Green Building Report
March 03, 2003
Appeared in Building Operating Management/FacilitiesNet
While fuel cell technology has long held the promise of providing greater energy efficiency while reducing emissions, until recently the economics of employing fuel cells often proved to be an obstacle to getting projects approved. Now, in certain industries where there is demand for heat and power, fuel cell technology has advanced to a point where it may begin to compete with other energy sources. Verizon shows that the technology can be cost effective where power quality is of utmost importance. The company plans to install seven phosphoric acid fuel cells at its 332,000-square-foot, Garden City, N.Y, facility, which is currently under design. Initial engineering studies conclude that the initial project cost would be recovered within five to six years based on offset electric costs and recovered waste heat.
Fuel Cell Principle
A fuel cell is an electrochemical system that consumes fuel to produce an electrical current. In simpler language, a fuel cell converts hydrogen from natural gas via a chemical process into direct current electricity, with heat and water as byproducts. An integral inverter changes the direct current to alternating current for transmission into the facilitys electrical distribution systems. Compared to utility power generation, fuel cells offer the advantage of being more environmentally friendly, with reduced emissions.
Fuel Cell Types
There are four main types of fuel cells, classified by the type of electrolytes that produce the chemical process: phosphoric acid, proton-exchange membrane, sulfuric acid and molten carbonate. For commercial real estate applications, a 200-kilowatt (kw), 480-volt, 3-phase phosphoric acid fuel cell is commercially available and has more than 1 million hours of operating experience, according to the company that makes the fuel cell. Most fuel cells have an energy efficiency of 37 to 40 percent for power generation only; efficiency can increase to more than 80 percent if the generated waste heat is used for facility heating, cooling or process demands.
For a single 200-kw phosphoric acid fuel cell, annual emission of pollutants is reduced by 40,000 pounds as compared to traditional combustion plants, and carbon dioxide emissions for the fuel cell itself are reduced by 56 percent, or more than 2.4 million pounds per year. Most fuel cells, however, require reformers, which break natural gas down into hydrogen. Reformers do release substantial amounts of carbon dioxide. But because fuel cells are more efficient than traditional power plants, they release less carbon dioxide on a watt-for-watt comparison.
A fuel cells primary drawback is its installed cost. For this project, the cost is $4,500 per kw. Federal and state governments offer subsidies that will cover $1,000 per kW or more of the cost.
The fuel cells planned for the Verizon facility are expected to be fully operational in 2004. They will operate in parallel with four new natural-gas-powered engine generators, totaling more than 4 megawatts of generating capacity. The fuel cells and engine generators will provide the electricity required for the entire facility; commercial electrical power and Verizons existing turbine generators and batteries will remain as backups to achieve power reliability in excess of 99.999 percent.
This may be the first hybrid fuel cell and power generating system, and this facility may be the largest fuel cell deployment in the world. Verizon is receiving technical and financial support from the U.S. Department of Energy and the State of New York.
The Verizon fuel cells and natural gas generators will produce enough electricity to power the equivalent of 400 homes.
Jon Hettinger is an associate partner with Syska Hennessy Group, a consulting, engineering and construction firm, which designed the Verizon fuel cell installation.