ELECTRIC LIGHT AND POWER

Gisborne Times, Volume XXVII, Issue 2626, 7 October 1909, Page 2

ELECTRIC LIGHT AND POWER

THE GISBORNE PROPOSALS. REPORT .BY MESSRS NIVEN AND' CO. Messrs Jas. J. Niven and Co., mechanical. electrical,, and consulting engineers, of Napier, have furnished the following report on the proposals for an electric light and power installation for Gisborne:— “To the Mayor and Councillors of the Borough of Gisborne. —Dear sirs, —Wo herewith have the honor of placing before you our report and estimated cost of an electric light and power installation. “Before proceeding we bog to draw your attention to the fact that this report covers the supuly of electricity to all and sundry who may wish to be connected to, and become users of, the current. and is not limited to the supply of electricity for municipal purposes only, as was the case with the verbal estimate given to your Council by Mr. Jones.

“Extent of Report.—This report covers the estimated demand for electric current for public and private power and heating purposes in the borough of Gisborne, including the current for driving the drainage pumps proposed under Mr. Marcliant’s scheme. It provides for the cost of the supply, delivery and erection of all machinery and accessories necessary for the generation and transmission of current to consumers, and also five sewage pumps and one spare pump for a standby; these are virtualy a portion of the drainage proposals but are taken into consideration here so that the electrical problem may he dealt with as a whole.

“Demand for Current: —The present number of houses in the borough is one thousand six hundred, and according to the average results detained in other towns, one-fourth are connected to the supply, each connection averaging seven points of sixteen candlepower each; therefore, we presume that there will bo in the ease of Gisborne four hundred connections serving 2800 sixteen candle power lamps, or 44,800 candle power in all for private consumption. and 100 50-candle power, or 5000 candle power for street lighting. In addition to the demand for lighting current, there is the sewage pumping plant which we have allowed for at Mr. Marchant's estimate of 20 8.H.P.; in addition. we have allowed that there will be 25 B.H.P. of small motors on simultaneously with the lighting and drainage load. " “Although your town is at present served by an established Gas Company, this fact does not to any extent weigh in opposition to an electrical proposal, in consideration of the facts that the present gas supply is inadequate and that electricity when available creates a demand owing to its inherent advantages, such as are hereunder briefly summarised: — “1. Electric light is odorless and gives off no gaseA deleterious to fabrics or merchandise in close proximity. “2. By its popular and inexpensive adoption for smaller powers, than can conveniently be obtained from gas engines. viz., for watchmakers’ machinery, ventilating fans, horse clippers, dentists’ appliances, sewing rooms, etc., etc., requiring only a fraction of a horse, power. “3. For lighting hotels, halls, stables, factories, restaturants, schools, and such places where the very presence of lucifers is attended with considerable ns*. “4. The ease and small expense with which extensions and alterations can he effected. A main can be run along a street at half the cost of an equal power gas main; therefore one-haif of the support is sufficient to warrant a main being placed aiong a. street, and when once the street is served future additions are easily captured. “Power House. —The power house will be situated upon the corporation section between the railway ends of Cobden and Carnarvon streets.

“ The primary powers to be suction gas and the waste water during the night time from the town mains operating a pelton wheel; as the demand for electricity is inverse to the demand for water, this can be availed of and effect a considerable amount of economy. “The installation of the Pelton wheel naturally increases the expenditure on plant, but this, we consider, will be justified by the economy of running which will be effected, besides acting as a standby in the event of anything interfering with the main generator. “As the generating plant would be capable of producing the maximum demand for current the town could be put on it with the estimated number of connections, and although such a demand would be a most exceptional circumstance, it must bo provided for; provision is made for storing the output beyond the average consumption by the installation of a set of accumulators; this would enable the generators to work on their most efficient load, the surplus being stored. By the foregoing arrangement .the power plants are run upon the most economical basis, and the. accumulators can be stopped, leaving the former to take up the duty of supplying current by discharge. “That the current whrtJfr~*it will be necessary to supply for factory or motor power purposes, being practically only required between the hours of 7 a.m. and 6 p.m., will only represent a fraction of the amount available, leaving a considerable balance available for storage. “This stored electricity will be sufficient for night light demand from 11 p.m. to 7- a.m.. and with the Pelton wheel generator in use the sewage pumps will also be run. “As Mr. Marchant’s drainage report does not give anything definite from which to calculate the amount of pumping that will be necessary, we are not in a position to say that the power house can bo run on two shifts. If. Mr. Marchant lias allowed for the capacity of the pumps to be equal to the discharge of their duty in 16 hours and the size of the sumps in like proportion, then the power-house would need no attendant between tbe hours of 11 p.m. and 7 a.m., which would mean an additional expenditure of about £3OO ioi the necessary equipment to enable the pumps to bo put in and out of circuit at the main switchboard, dispensing with the services of a third engineer, an annual charge of £IBO being saved.

“System of Supply.—The voltage will be 220 and 110 distributed on the three-wire system. This system is especially reoommendable to small towns where it is desired to supply light 'and small powers from one set of generators, the 220 volts being admirable for motion work and the 110 lor lighting. The 110 voltage might have been taken exception to a year or so back, but with tbe advent of the metallic filament lamps, has become popular, the high efficiency of these lamps milking them more economical than the carbon filament lamps which have to bo used on the 220 current for lights under 25 c.p., whereas the metallic filaments are made for 16 c.p. lights on the HO volts, a size more generally useful than the 25’s, which are larger and usually required i<>r private^house lighting, and take, of course, 50 per cent, more current. “Mains for Service.—Herewith we hand you a street map of the borough of Gisborne, indicating by blue filling and red dots tbe streets we propose should be served and the position oi street lamps; in all there are twenty miles of mains; the exact distribution of these would need to be ascertained by actual canvass, the results of which would determine any alterations or additions to the mains we have indicated. “Street lighting would be run upon an independent circuit, and each locality controlled Irom the main switchboard and the consumption registered by motor. “Private lighting and power for motors would bo registered by metet and sold by the Council on a scale, similar to that estimated upon in our assumed output and revenue schedule. “Consumption of Current and Revenue. —Averages taken over, a wide range of installations set this at 150 units per connection per annum. “Street lighting is a definite quantity, and in respect to revenue must be treated as a consumer, a comparison being made between the .present cost of street lighting and that of electricity; the lights being controlled by the main switchboard, the expense of employing lamplighters is eliminated, and moreover the maintenance of electric lamps is less than one-half that of gas lamps. „„ . . ..... “Current for Motors.—This is difficult to ascertain, as the adoption of electricity for this purpose is greatly dependent upon the competing advocates for-either source of power; there are certainly some purposes for which electricity is .admirably suited and for which gas could not be used, and wo have taken the moderate figure of 25 b.h.p. as the likely consumption during lighting hours, during the day about 75 h.p. would he available in addition to the sewerage pumps. “Sewerage Pumps.—The question of power for raising sewerage being now a question of pressing necessity, electrical supply or otherwise, you will bo laced with the expense of equipment and annual expenditure. “Mr Marcliant’s suggestion of automatically operated pumps points to the conclusion that the pumps will he float controlled, and thus being the case may pump at all hours according to the time taken for the pumps to fill, therefore an attendant will need to be in the engine- room constantly ; this would mean that the amalgamation of the two schemes would be a direct saving of about £SOO annually; the greater the amount of dutv which can be thrown upon the one installation of power generators the greater the economy, and the drainage, like the lighting, becomes a consumer, and an important factor m support of a municipal electrical supply. “The value of one electrical unit in comparison to 1000 cubic feet of gas: “Electricity at 6d per unit equals town gas at 3s. Use Quantity Charge Rev-

units nor unit enue £ Private Lighting 60,000 Sd 2000 Street lighting 12,000 Private power 30,000 4d 500 Sewerage power 45,000 3d 562 147,000 £3287 “One hundred and forty-seven thousand units represents the net output, and as the transmission line represents another 10 per cent., we have 161,000 as the gross output. CAPITAL COST. Power-house and pumping stations, buildings, and, equipment, but no land £i ,no 20 miles of street mains and 100 street lamps 5,150 500 meters 1,500 Allowance for interference with telephone wires 250 £14,675 Engineering expenses and contingencies, 10 per cent. ' ... 1,467 £16,142 “This includes a sum of £1250 for drainage pumps and pumping stations, which are an essential portion of the drainage scheme, and have been allowed for by Mr Marchant, and so the v. .vomit must be deducted either from his estimate or from the present one. If this scheme is proceeded with there would be a further deduction to be made from the drainage scheme for the cost of generating plant which lias already been included in the drainage estimate, but which would not under the altered circumstances he necessary. This amount you could ascertain from Mr Marchant. ANNUAL CHARGES.

Interest 4J per cent., and sinking fund -J- per cent, on £16,142 807 Depreciation 5 per cent. ... 807 Maintenance and Renewals 2} per cent. 403 Wages 750 Fuel and Stores 500 £3267 “Maintenance and renewals have been allowed for at the rate of 21 per cent. It is unlikely to be so much as this for the first few years, and later on as it increases there will be an increased revenue to meet it. “Should any further information be desired by you we shall hold ourselves at your service.’’ The report was brought up at the meeting of the Council last night, and was held over for future consideration. Several Councillors expressed their appreciation of the report.