Brewing high-quality beer requires a high-quality, reliable source of power. A brewing company that regards earth-friendly production processes with the same degree of importance as the brewing of its premium beers wants to produce that power cleanly and efficiently. How can a brewer use all its natural resources wisely and realize new efficiencies in the process? With an onsite stationary fuel-cell power plant that provides reliable power, fuel flexibility, and produces the highest possible electricity from the available biogas.

The Sierra Nevada Brewing Company in Chico, Calif., has installed a 1-megawatt (MW) carbonate fuel-cell power plant to address its clean energy requirements. The system is fueled by digester gases given off in the beer production process, augmented with natural gas. The power plant provides virtually 100 percent of Sierra Nevada’s baseload electrical requirements, using a non-combustion hydrogen reforming process that produces almost no pollutant emissions and dramatically reduced greenhouse gases compared with traditional fossil-fuel power plants. The result is high-quality, utility-grade electric power, usable heat from cogeneration, and ultra-clean emissions. In addition, overall energy efficiency for the new power system is twice that of power supplied from the electrical grid.

The new fuel cell is part of a large commitment to environmental responsibility by Sierra Nevada, which has incorporated heat recovery, byproduct recycling, and computerized energy reduction equipment into its state-of-the art beer-making processes. But Sierra quickly discovered that its fuel cells, more than just another addition to its environmental efforts, became the “heart” of an energy-cycle system of clean power, cogeneration and wastewater recycling.

The Fuel Cell Power Plant

Sierra Nevada’s world-renowned beers are produced with high-quality electricity and high-value heat from the brewery’s own fuel-cell power plants. >> Photo courtesy of Sierra Nevada.

There are many types of fuel cells, from experimental mobile systems in Detroit’s show cars to the ultra high-tech system found on the Space Shuttle. But one type—large stationary carbonate fuel cells like the one at Sierra Nevada—already has a history of proven results in distributed generation systems around the world. When Sierra Nevada founder Ken Grossman went looking for a fuel cell in 2004, products like the DFC300, a 250-kilowatt (kW) fuel-cell plant produced by FuelCell Energy, Inc., was an obvious choice. The fuel flexibility offered by the company’s Direct FuelCell (DFC) power plants was an important part of the decision criteria.

Configured in size for such applications, the DFC300 is a high-temperature, high-efficiency carbonate fuel cell. The installation of four DFC300s offered Sierra Nevada the ability to provide virtually all of its baseload electrical power. DFC power plant operate on biofuels—gases from food processing, landfills, and wastewater treatment—in addition to natural gas, ethanol, diesel and coal gas. Sierra Nevada’s four DFC300s use a combination of digester gas and natural gas to complete the hydrogen reforming process. Natural gas is provided through a standard distribution network. This ability to maximize electricity production from readily available onsite fuel resources is an important advantage. Other types of fuel cells require external fuel processing to obtain a supply of hydrogen.

The DFC power plant uses a modular design containing separately configured units for power generation (i.e., fuel cell modules), Electrical Balance of Plant (EBOP) including power conditioning and grid interconnect, and Mechanical Balance of Plant (MBOP) including fuel supply and conditioning, and heat recovery. Each module is arranged on its own skid to provide efficient transport to the installation site, installation flexibility, and ease of access for plant maintenance.

The MBOP incorporates a fuel and water treatment module and de-oxidizing reactors to treat the natural gas. The Heat Recovery Unit/Anode Gas Oxidizer (HRU/AGO) module then takes the treated fuel and cold water and produces a heated fuel/water mixture for delivery to the fuel-cell module, which consists of fuel cells arranged into stacks that produce DC power. The EBOP converts DC to AC for use in conjunction with the existing utility grid. This module contains the inverter, control system, operator interface, transformers and all grid interconnection hardware.

Green is Just the Start

This type of fuel cell initially gained popularity for its ultra-clean emissions signature, and recent installations have only served to heighten that advantage. The DFC300 is certified to meet the stringent distributed generation emissions standards established by the California Air Resources Board (CARB), which qualifies the fuel cell as an Ultra-Clean technology, and also exempts it from air-pollution control and air-quality district permitting requirements. The certification also qualifies the fuel cell for preferential rate treatment by the California Public Utilities Commission (CPUC), which includes the elimination of additional exit fees and standby charges. Combined with additional incentives from CPUC’s Self-Generation Incentive Program (SGIP), the fuel-cell system demonstrated its ability to save Sierra Nevada money, not only with its efficient operation, but also with fast-track installation and rate benefits.

For an environmentally-conscious brewer in a state devoted to green solutions, such advantages can be priceless, because beyond the regulations lie the actual clean-air benefits at and around the brewery site. Because the fuel cells make their energy through a non-combustion process, they produce virtually zero emissions of nitrogen oxides (NOx), sulfur oxides (SOx), and particulate matter.

Thus, in addition to reducing overall fuel requirements and carbon dioxide emissions, the system eliminates air pollutants equivalent to removing 500 gasoline-powered cars from California roadways each year. These advantages, and Sierra Nevada’s commitment to generating clean power, were highlighted by Governor Arnold Schwarzenegger in his speech at the dedication of Sierra Nevada’s fuel cell plant in July 2005: “Like any business, Sierra Nevada was looking for stable, affordable, reliable power, and they wanted to limit the environmental impact of their operation,” Schwarzenegger said. “They found the answer in a hydrogen fuel cell system that generates power onsite.”

As Sierra Nevada joined the ranks of institutions noted for providing clean, distributed generation of electrical power, it began to realize that making the most of clean natural gas was only the beginning. The fuel cells quickly became the heart of a power cycle that maximizes their benefits, further reducing emissions and increasing the brewer’s efficiency. The secret is twofold: Using the waste heat from the fuel cells to produce steam for the brewing process, and using a key byproduct of that process called Anaerobic Digester Gas (ADG) to fuel the DFC power plant. The DFC power plant converts the limited supply of ADG gas into the most electricity possible by a distributed generation technology, thereby maximizing the resource.

Cold Beer Starts With Hot Steam

Because of their high operating temperatures, carbonate fuel cells are an excellent source of heat energy, and that heat energy is typically recovered to boost the cell’s overall energy production efficiency. At Sierra Nevada, the 650-degree waste-heat from the fuel cells are harvested as 125-PSI steam, used not only for heating and boiler needs throughout the facility, but also to help power the brewing process itself by boiling the beer. The brewery’s world-renowned beers are produced with high-quality electricity and high-value heat from its own fuel-cell power plants.

This cogeneration of useful energy from the waste heat associated with the conversion process is a key differentiator for large stationary fuel cell applications. Sierra Nevada’s 1 MW fuel cell installation provides over 1.5 million BTUs of waste heat each year, which, when put to good use, can significantly boost the plant’s overall efficiency and save money.

Cleaner Power From Cleaning House

The installation of four DFC300 high temperature, high-efficiency carbonate fuel cells provide the brewery virtually all of its baseload electrical power. >> Photo courtesy of Sierra Nevada.

Beer brewing produces a variety of byproducts, including large amounts of wastewater. As part of the water-treatment process, anaerobic digesters use natural biological processes to generate methane from this wastewater. The brewery site’s filtration system then purifies this methane gas and feeds it to the fuel-cell power plants, further reducing the plant’s need for pipeline fuel.

The DFC300 can operate with this natural fuel just as efficiently as with natural gas. Two of the plant’s four DFC300s can now operate on ADG, natural gas, or any combination of the two fuels. Using this system, the fuel cells can provide up to 400 kW of electricity exclusively from ADG, reducing the brewery’s fuel costs by up to 40 percent each year, and maximizing electricity production from the available biogas. Not only does this multi-fuel ability reduce reliance on the power grid, it further reduces the net levels of carbon released into the atmosphere, and saves money. And regardless of the fuel used, the fuel-cell plants are classified as an Ultra-Clean installation under California law.

A Responsible Neighbor

By producing power onsite at the facility, Sierra Nevada reduces the need for power from the local utility, allowing the grid to operate in a less congested, and therefore more efficient, manner. This benefit came into clear focus during the California heat wave of 2006, when the utility asked the brewery to reduce its energy use to the baseload amount supplied by the fuel cells to avoid leaving nearby Chico residents with no power to support critical air-conditioning needs in the 110-degree Fahrenheit heat—a potentially life threatening scenario. The brewery was able to maintain normal operations thanks to the fuel cells, and the citizens of Chico continued to have electricity without the need to resort to emergency diesel generators.

Power, Profits and Profile

The overall process, as described by Grossman, is a “hand in glove” cycle of benefits. Sierra uses high-efficiency fuel cells to maximize electricity production from available fuels, taps the cogenerated heat to brew its high-quality beers, then recycles once-wasted byproducts to create additional fuel, which the versatile DFC power plants use to maximize electricity production and begin the process again. For a company like Sierra Nevada, whose dedication to environmental stewardship plans include everything from water conservation to carbon dioxide recycling, this cycle pays benefits with every turn.

And there is a second cycle of benefits: money savings, plant efficiency and corporate image. The fuel cells produce electricity at high efficiency, and cogeneration reduces the need for fuel, increasing profit. The ADG produced reduces fuel demand, further increasing profit. And the environmentally-friendly corporate image of Sierra Nevada receives a big lift from beer drinkers, increasing potential sales—and boosting profit. Far from an added expense or regulatory hassle, multi-fuel Ultra-Clean fuel-cell power plants can provide energy savings, cost savings and a green, friendly corporate image—an image Sierra’s customers can savor with each sip of their premium beer.