On a daily basis and with a time horizon of two months, the gas system operator revises operational plans to ensure the security of supply. The operator is entitled to: ✔✔ authorize bilateral agreements between agents ✔✔ verify the correct operation of the system in the short run (up to two months ahead) 450 March 2009 March 2013 400 350 (MWh) 300 250 200 150 100 50 1 13 25 37 49 61 73 85 97 109 121 133 145 157 169 181 193 205 217 229 241 253 265 277 289 301 313 325 337 349 361 373 385 397 409 421 433 445 457 469 481 493 505 517 529 541 553 565 577 589 601 613 625 637 649 661 673 685 697 709 721 733 0 (Hour) figure 7. The hourly dispatch for a CCGT during March 2009 and March 2013. 450 400 350 (MWh) 300 250 200 150 100 50 1 4 7 10 13 16 19 22 25 28 31 34 37 40 43 46 49 52 55 58 61 64 67 70 73 76 79 82 85 88 91 94 97 100 103 106 109 112 115 118 121 124 127 130 133 136 139 142 145 148 151 154 157 160 163 166 0 (Hour) figure 8. A typical CCGT weekly plant operation. 44 ieee power & energy magazine november/december 2014