Chico in 1980, SNBC applies resource and energy conservation and reusing/recycling raw materials as guiding operating principles. The company employs over 450 people and has a distribution range of all 50 US states, the UK, and a handful of other European markets.


The elevated, sun-tracking system covers roughly three acres (1.2 hectares) of parking spaces at the brewery
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SNBC understands that its success is not just predicated on the quality of its ales and lagers; success comes also from the deep, abiding concern for the environment it seeks to sustain by ensuring that the region from which it garners its profitability remains whole, viable, and vibrant. The urgency for reducing the impact on the environment has taken the lead in policy decision making and every effort is made within the brewery to have the smallest environmental footprint possible.

The current rising cost of fuel and electricity, the persistent unreliability of power from the local utility, and a vision of being 100% off the grid through clean and renewable technologies led Sierra Nevada to begin looking at alternatives for generating energy on site. The production needs of brewing beer place a very large demand on the energy grid, so SNBC needed something that would generate a significant amount of power on a consistent basis. SNBC looked at a number of options and settled on two forms of renewable energy that suited its needs the best. Prior to installing any renewable energy technologies on site, however, SNBC first worked to make sure the plant was operating as efficiently as possible.

ENERGY EFFICIENCY CUTS DEMAND FIRST

If green, renewable energy is not used efficiently and effectively, the purpose has greatly been defeated. Sierra Nevada understands this and took a good look at the energy being used as well as the energy being wasted at its facility and began taking measures to reduce both. Wasted energy was primarily in the form of heat from boilers and brew kettles.

To remedy this, SNBC installed heat recovery units on both the boilers and the brew kettles. These installations capture exhaust heat, which is run through a heat exchanger to produce steam that is recycled back into the brewing process. This reduced the demand placed on the boilers while reducing the need for excess natural gas purchases.

SNBC has also upgraded all lighting in the plant. High efficiency T-5 fixtures have been installed in all storage warehouses ” roughly 130,000 sq ft (12,078 m2) ” and the 45,000 sq ft (4180 m2) bottle shop. In the bottle shop and most of the storage warehouses, SNBC has taken advantage of natural daylight and installed skylights throughout. Ambient light sensors were also installed that control the electronic ballasts and turn light tubes within each fixture on and off according to how much natural light is coming in. The ambient light sensors have proven to be a cost-effective, simple way for employees to help save electricity.

In addition to these large energy conserving installations, SNBC has installed numerous motion sensor and timer lights; air compressors have been upgraded with ultra-efficient, speed-controlled drives; high-efficiency motors and refrigeration systems are in use; energy efficient electronics and appliances are in use throughout the brewery. Energy conservation is also a common and encouraged practice that all employees engage in. Employees are encouraged to work constantly work within their departments to make them as efficient as possible, while all new installations are to be fitted with energy-saving equipment.

1.2 MW OF FUEL CELL COGENeration UNITS

Once energy efficiency installations were made at the plant, SNBC installed one of the largest direct fuel cell installations in the US: four 300 kW cogeneration fuel cell power units, totaling 1.2 MW of power. The fuel cell installation was commissioned in early 2005.

SNBC chose to use fuel cell technology for several reasons: it is much cleaner than typical power generation and would not pollute the local community; there was potential to use biogas as a feedstock; and it generates a constant supply of electricity and heat 24 hours a day.


Four fuel cell units, with heat recovery units, supply electricity and steam directly to the brewery.
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The fuel cells, coupled with heat recovery units, supply electricity and steam directly to the brewery. The 1.2 MW of power produced by the cells supplies roughly 55% of the brewery’s total electrical demand. The overall energy efficiency of the installation is approximately double that of grid-supplied power and emissions are significantly reduced. In recognition of this installation, Sierra Nevada was awarded the 2005 Governor’s Environmental and Economic Leadership award and the 2005 Flex Your Power Award from the State of California.

The fuel cells that SNBC installed are FuelCell Energy ‘direct’ fuel cells; meaning that they produce the hydrogen required to run directly within the units, rather than running on a pure feedstock of hydrogen. The cells run on a combination of natural gas and methane-rich biogas. The natural gas is supplied from the local utility and the biogas is a by-product of the on-site SNBC wastewater treatment facility.

The SNBC water treatment facility consists of a two-stage anaerobic then aerobic treatment process. The anaerobic treatment process involves a sludge blanket for treatment and produces methane-rich biogas in the process.


Fuel cells in front of the heat recovery units, with fermentation tanks in the background.
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SNBC was the first FuelCell Energy installation to blend two gases ” units typically run on one gas source only. At current biogas production levels, SNBC is expecting to offset approximately 13% of the total natural gas needed to run the cells. By using the methane generated on site, SNBC is further lowering its demand on the energy grid as well as eliminating a substantial amount of greenhouse gas from the atmosphere.

The cogeneration part of the fuel cells is the addition of the heat recovery units to each fuel cell. The exhaust coming off the fuel cells is approximately 370à‚ºC (700à‚°F) ” there is great energy potential in this heat and SNBC has taken advantage of it. The exhaust is run through a steam-generating heat recovery unit. The steam is then piped back into the brewery where it is recycled in the boiling process. The heat recovery units add approximately 15% efficiency to the fuel cell installation.

Funding for the fuel cells came from private investment from SNBC, a rebate from the local utility, a federal tax credit, and a rebate from the Department of Defense. The fuel cells were installed in 2005 and are currently expecting a payback period of six to seven years ” depending, of course, upon the cost of natural gas and how much of that is offset by the use of biogas.

Since SNBC was the first installation to blend two gases, there has been a slight learning curve with the installation. The maintenance and servicing of the fuel cells are done by FuelCell Energy through a service agreement. The fuel cells have performed well and SNBC is satisfied with its choice of renewable energy technology.

1.8 MW OF SOLAR photovoltic PANELS IN TWO ARRAYS

Another major contribution to SNBC’s energy generation programme is the utilization of the sun to produce 1.8 MW of solar electricity. With an average of 285 days of sunlight each year, a photovoltaic (PV) system is a logical method for generating power in Northern California. Solar panels also provide a significant amount of power during the hours it is consumed the most. Being that peak hour consumption is the most costly for the brewery, solar panels provide a large economic benefit.

The solar panels at SNBC were installed in two separate systems. The first is a 503 kW solar array installed by PowerLight Corporation in 2007. This system is an elevated, sun-tracking system that covers roughly three acres (1.2 hectares) of parking spaces at the brewery. The system is tied to the water treatment plant with excess power being routed to the rest of the brewery. Having the sun-tracking element on the system adds ~30% efficiency over a stationary system. The parking structure contributes close to 10% of the total power demand to the brewery.


Brew kettles
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The second PV installation includes 6800 Mitsubishi Electric 185 Wp solar panels and supplies 1.26 MW of electricity to the SNBC plant. The second installation is a roof-mounted system that covers ~160,000 sq ft (14,865 m2) of roof space and sends power directly into the SNBC plant. Both PV systems ” the roof-mounted system and the parking structure ” are grid-tied, which allows SNBC to sell unused power back to the electricity grid.


The fuel cells run on a combination of natural gas and methane-rich biogas ” a by-product from the on-site wastewater treatment facility.
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Neither of the solar installations is equipped with battery storage. To store the amount of excess power produced by the fuel cells, it would require a tremendous amount of battery space and would not be economically viable. It was more feasible to sell the power back to the utility as SNBC receives peak hour payment for the solar electricity. Both solar installations were partially funded through rebates from the local utility and federal tax credits. Each installation is currently expecting payback in less than seven years.

The two solar installations combined make SNBC one of the largest privately owned solar systems in the United States. With the fuel cells and the solar panels, SNBC is over 100% self-generating during peak hours ” 80% self-generating overall ” and will offset 4678 tonnes of carbon annually. In order to achieve 100% overall self-generation, SNBC is now entering a second wave of conservation and efficiency.


The final product!
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SNBC has something of an advantage when it comes to investing in renewable energy technology ” SNBC is privately held and is not faced with the need to focus on the next corporate financials in order to appease stakeholders. As a result, SNBC is able to focus on the long-term return on investments with the goal of being able to sustain the business over several generations. The renewable energy installations at SNBC are the direct result of the owners’ desire to install such systems, supported by upper management and a commitment to making the brewery as sustainable as possible.

WHAT’S NEXT

As mentioned above, SNBC is working to cut consumption by 20% in order to reach the 100% self-generation mark. The company is looking to do this through an improved refrigeration system for the beer warehouses, better machine efficiency, and repairing numerous air leaks throughout the plant. SNBC is also researching the utilization of solar thermal water heating as a heat source for brewery water. The solar-heated water would be used for brewing as well as in the SNBC Restaurant and Taproom. This is expected to cut down tremendously on the use of natural gas needed to heat the water, and in the process, reduce emissions.

Cheri Chastain is the Sustainability Co-ordinator for Sierra Nev US.
e-mail: cheri@sierranevada.com

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