Provisional Data on Operation of the Italian Power System 2002 www.grtn.it
Table of Contents Page 11. Introduction... 3 12. Electricity Balance... 4 13. Electricity Demand... 6 14. Load Demand... 8 15. Hourly Load Curve of Electricity Supplied... 10 6. Hydro Power Plants: Energy Capability and Reservoirs... 11 17. Transfer Capacity Limits under Conditions of Operational Integrity of the Grid... 12 18. Balance of Physical Exchanges of Electricity... 13 19. Physical Exchanges of Electricity between Italy and Neighbouring Countries... 14 10. Time Curve of Net Import/Export... 15 11. Interruption Time Indices and Energy not Supplied... 16 12. Commissioning of Grid Facilities... 16 13. Italian 380 kv Grid... 17 14. Legend... 18 All rights reserved. The information presented herein are the exclusive property of GRTN and may not be used in whole or in part without prior permission of GRTN and proper acknowledgement of the source. 2
Introduction Monitoring & control of the power system are part of GRTN s core business. As electricity cannot be stored, generation should balance demand at any time. Any imbalance between generation and demand makes the generation & transmission system critical. To ensure reliability and quality of electricity supply under maximum security conditions, GRTN must, instant by instant, collect data on the status of the power system. These data represent the identification parameters of the system, i.e. its main items or variables. This publication reports the variables and events that characterised the Italian power system in 2002. Among the 2002 highlights, it is worth mentioning the general increase of electricity consumption, which was up by 1.8% on 2001. Taking into account the 2002 slow economic cycle (GDP growth rate slightly above zero), this increase is fairly significant, albeit smaller than in 2001 (+2.3% on 2000). In 2002, electricity demand reached 310.4 billion kwh and was covered by domestic production allocated for consumption (83.7%, +1.3% on 2001) and by imports (16.3%, +4.6% on 2001). Two other highlights characterised 2002: i) a new historical peak load on the national power system (52,590 MW, +1.2% on 2001), recorded on 12 December 2002; and ii) a new Summer peak load (50,974 MW, +4.8% on 2001), recorded on 21 June 2001 upon an exceptional heat wave. The following pages give more insight into these and other aspects of GRTN s management & operation of the Italian power system in 2002. 3
Italian Electricity Balance TWh (2001 data between parentheses) Thermal production 229.8 (219.3) Hydro production 48.1 (53.9) Wind, photovoltaic and geothermal production 5.8 (5.7) 15.5% (17.7%) 1.9% (1.9%) Net import/export 50.6 (48.4) 16.3% (15.9%) 74.0% (71.9%) Total gross production 283.7 (278.9) 3.4% (3.1%) 4.3% (4.3%) 13.3 (13.0) Electricity consumed by auxiliary services 10.6 (9.5) Electricity consumed by pumping 100% Electricity supplied (consumption + losses) 310.4 (304.8) 2002/2001 variation +1.8% 4
Electricity Balance by Regional Area and Total (GWh) TURIN MILAN VENICE FLORENCE ROME NAPLES PALERMO CAGLIARI Total 2002 2001 % Var Hydro Production 11,588 11,975 14,750 2,129 3,886 2,787 635 313 48,063 53,926-10.9 Thermal Production 23,741 32,577 34,881 21,418 39,049 39,059 25,177 13,918 229,820 219,379 4.8 Wind, photovoltaic and geothermal production 0 0 0 4,660 155 839 26 100 5,780 5,690 1.6 Total gross production* 35,329 44,552 49,631 28,207 43,090 42,685 25,838 14,331 283,663 278,995 1.7 Electricity consumed by auxiliary services 1,330 2,331 1,967 1,133 1,574 2,687 1,331 970 13,323 13,029 2.3 Total net production 33,999 42,221 47,664 27,074 41,516 39,998 24,507 13,361 270,340 265,966 1.6 Electricity consumed by pumping 2,626 3,733 339 602 253 1,873 782 361 10,569 9,511 11.1 Net production allocated for consumption 31,373 38,488 47,325 26,472 41,263 38,125 23,725 13,000 259,771 256,455 1.3 Net import/export 24,527 19,359 6,943 0 0 138 0-369 50,598 48,377 4.6 Balance of physical exchanges between regional areas - 21,074 5,938-8,592 20,144 2,727 4,678-3,275-546 Electricity supplied 34,826 63,785 45,676 46,616 43,990 42,941 20,450 12,085 310,369 304,832 1.8 Year 2001 34,754 63,387 45,110 45,264 42,691 41,752 20,062 11,812 % variation 0.2 0.6 1.3 3.0 3.0 2.8 1.9 2.3 *of which CIP-6 production (estimated) 2,342 4,322 8,374 11,929 7,758 10,205 5,088 4,436 54,454 53,100 2.5 N.B. Net import/export excluding the Republic of San Marino and the Vatican City. During the year, electricity demand reached 310.4 billion kwh (+1.8% on 2001). Its monthly trend was fairly variable. Demand was covered for 83.7% by net domestic production allocated for consumption. In particular, thermal and geothermal production grew by 4.8% and 3.4%, respectively. Hydro and wind production dropped sharply (-10.9 and -5.3%, respectively). As a whole, net domestic production was up by 1.6% vs the previous year. Physical exchanges of electricity with neighbouring countries rose significantly and net imports went up by 4.6% on 2001. Due to high temperatures at the start of the Summer period, electricity demand soared, reaching historical daily peaks in almost all Italian areas. 5
Electricity Demand on the Italian Grid Trend and Coverage TWh 350 300 250 247 254 261 263 271 279 286 299 305 310 200 150 100 50 0 1993 1994 1995 1996 1997 1998 1999 2000 Net import/export Net production allocated for consumption 2001 2002 Monthly and Cyclical Percentage Variation % 7.0 6.0 5.0 4.0 3.0 2.0 1.0 0.0-1.0 J F M A M J J A S O N J F M A M J J A S O N J F M A M J J A S O N -2.0-3.0-4.0 2000-1999 2001-2000 2002-2001 Monthly Cyclical (referring to the last 12 months) 6
Percentage Variation by Regional Area % 5.0 4.0 3.0 2.0 1.0 0.0 TURIN MILAN VENICE FLORENCE ROME NAPLES 2001-2000 2002-2001 PALERMO CAGLIARI Components (%) of Electricity Supply Side Hydro* 15.2 % Wind, photovoltaic and geothermal 1.9 % Imports 16.3 % Thermal* 66.6 % *% net of electricity consumed by auxiliary services and pumping 7
Hourly Load Demand on the Italian Grid Load Curve on Maximum and Minimum Peak Days GW GW GW 60 50 49.0 20 Dec. 2000 60 50 52.0 11 Dec. 2001 60 50 52.6 12 Dec. 2002 40 40 40 30 30 30 20 18.1 24 Apr. 2000 20 19.1 16 Apr. 2001 20 19.3 12 Aug. 2002 10 10 10 0 time 0 6 12 18 24 0 0 time 0 6 12 18 24 time 0 6 12 18 24 Max 2000 Max 2001 Min 2000 Min 2001 Max 2002 Min 2002 Daily Values 2002 MAX MIN GW date-time GW date-time LOAD Gross thermal production 38.2 24 January 18:00 15.2 26 December 05:00 Gross hydro production 14.0 25 November 17:00 1.0 4 February 03:00 Hourly peak load 52.6 12 December 17:00 19.3 12 August 04:00 GWh date GWh date ENERGY Gross thermal production 816.7 17 January 389.2 26 December Gross hydro production 206.5 21 June 38.9 17 February Daily electricity demand 1,018.3 21 June 544.6 15 August N.B.: Data are net of electricity consumed by auxiliary services and pumping In 2002, electricity demand on the national power system recorded a new historical peak (52,590 MW at 17:00 of Thursday, 12 Dec.) and was up by 1.2% on 2001. In June, owing to an exceptional heat wave, electricity demand on the national power system reached 50,974 MW (at 11:00 of Friday, 21 June), hitting a new historical Summer peak (up by 4.8% on the previous peak of 48,634 MW of Thursday, 12 July 2001). 8
GW 60 Peak Loads by Month 50 51.2 49.7 49.7 48.3 47.3 46.6 47.3 46.3 45.4 46.0 51.0 50.5 48.1 48.6 46.9 45.9 45.7 44.4 48.3 46.7 50.5 50.0 52.0 52,6 40 30 20 10 0 Jan Feb Mar Apr May Jun Jul Aug Sept Oct Nov Dec 2002 2001 GW 60 50 (*) Utilisation Curve of Hourly Load Demand 40 30 20 2002 2001 2000 10 0 0 10 20 30 40 50 60 70 80 90 100 % GW 56 (*) 54 52 50 48 46 44 0 1 2 3 4 5 % N.B.: Data are net of electricity consumed by auxiliary services and pumping 9
Hourly Load Curve of Electricity Supplied aaaaaaa aaaaaaaaaaaaa aaaaaaaaaaaaa aaaaaaaaaaaaa aaaaaaaaaaaaa GW aaaaaaaaaaaaa aaaaaa GW 60 60 50 50 40 40 30 30 20 20 10 10 0 500 1,000 1,500 2,000 2,500 3,000 3,500 4,000 4,500 5,000 5,500 6,000 6,500 7,000 7,500 8,000 8,500 Jan Feb Mar Apr May Jun Jul Aug Sept Oct Nov Dec N.B.: Data are net of electricity consumed by auxiliary services and pumping The hourly load curve of electricity supplied is a detailed representation of the electricity injected into the Italian power system in each of the 8,760 hours of 2002. The diagram clearly shows low-demand periods (Easter, August and Christmas). 10
Hydro Power Plants Energy Capability Factor 2.00 1.80 Yearly Factor 0.90 (1.04 in 2001) 1.60 1.40 1.20 1.00 0.80 0.60 0.40 0.20 0.00 J F M A M J J A S O N D Max 1950-2001 Min 1950-2001 2001 2002 Fullness Factor of Hydro Reservoirs at the end of Each Month % 100 90 80 70 60 50 40 30 20 10 0 J F M A M J J A S O N D Max 1970-2001 Min 1970-2001 2001 2002 The monthly energy capability factor shows a fairly variable trend with: i) below-average values in the first quarter of 2002, when precipitation was low; and ii) above-average values in the last months of the year. The yearly energy capability factor (ratio of the energy capability in a given year to the mean energy capability over multiple years) lay below the corresponding value of the previous year. 11
Transfer Capacity Limits under Conditions of Operational Integrity of the Grid France + Switzerland 4,800 5,400 200 220 380 Austria 4,800 4,600 300 350 Slovenia 1,700-2,000 2,200 France (Corsica) 300 500 Greece 600-350 TRANSFER CAPACITY (MW) Winter period: October-April Summer period: May-September (excluding August) Maximum Load Flows between Geographic Areas (MW) FRANCE SWITZER. AUSTRIA SLOVENIA GREECE NORTH FLORENCE ROME PALERMO FLORENCE FLORENCE ROME NAPLES NAPLES CAGLIARI 16 Nov. 2002 14 Jul. 2002 24 Oct. 2002 27 Nov. 2002 10 Sept. 2002 28 Oct. 2002 24 Dec. 2002 20 Jun. 2002 14 Jan. 2002 14 Jul. 2002 19:00 05:00 12:00 05:00 23:00 18:00 20:00 21:00 16:00 01:00 FRANCE 3.138 3,410 650 1,420 2,736 2.261 865 2,348 2.314 2,107 1.727 2,730 1.761 2,354 2.136 2,209 1.835 1,647 1,737 SWITZERLAND 2.693 2,087 4.048 3,953 2,245 3.417 3.714 2,377 2.717 2,631 1.846 2,432 2.918 2,725 2.872 3,346 2.747 3,245 3,502 AUSTRIA 239 277 180 211 325 321 275 264 204 280 219 129 253 196 246 272 289 180 210 SLOVENIA 851 476 913 1,530 617 1,005 744 207 719 365 GREECE 294 204 804-93 384 149 1.301 156 112 499 695 206 397 156 685-183 1.0130-161 NORTH FLORENCE 2.023 4,560 3.709 3,329 4,466 3.749 2.250 2,769 5.335 2,559 4.526 5,596 4.817 4,554 3.074 5,044 3.406 2,357 3,323 FLORENCE ROME - 2,130 589 161 1,623 764-1 907 1,464 1.805 173 2.966 1,648 2.259 2,797-2,223 494 1.689-330 1,166 ROME NAPLES - 133-845 1.066 1,334 175 303 455 982 228-226 1.336 207 2.637 894-2,414 897 154 857 956 PALERMO NAPLES 492 555 636 227 322 526 169 184 62329-37 464 362 495 765-142 403 734 400 FLORENCE CAGLIARI - 14786-134 103-102 168 93-127 78-161 104-135 212-146 - 79 185 269-209 282 12
Balance of Physical Exchanges of Electricity (GWh) France France 19,006 Switzerland Turin 5,521 34,826 19,359 12,369 Milan 63,785 8,705 6,910 479 8,113 45,676 Venice 1,787 5,156 Austria Slovenia Florence 46,616 4,130 France (Corsica) 546 Rome 43,990 369 1,403 Naples 42,941 12,085 138 Greece Cagliari 3,275 Palermo 20,450 EXCHANGES DEMAND The balance of physical exchanges of electricity shows the flows between the various areas of the Italian power system. Note the high flows going from Piemonte to Lombardia, which then converge towards central Italy. In 2002, thanks to the use of a 380 kv link for transmission from Sicily to Mainland Italy, the power system of Calabria and Sicilia was operated under security conditions. 13
Physical Exchanges of Electricity between Italy and Neighbouring Countries (GWh) Electricity imported to Italy from Electricity exported from Italy to Net 2001 France Switzerland Austria Slovenia Greece TOTAL France Switzerland Austria Slovenia Greece TOTAL imports January 1.711 1,711.6 2,021.0 2.021 165.3 546.9 547 0.0 0 4,444.84.444 26.526 0.00 0.00 0.10 0.0 0 26.6 26 4,418.2 February 1.522 1,521.9 1,788.0 1.788 137.1 542.8 543 0.0 0 3,989.83.990 28.429 0.00 0.00 0.00 0.0 0 28.4 29 3,961.4 March 1.818 1,818.5 1,862.8 1.864 146.8 147 625.6 625 0.0 0 4,453.74.454 29.129 0.10 0.00 0.00 0.0 0 29.2 29 4,424.5 April 1.676 1,676.2 1,828.7 1.829 161.7 162 594.3 594 0.0 0 4,260.94.261 31.031 0.20 0.00 0.00 0.0 0 31.2 31 4,229.7 May 1.411 1,410.6 1.915 1,914.5 168.6 169 456.3 0.00 3,950.0 3.951 45.646 0.4 0 0.00 0.0 0 0.00 46.0 3,904.0 3.905 June 1.411 1,410.8 1,902.7 1.904 165.1 311.3 311 0.0 0 3,789.93.791 30.931 2.03 0.00 6.4 6 0.0 0 39.3 40 3,750.6 July 1.590 1,590.8 1.852 1,851.8 163.9 164 247.9 248 0.00 3,854.4 3.854 32.632 1.8 2 0.00 17.017 0.00 51.4 3,803.0 3.803 August 1.136 1,137.9 1,113.4 1.115 72.8 73 111.7 112 0.0 0 2,435.82.436 61.862 31.331 0.00 20.8 21 0.0 0 113.9 114 2,321.9 September 1.339 1,335.3 2,143.1 2.138 164.6 166 341.3 340 0.00 3,984.33.983 21.522 7.88 0.00 3.03 0.0 0 32.3 33 3,952.0 October 1.684 1,678.3 2,441.9 2.436 176.5 177 369.7 369 6.0 0 4,672.44.666 13.213 0.00 0.00 6.4 6 14.2 8 33.8 27 4,638.6 November 1.626 1,617.9 2,309.0 2.313 163.8 165 430.3 429 0.7 0 4,521.74.533 29.343 0.0 0 0.00 8.5 8 0.8 0 38.6 51 4,483.1 December 1.361 1,360.1 2,448.3 2.448 174.8 175 585.6 586 0.1 0 4,568.94.570 77.878 0.0 0 0.00 0.8 1 0.0 0 78.6 79 4,490.3 YEAR 18.285 18,269.9 23.623 23,625.2 1,861.0 1.865 5,163.7 5.160 6.80 48,926.6 48.933 427.7 442 43.644 0.00 63.062 15.08 549.3 556 48,377.3 48.377 Electricity imported to Italy from Electricity exported from Italy to Net 2002 France Switzerland Austria Slovenia Greece TOTAL France Switzerland Austria Slovenia Greece TOTAL imports January 1!711 1,551.7 2,322.7 2!021 166.4 165 466.6 547 0.3 0 4,507.7 4!444 57.126 0.0 0 0.0 0 3.8 0 0.4 0 61.3 26 4,446.4 February 1!522 1,460.2 2,121.9 1!788 138.2 137 466.9 543 0.0 0 4,187.2 3!990 36.529 2.4 0 0.0 0 1.7 0 0.0 0 40.6 29 4,146.6 March 1!818 1,868.7 2,144.1 1!864 154.1 147 494.5 625 0.0 0 4,661.4 4!454 36.429 2.0 0 0.0 0 0.4 0 0.0 0 38.8 29 4,622.6 April 1!676 1,752.5 2,106.6 1!829 159.2 162 382.9 594 1.0 0 4,402.2 4!261 34.131 0.4 0 0.0 0 0.3 0 18.4 0 53.2 31 4,349.0 May 1!411 1,617.3 1!915 2,188.1 162.2 169 219.1 456 6.00 4,192.7 3!951 42.346 1.3 0 0.0 0 37.9 0 76.1 0 157.646 4,035.1 3!905 June 1!411 1,534.6 1!904 2,142.9 147.4 165 254.4 311 0.00 4,079.3 3!791 45.931 0.7 3 0.0 0 26.6 6 96.7 0 169.940 3,909.4 3!751 July 1!590 1,410.5 1!852 2,357.0 158.0 164 265.8 248 0.70 4,192.0 3!854 37.232 1.8 2 0.0 0 8.017 146.2 0 193.251 3,998.8 3!803 August 1!136 1,015.8 1,614.3 1!115 70.1 73 266.2 112 56.3 0 3,022.7 2!436 56.462 1.5 31 0.0 0 2.4 21 17.3 0 77.6 114 2,945.1 September 1!339 1,547.0 1,958.7 2!138 151.8 166 378.2 340 101.2 0 4,136.9 3!983 23.122 0.1 8 0.00 0.1 3 2.8 0 26.1 33 4,110.8 October 1!684 1,783.1 2,063.7 2!436 170.0 177 709.8 369 128.8 0 4,855.4 4!666 22.713 2.2 0 0.0 0 0.0 6 0.0 8 24.9 27 4,830.5 November 1!626 1,802.3 1,794.1 2!313 160.1 165 704.8 429 99.0 0 4,560.3 4!533 31.843 9.6 0 0.0 0 0.0 8 0.0 0 41.4 51 4,518.9 December 1!361 1,752.6 2,090.2 2!448 149.8 175 627.3 586 102.4 0 4,722.3 4!570 35.978 2.0 0 0.0 0 0.0 1 0.0 0 37.9 79 4,684.4 YEAR 18!285 19,096.3 23!623 24,904.3 1,787.3 1!865 5,236.5 5!160 495.70 51,520.1 48!933 459.4 442 24.044 0.0 0 81.262 357.9 8 922.556 50,597.6 48!377 Physical Exchanges of Electricity between Italy and Neighbouring countries from 1963 to 2002 (GWh) 60,000 50,000 40,000 30,000 20,000 10,000 0 1963 1969 1975 1981 1987 1993 1999 2002 Net imports Import Export In the course of 2002, electricity imports from neighbouring countries increased further, exceeding 50 billion kwh. Note the physical exchanges of electricity between Italy and Greece (made possible by the provisional experimental operation of the 400 kv DC link), with 138 million kwh of net imports. 14
Time Curve of Net Import/Export aaaaa aaaaaaaaaaaa aaaaaaaaaaaa aaaaaaaaaaaa aaaaaaaaaaaa MW 8,000 7,000 6,000 5,000 4,000 3,000 2,000 1,000 0 Jan Feb Mar Apr May Jun Jul Aug Sept Oct Nov Dec Net Transfer Capacity The red line shows the limit value of the maximum transfer capacity on the interconnected system. In 2002, the transfer capacity limit was equal to 6,000 MW in the Winter period (January- April- October-December 2002) and to 5,300 MW in the Summer period (May-September 2002, excluding August). In August, the limit was equal to 3,500 MW. 15
Interruption Time Indices on the 380-220-150-132 kv Grid YEAR 2002 YEAR 2001 Interruption Energy Interruption Energy Regional Area Time Indices Not Supplied Time Indices Not Supplied (minutes and seconds) (MWh) (minutes and seconds) (MWh) Turin 2:15 9:20 196.83 808,70 3:47 9:20 321,47 808.70 Milan 1:17 0:37 217.43 104,63 2:26 0:37 391,87 104.63 Venice 1:08 1:22 134.68 154,78 1:17 1:22 138,27 154.78 Florence 0:33 1:34 198,17 71.08 1:03 1:34 123,09 198.17 Rome 2:12 1:24 260.60 165,23 1:20 1:24 145,02 165.23 Naples 2:37 4:17 291.17 479,77 2:48 4:17 284,95 479.77 Palermo 3:17 8:16 164.77 412,40 1:54 8:16 87,96 412.40 Cagliari 1:54 152:23 4.053,65 50.45 152:23 38:30 4,053.65 992,48 TOTAL 1:43 8:03 1,387.02 6.377,33 3:32 8:03 2.485,11 6,377.33 The interruption time index is one of the most significant measures of the quality of electricity supply. A high-voltage (380-220-150-132 kv) power grid with a typical interruption time index in the range of 10 minutes (European reference value) has good performance in terms of reliability of supply. In 2002, the performance of the Italian high-voltage grid, with a total interruption time index of 1 minute and 43 seconds, was in line with the above quality standard. Commissioning of Grid Facilities Thermal Production CET PIO (FI) gas turbine 2 + unit 3 (13.6+51.5) MVA Elettra GLL S.p.A. La Casella (PC) gas turbine C + unit 2 (300+140) MVA Enel Produzione La Casella (PC) gas turbine E + unit 3 (300+140) MVA Enel Produzione Pietrafitta (PG) gas turbine A 300 MVA Enel Produzione Porto Corsini (RA) gas turbine E + unit 3 (300+170) MVA Enel Produzione Porto Corsini (RA) gas turbine G + unit 4 (300+170) MVA Enel Produzione Priolo Gargallo (SR) gas turbine C 300 MVA Enel Produzione Production from Renewables Cutro (KR) Biomass 18 MVA E.T.A. s.r.l. San Marco Bioenergie S.p.A. (FE) Biomass 13.8 MVA San Marco Bioenergie S.p.A. Terni (TR) Biomass 16 MVA EN.A. Accadia (FG) Wind 10.8 MVA Lucky Wind S.p.A. Avigliano (PZ) Wind 13.2 MVA IVPC4 s.r.l. Cà del Bue (VR) Municipal Solid Waste 28 MVA AGSM Verona Filago (BG) Municipal Solid Waste 11.8 MVA Ecolombardia 4 Tecnoborgo (PC) Municipal Solid Waste 16.4 MVA Tecnoborgo S.p.A. Trezzo d'adda (MI) Municipal Solid Waste 25 MVA Prima Caltabellotta (AG) Wind 7.5 MVA Enel Greenpower 8 plants Geothermal 246 MVA Enel Greenpower Transformers 380/220 kv 400 MVA 380/150 kv 500 MVA 380/132 kv 1250 MVA 220/150 kv 220 MVA 220/132 kv 710 MVA Lines 380 kv Ravenna Canala - Porto Corsini 12.860 km TERNA 150 kv Cagliari Sud - Santa Margherita 2.290 km Enel Trasmissione 150 kv Gallicano - Roma Est 0.465 km IRICAV-UNO 150 kv Ceprano - Anagni F.S. 58.120 km IRICAV-UNO 6 new 150/132 kv links 29.104 km Transmission Facilities 380 kv substation of Villavalle TERNA 380 kv substation of Pian della Speranza TERNA 380 kv substation of Porto Corsini TERNA 220 kv substation of Pietrafitta TERNA 150 kv substation of Monteferrante TERNA 150 kv substation of Gallicano IRICAV-UNO 12 new 150/132 kv substations Enel Distribuzione Capacitor Banks Candia (AN) 54 MVAr TERNA Fano E.T. (PU) 54 MVAr TERNA Parma Vigheffio (PR) 54 MVAr TERNA S. Damaso (FI) 54 MVAr TERNA 16
Italian 380 kv Grid as of 31 December 2002 17
Legend The electricity supplied (or electricity demand) is the electricity to be injected into the grid for covering its net internal consumption. In the case of a national grid, it is equal to the sum of net electricity production and of imports from neighbouring countries, after deducting electricity consumed by pumping and exports to neighbouring countries. The trend variation is the percentage change with respect to the same month or period of the previous year. The gross electricity production of a group of power plants in a given period is the sum of the amounts of electricity generated, measured at the terminals of electrical generators. The electricity consumed by auxiliary services is the sum of the electricity consumed by all the auxiliary services of power plants and of losses in the main transformers. The net electricity production is equal to the gross electricity production, after deducting the electricity consumed by auxiliary services and the losses in the main transformers. The electricity consumed by pumping is the electricity used for the sole purpose of pumping water and storing it for subsequent electricity generation. Regional areas consist of one or more nearby regions, which are grouped as follows: TURIN - Piemonte - Liguria - Valle d Aosta MILAN - Lombardia VENICE - Friuli Venezia Giulia - Veneto - Trentino Alto Adige FLORENCE - Emilia Romagna - Toscana ROME - Lazio - Umbria - Abruzzo - Molise - Marche NAPLES - Campania - Puglia - Basilicata - Calabria PALERMO - Sicilia CAGLIARI - Sardegna The hydro energy capability factor is the ratio of the energy capability in a given period to the mean energy capability in the same period. The energy capability of a group of power plants in a given period is the maximum amount of electricity that all the inflows observed in the same period would enable them to generate under the most favourable conditions. The interruption time index of a service area in a given period is defined as the ratio of the energy not supplied, owing to disturbances in the power system, to the peak load demand in the same period. The interruption time index is expressed in minutes and seconds. 18
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