Publication: Electrical World
New York, NY, United States
Hydro-Electric Development in Maine.
At a meeting of the Massachusetts Street Railway Association held in Boston on Feb. 10, Mr. John R. Graham, president of the Bangor Railway & Electric Company, Bangor, Maine, read a paper entitled "The Electrification of a Part of the State of Maine." In the course of his address special consideration was paid to the recent important hydro-electric developments in Maine.
The history of the Bar Harbor & Union River Power Company is typical of the usual course of hydro-electric developments in Maine. The project of combining the water powers in use on the Union River, at Ellsworth, Maine, had been in mind for about 30 years. The originator of the plan finally succeeded in interesting a fellow townsman sufficiently to employ an engineer to investigate the feasibility of the project. The report was favorable, and plans were drawn for the installation. As the Union River is in a somewhat remote portion of the country, had never been mapped by the government and was so little known that the numerous engineers who investigated the project for various capitalists could not be convinced that sufficient power was available, it was difficult to secure the money needed to develop the work. Finally, in 1907, the Bangor Railway & Electric Company interests decided to buy the property. Although the project was condemned by many engineers, it is a fact that during the past year, when water was the lowest on record, the Ellsworth plant was about the only plant in Maine which had an abundant supply of water. With the enlistment of capital the third step was completed, but much remained to be done. Detailed plans were to he drawn, contracts for construction were to be let, property rights to he obtained, highways to be relocated, buildings were to be moved from the area to be flooded, and new bridges had to be erected. Actual construction was begun on March 1, 1907. The first three months were occupied in removing sawmills with their accompanying dams, which had occupied the site of the plant for many years, installing the contractors' plant necessary for the rapid and economical construction of the work, and in blasting out the rock required to be removed from the tailrace and canal. On June 9, 1907, the actual construction of the dam was begun, and the work proceeded so rapidly that on Jan. 1, 1908, the plant was practically completed.
The Ellsworth dam is located between two granite bluffs rising 100 ft. above the bed of the river. The dam is of the Ambursen steel and concrete construction, rising 71 ft. above the river bed, and is probably the highest dam in New England. The power house is built of concrete blocks. At one side of the building is a heavy concrete wall forming one side of a canal, the latter having been blasted out of a solid ledge and serving as a forebay from which the water is drawn through penstocks 8 ft. in diameter, which carry the water to the turbines located 60 ft. below. At intervals of 15 ft. in the interior of the dam, which is hollow, buttresses of concrete were built parallel to the flow of the stream. These buttresses were built A-shaped, being about 100 ft. wide at the base and from 60 ft. to 71 ft. high. They vary from 16 in. in thickness at the top to 36 in. at the base, and are stiffened by concrete beams reinforced by steel bars placed at right angles to the flow of the stream. These buttresses form the supports of a deck or slab of reinforced concrete extending from buttress to buttress entirely across the stream. The deck ranges from 36 in. in thickness at the bottom to 18 in. near the crest. This is the highest dam of this type that has so far been built, and is to all indications thoroughly satisfactory.
The Bar Harbor company has secured practically the control of the whole river with its water supply. The Union River drains a basin covering 525 sq. miles, included in which is a lake area of 40 sq. miles. The annual rainfall of the region is about 34 in. The average temperature is about 42 deg., and as the amount of evaporation is governed by the temperature, this low average is of great value, leaving as it does a large amount of water for the run-off. It is a fact that at no point except in North China does the isotherm of 42 deg. approach so near the equator. Within two miles of the present power station it is possible to construct another dam, thereby raising the present level of the river at that point by about is ft. and forming a reservoir which will impound 5,000,000,000 cu. ft. of water that can be used at the power plant at a head of 6o ft. This arrangement would insure about m000 hp continuously.
The present development is for 1500 kw. The power station contains two units; one consists of two S. Morgan Smith turbines rated at 1700 hp and directly connected on a horizontal shaft to a 1000-kw, 2300-volt, three-phase, 60-cycle General Electric alternator; the other consists of two turbines rated at 850 hp, driving a 500-kw generator. The e.m.f. is increased to 33,000 volts for the transmission of energy to Bar Harbor and Bangor. One of the novel futures of the work is that the transformers and all of the high-tension apparatus are placed in one of the hollow compartments of the dam, in what would otherwise be wasted space.
Energy is transmitted for operating the trolley cars of Bangor, both in passenger and freight service; street lighting in Bangor, Ellsworth and Bar Harbor, industrial service and pumping water for many communities. At Ellsworth, a town of 5000 inhabitants, the company lights the streets and houses, furnishes energy to several local industries, and owns and operates the local water supply system. The energy for the local service is transmitted at the generator voltage of 2300, the e.m.f. being decreased to 500 volts for the motor service and 105 volts for lighting.
The Bar Harbor transmission line is 21 miles long. Use is made of cedar poles placed partly on the highways and partly on private right of way purchased by the company. The three conductors are placed in the form of an equilateral triangle, with the apex on top of the pole, and the two lower wires near the opposite ends of a cross-arm 7 ft. long, the spacing of the wires being 4 ft The insulators are of brown porcelain, of the Locke type, having double petticoats; they are carried by steel pins covered with porcelain sleeves to guard against short-circuit from the conductors to the pin.
Use is made of six-strand aluminum wire which, thus far, has been very satisfactory. Aluminum as a conductor, in the company's experience, seems to have taken the place of copper perfectly and has the advantages of lower first cost and considerable decrease in the cost of erection.
It was necessary to cross an arm of the sea, called Mt. Desert Narrows, between Ellsworth and Bar Harbor. These are navigable waters and the government authorities required that the lowest wires should be at a minimum height of 125 ft. above mean tide. This action necessitated the erection of two steel towers 160 ft. high and about 900 ft. apart. These towers are erected on opposite shores, on concrete foundations, and carry three conductors of No. 2-0 hard-drawn copper, strung with a sag of 40 ft. at the center of the span. At the shore ends of the spans, and 400 ft. distant, the wires are dead-ended on steel poles 60 ft. high, these being strongly guyed with galvanized steel cables 3/4 in. in diameter. At the Bar Harbor end of the line the e.m.f. is decreased to a value suitable for local lighting and industrial service, a portion of the energy, however, being sent II miles farther to light Northeast Harbor, the transmission potential being 10,000 volts.
From the plant at Ellsworth a line similar to that going to Bar Harbor is extended to Veazie, the company's present waterpower plant, a distance of 25 miles, where the transmitted energy is used—in times of low water or when anchor ice is giving trouble—to assist in operating the trolley system of Bangor and to carry the Bangor lamp and motor load. At Veazie the company owns a 2500-hp steam plant, and at Bar Harbor one of 1200 hp. These plants are so interconnected that in case of a breakdown at Ellsworth energy can be sent to Ellsworth or Bar Harbor or to Bangor, as needed. The new dam has had no trouble from anchor ice on account of the great depth of the pond.
There are five principal lake chains in Maine connected by rivers and discharging into main channels which deliver into the ocean. These are the Umbagog-Rangeley series, with an area of about 90 sq. miles, drained by the Androscoggin River; the Moosehead series, forming the headwaters of the Kennebec River; the Penobscot series the Schoodic Lakes, drained by the St. Croix River, and the headwaters and stream of the St. John River. The topography of Maine tends to equalize the rainfall over the watersheds, and the effect of the heavy forests also tends to equalize the yearly flow of the streams. The lakes are most valuable at times of low river stages, tending to preserve the regularity of flow and to avoid the need of auxiliary steam plants. Though much has been done to control the storage water in the lakes of Maine and thereby increase the dry-weather flow of the streams, co-operative development is most desirable, such as has taken place on the Presumpscott and Cobbossecconte rivers from artificial storage.
The Penobscot has the largest drainage area of all the rivers in Maine, or about 8500 sq. miles, or more than one-fourth of the State. An area of 800 sq. miles of the river basin discharges its waters into the main river below the lowest water power at Bangor.
Several hydro-electric developments have been made in the Penobscot within 14 miles of Bangor, passing upstream, the river dropping about 88 ft. in that distance. Dams are built across the main channel at five points, using an aggregate fall of from 55 ft. to 60 ft. There are also three dams on Stillwater branch, Stillwater and Orono. At Montague a 20-ft. fall is utilized. At Veazie, on the Penobscot, there are several small falls where the working head varies from 7 ft. to 11 ft. Under the larger head the wheels at present installed furnish 1653 hp, 1500 hp being used for electricity and the balance for pumps to furnish the water supply for the towns of Veazie and Brewer. There is in use a steam plant of the same rating as the turbines, for some steam power is required in the summer. The electricity developed at this station is utilized for street lighting at Brewer, for commercial arc and incandescent lighting in Bangor, and for trolley service in Bangor and to Winterport and Old Town.
The Kennebec River basin extends from the Canada line to the ocean. It is iso miles long, varying from 5o to So miles in width, and embraces a total area of 6330 sq. miles. The general elevation is less than that of the Androscoggin basin. Moosehead Lake, with an area of 120 sq. miles, forms about one third the entire lake surface in this basin. The sources of the streams forming the Kennebec are at an elevation of from 1800 ft. to 3000 ft. There is a mean descent of about 9.1 ft. per mile, throughout the water-power portion of the river.
The seven waterfalls at present utilized are between Carritunk Falls and Augusta and aggregate in rating 24,000 hp; they utilize about 142 ft. of the total fall of 354 ft. between those points, The International Paper Company uses 3500 hp at Carritunk Falls under a head of 30 ft. At Madison during normal stages of the river a head of 20 ft. is utilized, the power being at present about 2250 kw. The larger consumers at Madison arc paper companies, textile companies and a local pumping station. The Great Northern Paper Company uses about 1200 hp in electrical service at all times.
Only a small part of the power available at Madison is employed as yet. The Great Northern Paper Company has made plans for utilizing two falls just below the town. One is a 20-ft. fall, to he used exclusively for electrical service. A dam about 640 ft. long will be built and sufficient apparatus will be installed to generate 3000 hp. The other fall will be used mechanically for grinding wood pulp.
At Skowhegan a 17-ft. fall is utilized, giving 5500 hp. About 750 hp is used exclusively for electrical service. Energy is used by grist, saw, planing and woolen mills, sash and blind, and scythe factories. At Augusta, the head of tide water, a crib darn 17 it. high and 950 ft. long has been constructed, impounding water 17 miles upstream to Waterville. On the east bank of the river the Cushnoc Paper Company and the Kennebec Light & Heat Company use 1500 hp, the latter company furnishing the municipal lighting for Augusta, Gardiner, Hallowell and Togus. The fall is affected somewhat by the tide.
On the Androscoggin River at Brunswick about 1000 hp is used by the Brunswick Electric Light Company for service in Brunswick and Topsham. No lack of water at this privilege has ever been experienced. At Lewiston the large cotton mills and the city employ water power extensively, the rates for the older companies being by lease, from $5 per hp-year to $12.50 for the later corners. These prices apply to the net power on the shaft, assuming the latter to he 75 per cent of the gross power of a given fall and quantity of water, The mills run 60 hours a week, and in some cases daily measurements are made of the power. Auxiliary steam power is somewhat used.
At Deer Rips a dam is being constructed to make available a fall of 28 ft. for electric power in Lewiston. At the Crooked Rips, opposite the town of Turner, there is a dam, built some years ago and giving a moderate fall, but now serving no useful purpose. At Livermore Falls 500 hp is developed for electric lighting and 2500 hp for mill work. The head realized is about 16 ft., but the rapids extending downstream indicate that an additional fall of about 25 ft. is available.
Mr. Graham stated that there are many other water powers in use for both mechanical and electrical service, and quoted others of the former type in conclusion. The electric developments cited were those with which he is in close touch.