The Sacramento Municipal Utility District provides electricity to Sacramento County, California, and a small portion of adjacent Placer County. It is one of the ten largest publicly owned utilities in the United States, generating the bulk of its power through natural gas and large hydroelectric generation plants , and SMUD's green power energy output was estimated as 19% in 2009.SMUD owned the Rancho Seco Nuclear Generating Station nuclear power plant, shut down by a vote of the utility's rate-payers in the late 1980s. Although the nuclear plant is now decommissioned, its now-empty iconic towers remain on the site. Solar arrays and the 500-megawatt Cosumnes gas-fired plant have risen in proximity to the towers.SMUD's headquarters building, built in the late 1950s on the edge of the East Sacramento neighborhood, is notable for its mural by Sacramento artist Wayne Thiebaud. The mural wraps around the ground floor of the building and is accessible to the public. It is one of the earliest major works by the artist, and remains his largest installation to date. Wikipedia.
Belarde T.A.,Sacramento Municipal Utility |
Railsback S.F.,Humboldt State University
Ecological Modelling | Year: 2015
Predicting cumulative effects is an important challenge of theoretical and management ecology. If a population will be exposed to multiple stressors (e.g., toxins, introduced competitors, climate change), will their cumulative effects be independent and hence multiplicative (the population survival rates due to each stressor can be multiplied together to determine the total reduction in abundance), synergistic (cumulative effects are greater than multiplicative), or antagonistic (stressors offset each other so cumulative effects are less than multiplicative)? Further, the effects of each stressor can vary with such factors as habitat quality, population density, and weather. It is difficult to predict cumulative effects with traditional population-level models because such models must assume the type and strength of stressor interactions a priori, and measuring stressor effects and interactions empirically is rarely practical. Instead, we used an individual-based model in which cumulative effects emerge from how each stressor affects the growth and survival of individuals, and how individuals interact. Our model is in fact based on theoretical concepts explored in the landmark 1980 paper of DeAngelis et al. (Cannibalism and size dispersal in young-of-the-year largemouth bass: experiment and model, Ecol. Model. 8, 133-148): in a community of fish that eat each other, initial differences in size among individuals have strong effects on subsequent abundance and size distributions. We model survival and growth of juvenile Colorado pikeminnow (Ptychocheilus lucius) during their first year, and two stressors they are subject to. The first stressor is a daily cycle of flow fluctuations imposed by an upstream hydroelectric dam; these fluctuations affect habitat area, food supply, and temperature, which then affect juvenile fish growth. Second is an introduced fish species that competes with pikeminnow for food, while both species can prey on each other via the size-based mechanism described by DeAngelis et al. We simulated the effects of the 36 combinations of six levels of these two stressors in each of 28 sites and weather year to produce 840 scenarios, using 7 weather year datasets as replicates. Emergent cumulative effects were multiplicative in 69% of these scenarios, synergistic in 22%, and antagonistic in 9%. Therefore, any a priori assumption about stressor interactions would be wrong in many situations. Synergistic effects were most common in deeper and larger habitats favorable to the introduced species; antagonistic effects were most common in smaller habitats where the introduced species had low growth, because flow fluctuations further reduced the small food supply. © 2015 Elsevier B.V. Source
Bing J.,NEO Virtus Engineering Inc. |
Bartholomy O.,Sacramento Municipal Utility
IEEE Power and Energy Society General Meeting | Year: 2012
This paper describes ongoing research in the area of solar PV production forecasting intended to address a range of effects on the utility grid associated with high penetrations of PV. The ability to anticipate near-term -minutes ahead to hours ahead to day or multiple-day ahead- production of the variable solar resource will be key to successfully integrating ever larger PV capacities with minimal costs. A number of forecast methodologies are surveyed and a mechanism for validating their performance is described. © 2012 IEEE. Source
News Article | March 4, 2016
The board of directors at Sacramento Municipal Utility District has decided not to proceed with construction of the 400-MW Iowa Hill pumped-storage hydro project.
New research suggests that in the future, one of the most lowly, boring, and ubiquitous of home appliances — the electric water heater — could come to perform a surprising array of new functions that help out the power grid, and potentially even save money on home electricity bills to boot. The idea is that these water heaters in the future will increasingly become “grid interactive,” communicating with local utilities or other coordinating entities, and thereby providing services to the larger grid by modulating their energy use, or heating water at different times of the day. And these services may be valuable enough that their owners could even be compensated for them by their utility companies or other third-party entities. “Electric water heaters are essentially pre-installed thermal batteries that are sitting idle in more than 50 million homes across the U.S.,” says a new report on the subject by the electricity consulting firm the Brattle Group, which was composed for the National Rural Electric Cooperative Association, the Natural Resources Defense Council, and the Peak Load Management Alliance. The report finds that net savings to the electricity system as a whole could be $ 200 per year per heater – some of which may be passed on to its owner – from enabling these tanks to interact with the grid and engage in a number of unusual but hardly unprecedented feats. One example would be “thermal storage,” which involves heating water at night when electricity costs less, and thus decreasing demand on the grid during peak hours of the day. Of course, precisely what a water heater can do in interaction with the grid depends on factors like its size or water capacity, the state or electricity market you live in, the technologies with which the heater is equipped, and much more. “Customers that have electric water heaters, those existing water heaters that are already installed can be used to supply this service,” says the Brattle Group’s Ryan Hledik, the report’s lead author. “You would need some additional technology to connect it to grid, but you wouldn’t need to install a new water heater.” Granted, Hledik says that in most cases, people probably won’t be adding technology to existing heaters, but rather swapping in so-called “grid enabled” or “smart” water heaters when they replace their old ones. In the future, their power companies might encourage or even help them to do so. Typically, a standard electric water heater — set to, say, 120 degrees — will heat water willy-nilly throughout the day, depending on when it is being used. When some water is used (say, for a shower), it comes out of the tank and more cold water flows in, which is then heated and maintained at the desired temperature. In contrast, timing the heating of the water — by, say, doing all of the heating at night — could involve either having a larger tank to make sure that the hot water doesn’t run out, or heating water to considerably higher temperatures and then mixing it with cooler water when it comes out to modulate that extra heat. Through such changes, water heaters will be able to act like a “battery” in the sense that they will be storing thermal energy for longer periods of time. It isn’t possible to then send that energy back to the grid as electrical energy, or to use it to power other household devices — so the battery analogy has to be acknowledged as a limited one (though the Brattle report, entitled “The Hidden Battery,” heavily emphasizes it). But the potentially large time-lag between the use of electricity to warm the water and use of the water itself nonetheless creates key battery-like opportunities, especially for the grid (where utility companies are very interested right now in adding more energy storage capacity). It means, for instance, a cost saving if water is warmed late at night, when electricity tends to be the cheapest. It also means that the precise amount of electricity that the water heater draws to do its work at a given time can fluctuate, even as the heater will still get its job done. These services are valuable, especially if many water heaters can be aggregated together to perform them. That’s because the larger electricity grid sees huge demands swings based on the time of day, along with smaller, constant fluctuations. So if heaters are using the majority of their electricity at night when most of us are asleep, or if they’re aiding in grid “frequency regulation” through instantaneous fluctuations in electricity use that help the overall grid keep supply and demand in balance, then they are playing a role that can merit compensation. “If the program is well-designed, meaning in particular, you have a well-designed algorithm for controlling the water heater in response to these signals from the grid, then what’s really attractive about a water heating program is that you can run these programs in a way that customers will not notice any difference in their service,” says Hledik. In fact, using electric water heaters to provide some of these services has long been happening in the world of rural electric cooperatives — member-owned utilities that in many cases control the operation of members’ individual water heaters, heating water at night and then using the dollar savings to lower all members’ electricity bills. Take, as an example, Great River Energy, a Minnesota umbrella cooperative serving some 1.7 million people through 28 smaller cooperatives. The cooperative has been using water heaters as, in effect, batteries for years, says Gary Connett, its director of demand-side management and member services. “The way we operate these large volume water heaters, we have 70,000 of them that only charge in the nighttime hours, they are 85 to 120 gallon water heaters, they come on at 11 at night, and they are allowed to charge til 7 the next morning,” Connett explains. “And the rest of the day, the next 16 hours, they don’t come on.” Thus, the electricity used to power the heaters is cheaper than it would be if they were charging during the day, and everybody saves money as a result, Connett says. But that’s just the first step. Right now, Great River Energy is piloting a program in which water heaters charging at night also help provide grid frequency regulation services by slightly altering how much electricity they use. As the grid adds more and more variable resources like wind power, Connett says, using water heaters to provide a “ballast” against that variability becomes more and more useful. “These water heaters, I joke about, they’re the battery in the basement,” says Connett. “They’re kind of an unsung hero, but we’ve studied smart appliances, and I have to say, maybe the smartest appliance is this water heater.” Of course, those of us living in cities aren’t part of rural electric cooperatives. We generally buy our electricity from a utility company. But utilities also appear to be getting interested in these sorts of possibilities. The Brattle Group report notes ongoing pilot projects in the area with both the Hawaiian Electric Company and the Sacramento Municipal Utility District. Thus, in the future, it may be that our power companies try to sign us up for programs that would turn our water heaters into grid resources (and compensate us in some way for that, maybe through a rebate for buying a grid-interactive heater, or maybe by lowering our bills). Or, alternatively, in the future some people may be able to sign up with so-called demand response “aggregators” that pool together many residential customers and their devices to provide services to the grid. And as if that’s not enough, the Brattle Group report also finds that, since water heating is such a big consumer of electricity overall — 9 percent of all household use — these strategies could someday lessen overall greenhouse gas emissions. That would be especially the case if the heaters are being used to warm water during specific hours of the day when a given grid is more reliant on renewables or natural gas, rather than coal. Controlling when heaters are used could have this potential benefit, too. Granted, these are still pretty new ideas and the Brattle Group report says they need to be studied more extensively. But as Hledik adds, “I haven’t really come across anyone yet who thinks this is a bad idea.”
News Article | December 10, 2015
A version of this article was originally published on December 1, 2015 on Greentech Media. Market forces are precipitously changing the role of utilities. Private companies are offering customers more choices and control over their electricity through energy efficient products and services, demand management, self-generation like rooftop solar, smart electric vehicle chargers, and on-site storage. At the same time, the role of utility-scale wind and solar is growing, as costs have plummeted since 2010. Whether or not utilities, their boards, and their regulators keep up with these market forces depends mightily on the utility ownership model. For a majority of electricity consumers in the U.S., private companies (investor-owned utilities, or IOUs) provide electricity service, and their commissions can use performance-based regulation to align incentives with customer values. But another important tranche of the population is served by publicly-owned utilities (POUs), non-profit entities directly governed through a democratic body. These utilities must also adapt to new customer demands and market forces, and this transition is just as challenging for public utility management and their boards. Very few resources exist on how POUs can improve performance, which is why we have put together a new set of case studies and lessons on “Maximizing Performance of Public Power Utilities” to illuminate some examples of how POUs can deliver the outcomes desired by their customer-owners. This new piece of research focuses on high-level performance management, but other changes—e.g., rate design, as touched on by 51st State submissions from theAmerican Public Power Association and the National Rural Electric Cooperative Association—are also important levers for improving POU performance. POUs serve about a quarter of all customers in the U.S., but their governance and ownership structures are diverse and their constituencies range from large cities to sparsely populated rural areas. POUs fall into three main categories: cooperatives (co-ops are private, non-profit entities owned by their customers and governed by a customer-elected board), municipal utilities (munis are owned by a city and governed either by a city council or an appointed board), and public utility districts (PUDs are government agencies designed to fill a utility role, either within an existing government agency or in its own jurisdiction). Though they have diverse governance structures, these three kinds of POUs possess many commonalities that justify examining them together. POUs can be pulled in many directions that go beyond strict utility concerns, including stimulating local economic development and collecting new revenue for municipal funds or co-op dividends. Many POUs are also challenged by lack of capacity; many POUs represent small jurisdictions and don’t have the financial and technical resources to stay current with new technologies or broader market trends. Here, we lay out three steps for public power governing boards to consider: First, there are a couple of very low-cost, no regrets steps that POUs can take today: collect diverse perspectives (customers and other local interests), work with folks to define the outcomes they want, and develop repeatable metrics to measure performance against those outcomes. No doubt, this takes some work upfront, but many existing resources can help, including this initial list of metrics offered by Synapse. And the upfront work is worth it: the process can improve operational efficiency and help utilities take advantage of modern technologies to deliver customer needs. Two examples… For Toronto Hydro, a large municipal utility, the first step toward improving performance was engaging a diverse set of local interests to prioritize performance categories and put everyone on the same page about each other’s desired outcomes. In 2013-2014, Toronto Hydro surveyed the City of Toronto, customers, contractors, suppliers, industry associations, public interest organizations, government, academia, and employees: Since they completed that first survey, Toronto Hydro has begun to track performance by compiling “scorecards” in four categories: customer focus, operational effectiveness, public policy responsiveness, and financial performance. The scorecard reports quantitative metrics to indicate whether performance has been achieved and whether the utility is continuously improving. Simply having a conversation with local interests about what they really want out of the electric system can foster important alignment, particularly for POUs that consider a wider range of policy objectives. Associated quantitative metrics should be repeatedly measured and recorded to improve POUs’ ability to deliver customer value. Performance metrics should not be developed in isolation. Instead, to maximize performance in each of the measured areas, POUs that own generation resources can integrate performance metrics into their Integrated Resource Plans (IRP). Public IRP processes can help shed light on potentially divergent performance goals, and create a forum for utilities, board managers, and other local interests to reach consensus on the best way forward before major investments are undertaken. In 2014, the Austin City Council adopted a resolution, which set a 65 percent renewable energy goal for 2025 and capacity targets for solar, wind, and storage, forcing Austin Energy (a large muni) to update its ten-year IRP. At the same time, the Council also mandated that rates not increase more than two percent annually. Austin Energy’s first analysis found that the resolution would raise rates by an average of six percent annually, so the muni instead proposed a cost-saving plan that would reach 50 percent renewables by 2025. City councilmembers and environmental advocates were dissatisfied with the lower renewable energy target, so Austin Energy further revised its proposal to include several innovative mechanisms to reach 55 percent renewables – including demand response and energy efficiency, reverse auctions to minimize the costs and risks of renewable power procurement,new thermal and battery storage technology, and biannual planning updates. Through a public IRP process with metrics clearly reported, Austin Energy was able solicit feedback that ignited innovation and landed on a set of outcomes that worked for everyone, allowing the utility to keep rates below the Texas average while setting country-leading clean energy standards. If POUs are still not delivering value to customers after the “no regrets” actions described above are taken, government agencies, cities, and communities can explore ways to enhance board governance. Two examples demonstrate how evolutions in governance can improve overall utility performance. In 2002, the board of the Sacramento Municipal Utility District (SMUD) had become disconnected from utility executives’ decision-making process. To remedy this disconnect and improve governance, the board and executive team recognized that the board must redefine its role and clarify its strategic direction while giving utility executives sufficient leeway to accomplish the city’s goals. So, SMUD’s board implemented twelve “Governance Process Policies” requiring it to set and measure utility achievement of performance goals to ensure board governance supports utility performance. The new policies essentially clarified that the board should focus on defining high-level outcomes for the utility, and utility executives should be free to decide how to accomplish those high-level objectives. As a result, SMUD’s board regularly revises its goals in response to public policies and changing market conditions. According to SMUD’s annual report, this has helped make it California’s top-rated electric utility in customer satisfaction, while beating comparable utilities on average residential electric bills and keeping pace with state renewable energy targets. To boot, self-evaluations by the board and utility management team indicate that effectiveness of the board increased dramatically from 2002-2012. If, after implementing the changes described in steps one and two, utility governing boards are further interested in keeping utility management focused on its core strengths, they can consider bringing in a third-party to take on a subset of utility goals. Vermont Efficiency Investment Corporation (VEIC) is a publically-owned non-profit spin-off that serves both POUs and the IOU in Vermont, and its singular function is to pursue energy efficiency. This example demonstrates how utility functions can remain publicly-owned while a non-profit third-party improves performance. Since 2000, VEIC has saved customers 13.7 million megawatt-hours (MWh), meeting or exceeding many of its efficiency performance metrics. This singular focus on efficiency allows sophisticated customer outreach and data-driven identification of the best opportunities for energy savings, making Vermont a national leader in efficiency, according to the American Center for an Energy Efficient Economy. VEIC’s board also adjusts the utility’s compensation by up to three percent based on performance—and this compensation gets passed through directly to employees. This further incents good performance by “increasing cash reserves, improving the credit rating and keeping costs of debt low; mitigating risks during economic downturn; and maintaining a culture of continuous improvement and competition.” As a more drastic option for utilities struggling to achieve important outcomes, a third-party non-profit is an interesting model for improving performance in a specific area. Though by no means an exhaustive list, these steps can help POUs and their governing bodies improve performance and meet new power sector goals. 3. If performance lags, consider more drastic measures. Options include: