TODAY’S STUDY: Getting More New Energy On The Grid
Managing variable and distributed energy resources: A new era for the grid
Marlene Motyka and John McCue, November 2016 (Deloitte Center for Energy Solutions)
The ongoing electric power industry transformation has ushered in a wave of variable and distributed energy resources on electric grids across the US and globally. Wind and solar installed capacity soared 85 and 1,169 percent, respectively, in the US from 2010 to 2015.1 And now resources such as battery storage, home energy management systems, and electric vehicles appear poised for strong growth. Forces propelling the overall power industry transformation seem to be some of the same ones prompting this flood of new resources— the drive to reduce carbon emissions from the power supply; to deploy rapidly improving technologies as they travel down the cost curve; and, to respond to changing customer needs and expectations.
US deployment of variable and distributed energy resources accelerated from 2008-2015, with a surge of utility-scale wind power in wind-rich areas such as the Midcontinent. It then gathered momentum with grid-scale solar plants in the West and Southwest, and it is now spreading swiftly down the electric power value chain, as grids in many regions become increasingly decentralized and host a growing number and variety of distributed energy resources (DER).2 Wind and solar power are variable energy resources (VER), labelled “non-dispatchable” since their output is dependent on weather conditions. While they bring many benefits, integration of these resources can be challenging for grid operators, who must ensure generation and load remain in constant balance and power quality is not compromised. Fortunately, there is a large and growing toolbox of solutions to manage wind and solar variability, including the increasingly promising potential of dispatchable DER, such as energy storage, demand response, and (non-variable) distributed generation sources like fuel cells, natural gas-fired turbines, and combined heat and power systems (CHP).
Whether variable, non-dispatchable resources reside at the transmission or distribution level, the industry’s capacity to integrate them is evolving rapidly. Those who see their potential as limited because they are difficult or costly to integrate may be underestimating the capacity for electric systems and markets to innovate. So far, US utilities and grid operators in some regions have successfully integrated annual VER penetration levels of up to 30 percent, with 13 states generating more than 10 percent of their power from VER in 2015, eight states above 15 percent, and three exceeding 20 percent.3 Short-term or “instantaneous” VER penetration levels—for hours at a time—have surpassed 50 percent and even reached 60 percent in some areas, while maintaining a high standard of reliability.4 Some European countries have supported even higher levels. Costs have generally not been prohibitive in the US, with the Electric Reliability Council of Texas (ERCOT) estimating integration of its first 10,000 megawatts (MW) of wind capacity at roughly $0.50 per megawatt hour (MWh) of generation.5 Early forecasts that substantial new generation must be built to back up variable resources like wind and solar power are also not playing out, as the industry innovates and modernizes the grid to increase its responsiveness and flexibility.
How are grid operators handling the growing influx of variable resources? By deploying a broad set of solutions such as expanding transmission; tapping dispatchable, centralized generation resources as well as DER; and deploying energy storage. This paper focuses on the growth path of VER in selected US states and countries with the highest current or projected penetration of these resources, and the benefits and challenges they pose for grid operators. It explores the variety of solutions being implemented across regions with high or rapidly increasing VER penetration, and discusses how dispatchable DER can play a growing role in those solutions.
The discussion concludes that building new generation or transmission assets are not the only solutions for integrating VERs, and they may not be the most cost-effective ones either. Greater potential may lie in redesigning and expanding markets, improving coordination across regions, and most of all, taking advantage of the vast, often unused potential of DER. A growing legion of power-generating or load-reducing resources resides on the distribution system, often behind the customer’s meter—and new tools and market designs to help utilities harness them are continually being developed. In many instances grid modernization investments will be needed to enable greater deployment of DER. As utilities add smart sensing, communications, and control technologies to the grid, the system gains the flexibility to incorporate DER both operationally and economically, and this in turn may enable smoother VER integration.
As states and countries continue down the path toward low or no-carbon energy supplies, the role of variable and distributed energy resources will likely grow and VER integration tools are expected to become increasingly critical. While integrating VER can be challenging for grid operators, in reality these resources have been integrated at higher levels than expected,69 reaching nearly 44 percent of power generated annually in Denmark without impacting reliability. In the US, costs of VER integration have generally been lower than analysts predicted, largely thought to be because the set of tools for integrating them has been expanding. We expect it to be increasingly important to deploy VER integration solutions as penetration rises. In some European countries, such as Germany, rapid VER adoption occurred before some of the solutions described here could be implemented, which contributed to supply-demand imbalances and rising electricity prices. Germany is now pursuing policies to slow VER growth and implement DER solutions such as demand response, CHP, and storage. Another area with rapid VER adoption, the Australian state of South Australia, is reviewing its integration strategies and particularly its wind plant settings that interface with the electric grid, after a recent storm-related blackout that involved, though was not caused by, several of the state’s wind farms.
Across the globe, solutions that were originally thought to be the primary tools for VER integration, such as building backup power plants, have not been used extensively. Instead, operators are relying more heavily on solutions like improved weather forecasting, expanded regional and inter-regional coordination, and perhaps most significantly—on a growing wave of DER that is becoming increasingly accessible to operators as the grid is modernized and new market services and technologies become available. Grid modernization seems particularly critical to unlocking the potential of DER, just as it is to improving efficiency and cutting costs across all grid operations. An “intelligent grid” would allow operators to monitor, analyze, manage and control the VER and DER on the system.
While once viewed primarily as a threat to utility business models, DER are beginning to be seen as valuable tools to add flexibility to the grid and integrate growing volumes of VER cost effectively. As grids evolve into two-way energy platforms, electricity markets are also evolving, and may increasingly acquire characteristics of the new “sharing economy,” as customers make their DER available to utilities and grid operators to balance the grid. In this environment, utility planners are starting to see DER more as enablers, rather than competition, and increased coordination across systems, markets, and resource owners as the most effective and efficient solution for integrating VER and DER.