8551 Why Use Energy Swaps

An energy producer that is constantly selling energy into the open market is exposing its revenue stream to the volatility of the market. The company's risk can be neutralized by converting the variable market price that it receives on its sales to a fixed price. A swap is then set up in which the company receives fixed payments from the buyer, based on the fixed price, and pays a variable amount to the buyer, based on the index. An energy consumer, who is concerned about rising prices, takes...

124US Power Generation Assets

In 1996, the U.S. had a total electricity-generating capability of 775,872 megawatts (MW) 91.5 was owned by utilities. The largest portion of utility capability in the country is fueled by coal. The largest plant, Grand Coulee of the Bureau of Reclamation, is a hydroelectric plant on the Columbia River in Washington. The largest utility in the country is the Tennessee Valley Authority (TVA), which provides electricity to seven southeastern states. Although investor-owned utilities account for...

6111Cost Reduction

The high capital cost for fuel cells is by far the largest factor contributing to the small market penetration of fuel cell technology. The high capital cost (on a kW basis) has led to an electric power sector wary of installing fuel cells or using them in other systems (e.g., transportation applications). Reducing the installed cost of fuel cell technology is perhaps the most important driver of fuel cell research, development, and demonstration (RD& D) today. This RD& D encompasses many...

93 Electric Utility Industry Restructuring and DG

The fate of distributed generation is tied to how the provisions of EUIR legislation are written and implemented in restructured states and specifically whether the distribution utility rules in any state, restructured or not, are opened to allow market access by new technologies. By way of background, the intense EUIR debate began soon after the passage of EPAct. The early tier of EUIR states, such as California and New England, had high electric rates. These were followed by many other...

4611 Safety Standards

Safety standards are important to continue the safe operation of distribution systems. Changes in other requirements should not unduly compromise safety standards. Safe operation is a concern of the host utility, the owners of distributed generation, and the operators of these facilities. Safety standards implemented by most electric utilities have a long history. Safety must not be unduly compromised in order to implement distributed generation in the State of Texas. However, in order to...

1821Distributed Control

Traditionally, distributed control refers to a class of concepts and techniques used to solve complex control problems which may be formulated as a number of smaller interconnected sub-problems. The sub-problems involve some degree of coordination in their solutions. Distributed control systems are appropriate for large-scale systems with hundreds of variables that make centralized control infeasible. A typical application of distributed control is for designing fault tolerant systems where the...

652 Pressure

The direct effect of the operating pressure of a fuel cell is to change the concentration of reactants at the electrode surfaces. Thus, according to the Nernst equation, as operating pressure increases, partial pressures of reactants increase and the reversible cell potential increases. In addition, as operating pressure increases, gas solubility and mass transfer rates increase, reducing some overpotential associated with these processes. Electrolyte loss by vaporization is typically reduced...

5121 Combustor Overiew

Scaling techniques for the design of mini combustors are less defined, due, in part, to the effects of (1) surface area volume changes with size, (2) increased effects of wall quenching, (3) low fuel flows necessitating a small number of injectors and orifice sizing, and (4) increased effect of leakage gaps on pattern factor. As a consequence, there is reluctance to directly apply scaling from larger combustors, and alternative design solutions have been considered, for example, by Rodgers...

1324Propane

Propane in the U.S. is a mixture of approximately 85 propane and 15 butane small amounts of pentane and isobutane are also incorporated. Outside the U.S. and Canada, the mixture can vary greatly from 80 20 to 30 70 propane to butane. Propane has a boiling point of -42 C (-44 F) at atmospheric pressure therefore, when kept in a sealed vessel, propane has a vapor pressure that moves depending on outside temperature. For example, at 70 F, the vapor pressure of propane is 127 psi and of butane is...

4141 Single Crystal and Polycrystalline Silicon

Single crystal silicon cells are produced by a series of processes (1) growing crystalline ingots of p-silicon, (2) slicing wafers from the ingots, (3) polishing and cleaning the surface, (4) doping with n material to form the p-n junction, (5) deposition of electrical contacts, (6) application of antireflection coating, and (7) encapsulation. The Czochralski process is the most common method of growing single crystal ingots. A seed crystal is dipped in molten silicon doped with a p-material...

1721 Federal Regulations

The Clean Air Act (1963) imposes a complex regulatory structure on air pollution sources (Leonard, 1997). From a historical perspective, the regulatory environment for a major emission source has been largely dependent on two factors where the facility is located (that is, whether in an area meeting clean air standards or not) and the facility age (new or old source). At the federal level, the CAA and its various amendments (1965, 1967, 1970, 1977, and 1990) provide the critical statute for...

1113System Protection

To protect distribution system equipment from damaging overloads, that equipment contains protective devices. This protection can be manifest in a * A common way to denote three-phase service is to list the line-to-neutral followed by the line-to-line voltage. Three-phase circuits are defined by the line-to-line voltage, with its line-to-neutral voltage multiplied by J3 . variety of forms, but usually through fuses or circuit breakers. The devices sometimes employed to provide the logic to...

45 PV System Capacity Credit

PV systems differ from other DG systems in that they are not dispatchable unless equipped with storage. For that reason, they have been viewed as generator fuel saving. However, recent work has shown that there is significant PV capacity credit for grid penetrations of 20 or less. Using the standard Institute of Electrical and Electronic Engineers (IEEE) load duration curves, Rahim and Kreider (1992) showed, using an hourly simulation, that the equivalent load carrying capacity (ELCC) of a PV...

Contributors

Curtiss Jeffrey Dagle Peter Fusaro Michael Godec Yogi Goswami Bruce Hedman Tina Kaarsberg Jan F. Kreider Ken Nichols Ari Rabl Colin Rodgers Pacific Northwest National Laboratory, Richland, Washington Solar Turbines Incorporated, Washington, D.C. University of California, National Fuel Cell Research Center, Irvine, California Sixth Dimension, Inc., Fort Collins, Colorado Kreider and Associates, LLC, Boulder, Colorado Pacific Northwest National Laboratory, Richland,...

10314 Footprint

Three technologies in particular offer compact packaging and have an appeal to end users seeking an unobtrusive CHP system. Stirling engines are the smallest, followed by fuel cells and microturbines. Larger steam turbines, gas turbines, and reciprocating engines are generally isolated in either a factory enclosure or a separate building along with ancillary equipment. Table 10.2 shows equivalent footprint size for several different CHP types. Equivalent Footprint Size for Different CHP Types...

99 Participation at the PUC

Advocates of distributed generation (including Discos, manufacturers, customers, and others) will strategize on how best to seek the rules and rates from PUCs. As mentioned before, the regulatory focus is concentrated on the 5000 megawatt level utility system. Of course, regulators do focus on customers, but primarily as a matter of rate design, not so much as a matter of engineering design. There is a threshold, often at a level of 10 megawatts or less, where PUCs allow utilities to make...

256Costs

Free-piston Stirling cycle engines and generators are currently available on a prototype basis for development and technology evaluation programs. Work is under way to have several sizes of generators mass produced. Full scale production of STC's 1 kW generator is planned for the year 2002, with limited production of the 3 kW generator to follow. Early commercial engines will have higher capital costs than IC generators, but lower than initial costs for PV and thermoelectric systems. Despite...

255Utility Interfacing

As previously noted, Stirling generators can be used for both on- and off-grid applications. It is left to the utility companies and their customers to decide what is most appropriate. Stirling generators are reliable enough that a utility company may consider leasing a unit to a remote off-grid customer, thus avoiding the costs of building power lines or larger generators on site. An off-grid Stirling micro-cogeneration system is a very reliable and cost-effective solution for providing heat...

1026 Stirling Engines

The Stirling engine so named because it is based on the Stirling thermo-dynamic cycle was conceived more than a century ago. Stirling engines produce power not by explosive internal combustion, but by an external heat source usually a continuous-combustion burner. Until recently, reliability problems have limited their use to hobbyists. It is only in the past generation that a viable free-piston Stirling was developed. All Stirling engines can be operated with a wide variety of fuels, including...

254 Controls and Communications Dispatchability

The characteristics of Stirling generators allow them to be located inside homes, businesses, and similar environments where IC generators would be intolerable because of their high noise and maintenance levels. The most popular application of Stirling generators is in micro-cogeneration systems. In these systems, the generator is coupled to a household boiler (a water heater for hydronic space heating), so electricity and hot water are produced simultaneously from the same fuel. Stirling...

25 Stirling External Combustion Engines

A Stirling engine is an external combustion heat engine and, therefore, does not require a specific fuel a Stirling engine-generator can convert any sufficient heat source into useful electrical power. These generator sets are also physically small and very efficient even below 100 W (e). With the added advantages of high reliability, long life, very low noise, and maintenance-free operation, Stirling engines are ideal for distributed generation applications where the generator must be located...

252 Fuels

One of the singular advantages Stirling engines have over internal combustion engines is that they are truly multi-fuel capable. The Stirling cycle requires only a sufficient heat source to operate and does not rely on carefully timed fuel injection and combustion processes as do internal combustion engines. Practical Stirling cycle engines may be operated using propane, natural gas, gasoline, diesel, radioisotopes, solar energy, and even wood or other biomass. The only limitation on fuel...

51 Single Shaft Gas Microturbines

The classic open Brayton cycle described in Chapter 3 is also the basis of gas-fired microturbine (MT) engines. The reader is referred to that chapter for cycle basics. Several single-shaft MTs have been developed recently by Capstone, Elliott, and Honeywell with ratings between about 20-150 kW. Some published specifications for these four MTs are listed in Table 5.1. A number of MT flow-path configurations are depicted in Figure 5.1, the most compact of which is the wrap-around recuperator...

251 Design

Stirling engines operate on a closed thermodynamic cycle where a temperature differential is converted into mechanical and or electrical power. External heat is supplied at a high temperature to the engine heater head, and thermodynamic waste heat is rejected to ambient temperature. An internal displacer piston physically shuttles the helium working fluid between the hot and cold regions, creating a varying pressure value. That pressure wave causes the power piston to reciprocate. The...

1041 CHP Technology Cost and Performance Characteristics

Table 10.4 shows characteristics for application sizes from as small as 50 kW to as large as 25 MW. The heat rates and recoverable thermal energy factors are based on commercial product specifications, with the exception of the microturbine, for which performance factors are estimated. Microturbine cost factors were estimated based on assessment of early market entry economics and not manufacturers' projections for high volume production. Package costs, heat recovery equipment costs, and...

253 Technical Developments and Outstanding Barriers

Stirling cycle engines have developed considerably in recent years. The free-piston configuration has served as an enabling technology for a great deal of energy conversion development. Stirling Technology Company (STC) and Sun Power Inc. are the leading developers of free-piston Stirling cycle engine generators with capacities ranging from 10 W to 5 kW. These generators have demonstrated maintenance-free operating lives far beyond that of gasoline or diesel engine generators. Ongoing endurance...

14 The Distributed Generation Technologies

Distributed generation is any small-scale electrical power generation technology that provides electric power at or near the load site it is either interconnected to the distribution system, directly to the customer's facilities, or both. According to the Distributed Power Coalition of America (DPCA), research indicates that distributed power has the potential to capture up to 20 of all new generating capacity, or 35 Gigawatts (GW), over the next two decades. The Electric Power Research...

What Is The Future Of Fuel Cells

Distributed Generation An Introduction Anne-Marie Borbely and Jan F. Kreider Distributed Centralized Distributed Again 1.1.2 De-Integration of Vertical Stages 1.1.3 Convergence of Utility Companies 1.2.1 The U.S. Transmission System 1.2.2 Utility Choices and Deregulation 1.2.3 Transmission Loading Relief TLR 1.2.4 U.S. Power Generation Assets 1.2.4.1 Non Utility-Owned Power Generation 1.2.5 Double Counting How Much Is Really Out There 1.3.1 Restructuring and Competition 1.3.2 The Future of...