El Salvador - Hydro-Electric Power Development Project of the Rio Lempa at Chorrera del Guayabo

C-4 A Report on PROPOSED HYDRO- ELECTRIC POWER DEVELOPMENT OF THE RIO LEMPA AT CHORRERA DEL GUAYABO EL SALVADOR, C. A. for The International Bank for Reconstruction and Developm-e-n Washington, D. C. by H. R. Faison Engineering Consultant June 27, 1949  RIO LM1,:PA HYDRO - ELECTRIC PULER PROJECT El Salvador, C, A, SUMs,1hRY 1. El Salvador is the smallest and most densely populated of the Central iumerican republics. Its people are energetic and progressive. Its leadership in the production and exportation of coffee gives it a favorable foreign trade balance. Its industrial development has been seriously retard- ed by a shortage of electric pow-ver and the necessity for importing fuel. Power is not a political question in El Salvador, as all factions seem to be united in the purpose to develop the latent hydro-electric power of the Lempa River to remove the impediment to national progress and security. 2. A plan has been submitted by the Harza Engineering Company, of Chicago, for the ultimate development of 75,000 kilowatts of generating capa- city at the Chorrera del Guayabo site and transmission of the power to all load centers of the country. The reservoir 7vill provide 128,000 acre-feet of effective storage. The Harza report recormmends the initial installation of only 30,000 KV! and delivery of the power through two separate 115,O0C volt transmission lines to the San Salvador load center for wholesale dis- posal to the various utility systems through their existing and proposed interconnections, According to the report, the power market is expected to absorb the entire output of the Guayabo installation, 182,000,000 kilow^vatt- hours per annumi, by the time the plant has been in operation five years. The first cost of this initial development, at June 1949 prices,is estimated -by the Comision Ejecutiva Hidroelectrica del Rio Leripa at $l5,h+87,000, of which tilO,242,000, or about 66% of the total would be required in foreign exchange. However, an additional capital expenditure of P1460,000 for which there is  no breakdowm between foreign and local funds wiould be needed to provide 162,000 acre feet of necessary additional controlled stora:;e in Lake Guija, bringing the total cost of the project to 1sl159h7,000. The cost of power delivered at San Salvador, is estimated at 0.o0080 per khrh by the Comision. 3. The site has been inspected, the revised plans and estimates of June 1949, checked and the potential powier market inivestigated. The site is well adapted to the purpose, but an access road will be needed. The plans and es- timates for the power generation are found to be technically sound and con- servative. A sound modification of the transmission plan would provide needed access to the eastern load centers in the Sani 71U.iguel area, without exceeding the cost estimates. This modification should be made. The protracted scarcity of power has discouraged the establishment and expansion of indiustries to the point wvhere reliable forecasts of the demand under conditions of ample powTer are extremely difficult. in view of the uncertainty, both as to the rate of progress on construction and the rate of maturity of demand, all of the prospective loads within practical reach may be needed to absorb the Rio Lempa output within a reasonable developmental period and definite measures for reaching them should be included in the plan. 4. Investigation of the power market of El Salvador gives convincing evidence of the eventual maturity of ample demand to absorb all of the firm power produced by the initial installation at Guayabo wvithin the accessible areas now served, howviever inadequately, by existing central utility systems. It should not be necessary to reach into the more remote and inaccessible areas to pick up the loads of isolated industrial plants or municipalities, as claimed by opponents of the project. Disposal of the secondary pouer pro- duction is not of major importance in this case. 5. Taking all aspects of the project into consideration, it is the vwriterfs opinion that the Guayabo site on the Lempa River is adapted to lhydro- electric developiment on the scale proposed; that the plans and cost estimates -2_  of the Comision Ejectuvia Hidroelectrica are sound; and that a sufficient market for the power can be built up within a reasonable developmental period to absorb the output of tlhe initial installation of 30,000 kvr at ccrpensatory rates. AUTITP ITY 6. This report is submitted in response to a directive of Air. F. A. Consolo, Loan Officer of the Internatiornal Bank for Reconstruction and Develop- ment and head of the mission to El Salvador, corfirmed by letter of the Per- sonnmel Officer, dated &ay 17, 1949, reading in part as folloyw7s: To 1.r, H. R. Faison 1220 S. Geo. iMason Drive Arlington, Virginia 'Dear hr. Faison: This will confirm yoLr appointment as Engineering Consultant to the International Bank for Reconstruction and Development.. You will accompany the Bankts mission to El Salvador for a period of one week beginning approximately Iffay 23, 1919. You are hereby designated a Consultant to the Bank and will be subject to the established policies of the Bank wYith respect to consultants in travel status. As a consultant of the Bank, yyou will be under the sup rvision of the Loan D-irector a-nd while on the mission to El Salvador, you wfill report directly to the head of the mission, ihr. F. A. Consolo. ....... ..*........ Sincerely yours, (Sgd) UTichael L. Lejeune Personnel Officer". The objective of the mission so far as it concerned the engineering consultant was an examination of the Government-sponsored project for a hydro-electric development on the Rio Lempa at thwe Chorrera del Guayabo site and an, investi, gation of the prospective market for the power. SOURCES OF INFOP-IATION 7. The report of the Harza Engineering Company, dated November 17, 1948, supplemented by revised estimate sheets dated June 20, 1949, form the principal basis of this report, The report of George A. Fleming of the U.S. Bureau of Reclamation, dated July 1948, has also been consulted for hydrological data on - 3-  the Lempa River. The 1948 report of the U.S. Tariff Commission on I,ining and M'anufacturing Industries in -1 Salvador has been consulted for powe4r market statistics. Brief of the Cia. de LiLnwmbrado Electrico de San Salvador (herein- after called C.A.ES.S.), dated MTay 21, 19L9, embodying adverse notes and co.-;- ments on the economics of the Rio Lempa project, has been considered in arriv- ing at the conclusions set forth herein. A forecast of future receipts and dis- bursements of the Comision fjecutiva Hidroelectrica de' Rio Lempa, submitted bv its president under date of June 20, 1949, is given in the tables annexed hereto as an appendix followTing paragraph 39, in w,rhich paragraph is submitted a prospective balance sheet giving,in the writerts opinion, a more realistic estimate. Conferences w;ere held w.ith the Consejo de Gobierno Revolucionario de El Salvador, with the president of the Central Reserve Bank of El Saivador,.mem- bers of the Comision Ejecutiva Hidroelectrica del Rio Lempa, members of thle Com- ision Nacional de Electricidad, the Secretary of the iiinistry ofC Public Y`orks, the President of the Harza Engineering Company, the General t.anager of the inter- national Railways of Central America, the president of the National Association of Coffee Producers, the managers of the electric utility systei.]s of San Sal-. vador, Santa Ana, San Luis, Santa Tecla, Sonsonate, Cucumaca-an, AThaachapan and Santiago de lUlaria, the alcaldes of Santa Ana and Coatepeque. Pertinent records and statistics of the Comision iJacional de Electricidad, the Ministry of Developmaent and Public 'orks, and the Directory General of Statistics wrere examined and the results of analrsis included in this report, Visits of in- ., spection were made to the Poza del Silencio and Chorrera del Guayabo sites on the Lempa River; to the Cucumacayan hydro-electric pla t; to the Bolulu and Juayua hydro-electric developments under construction; to the Agua Caliente steam plant and the Santa Ana and Coatepeque distributing stations. Visits were also made to the municipalities of San Martin, Suchitoto, Colon, Sonsonate, Arm.enia, Szalco, Nahuizalco and Acajutla. - 4 -  EL SALVADOR 8. El Salvador, :mallest of the Central American republics, has an area of about 9,000 square miles (liarza). A mountain range separates the count.r from Guatemala on the west and Honduras on the north and east. M"ost of the area lies in the central plateau separated from the Pacific Ocean on the south by a narrow strip of coastal plain. Of the several rivers th,at traverse E-1 Salvador, the Rio Lempa, described more fullY in paragraph No. 17, is the largest ard most important. The climate is tropical, the y-early seasons being about equally divided between wet and dry. Rainfall averages bet-wveen 70 and 75 inches a year concentrated in the wet season, There are no knovwn depo- sits of coal or petroleum, There is some mining of gold and silver in the northeastern section, and ample deposits of limestone suitable for cement manufacture in the northwvestern corner, Other known mineral deposits are small and relatively inaccessible. 9. The population, officially estimated in 19h8 at 2,122 71, is slightly more concentrated in the west central portion of the plateau, includ- ing the metropolitan area of the national capital, numbering about 165,000 urban residents, and Santa Ana, the second largest city with an estimated urban population of 104,000. The people are hard-working and the local unskilled ' labor supply is generally plentiful. The activities of the popula.tion are predominantly agricultural, the production aid export of a superior quality of coffee dominating the national economy. The paved Pan Amnerican Highway aid one narrow-gauge railroad traverse the country lengthwvise, the latter con- necting the ports of Puerto Barrios, Guatemala, and La Union, El Salvador. Another narrowi-gauge railroad connects the port of Acajutla aith the San Salvador area. Considerable progress has been made toward a system of roads connecting the capitals of the various departments, A modern airport near San Salvador is a regular stop on the international ainrays between the United States and the Panama Canal Zone. -5-  10. Comparatively speaking, there are few raw materials and a sorme- what limited rmarket for the products of heavy industry, There is a tendency toward healthy, development in the form of scattered plants for processing agricultural products and s-mall factories producing light consurmers' goods for the domestic market. The growth of these industries has been hampered by the necessity of importing basic materials, fuel, equipment, machinery, re- pair parts and the skill necessary to operate and maintain them. lost import- ant of all, normal growth has been held at a standstill through the shortage of electric power. The favorable export-import balance aid sound dollar posi- tion of the country, as a result of the demand for Salvadorean coffee on the Ui.S;. market, should be conducive to expanded industrial development vrhen the scarcity of power is relieved. P?0.!ER 'iIIST0XR 11 The oldest hydro-electric unit in El Salvador bears the date 1908 on the name plate, and the oldest diesel-powered unit, that of 1912. The com- paratively large number of power plants of various sorts, (about 200), scat- tered throughout the country bear witness to the inadequacy of such central uti- lity services as now exist. Approximnately 75 percent of the 20,000 horsepower represented in these scattered plants is in direct drive stear- prime movers for processing agricultural products, using sugar cane bagasse or coffee berry refuse along with forest cover trimmings for fuel. From 1916 to 1924, expansion in street lighting and ice making gave rise to the formation of central utility services which depended mainly upon small local hydro-electric develop.ents without much pondage and later upon diesel motors, both types of European make. In 1936, the Comision Nacional de Eleotricidad was established to re- gulate power distribution, keep statistics on production and initiate stream- gauging of the Lempa River at the dovmstream La Pintada site. English engineers -6  had first investigated the pamrer possibilities of Rio Lempa in 1913, but little action -was taken until the second world -rwar boom brought recogni- tion of the stringent power shortage and the need for remedial measures, This was also a period of accentuated scarcity of materials, equipmenat and technical skills which, under the sharply increased demand for power resulted in sagging voltage, outages and shut-offs, and the strLct rationing or the available powrer supply by the I'lational Electricity Commission. 12. In 19h5, the Government of El Salvador appointed the Comision Ejecutiva Hidroelectrica del Plio Lempa to determine the best way to utilize that river to increase the national supply of electric power. That Comision took immediate steps to initiate a control traverse and further stream-gauging along the river; obtained the services of uKr. Geor-ge A. Fleming, engineer viith the U.S. Bureau of Reclamation to make hydrological studies; instituted a sur- vey of Lake Guija on the headwaters, and on lay 12, 1947, retained the Harza Engineering of Chicago, Illinois, to survey and report upon the physical and economic possibilities of developing the intermediate Chorrera del G-uayabo and Poza del Silencio sites, EXISTING POVTER POSITION 13, The acute scarc4ty of electric power for all familiar uses is borne in upon the casual visitor to the various municipalities of El Salvador. Even in the capital of the Republic, water, light, refrigeration, elevator and tele- phone services were recently available only under rigid restrictions and tern- porary suspensions to conserve energy are frequent during tt"off" hours ot only have contracts for additional powrer been unobtainable for several yews.,but the maintenance of voltage for existing service had, according to the Comision Na- ciornal de Electricidad, fallen so far below efficient levels that only one-half of the additional 5,000 kilowatts of steem-produced generating capacity recently installed at Agua Caliente (San Salvador) could be rationed among the most -7-  urgent domestic and coTmercial loads, the balance being dravrn upon to stanizar- dize the service already obligated. This condition is aggravated for tlhe majority of users through the practice of restoring voltage by those customers fortunate enough to have booster equipment. 1h. The total power capacity of El Salvador in 1949 corresponds to about 33,500 Kw of which 1B,X50 Ibi is supplied by utility systems and the balance by more than 200 unconnected private industrial plants largely through direct-drive diesel and steam engines. There is also under construction 1,850 Kw of additional electric utility capacity in the central-iwfestern section of the country and some 3I500 horsepower of prime movers, both electric and direct-dxive, on order or under erection throughout the country. The distri- bution of this existing capacity is given in the followring table: .~~~~~~~5  Table 1 SUL~ALkIY OF 1949 PUBLIC UTILITY C`.PACITY IN KILOAII,O,.TTS SYSTEM INiSTALLED CAPACITY Under Hydro Diesel Steam i Total Constructior. Cia de Alumbrado Electrico (San Salvador) 3,320 2,700 5,000 11,020 (Coatepeque) 240 240 (Zacatecoluca) 60 30 90 (San Vicente) 120 120 (San liguel) 280 200 4ao Total C.A.-.S.S. 4,020 2,930 5,000 11,950 iielendez Lviills 508 200 708 Interiamo, Gonzales & Cia (Cucumacayan) 2,260 2,260 Cia de Luz Electrica 1,370 1,000 2>370 1,250 (de Santa Ana) Cia de Luz Liectrica 330 330 600 (de Sonsonate) Cia de Luz Electrica 175 175 (de Ahuachapan) !Leardi Hrmnos. (Berlin) 390 390 Mungia (Usulutan) 40 Lo Manzano (Chalatenango) 20 30 50 i&unic ipal La Libertad 60 60 La Union 35 35 P,I1etapan 18 18 Minor Plants 12 52 64 Total 9,125 4,325 5,000 18,450 1,8r0 The total production of~ the existing utility plants vw-as 42,200,00O kilolwatt- hours in 1946. The Comision Nacional de Electricidad estLiates the probable production in 1949 with the addition of 5,000 ITi, of steam power rece-ntly installed by the C.A.E.S.S. and the 600 I,J installed by the C.L.E.S.A., at 68,100,000 K. Consumers throughout El Salvador are numbered at 37,146, of which only 7,456 take metered service. The major public utility in point of capacity and production as _ 9-  showmn in Table 1 is the Cia de Alunbrado Electrico de San Salvador, a subsidiary of the Interrnational Power Co., Ltd., of lontreal, Canada. This company has connected, or is in the process of connecting its $an Salvador system vdth those of Cojutepeque, Zacatecoluca and San Vicente, by 22,000 volt transmission lines and is served from the Cucumacayan hydro plant through a 35,000 volt line. This latiter system is interconnected with the Santa Ana system by a 35,000 volt line and with the Sonsonate area by a 13,000 volt line. It is also planned to bring the Ahuachapan system into this grid at an early date by a 13,000 volt line. Thus thle ceintral and wvestern portion of the central plateau, cor-prising one-tUrd of the area and approximately half the population is now served, although in- adequately, by an interconnected utility system. 15. This is not truae at present of the eastern portion of the country which has 7 utility systems as yet unconnected with each other, includiiig the important commercial center of San Mliguel, with its 480 k-a utility system and its textile mill plant which -uill have a capacity of 1590 k-i when the installa- tion is completed. At the time the Harza report was made the Cia de klumbrado (C.k.E.S.S.) planned an additional steam installation of 7s500 kw, w;ith a pro- posed station in San "Tiguel, but owing apparently to a lack of agreement be- tween this company and the Niational Electricity Commnission on its application for increased rates, the projected additional steam installation is being heLd in abeyance. 16. The so-called Regalado system, er:bracing the developrents of Sorsonate and Santa Ana, vith a combined capacity of about 5,000 kwnf is thle next largest utility company operating in El Salvador. It ovwns highly efficient hydro-electxEc plants at Cucumacayan and San Luis totalling 4,000 IvT capacity and is adding 1,250 1n-. in hydro capacity within the next year, in addition to the acquisition of the 175 kvy Ahuachapan system. The Regalado system is bound by a 25-year con- tract to furnish 900I kwJ of prime power,increased to 1500 kwYT ahen available,to the C.A.E.S.S. at San Salvador.The arrangement is conceded by both parties to be - 10 -  kilowatt-hours for the initial development alone, and 202,000,000 kwh with Guija storage. 19. The duration curves shoni in the Harza report indicate that the Guayabo reservoir without the Lake Guija development will provide sufficient -* storage for a minimum continuous output of 17,000 kr; for an output of 21,000 kw for 92 per cent of the tim.e, and for the full capacity output of the 30,000 kw installation 52 per cent of the tine, at 50 per cent load factor. However, with thle provision of the Guija development stored water released therefrorm during the dry season w;.ould be rmore than adeauate to build up the full poten- * tialitry of Guayabo ard to prime the output of the initial 30,000 .kw installa- tion throughout the entire year at 50 per cent load factor, producing appro- ximately 132,000,000 k-vh of firm power at Sarn Salvador, thus increasing the saleability of the power and thereby augmenting the income frrom the project. The balance of the estimated 182,000,000 kwh would be produced during the wet season. Two high tension transmission lines from Guayaoo to San Salvador at 11,000 volts are planned for the initial stage. 20. The Guayabo site, some 38 miles northeast of San Salvador, is but little slDrt of ideal for a gravity-type concrete dam.J Firmly bedded basaltic ' agglormerate forms an excellent foundation and steep natural abutments about 320 feet apart at spillway crest-gate level, (580 feet above mean sea level)., A good sand and gravel bed and adequate quarry of igneous rock suitable for concrete aogregate lie a scant 12 miles upstream. A site for a by-pass spill-gay 656 feet long in a nearby saddle can be utilized to limit flood discharge over the dam to safe heights, The gorge opens out dowi,nstream decreasing the rise in tailwater level during floods. The average working head w4l be 172 feet, with a seasonal draw-do m of 33 feet. Com-puted annual evaporation will cut - 13 -  the useful net storage to 128,000 acre-feet, Twithout count-ng the net storage of 162,000 acre-feet that can be obtained from Lake Guija. Turbine capacity will limit the output of the two initial units 52 per cent of the time and the flow of the river, 40 per cent of the time. Loss of head due to excessive draft on the reservoir, without Lake Guija storage would appreciably affect the output for as much as 8 per cent of the year at the ends of unusually dry seasons. The Harza report computes the life of the Guayabo reservoir before serious curtailment of useful storage by sedimentation at about 90 years. It is recognized that basic observations upon lwhich these computations rwere made did not cover a suff'iciently representative period to be entirely conclusive, and fears have been expressed by some of the local engineers of possible ex- cessive silting from a super-flood of the magnitude of that of 1934 although valves provided in the dam iwill clear some of the sediment. The proposed m.easures to utilize the storage potentialities of Lake Guija also take or. added signi- ficance as insurance against such an eventuality. Altogether, however, the Harza Engineering Companyts survey has been thorough, the designs wrell adapted to the site and tlhe purposes of development, and the cost estimates conser- vative. ' 'CCOST EST7'TES 21. The cost of the initial step in the proposed development of the Guayabo site (excluding the cost of Lake Guija storage) in terms of total, local and foreign currency requirements over the prospective t'hree-irear con- struction period and including suitable provision for ultina te enlargermernt, is estimated by the Comision Ejeoutiva Hidroelectrica as of June 20, 1949, in the three tables iwhich follow on succeeding pages. Of the total cost of rl,15,487,000, almost 66% (;10,242,000) wvill be required in foreign currencies. - 114 -  TA1,.BLE "Al DISTJIBUTI.ON OF TOTAL COST, GUAYABO DA71.N (in iho-asand U.S. Dollars) Item 1946-48 1949 1950 1951 1952 Total DAI AND TIRLA,1SKISSION Dam Gravity Dam 1,80oo 2,700 936 5,436 Auxiliary Spillway) - - 150 61 211 Dikes Intake Structures - 400 395 - 795 Tunnels and Penstocks - 160 260 97 517 Powerhouse Substructure - 244 40 -- 644 Superstructure - - 15o 152 302 II tt Equipment - 300 1,000 200 1,500 Equipment, Accessories - 252 - - 252 Substation - - 420 - 420 Construction Rds. & Bldgs. - 75 - - 75 it Bridge - 150 50 - 200 TOTAL NDAN 3,381 5,525 1,446 10o, 352 Contingencies 338 553 144 1,035 Transmission 200 800 1,400 2,400 TOTAL DIA" ANTD TRANS1IESSION 3,919 6,878 2,990 13,787 OTHiR COSTS Preliminary and Engineering 78 120 452 225 1259 1,000 Land, Flowage & Water Rights - - 100 - - 100 General Property - - 160 20 20 200 Wlorking Capital - - - - 0oo 4oo TOTAL OTHER 78 120 712 245 545 1,700 TOTAL COST 78 120 4,631 7,123 3,535 15,487 - 15 -  TABLE "1B'' DISTRIBUTJION OF LOC.AL CURBRE7NC`Y COST, GUAYABO DAM (In 'Ihousand U.S. Dollars) Item 1946-1948 1949 1950 1251 1952 Total DAM ANT.\D TP.NSMLICSTON Dam Gravity Dan - 700 900 336 1,936 Auxiliary Spillway) - 50 21 71 Dikes Intake Structures - 150 95 - 245 Tunnels and Penstocks - 60 100 20 180 Powerhouse Substructure - 94 100 - 194 Superstructure - - 20 12 32 Equipment - - - - Equinment, Access. - 152 - - 152 Substation - - - - Construction Rds. & Bldgs. - 50 - - 50 ti Bridge - 50 10 - 60 TOTAL LDA - 1,256 I,275 379 2,920 Contingencies 238 385 99 725 Transmission 50 200 350 600 TCTAL DIMUi AMD TRAITSiafSSION 1,544 1,863 838 4,245 0T1FR COSTS Preliminary and Enginc-ering 26 60 64 75 75 300 Land, Flowage & Water nights 100 - - 100 General Prouerty 160 20 20 200 lTiorking Capital - L00 400 TOTAL OTHER 26 60 324 95 495 1,000 TOUL COST 26 60 1,868 1,958 1,333 5,245 - 16 _  TABULT "C" DISTRIBUTION OF FOP.-17.IGIN CUR.7N,1NiCY COST, GUAYABO D.AL.!i In iLoasand fTJ. T olJars Item 1946-1948 1949 1950 1951 1952 Total DAI. A"ID TRANSI-'ISSION Dam Gravity Dam - 1,100 1,800 600 3,500 Auxiliary Spillway) - -