Helman U.,California Independent System Operator |
Hobbs B.F.,Johns Hopkins University
IEEE Transactions on Power Systems | Year: 2010
This paper presents results from a large-scale Cournot model of the U.S. Eastern Interconnection using a DC load flow network. There are 100 network locations (at the level of control areas) along with 2725 generators owned by 99 Cournot firms and 200 competitive fringe suppliers. These results demonstrate that this modeling approach can analyze potential generation market power with a reasonable approximation of the actual transmission network over a large integrated region. While such models have been used to analyze market design alternatives, their application to regulatory decision-making concerning generation market power mitigation has been more controversial. We suggest that such large-scale market price simulations could improve upon aspects of the existing generation market power screening methods used in the United States for mergers and market-based rates, illustrating such applications using this model. © 2010 IEEE.
Jin L.,California Independent System Operator |
Kumar R.,Iowa State University |
Elia N.,Iowa State University
IEEE Transactions on Power Systems | Year: 2010
The objective of power system controls is to keep the electrical flow as well as voltage magnitudes within acceptable limits in spite of the load and network topology changes. The control of voltage level is accomplished by controlling the production, absorption as well as flow of reactive power at various locations in the system. This paper presents an approach to determine a real-time system protection scheme to prevent voltage instability and maintain a desired amount of post-transient voltage stability margin (an index of system security) following the occurrence of a contingency by means of reactive power control. This approach is based on the model predictive control (MPC) theory. According to an economic criterion and control effectiveness, a control switching strategy consisting of a sequence of amounts of the shunt capacitors to switch is identified for voltage restoration. The effect of the capacitive control on voltage recovery is measured via trajectory sensitivity. The sensitivity of voltage stability margin with respect to the capacitive control is used to construct a security constraint for post-fault operation in the MPC formulation. The efficacy of the proposed approach is illustrated through applications to the WECC system for enhancing the voltage performance and to the 39-bus New England system for preventing voltage collapse. © 2010 IEEE.
Yu N.-P.,Iowa State University |
Liu C.-C.,National University of Ireland |
Price J.,California Independent System Operator
IEEE Transactions on Power Systems | Year: 2010
The California energy crisis in 20002001 showed what could happen to an electricity market if it did not go through a comprehensive and rigorous testing before its implementation. Due to the complexity of the market structure, strategic interaction between the participants, and the underlying physics, it is difficult to fully evaluate the implications of potential changes to market rules. This paper presents a flexible and integrative method to assess market designs through agent-based modeling. Realistic simulation scenarios are constructed for evaluation of the proposed PJM-like market power mitigation rules of the California electricity market. Simulation results show that in the absence of market power mitigation, generation company (GENCO) agents facilitated by Q-learning are able to exploit the market flaws and make significantly higher profits relative to the competitive benchmark. The incorporation of PJM-like local market power mitigation rules is shown to be effective in suppressing the exercise of market power. © 2009 IEEE.
News Article | September 7, 2016
The mix of energy sources used for power generation in California this summer changed from last summer, as renewables and imported electricity offset lower natural gas use. During summer 2016 (June, July, and August), thermal generation (almost all from natural gas) in the area serviced by the California Independent System Operator (CAISO) was down 20% from the previous summer, while generation from hydroelectricity, other renewables, and electricity imports was higher than the same period last year. The overall level of electricity consumption was 2% higher this summer as temperatures were slightly warmer than the previous summer. Hydroelectric generation in CAISO increased from last summer because the West Coast drought situation has improved. According to the U.S. Drought Monitor, 59% of California experienced a severe, extreme, or exceptional drought during July 2016. In contrast, 95% of the state experienced similar conditions last July. These improved water conditions have also helped increase hydroelectric generation in the Pacific Northwest, some of which is imported into CAISO. The addition of new generating capacity has also contributed to the change in generation mix. Data from CAISO indicate that nonhydro renewables, mainly solar and wind, represented 26% of capacity in June 2016. Utility-scale solar photovoltaic (PV) capacity has shown the most growth in CAISO recently, increasing by 1.4 gigawatts (27%) between June 2015 and June 2016. This increase in utility-scale solar capacity has reduced the need for summer thermal generation in CAISO, especially during the daylight hours. California also has added a significant amount of distributed solar PV capacity. EIA’s latest data show that distributed solar PV increased from 2.8 gigawatts in June 2015 to 3.8 gigawatts in June 2016. Distributed generation reduces the amount of electricity that utility-scale power plants need to supply.
News Article | September 6, 2016
Southern California Gas Company (SoCalGas) can meet its summer and winter peak demand without the Aliso Canyon gas storage facility, despite the company’s repeated warnings that blackouts could occur if Aliso stays offline. This is according to a new report prepared for Food & Water Watch and the community group Save Porter Ranch. The report, Critical Review of Aliso Canyon Winter Risk Assessment and Action Plan, by Bill Powers, P.E. of Powers Engineering, finds that as long as existing mitigation measures remain in place, Aliso Canyon, one of the largest natural gas storage fields in the western U.S. and site of the largest methane leak in U.S. history, is not needed to guarantee either summer or winter gas supplies in the Los Angeles Basin. In Thursday’s report, Powers refutes SoCalGas claims that permanent closure of Aliso Canyon would threaten gas supplies during peak usage by critiquing two documents released this year by California state regulators. Powers says those documents, a winter risk assessment released in April and a winter action plan released last month, use faulty assumptions about usage and standard mitigation practices and then “editorialize” to create an impression that Aliso Canyon is needed. The April report, created by the California Public Utilities Commission, California Energy, the California Independent System Operator, the Los Angeles Department of Water and Power, and SoCalGas, was the more problematic of the two reports, Powers tells DeSmog. “[The agencies] were hammered back in April, and not just by me, for crying wolf by using obsolete numbers to do their modeling,” Powers says. “In the August report, which SoCalGas was not a part of, more accurate data is used but it’s presented with misleading language to reach the conclusions they want.” Both reports require more expertise to connect those dots than a layperson has, Powers adds. Powers points out one key way the winter action plan presents data in what he calls an “uncontrolled” manner. The plan’s scenario assumes, without Aliso Canyon, a usage of 5.2 billion cubic feet per day (bcfd) during a peak winter event in 2016-2017. But the same report also states that, factoring in the new winter mitigation measures and continuing those from summer 2016, the maximum demand would be much lower, in the range of 4.1 to 4.2 bcfd. “They frame mitigation factors like balancing supply and demand and limiting the generators as a curtailment. It’s not. It’s a good management technique,” says Powers. Powers also criticizes the winter action plan for its assumption that shifting generation outside of the L.A. Basin to minimize natural gas demand on forecasted peak winter days amounts to a “curtailment” of service. As he says in the report: Aliso Canyon contains less than 20 percent of its capacity after a four-month-long leak that began with the October 23, 2015 blowout, which forced the company to release much of the facility’s supply. The state then ordered a moratorium on new natural gas injections and storage at the plant while inspectors checked the wells for safety. Without Aliso Canyon, three other storage facilities owned by SoCalGas — La Goleta Gas Field west of Santa Barbara, Honor Rancho near Newhall, and Playa del Rey — still produce an “overabundance” of gas, according to Powers and Food & Water Watch. State regulators and Southern California Gas warned in their April report — and continued to claim for months — that without Aliso Canyon, Southern Californians could face as many as 14 days of blackouts this summer, a threat that many residents of nearby Porter Ranch called “blackout blackmail.” As of September 2, the L.A. basin has seen none of the threatened blackouts. Powers says the company’s scare tactics were “bogus” from the beginning. SoCalGas maintains its position that Aliso Canyon must reopen to meet peak winter demands for gas in the region. A spokesperson for the company, Melissa Bailey, told DeSmog that SoCalGas executives have not seen the report by Powers and Food & Water Watch, but she pointed to separate and independent analysis conducted by Los Alamos National Laboratory that “concluded that the facility is an integral part of the SoCalGas system” and still necessary to handle potential shortages. “Restoring natural gas injection at Aliso Canyon to support energy reliability for the winter heating season is critical and without the facility there is an increased risk of natural gas curtailments affecting electric generation plants, hospitals, manufacturers, refineries, and other large users,” says Bailey. “That’s exactly the kind of muddy language I highlighted in my review,” Powers says about Bailey’s statement. “It’s politicizing with language. Their conclusions are not supported by their own numbers.” Powers’ review also shows that keeping Aliso Canyon closed could save ratepayers about $70 million a year. “The good news is, these documents by state agencies, no matter how they spin it, actually show a road map for not using Aliso,” Powers says. The Aliso Canyon storage facility leak, which released an estimated 100,000 metric tons of natural gas, caused 8,000 residents, mainly in the nearby Porter Ranch community, to be relocated for months. Some residents who have moved back still complain of headaches, nosebleeds, and nausea. Some have decided to leave permanently. Residents who want the facility shut down say Powers’ conclusions are vindication of their position. “There’s a greater chance of a big earthquake happening here than a blackout if Aliso Canyon is shut,” Save Porter Ranch President Matt Pakucko told dozens of protesters rallying near the facility on September 1. At the same rally, Alex Nagy, senior organizer with Food & Water Watch, told protesters that SoCalGas is still using scare tactics in order to keep Aliso Canyon open because it’s a huge money maker. “SoCalGas stores gas here and does commodities trading, selling it to the highest bidder, to other states and to Mexico,” she said. In a visit to the site during the leak this past winter, U.S. Secretary of Energy Ernest Moniz said Aliso Canyon showed the need for a fresh look at gas storage safety standards nationwide. One potential reform may be signed by California Governor Jerry Brown this month. On August 26, the California Senate sent SB 887, a bill establishing proactive safety standards for natural gas wells, to the governor. SB 887, approved overwhelmingly by both houses of the legislature, calls for continuous monitoring for leaks, regular inspections of wells to test their mechanical integrity, and that all wells be equipped with safeguards to ensure that no single point of failure can result in a leak. The standards in the bill are aligned with new regulations proposed by the Division of Oil, Gas & Geothermal Resources, and could become a national model for safety reforms, according to its author, Senator Fran Pavley. The Senate sent a companion bill to Gov. Brown last week. SB 888, authored by Senator Ben Allen, establishes the state Office of Emergency Services as the lead agency to coordinate responses to any future gas leaks. Gov. Brown has until September 30 to act on all bills sent to him by the legislature in August.