Introduction This article covers post-prototype fuel cell FC systems in stationary or ‘on-site’ applications, for use in non-grid-con-nected dispersed generation, or grid-connon-grid-con
Trang 1Fuel Cells
AJ Appleby,Texas A&M University, College Station, TX, USA
& 2009 Elsevier B.V All rights reserved.
Introduction
This article covers post-prototype fuel cell (FC) systems in
stationary or ‘on-site’ applications, for use in
non-grid-con-nected dispersed generation, or grid-connon-grid-con-nected distributed
generation Both are referred to here as DG They include a
range of sizes from kilowatt to megawatt scale, and may be in
combined heat and power (CHP, cogeneration or dual
en-ergy use systems), or as electricity-only units Trigeneration
(combined heat, power, and cooling) is a further possibility
The article starts with a general discussion of on-site
power systems, and introduces the different types of FC
devices for these applications This is followed by general
sections on on-site power systems and their characteristics,
and on fuels for DG applications Sections follow on the
subsystems’ aspects of FC systems, and on their scaling
characteristics Detailed sections on each FC technology,
named for the electrolyte used in the electrochemical fuel
gas-to-direct current (DC) power converter (the FC
stack), are then given
The FC systems considered are the phosphoric acid
fuel cell (PAFC), the molten carbonate fuel cell (MCFC),
the solid oxide fuel cell (SOFC), the proton-exchange
membrane or polymer electrolyte membrane fuel cell
(PEMFC), and the alkaline fuel cell (AFC) Except for
the PAFC, each technology is reviewed up to that of
prototype stationary systems inFuel Cells – Overview:
Introduction The PAFC up to this stage is discussed in
Fuel Cells – Phosphoric Acid Fuel Cells: Overview
In the case of the PAFC, the most important
devel-oper has been International Fuel Cells (IFCs, a
part-nership of United Technologies Pratt and Whitney
Aircraft Division, South Windsor, CT, and Toshiba
Corporation, Kawasaki, Japan), which is now UTC Power
Corporation Other important work has taken place at
Westinghouse (Pittsburgh, PA, USA) and successor
companies Work in Japan took place at the Fuji Electric
Company and Mitsubishi Electric Corporation (both
Tokyo, Japan), Toshiba, and Hitachi (Hitachi-shi, Japan)
The prime US developer of the post-prototype
MCFC was Energy Research Corporation (ERC;
Dan-bury, CT, USA), which became FuelCell Energy in 1999
The second US MCFC developer in the late 1980s was
MC-Power (Burr Ridge, IL, USA), a consortium of the
Institute of Gas Technology (IGT, Des Plaines, IL,
providing technology), Bechtel Corp (engineering), and
Stuart and Stevenson (packaging), associated with
Ishi-kawajima-Harima Heavy Industries (IHI, Tokyo, Japan)
The latter had an early exchange agreement with IGT,
but it did not share MC-Power’s technology The pioneerSOFC developer was Westinghouse Electric Company(now Siemens Westinghouse Fuel Cells, Pittsburgh, PA,USA), but in recent years a large number of other de-velopers have come into the field, both in the UnitedStates and overseas The PEMFC was originally de-veloped at the General Electric Company R&D La-boratories (Schenectady, NY, USA), and then by BallardPower Systems (North Vancouver, BC, Canada) Again,there are now numerous developers of this technology Incontrast, the stationary AFC is represented by only ahandful of developers The AFC section includes anextensive discussion of future sources of hydrogen (H2)fuel for this (and possibly other) FC technology.Following this discussion are sections on electricalissues for stationary FCs, economics, and the conclusions.Throughout costs have been adjusted to third-quarter
2007 US dollars, unless otherwise stated
General
The electric utility industry has been traditionally based
on large central generating stations feeding a radiatingtransmission and distribution system A process of de-regulation, liberalization, and privatization is now inplace worldwide This started in 1978 in the UnitedStates with the Public Utility Regulatory Policies Act.The deregulation process allows wholesale and retailpower trading, which is tending to make central powergeneration and transmission trend toward a distributedpower supply with decentralized power generation.There are arguments beyond the existence of de-regulation for the evolution toward decentralized gen-eration and a distributed power supply These involveeconomics, ecology, and security
Large central power plants have operational and costadvantages, particularly economies of scale However,unless they are integrated into industrial complexes, thewaste heat that they produce cannot be used, because ofthe high cost of long-distance heat transport to populatedareas, since environmental considerations demand thatnew plants must be remote from these One solution tothis problem is decentralized generation, that is, thecogeneration of electrical energy and heat energy at theplace where both are required, consistent with environ-mental requirements Decentralized plants will be muchsmaller than central stations, and will require the use ofclean fuel for use on-site Their pollutant emissions must
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