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 balance-of-plant costs can vary widely by application and the degree of competition. The costs in the table reflect realistic estimates for costs for these technologies. The bottom two rows of Table 10.4 are examples of generated power costs. These are effective average power costs achievable by base-load operation of these technologies at the assumed costs for both power-only and CHP applications. The small engine and microturbine technologies are assumed to have an economic life of 10 years; the remaining technologies are assumed to have an economic life of 15 years. The CHP costs differ from the power-only costs by the addition of the heat recovery capital costs and the assumption that the heat recovered replaces that produced by an 80% efficient gas-fired boiler. The gas cost for the analysis was assumed to be $2.50/MM Btu.

Operating costs include both fuel and nonfuel expenses (such as replacement of spark plugs for engines, and replacement of stacks for fuel cells). As discussed above, many of the most efficient technologies can operate on only very pure (expensive) fuels. Per Btu, the cheapest fuel is coal, which can be used only with boiler/steam turbine and Stirling engine CHP applications. The primary economic driver for CHP is production of power at rates that are lower than the utility's delivered price. Figure 10.5 demonstrates graphically how CHP compares with traditional central station generation combined with the necessary transmission and distribution (T&D) to move the power to the load.

By comparison, the cost to produce electricity from a CHP system using an industrial-sized gas turbine, including fuel, capital, and operation and maintenance (O&M) expenses, is less than $0.04/kWh for base-load purposes. This cost compares favorably with a base-load central-station combined-cycle plant at the busbar, even before T&D charges are added in. As shown in Figure 10.5, CHP can also compete against large simple-cycle gas turbine plants for intermediate-load purposes and peaking power once T&D costs are factored in. The T&D charges represented in this exhibit include 7% line losses and a $150/kW investment.

The cost of CHP varies, of course, by application, technology, and grid circumstances, but, as this example illustrates, the economic fundamentals will

TABLE 10.4

CHP Technology Cost and Performance Estimates

Cost/Performance Characteristics Microturbine Gas Engine Gas Engine Gas Turbine Gas Turbine

Performance Size kW

Heat rate (Btu/kWh HHV) Exhaust heat (Btu/kWh) Coolant (Btu/kWh)

Cost

Package cost ($/kW) Heat recovery Emission controls Project management Site & construction Engineering Civil

Labor/installation CEMS

Fuel supply-compressor Interconnect/switchgear Contingency

General contractor markup Bonding/performance Constr. carry charges Basic turnkey cost ($/kW) Maintenance cost ($/kWh)

No heat recovery With heat recovery

50 13,306 4498

$500 $150 $0 $25 $35 $20 $50 $100 $0 $40 $150 $25 $164 $44 $83 $1375 $0.010

100 13,127 1786 3404

$650 $100 $70 $33 $46 $26 $75 $130 $0 $0 $150 $33 $197 $39 $99 $1647 $0.014

800 10,605 1443 2750

$350 $75 $29 $18 $25 $14 $38 $44 $0 $0 $63 $18 $101 $20 $51 $842 $0.011

5000 11,779 5193

$400 $75 $102 $20 $28 $16 $15 $60 $30 $20 $20 $20 $81 $24 $87 $998 $0.003

25,000 10,311 4522

$300 $75 $100 $15 $21 $12 $13 $45 $20 $15 $8 $15 $64 $19 $69 $789 $0.003

Comparative Retail Economics (©/kWh)

Peaking

150 MW Simple Cycle DG (5 MW Gas Turbine)

225 MW Combined Cycle CHP (5 MW Gas Turbine & HRSG)

225 MW Combined Cycle CHP (5 MW Gas Turbine & HRSG)

FIGURE 10.5

Cost of power from on-site CHP versus delivered price. From ONSITE SYCOM Energy Corporation, Market Assessment of CHP in the State of California, draft report to the California Energy Commission, September 1999.

150 MW Simple Cycle DG (5 MW Gas Turbine)

Intermediate

225 MW Combined Cycle CHP (5 MW Gas Turbine & HRSG)

Baseload

225 MW Combined Cycle CHP (5 MW Gas Turbine & HRSG)

FIGURE 10.5

Cost of power from on-site CHP versus delivered price. From ONSITE SYCOM Energy Corporation, Market Assessment of CHP in the State of California, draft report to the California Energy Commission, September 1999.

frequently favor CHP. In a restructured environment, users may also begin to place significant economic value on the standby capability and increased power reliability that CHP can provide, further enhancing the potential economic benefits of on-site CHP.

Figure 10.6 shows the convergence of first cost of many CHP technologies. While it is true that the costs of all the technologies have fallen steadily, Figure 10.6 (which shows the average capital cost of each technology) reveals that some have declined more quickly than others. Technologies just becoming commercial, such as fuel cells and Stirling engines, are much more expensive, but have faster falling costs than those of established technologies.

While smaller technologies were more expensive in the past, with manufacturing advances and material and sensor enhancements this is no longer the case. The ability to use volume manufacturing is now the variable that drives the cost.

Solar Stirling Engine Basics Explained

Solar Stirling Engine Basics Explained

The solar Stirling engine is progressively becoming a viable alternative to solar panels for its higher efficiency. Stirling engines might be the best way to harvest the power provided by the sun. This is an easy-to-understand explanation of how Stirling engines work, the different types, and why they are more efficient than steam engines.

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