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Suggested Citation:"3 Recommended Additional Analyses." National Research Council. 2009. Evaluation of Future Strategic and Energy Efficient Options for the U.S. Capitol Power Plant. Washington, DC: The National Academies Press. doi: 10.17226/12719.
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Suggested Citation:"3 Recommended Additional Analyses." National Research Council. 2009. Evaluation of Future Strategic and Energy Efficient Options for the U.S. Capitol Power Plant. Washington, DC: The National Academies Press. doi: 10.17226/12719.
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Page 22
Suggested Citation:"3 Recommended Additional Analyses." National Research Council. 2009. Evaluation of Future Strategic and Energy Efficient Options for the U.S. Capitol Power Plant. Washington, DC: The National Academies Press. doi: 10.17226/12719.
×
Page 23
Suggested Citation:"3 Recommended Additional Analyses." National Research Council. 2009. Evaluation of Future Strategic and Energy Efficient Options for the U.S. Capitol Power Plant. Washington, DC: The National Academies Press. doi: 10.17226/12719.
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Page 24

Below is the uncorrected machine-read text of this chapter, intended to provide our own search engines and external engines with highly rich, chapter-representative searchable text of each book. Because it is UNCORRECTED material, please consider the following text as a useful but insufficient proxy for the authoritative book pages.

3 Recommended Additional Analyses Chapter 3 responds to the broader charge to the committee, asking it to “recommend how the Capitol Power Plant can be best positioned to meet the future strategic and energy efficiency requirements of the U. S. Capitol Complex.” The committee recommends an additional set of analyses that could be performed to this end. The common theme of these analyses is to differentiate the unique aspects of the CPP project from typical district energy projects, and to seize the opportunity for setting an example for the nation in regard to energy reliability, efficiency, cost-effectiveness, and security and with respect to environmental stewardship. The recommended additional analyses are as follows: 1. Reliability and risk assessments; 2. Comparative demand and supply projections; 3. Workforce demand evaluation; 4. Exploration of a wider range of technologies; 5. Benchmarking; and 6. Response to shortcomings identified. RELIABILITY AND RISK ASSESSMENTS One important area that has not received sufficient attention is the perceived ability of each option proposed in the 70% Report to continuously generate and deliver the required services. In order to provide a consistent comparative assessment of the proposed options it is necessary to conduct a comprehensive risk analysis of each one. The numerical analyses should provide quantitative reliability indices that respond to the actual factors that influence the ability of the CPP system to perform its required functions. This cannot be done using deterministic techniques. It requires the application of probability methods. The current CPP system reliability philosophy appears to be based on the provision of redundant elements at the system and subsystem levels. Firm steam and refrigeration capacity are defined as the capacities remaining after the loss of the largest boiler or chiller, respectively. Although it is recognized that this methodology is commonly used for complex systems and does provide very high reliability of such systems, this is a deterministic approach that does not incorporate the probability of failure of a boiler or chiller. A similar situation exists at the CPP subsystem level and in the delivery aspect of the CPP system mandate, involving tunnels and alternate flow paths. CPP Option 1 is an extension of the existing CPP using various fuel options. Reliability considerations are referred to in the 70% Report as security impacts and indicate only the ability to provide steam and chilled water under a PEPCO outage and the loss of water from the W ASA. The report provides no indication of the likelihood of a PEPCO or W ASA outage in the future, or details of past outages. 21

The 70% Report contains a summary of planned and unplanned outage times for the major components in the heating and refrigeration systems. This is useful information. The available capacities for each day in the heating and refrigeration systems were calculated by comparing the coincidental planned/unplanned outages of each major component in the two systems. The report states that the outage data were consolidated on a monthly basis and compared with the system peak load to determine the availability of the CPP to serve the monthly steam and chiller requirements of the U.S. Capitol Complex. The report notes that monthly availabilities greater than 100 percent indicate excess capacity. This is an interesting general analysis of the recent past performance of the existing plant. However, it does not provide a frame of reference or specific reliability indices that can be used in a comparative analysis of the present system and other options. The word “availability” in common reliability engineering analysis is typically used to express the probability or percent of time that a component or system is in the operable state where it can perform its intended function. In the case of the steam and chiller systems in the CPP, the concepts of availability and unavailability can be extended to provide the probabilities of various output levels in the two systems resulting from subcomponent failures and other factors such as fuel, water, and electricity supply. The steam and chiller probability models can be combined with the relevant CPP demand models to produce responsive plant reliability indices. These indices can also be used to assess the reliability implications associated with increased or uncertain load demands and the reliability effects of decreased load demands due to building efficiency or technology improvements. The CPP models can also be combined with probabilistic delivery system models to produce AOC building reliability indices. CPP Option 2 uses the concept of cogeneration to meet the electric, steam, and chiller requirements, while Option 3 involves the construction of a new conventional plant using different fuel mixtures. In each case, the ability to serve these functions can be examined using an approach similar to that applied to Option 1 and expressed by similar reliability indices. Similar analyses can be conducted for Primary Options 4 through 10, if required. These options involve advanced technologies that may not have yet matured and been placed in commercial service. In these cases, there may be relatively little or no available reliability data. The basic methodology and resulting indices should, however, be common to all the analyzed options. In summary, the committee recommends that a comprehensive risk analysis of the viable proposed options be performed before a commitment is made to any of them. This should include a clear statement of the governing reliability criteria and include numerical reliability indices that can be used to facilitate the decision-making process. The indices should express the ability of the CPP system to meet the future demands for electricity, heating, and refrigeration; account for the age of the primary and auxiliary equipment; and include the reliability of water, fuel, and grid- supplied electricity. The analyses should include the ability of the CPP to meet the electricity, heating, and refrigeration requirements and the ability of the tunnel configuration to deliver these requirements, including a differential analysis of looped tunnels versus pipe loops in single-tunnel configurations. An evaluation of the risk of cascading failures among steam, chilled water, and other utility lines within the tunnels may also be appropriate. The basic methodology used in evaluating the reliability indices should also be amenable to incorporating renewable fuel alternatives such as solar thermal, solar photovoltaic, and wind power generation in future applications. COMPARATIVE DEMAND AND SUPPLY PROJECTIONS Congress and the AOC’s other clients in the U.S. Capitol Complex need a strategic decision-making tool to aid them in planning and seeking funding for the upgrading of the CPP 22

and the utility distribution system. As part of the holistic approach described in Chapter 2, such a tool needs to present demand and supply projections based on: • The existing demand profile, including historic and forecasted levels of load growth; • An upgraded energy efficiency/conservation effort demand profile (which would entail future modernization projects for the AOC); and • An “optimum” demand profile, where Congress and the AOC could show leadership on the type of energy demand reduction “diet” they are striving for and that would go a long way toward underpinning the need for the selected CPP option. WORKFORCE DEMAND EV ALUATION The operational changes in the CPP and the distribution system that would be produced by the various options would have considerably different impacts on the AOC workforce in terms of training and staffing. For instance, the labor costs and skills to operate and maintain gas-fired boilers, co-generation plants, and coal-fired plants vary significantly. This crucial issue appears not to have been addressed in the 70% Report. As the range of options is narrowed down, differential scenarios for labor costs, training, and staffing for each option should be projected. EXPLORATION OF A WIDER RANGE OF TECHNOLOGIES The 70% Report considers a range of technologies deemed “warrantable” at the present time. Considering that the report addresses a planning horizon up to 25 years (and that public funding generally proceeds at a very slow rate), a long-term study of a wider range of technologies that may become warrantable should be undertaken. This will allow the consideration of successful technologies as the Strategic Long Term Energy Plan is periodically brought up to date. These technologies include, but are not limited to: • Novel fuel mix strategies; • Feasible alternative or renewable fuel options; • Heat recovery in the supply and use of energy; • Improved heat balance through the use of auxiliary drives; • Limiting supply of steam in the summer and satisfying small heating loads through other methods; • Use of superheated steam rather than saturated steam; • Chilled-water storage systems; • Metering technologies for all major plant equipment and energy destinations; • Fully integrated digital controls; • Real-time modeling of plant operations, chilled water and steam hydraulics, and environmental effects; • State-of-the-art tunnel construction methods; • Geothermal heating and cooling; and • Use of solar panels on building roofs and the grounds of the U.S. Capitol Complex. Such a study may evolve into a technology-monitoring program, however informal, for anticipating technologies that may become available in an even longer time span, say 50 to 100 years. 23

BENCHMARKING The committee recommends that the AOC develop a plan for measuring the performance of the CPP complex, using benchmarks for efficiency of operations, environmental compliance achievements, and other measures. A sample benchmarking form is shown in Appendix D. If feasible, the benchmarking of the AOC facilities should be augmented by collecting comparable data from other district energy systems, including those of the General Services Administration and the Washington Navy Y ard, and collecting and implementing best-in-class practices. RESPONSE TO SHORTCOMINGS IDENTIFIED As a general catchall category, the committee recommends that the AOC review the shortcomings identified in Chapter 2 that have not been explicitly addressed as recommendations for additional work, and develop an action plan to address those shortcomings it considers material. 24

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The U.S. Capitol Complex in Washington, D.C., comprises some of the most historic and symbolic buildings in the nation. The steam and chilled water required to heat and cool these buildings and related equipment is generated and distributed by the Capitol Power Plant (CPP) district energy system. Portions of the CPP system are now 50 to 100 years old and require renewal so that reliable utility services can be provided to the U.S. Capitol Complex for the foreseeable future.

Evaluation of Future Strategic and Energy Efficient Options for the U.S. Capitol Power Plant provides comments on an interim set of publicly available consultant-generated options for the delivery of utility services to the U.S. Capitol Complex. The report provides recommendations to bring the interim options to completion, including suggestions for additional analyses, so that the CPP can be best positioned to meet the future strategic and energy efficiency requirements of the U.S. Capitol Complex.

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