FuelCell Energy, Enbridge Announce Multi-Megawatt Hybrid Product

FuelCell Energy, Inc. (FCEL), and Enbridge Inc. (ENB) have announced that they have initiated production of the first multi-megawatt hybrid product, generating ultra-clean electricity while recovering energy normally lost during natural gas pipeline operations.

The new product, the Direct FuelCell-Energy Recovery Generation[TM] [DFC-ERG[TM]] system, combines a 1.2 megawatt [MW] Direct FuelCell[R] [DFC[R]] power plant with a 1 MW unfired gas expansion turbine. Operating at natural gas pipeline letdown stations, the system generates 2.2 megawatts [MW] of ultra-clean electricity.

Captures Previously Lost Energy
To transport natural gas across the continent, natural gas pipelines operate at high pressures and considerable energy must be injected to achieve the pressures required. This high pressure must be reduced when the gas enters lower pressure systems that deliver gas to homes and businesses. Currently, there is no commercial use made of the energy that is lost at that stage. Additionally, when pressure is reduced, the gas cools. To ensure reliable pipeline operations, the cooling must be offset -- by burning some gas in boilers, reheating the supply to an acceptable temperature.

With the new DFC-ERG system, high-pressure gas passes through a turbine, capturing some of the energy that was otherwise lost, and turns it into usable electricity. The integrated fuel cell also electrochemically converts some of the gas into low-impact, environmentally friendly electricity. Finally, heat normally generated by the fuel cell warms the gas to its proper distribution temperature -- thus eliminating the boiler (and its emissions). The combined system can achieve electrical efficiencies over 60 percent, with low noise and virtually zero smog emissions.

FuelCell Energy’s products are called Direct FuelCells because unlike other fuel cell technologies, Direct FuelCells can use hydrocarbon fuels without the need to first create hydrogen in an external fuel processor.

What distinguishes this hybrid concept from many other proposed hybrid systems is the novel approach of integrating the turbine with an atmospheric pressure fuel cell and recovery of the waste heat in a Brayton cycle. The fuel cell does not need to operate at the turbine pressure, instead it operates at the preferred ambient pressure and is independent of gas turbine cycle pressure ratio.

Key Product Features:
The system works efficiently with a wide range of turbine compression ratios (3 to 15). This means that in principle the concept can be applied from the multi-MW scale (with industrial size turbines operating at 9 to 16 pressure ratios), to smaller systems using microturbines at a lower pressure ratio. Key features of the system include:

• Unmanned Remote Operation—The design approach preserves the ambient pressure operation of fuel cell, avoiding the need for a high-pressure boiler. The power plants can be sited almost anywhere, including unattended remote locations, without the need for an operator and without complications from local safety codes for high-pressure boiler operation.

• Simplicity in Design—The system retains much of the simplicity of our direct fuel cell technology which eliminates fuel processing equipment including external reformer and shift reactors. This results in the most efficient and reliable fuel cell power plant configuration.

• Low Pressure Fuel—The required fuel supply pressure is at the natural gas line pressure which is typically available at about 15 psig on most commercial sites. A fuel compressor is not required.

• Load Following and Reliability—The turbine section can be used to load follow utilizing stored kinetic energy, while the fuel cell is efficiently operated at constant power. This is only possible because of the decoupled nature of the fuel cell and turbine sections of the plant. This feature, not realizable in other pressurized fuel cell systems, imparts attractive load following characteristics in grid-independent applications.

• Environmental Benefits—The Brayton cycle in the hybrid system is an unfired system, indirectly heated with fuel cell waste heat, normally at about 650°F. This results in low NOx generation and yields the highest efficiency, since all primary fuel consumption is done in the fuel cell - which is the more efficient portion of the system. The hybrid system has lower emissions per kWh than simple cycle power plants, due to the higher efficiency.

Enbridge's research has identified 40-60 MW of opportunities for the DFC-ERG system in just one of its operating areas. The North American market represents another 200-300 MW, consisting of the half dozen U.S. states currently seeking to add fuel cells' environmental attributes to their Renewable Portfolio Standards [RPS]. These jurisdictions recognize that a portfolio of low-impact energy supplies, renewables and near-zero emission fossil fuel technologies can provide immediate and long-term benefits.

FuelCell Energy develops and markets ultra-clean power plants that generate electricity with higher efficiency than distributed generation plants of similar size and with virtually no air pollution. Molten carbonate fuel cells produce base load electricity, giving commercial and industrial customers greater control over their power generation economics, reliability and emissions. Headquartered in Danbury, Conn., FuelCell Energy services over 50 power plant sites around the globe that have generated more than 128 million kilowatt hours.

Enbridge Inc., a Canadian company, is a leader in energy transportation and distribution in North America and internationally. As a transporter of energy, Enbridge operates, in Canada and the United States, the world's longest crude oil and liquids pipeline system. As a distributor of energy, Enbridge owns and operates Canada's largest natural gas distribution company, and provides distribution services in Ontario, Quebec, New Brunswick and New York State.

FCEL vs. ENB 1-yr chart: