« PreviousContinue »
The power authority used Mr. Fowle's transmission line and terminal station estimates for the installation cost of 66-kilovolt, 132kilovolt, and 220-kilovolt circuits. The estimated cost used for the 287-kilovolt circuits was obtained from the cost of the Boulder DamLos Angeles line. The annual charges on the transmission investment have been computed at 74 percent which includes maintenance.
Secondary generating capacity.—Mr. Fowle has discarded the secondary power which is available under the present plans for these hydroelectric developments and insists on measuring their economic status on their dependable power capability at 50 percent load factor. He justifies this measure on the assumption that secondary power has no value, saying:
No credit is given the hydro plant for secondary power because it has been assumed that there is no steam reserve.
If this assumption governed the design, the capacity of the powerhouses and generating units which are associated with these hydrodevelopments on the St. Lawrence River and at Bonneville, Grand Coulee, and Boulder Dam would change as would the projected method of operation. The dams and reservoirs would be unaffected, but the turbine installations would be designed to deliver the available firm power at 50 percent load factor on a dependable basis, over the given range of head. The minor change in design would have little effect on the unit cost of the powerhouse and generating capacity per kilowatt.
For such projects as Boulder Dam, Grand Coulee, and Bonneville, therefore, where the available storage will permit full utilization of the energy at minimum regulated flow, the capacity is installed to develop power on a 50-percent load-factor basis. In the case of Bonneville, however, the low head during flood conditions dictates the amount of turbine capacity to be installed.
The St. Lawrence development is different from the other three major projects. It must operate on the continuous flow of the river, and the firm power is measured by the head and flow available under winter conditions. In this plant the installation would be the same under both the 50- and 80-percent load-factor assumptions. If the load is such that the dependable capacity must serve a system incapable of absorbing St. Lawrence power on its base, much of the available energy will be wasted.
THE ST. LAWRENCE RIVER POWER DEVELOPMENT
The International Rapids section of the St. Lawrence River provides a head of 85 feet between Ogdensburg at the end of the Thousand Island section and the international boundary line.
The development of this section for navigation and power will be a joint enterprise between the United States and Canadian Governments and the State of New York and the Province of Ontario.
Under the pending treaty plan the development will be in two stages, although it can be developed in a single stage. The head water level of the upper stage will be the level of Lake Ontario. This natural reservoir is not counted on for pondage purposes to modify the flow in relation to the load, although in the years to come the present conception may change. The plant is, therefore, treated as a run-ofriver development. Because of the renowned even flow of the St. Lawrence River this limitation is not important at the higher load factors.
The project is a vital link in the Great Lakes to the sea navigation scheme and forms a slack-water pool that will permit ocean navigation of 27-foot draft ? through or over the present International Rapids. In fact, its conception as a link in the navigation scheme antedates, by many years, its conception as a power development.
The ultimate plans call for the installation of 1,640,000 kilowatts equally divided between the State of New York and the Province of Ontario. Thus, New York's share is 820,000 kilowatts of which 575,000 kilowatts is firm continuous power. The Power Authority of the State of New York has been charged with the development of this power for the benefit of the people of the State. The total cost of the project was estimated by the Joint Board of Engineers in 1932 at $274,742,000, of which the United States' share would be $137,371,000. Of this amount, according to an agreement on cost allocation between the United States Engineer Corps and the State power authority, the power development will bear $89,726,000, leaving a balance of $48,371,000 as a charge to navigation.
The allocation of cost between the Federal and State Governments covers an installation of 820,000 kilowatts but does not include interest during construction. The adjusted figure that takes account of a reduced installation necessitated by Mr. Fowle's assumption together with interest during construction has been determined as $89,025,500, as shown below:
Using the steam plant assumptions given previously, and $4 per ton coal, the comparative annual costs of equivalent energy delivered at the load center for St. Lawrence power and modern steam plant generation are computed in detail, for 50 and 80 percent load factors, in the following table:
? Initial draft with provision for future deepening.
St. Lawrence River power development—Comparison of annual costs necessary to
provide equivalent amounts of power and energy at the load center when produced by steam and by hydro
In the case of the St. Lawrence development the same plant is necessary regardless of load factor. Therefore, the total saving over equivalent steam cost at 80 percent load factor, or $8,970,468, is materially greater than the $4,975,468 saving shown for a 50 percent load factor.
The navigational features are estimated to cost $48,371,000. The annual cost of these facilities in the form of interest and amortization charges would amount to $48,371,000 at 4 percent, $2,176,670. This amount is returned twice over by the savings of the power development at 50 percent load factor and four times over by the power development at 80 percent, load factor.
The Bonneville development, on the Columbia River, is located 50 miles upstream from Portland, Oreg. The project will soon be in operation, with two 43,200-kilowatt generators as the initial power installation. The complete development includes a navigation lock and an extensive system of fishways to avoid interference with the annual salmon run.
The limiting features for power development are a reduced head under flood conditions, a minimum flow of 43,000 second-feet, and available storage of 100,000 acre-feet. The mean annual flow is 128,000 second-feet.
The ultimate cost of the project constructed for power and navigation, with 10 generating units of 432,000 kilowatts total capacity, is estimated at $70,040,000, which includes $5,158,000 for a navigation lock.
The following table sets up the installed capacity, dependable capacity, and investment cost as if the project were constructed for power alone as this basis is necessitated by Mr. Fowle's assumptions of 50 percent load factor and no market for secondary power. It also shows the corresponding set-up for 80 percent load-factor operation.
It should be noted that the figures are for the purposes of this analysis only and that while they are based, to a large extent, on the actual development, there are variations necessitated by the assumptions noted above.
The assumption of a cost based on construction for power alone is used only because no official allocation as between power and navigation has been announced. The final allocation, now under consideration by the Federal Power Commission, will unquestionably assign a portion of the cost of dams, reservoirs, and other joint works to the navigation development so that ultimately the cost of the power development will be less than the figures used here.
1 This design would require 16 units, the turbines capable of delivering 30.000 kilowatts under reduced head. The generators would be reduced in size from 43,200 kilowatts, those now installed, to 30,000 kilowatts.
In the following table the cost of Bonneville power delivered to Portland and the surrounding area on the assumptions noted above is
compared with the best possible equivalent steam generation, using fuel oil at $1.10 per barrel.
In the case of this project, the indicated saving of $4,427,760 for operation at base load will be increased to $5,281,710 as the generating capacity is expanded to permit operation at 50 percent load factor.
The navigation lock cost, $5,158,000, is but slightly more than the savings secured from 1 year's operation at 80 percent load factor under these assumptions.
As noted above, when official allocations between navigation and power have been made, the cost of Bonneville power will unquestionably be lower than here shown.
Bonneville power development Comparison of annual costs necessary to provide
equivalent amounts of power and energy at the load center when produced by steam and by hydro
The Grand Coulee Development is located at the headwaters of the Columbia River, 92 miles west of Spokane, Wash., and about 500 miles upstream from Portland, Oreg: The irrigation scheme has a pumping plant, dams, reservoir, and irrigation canals completely divorced from the dam, reservoir, and power plant of the power development.