In an Era of Distributed Energy Resources, Utilities Increasingly Leverage Analytical Solutions
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- February 19, 2019
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The era of distributed energy resources has arrived, bringing with it operational challenges for utilities and grid operators alike.
Public policy initiatives and increasingly cost-effective technological advancements are driving the rise of distributed energy resources (DERs). As a result, one-way energy flows from large-scale, central generating stations to end users is being supplanted. Today, two-way energy flows are increasingly common as DERs such as rooftop solar photovoltaic systems, plug-in electric vehicles, and energy storage systems blur the line between who is a generator and who is a consumer.
In many cases, the role switches frequently, if unpredictably, throughout the day, particularly as output from distributed solar resources fluctuates.
Utility and grid operations across North America, in Europe and around the world are being impacted, and a range of analytical tools are being put in place to help manage fast-changing and complex operational challenges.
To gain better insight into the analytical opportunities available to utilities, Energy Central sat down with Ton DeVries, Senior Director of Business Development, Bentley Systems.
Energy Central: What sort of growth trajectory are we looking at for DERs in the coming years?
Ton DeVries: The Energy Department forecasts that the installation of small-scale solar DERs on residential and commercial rooftops in the U.S. will grow by 44% by 2021 to around 9 gigawatts of installed capacity.
That scale certainly impresses. But think broadly about the potential market size for rooftop solar. A three-year research effort by the National Renewable Energy Laboratory suggests a technical potential of 1,118 gigawatts (GW) of distributed solar capacity. That equals roughly 40% of the nation's current electricity sales that could be met solely through small-scale, non-utility solar PV assets.
Public policy is moving toward greater support of DERs, too. The Federal Energy Regulatory Commission not long ago called for barriers to microgrid deployment to be removed all across the country. California’s Renewable Portfolio Standards call for growing amounts of solar plus energy storage. And New York officials want to see deployment of more microgrids and energy storage solutions.
Energy Central: How does the growing adoption of electric vehicles figure into the equation?
Ton DeVries: Plug-in electric vehicles are likely to be equally impactful on utility operations. In many utility planning scenarios, the family auto represents both a load center and a potential resource that is not only highly mobile but with an often-unpredictable charge/discharge profile.
Research that was done last year at NREL concluded that a PEV market share of around 7.5 million vehicles on U.S. roads might not significantly impact aggregate residential power demand. But, those scientists found that a small but concentrated number of PEVs in a specific geographic area could in fact significantly impact peak loads. The net effect could be the need for distribution infrastructure upgrades.
Energy Central: If that sort of scenario plays out with PEVs, what is a chief worry for utilities and grid operators?
Ton DeVries: One worry is that large portions of the distribution infrastructure might no longer reliably support local electricity demand. The possibility of uncoordinated demand as a result of PEV charging could shorten the expected life of equipment such as transformers. Gaining analytical insight into the deployment of charging equipment and PEVs themselves is becoming increasingly critical as utilities make infrastructure investment decisions.
Energy Central: PEVs are one type of energy storage device. We also can think of utility-scale lithium-ion battery energy storage and even pumped hydro. How does energy storage fit in?
Ton DeVries: Energy storage has long been considered as something of a holy grail for the electric power sector. The basic assumption has always been that energy must be consumed as it is produced. The rapid emergence of cost-effective and reliable energy storage changes that assumption. We are seeing utility-scale storage paired with solar and wind energy facilities to provide much more stable energy supplies, smoothing out what traditionally has been intermittent energy flows.
It’s also possible for energy storage systems to play in ancillary markets by providing a range of grid support services. And they were critically important during the big hurricanes that hit the Caribbean in late 2017, helping to keep the lights on in the Dominican Republic.
At a smaller scale are the growing amounts of battery energy storage that is deployed as part of microgrids. Because they are able to provide energy in packets that last anywhere from a few minutes to a few hours, battery energy storage enables a load center to disconnect, or “island,” itself from the larger grid and operate independently.
Energy Central: Microgrids have certainly gained a lot of attention in recent years and seem to be pushing a lot of DER investment. Can you elaborate a bit on the trend?
Ton DeVries: Microgrids have grown in popularity since Superstorm Sandy hit the northeastern U.S. in 2012, causing widespread blackouts. The storm left large portions of the northeast without electric power for days. Some of the most striking photo images taken after the storm showed some critical facilities such as hospitals with their lights on. They were self-generating in island mode, even as surrounding neighborhoods were pitch black and without power.
Battery energy storage also proved its worth in California in 2015 after the Aliso Canyon gas storage leak led state officials to turn to energy storage systems as a backup to conventional natural gas-fired power plants. Reliability and resiliency are driving microgrid investments. But here, too, their deployment at the margins of the grid have implications for the broader electric power infrastructure.
Energy Central: One hallmark of DERs is the two-way nature of their energy flow. What operational challenges does this present?
Ton DeVries: As DERs, PEVs, and energy storage advance across electric power distribution networks, the traditional model of one-directional energy flows is changing to one of highly dynamic two-way flows. We see everyone from power plant control room operators to generating fleet managers to regional transmission operators facing operational challenges in their day-to-day work that simply did not exist even a decade ago.
We know that utilities certainly can absorb some amount of distributed generating resources, but questions remain. For example, at what point do variations in power quality become an issue? At some relatively small percentage of the generating mix, say 3% or 5%, or at some percentage that is considerably higher?
Equally challenging are issues related to long-term investments in the distribution system. Will growing PEV adoption rates require upgrades to transformers and other localized infrastructure equipment than otherwise might be necessary?
Energy Central: Do any case studies come to mind to help illustrate this?
Ton DeVries: I recently spent some time in Australia where rooftop solar penetration tends to be higher than in the U.S. and in some cases approaches 20%. Regulations there stipulate that utilities must accept even small-scale rooftop solar of around 5 kW in size. One utility reported power quality issues and overloaded feeders in parts of its service territory with a high percentage of rooftop solar.
Rather than try to limit the deployment of such distributed generating resources, the utilities are looking to proactively assess and plan for rooftop solar of all sizes and configurations. Gathering actionable data is critical for those Australian utilities as they work to understand how power quality issues are impacted by expanding use of DERs.
It’s a complex equation that needs to be solved—and acted upon—thousands of times each day. Included in the equation are generation resources that are distributed across wide geographic areas and that are responsible for two-way power flows from inverter-based devices. Factor in the ever-present risk of extreme weather incidents that can disrupt power resources and you can see how critical actionable data can be to ensure reliable electricity.
Energy Central: Given the complexity, how do utilities and grid operators begin to leverage data to help them make investment and operational decisions?
Ton DeVries: With this increasingly complex and uncertain environment, it becomes necessary not only to collect data on operational conditions but also to use it across the enterprise to drive strategy and decision-making. Despite this imperative, we estimate that as much as 90% of data that is collected is considered to be “dark,” meaning that it is collected but ineffectively used, if it is used at all.
Informational silos remain the norm at many electric utilities even as digitalization becomes more widespread. The transformational change that is just beginning to take hold is for utilities to break down the silos, especially as artificial walls separate IT professionals from their engineering counterparts.
Connected data environments provide a suite of tools that allow data streams to be connected. Not only is the amount of “dark” data reduced through deployment of these tools, but it becomes easier for events that impact operations, for example, to more effectively guide engineering and asset investment decisions.
Enhanced data analytics and more effective decision tools are imperative for firms that are intent on thriving in this era of distributed energy resources, two-way power flows, and highly dynamic operational changes.
It’s clear that trends occurring in power utilities are causing disruption and operational challenges to the industry. The growing deployment of decentralized and distributed energy resources, such as solar panels, wind farms, community solar, electric cars, and more, will continue to have a major impact on the infrastructure.
The most progressive and, ultimately, the most successful utilities are already addressing how to maintain reliability and resilience within the grid, considering how DER interconnections affect network performance, and without disrupting current operations.