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Glendale City Hall, 613 East Broadway

(818) 548-4844

Grayson Repowering

There has been misinformation from various sources regarding the Proposed Grayson Repowering Project. Provided below are factual responses to frequently asked questions. For more information, visit GraysonRepowering.com

? Are you expanding the Grayson Power Plant?

✔ No, Glendale Water & Power (GWP) is not going to expand the Grayson Power Plant. The driving force for replacing the obsolete Units 1-5 and 8* at the Grayson Power Plant is to ensure a reliable electric supply for the citizens and residents of the City of Glendale. A majority of the facilities located at the Grayson Power Plant were completed between 1941 and 1977, and must be replaced. We are proposing to rebuild substantial portions of the plant by taking old generating units out of commission, dismantling them, and building new, modern units in their place. This process is called repowering. The new repowered units will be cleaner, more energy efficient, and will greatly increase the reliability of Glendale’s power grid.

* units 6 and 7 were retired several years ago and dismantled. Unit 9 is about 15 years old and will continue to operate.

? How is GWP going to pay for the repowering of the Grayson Power Plant?

✔ GWP is proposing to finance the repowering project which has an estimated cost of $500 million, through the issuance of revenue bonds. GWP sells bonds to finance capital projects, and the payments for the GWP bonds are covered by the revenue that GWP receives from its customers based on its rate schedule. The tax revenues that the City receives are not used to pay off GWP bonds. The final cost will not be determined until the detailed design is finalized.

The repowering will not impact rates. The cost of generation at the repowered plant will be less (more efficient units burn less natural gas to produce the same amount of energy), and for short-term energy needs, the new units can deliver energy more cheaply than spot market (emergency) power purchases that must be imported with their associated transmission costs. Additionally, the new units will be able to provide reserves (on-line generation that can respond to losses in supply) more cheaply than purchasing and importing reserve capacity from other sources. These savings will pay for the bonds.

? What if the City does not repower the Grayson Power Plant?

✔ Units (1, 2, 3, 4, 5, and 8) are all 40 to 70 years old, are not expected to continue running much longer and maintenance on these units is temporary and very costly. In addition, forthcoming air quality regulations will require GWP to do expensive retrofits, or shut down the plant within the next few years. If GWP does not repower the Grayson Power Plant, our sources of supply will be limited to purchased power, which is not always guaranteed and is very costly with extreme increases in costs for spot market purchases.

? Is GWP repowering Grayson to generate excess power in order to sell it for profit?

✔ No, the proposed repower is to meet the City’s energy needs and to ensure that there is a reliable source of power for Glendale. GWP is not repowering to sell energy for a profit. The capacity of the Grayson repower was driven solely by the reliability needs of Glendale and minimizing rate impacts to GWP customers.

? Glendale doesn’t need this much power. Why are you building such a large plant? Do we really need this much? 

✔ The capacity of the Grayson Repowering Project is driven to reliably serve the needs of the residents and businesses of Glendale. Without the Grayson repowering and after Units 1-8 are no longer capable of running, the available capacity through imports from outside sources and the one newer unit at Grayson Power Plant—Unit 9—is 287 MW. 

GWP must have in place sufficient reserve sources of power to cover both the “loss of the single largest contingency,” which is referred to as its “N minus 1” or “N-1” “contingency” and its second largest contingency, which is referred to as its “N minus 1, minus 1” or “N-1-1” “contingency” and involves two contingencies – the loss of Glendale’s two largest resources -- happening consecutively. This means that we must maintain enough generating capacity to power the City even if there is an unexpected failure or loss of our largest two sources of power. For GWP, the largest single source of power is the DC Intertie line, which transmits 100 MW of power to the City. See image of GWP’s sources of power here. In fact, partial and complete loss of the DC Intertie line has occurred in the past, and some of the outages have been for extended periods of time. In addition, reserves must also be in place to re-establish reserves within one hour. With the loss of GWP’s single largest contingency, the City would have only 187 MW of supply available for meeting its obligations.  

GWP’s next single largest contingency (N-1-1), after loss of the DC Intertie line, is assumed for planning purposes to be 71 MW, the loss of a unit at the power plant. If an N-1 event (the 100 MW loss of the Pacific DC Intertie) occurs, Glendale must plan and prepare for the loss of a 71 MW unit at the power plant (i.e., GWP’s N-1-1 contingency). This requires GWP to have 71 MW of replacement energy available within 10 minutes of the loss of the 71 MW generator. In this scenario, GWP has lost 100 MW of import capability on the Pacific DC Intertie and has subsequently lost 71 MW of local generation (before the 100 MW on the Pacific DC Intertie was restored).  Therefore, Glendale must replace 171 MW of “lost” energy supply on a potentially on-going basis (i.e., longer than one hour).  With the loss of GWP’s two largest single contingencies, the City would have only 116 MW of supply available for meeting its obligations.  

GWP’s system load exceeds 187 MW more than 80 days a year and exceeds 116 MW daily. With respect to a peak day, GWP’s peak load is 350 MW (with no allowance for reserve margin) and there would be a shortfall of 163 MW associated with GWP’s N-1 contingency and a 234 MW shortfall if GWP had N-1 and N-1-1 contingencies.  Such shortfalls would have to be supplied by resources internal to the City. 

The Grayson Power Plant, once repowered, would add a capacity of 262 MW at average annual conditions (64° F). On a hot day (95° F), that capacity would fall to 242 MW. On the peak load day (100°+ F), the available additional capacity would be slightly less.

With 242 MW available at Grayson Power Plant, the City would be able to cover both its N-1 and N-1-1 contingencies.  Thus, the Grayson Repower allows GWP to reliably serve Glendale by providing sufficient capacity to cover the loss of GWP’s two single largest contingencies and still meet load, as well as the non-operating reserve that could be started to provide the required spinning reserve.

Additionally, as GWP imports increasing amounts of wind, solar and other variable sources of renewable energy into the City, and as more solar power is generated locally in Glendale, this creates increased fluctuations on the power grid. A steady, constant source of energy such as that from the Grayson Power Plant is needed to balance out (“firm and shape”) the energy so that that a smooth and steady supply of power can be delivered to GWP customers. The old units at the Grayson Power Plant do not have the ability to rapidly adjust up and down to account for variances in solar output, based upon weather patterns on a minute-per-minute basis. Modernizing Grayson will allow us to manage renewable energy flows dynamically, so that energy deliveries will continue to be reliable.

? Will GWP install any renewable energy sources at Grayson?

✔ Yes, GWP will be placing solar panels onto the new buildings at the Grayson Power Plant, totaling approximately a ½ MW. GWP also plans to install 40 MW/80 Megawatt-hours (MWh)*** of short-term battery energy storage for regulation purposes at Grayson to reduce short-term cycling of the units. This will be done after the power plant is repowered. GWP is a leader within California in supplying renewable and carbon-free electricity. In 2016 GWP sourced 64% of the energy it supplied to Glendale from carbon-free sources (compared to 44% for all of California). Glendale is already close to meeting the requirement for 2030 that publicly-owned utilities procure 50 percent of their electricity from eligible renewable energy resources. Today, far ahead of the 2030 target date, Glendale procures 47 percent of its electricity from eligible renewable energy resources. GWP is committed to renewable energy and continues to expand our programs to use more solar and wind power.

*** A megawatt hour (MWh) equals 1,000 kilowatts of electricity used for one hour.

? Will potable water be used as part of the repowered Grayson Plant?

✔ The Grayson Power Plant would use recycled water for all process and cooling water requirements. The main use for recycled water includes boiler water makeup, cooling tower makeup, turbine power enhancement and cleaning, and NOx control for the simple cycle units. Recycled water would also be used for Unit 9 in place of potable water currently being used. The use of recycled water would eliminate the need for 20 acre-feet of ground water from wells in Glendale and 41 acre-feet of potable water currently being used, which is also water efficient and helps improve the City’s overall water conservation efforts. 

? California’s cap and trade program requires all power producers to pay a cost per ton of CO2 emitted. Is the cost being underestimated?  

✔ The cost of greenhouse gas credits would be incurred by Glendale whenever they use electricity from fossil fuel resources, whether GWP generates it or it is imported over the transmission system. Fossil fuel resources will be required until systems of energy storage have been proven on a utility scale for a utility such as GWP. The operating costs would therefore be incurred either way. Intermittent renewable purchase contracts also include a portion of fossil fuel generation.

? Does the Grayson Power Plant sit on a mapped Liquefaction Hazard Zone? 

✔ Like much of the Glendale area, the Grayson Power Plant site is located within a liquefaction hazard zone. A site-specific geotechnical study for the repowering project was performed and included analysis of both seismic and liquefaction risks. The geotechnical study included recommendations for project design in conformance with applicable building codes, which include considerations for seismic and site-specific liquefaction hazards. 

The site has been the home to the City’s local generation for over 75 years and has been subjected to several major earthquakes, including the Sylmar and Northridge earthquakes. Notably, GWP has been able to restore electricity to its customers faster than any other nearby city or Southern California Edison, in part due to having local units at Grayson that were either already operating or were started up, due to seismically-induced loss of transmission imports. 

? Why can’t GWP just have solar panels and batteries to power Glendale?

✔ GWP has reviewed the feasibility of solar PV with battery storage before and also considered solar PV with battery storage as a project alternative. GWP found that such a system is not feasible because of physical constraints. Glendale does not own or control sufficient real estate to develop a utility-scale solar with sufficient capacity coupled with energy storage to reliably serve Glendale’s power needs. Obtaining the required capacity through rooftop solar would be significantly more costly than the proposed repowering project and the pace of rooftop solar development is not rapid enough to replace the need for the Project.  Additionally, GWP does not control private rooftops within Glendale. For these reasons solar with battery storage was not considered a feasible alternative to meet Glendale’s current needs. However, we continue to pursue other renewable energy options, including solar power and battery storage as part of the integrated plan to meet the city’s energy needs. Through the efforts of private individuals, businesses and GWP, almost 15 MW of rooftop solar PV capacity has been developed within Glendale over the past 10 years and GWP has installed a 2 MW battery energy storage system at its Grandview Substation.

? Can Scholl Canyon be used as a solar site?

✔ GWP partnered with a private developer two years ago to study the possibility of developing a solar project at Scholl Canyon. The developer determined that the site constraints at Scholl Canyon made it unsuitable for solar development. For example, the existing environmental control systems for the landfill are required even for a closed landfill (these systems gather methane gas that would otherwise escape to the environment, a gas that has a global warming potential 21 times greater than CO2). Those systems require continued access, which consequently limits the land available for solar panels. In addition, the landfill is subject to significant settlement, which would take the solar panels out of alignment, as well as complicating the electrical gathering system design, necessitating regular rebuilding and realignment.

? What if the City does not repower the Grayson Power Plant?

✔ GWP partnered with a private developer two years ago to study the possibility of developing a solar project at Scholl Canyon. The developer determined that the site constraints at Scholl Canyon made it unsuitable for solar development. For example, the existing environmental control systems for the landfill are required even for a closed landfill (these systems gather methane gas that would otherwise escape to the environment, a gas that has a global warming potential 21 times greater than CO2). Those systems require continued access, which consequently limits the land available for solar panels. In addition, the landfill is subject to significant settlement, which would take the solar panels out of alignment, as well as complicating the electrical gathering system design, necessitating regular rebuilding and realignment.

? Will the repowered plant increase air pollution in the area?

✔ The permitted emissions from the Grayson Repower project will be less than the permitted emissions from the existing Grayson Power Plant. 

GWP developed emissions estimates for the Grayson Repower to use as a basis for permitting. The permitting process is based in part on the worst case daily emission and peak season monthly emissions coupled with the need to provide sufficient starts and operating hours for possible contingencies. Even with these conservative estimates, the permitted emissions from the repowered plant would be less than the permitted emissions from the existing plant.

? Demolition of the existing facility and soil remediation will take 9 months. How are you making sure no contaminants if any are emitted into the air?

✔ During demolition of the existing facility, waste removal plans will be developed and implemented to ensure that no lead or asbestos or other known contaminants are emitted into the atmosphere. Demolition will be done in accordance with applicable federal, state and local requirements. These requirements address containment and handling of materials, as well as a monitoring plan to ensure compliance. These requirements are not specific to the demolition of a power plant; they apply to all demolition work. The contractors we will use are licensed to do this type of demolition and meet these requirements.