American Gas - October 2012 - (Page 33)

CHARTS BY ALEX REARDON tors in New York City to burn oil or activate automatic fuel switching during periods when the gas system is constrained and an outage could affect electric reliability. In the event of a major gas system contingency, the generating units with automatic fuel switching automatically switch to oil within 45 seconds. Con Edison conducts semiannual studies to determine the specific electric load levels at which generators must preemptively switch to oil or arm automatic fuel-switching equipment. On the gas operations side, Con Edison, along with National Grid (the other owner of high-pressure gas transmission facilities within New York City), has taken steps to minimize sudden, unexpected changes in hourly gas flows. These efforts have included voluntarily developing an emergency communications protocol with NYISO, in accordance with North American Energy Standards Board requirements. Under that protocol, Con Edison and NYISO assess which generators are needed to maintain the reliability of the electric system when an operational flow order or equivalent electric system alert has been issued. Once such generators have been identified, NYISO and Con Edison estimate the amount of electric energy that each generator will need to produce during each hour, and then obtain fuel-use estimates from each critical generator. The hourly fuel-use estimates provided by the generator enable Con Edison and National Grid to examine whether the city’s gas system can accommodate the needs of the critical generators. As a result of this protocol and other efforts, OFOs have fallen significantly in recent years. Last winter, OFOs affecting electric generators on Con Edison’s gas system were in effect in only 101 hours, compared to 400-500 hours in the winters of 2010-11 and 2009-10. This past summer, no OFOs were issued, a striking reduction from the 24 hours that OFOs were in effect during the summers of 2009 and 2010, and the nearly 400 hours that OFOs were in effect in the summer of 2011. Electric market rules have been structured to account for New York City’s gas-electric coordination requirements. NYISO’s capacity market-demand curves for New York City reflect the fixed costs of dual-fuel capability, such as backup fuel storage costs. In addition, NYISO’s Market Services Tariff provides a mechanism for recovery of the variable costs of using backup fuel as well as the lost op- NYC’s Electric and Gas Load Con Edison’s electric and gas loads are complementary during most of the year, with gas customers using the most gas in the winter and electric generators concentrating usage during the summer. Recently, the construction of new generators with automatic fuel-swapping capability and the addition of electricity and natural gas transmission capacity have reduced the need for generators to preemptively burn alternative fuels to protect system reliability. A DELICATE BALANCE: NYC Annual Load and Minimum Oil Burn Thresholds 14,000 13,000 12,000 11,000 Electric Load (MW) 10,000 9000 8000 7000 6000 5000 4000 Jan 07 Jan 08 Oil Burn Auto Swap Daily Load Range Jan 09 Jan 10 Jan 11 Jan 12 NYC Summer 2012 Load vs. MOB Thresholds 12,000 10,000 Oil Burn Begins NYC Load (MW) AutoSwap Armed 8000 6000 Load 4000 5/1/12 6/1/12 7/1/12 8/1/12 Con Edison Gas Demand (dth/day) Generation Load Gas Load (Dt/day) Distribution Load 1/1/10 6/30/10 12/27/10 6/25/11 12/22/11 6/19/12 OCTOBER 2012 AMERICAN GAS 33

Table of Contents for the Digital Edition of American Gas - October 2012

American Gas - October 2012
Contents
President’s Message
Industry News
In the Know
Safety First
Tech Talk
Keep the Lights On
Buyer’s Guide 2012
Places to Be
Jobline
Advertisers’ Index
Noteworthies
Marketplace
Facts on Gas

American Gas - October 2012