Page 16 RAIN May 1978 Net ~nergy An analysis of the energy required·to create the WECS components is also summarized in Table 1. The total represents all the energy, in kWh equivalent, consumed to make the WECS, from mine shaft to readiness for the first breeze. This inclu?es all the e_nergy consumed in the mining, smelting, allo):ing_, processm~, transporting, m~chining, finishing and fabncating the vanous component parts.. This also includes the energy in the explosives, fuels used, chemicals, electric power and electrode consumption. All transportation of the ~o_ods by grader, tractor, conveyor, barge, railroad and truck 1s included. For example, the diesel truck transport is at the rate·of .7 kWh/ton-mile. All of the energy consumed was converted to kWh for comparison and includes losses and· inefficiencies in the machinery and processes. Transport to the site, site and foundation preparation, and final erection of the prefabricated components are all included in the energy cost. • The en.ergy cost analysis indicates that, to make them, large WECS consume 4.8 to 7 kWh per installed pound. The segmented aluminum blades are the rnost energy intensive COlll:~onents at 26. 7 to 30. 7 kWh/lb. The fabrication energy cost 1s calculated as a percentage of the material's energy basis by weight. For the turbine/generator components, it is 34.6%, tower 25% and foundation 17.3%. While the components would have to be hauled hundreds of miles from the manufa~turer, the foundation materials could be obtained nearby using local contract construction firms. The total energy cost of various WECS designed for different w_ind environments is shown in Figure 1. • When compared to the output of a WECS over its projected 30-year life, the resulting energy pay-back ratio is 48 to 1! It takes just 7-1/2 months for a 4 MW, 367' diameter WECS operating in a wind n':'.ironment averaging 7 mis to return all the energy used to make it! Even at a WECS capacity factor of .2 at a low wind speed site, the ratio is 18: 1. The WECS •rating and the mean wind speed have considerable effect on the pay,back ratio. Going from a 1 MW to a 4 MW WECS results in a 40 to 50% energy pay-bark ratio improvement, while using sites where'the V=9 mis instead of 5 mis results in an approxi111ately 70% improvement. The lowest pay-back ratio WECS design w~s the 1 MW, V=5 mis unit at 23.4: 1. 1000 KW " v-s The cumulative national effect, of 100 units 1delivered in 1980 and rising thereafter to 8100 WECS/yr. in 1986, is shown in Figure 2. .four scenarios are illustrated with national electric .demands rising at 6. 5 and 4.4%lyr. and fossil fuel cost escalations of 10 and 4%/yr. for high and low respectively, starting in 1975. Note that in 1984, 7600 WECS would be in place generating 105.5 billiop kWh. The resulting fuel savings would be equal to 187 million barrels of oil in 1984 alone. New Jobs The production of large WECS affects the labor market, both in the manufacturing centers and at the regional level. The gearing up for production and delivery of 100 WECS in 1980 would employ approximately 80,000 people. As annual production and installation rose to 8000 units per year, the direct ~abor_r~quired ~ould correspond to 645,900 people in the ~dustnes working on t~e WECS itself. For example, a 4 MW, V=7 mis WECS would require about 159,500 direct labor hours. The heavy manufacturing would account for 89.4% of the direct la?or, with the rema'inder of the effort being done at the regional and local level. Additional employment would also occur in the firms supplying the basic materials for the WECS construction, meteornlogical site investigation,· utility electrical tie-in, and peri'odic maintenance. In the manufacturing industry, approximately 25% additional man-hours would be required for management and engineering support. The $17.8 billion dollars spent on 8100 WECS would filter ?own through _the natio~al economy increasing the level of mcome, of savings, and the consumption of unrelated goods and services. • Regionai labor impacts resulting from the deployment of large WECS.cover many occupations. The transportation of the WECS i:naterials to the site would require the use of heavy trucking services. The concrete foundation would be constructed from locally available sand,and gravel and with the services of local contract construction outfits. These same outfits would prepare the site by cutting roadways, excavation and finally erecting the WEC~ compo'nents. .Local labor amounting to 16,900 direct man-hours would be expended on each unit installed. Accor.ding!y, it would take 771 local crews of 50 each to install 8100 units in a year, a total of 38,550 jobs. 4000 KW v=s -V •.7 WTG WEIGHT· COST- WEIGHT- COST· WEIGHT- COST· 1, 1: COMPONENT POUNDS KWH KWH/N ·POUNDS KWH KWH/I POUNDS KWH KWH/I TURBINE ASSEM. 49,077 1,322,587 26.9492 118,466 3,357.433 28.3409 89,211 2,484,610 27.8509 GEAR BOX 20,961 307,261 14.6587 88,872 1,302,739 14.6586 88,872 1,302,739 14.6586 GENERATOR 10,000 169,532 16.9532 21,000 356,019 16.9533 21,000 356,019 16,9533 ROTOR CONTROL 422 6:725 15.9360 579 9,226 1.5.9344 522 8,317 15.9330 OTHER TRANSMISSION 14.490 190,641 13.1567 '51,361 675,739 13.1567 51,361 675,739 13.1567 PLATFORM ASSEM. 52,200 563,544 10.7959 215,030 2,32(431 10.7958 192,541 2,078,645 10.7959 YAW CONTROL . 23,300 351,892 15.1027 95,996 1,449,803 15.1027. 85,956 1,298,181 15.1029 TOWER ASSEM 148.246 1,491,040 10.0579 211,402 2,126,254 10.0579 188,764 1,908,564 10.1108 FOUNDATION AND 656,500 1,030,733 1.5724 1,051,887 1,665,190. 1.5831 1,001,950 1,586,110 1.5831 EARTH MOVING TOTAL 974,196 5,433,955 1,854,693· 13,263,834 ·1,120,111 11,698,9"24 Table 1. Wind Turbine·Generator (WTG) Component Breakdown
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