Generac Grid Services Blog


Posted by Michael Ratliff on Jun 26, 2017 12:45:00 PM


When it comes to effectively leveraging distributed energy resources (DERs), there are three critical success factors that any DER management system or Virtual Power Plant (VPP) must embody. This is especially true as the number of distributed energy assets continues to grow and as the ways in which distributed energy can be used to keep the grid in balance grows along with them. They are: 

  • Speed
  • Scalability
  • Accuracy

In this blog, we tackle the topic of speed and exactly why this such an important success criteria.  

When it comes to how quickly distributed energy assets need to be aggregated, optimized and dispatched, how fast is fast enough? The answer depends on what they are being dispatched to do.  A recent survey of utilities conducted by Enbala revealed a fairly even split among those who said day-ahead response speeds were adequate and those asserting that they need response speeds of less than a minute. It’s clear though that more and more energy companies are recognizing that speed is an increasingly critical success factor. 

shutterstock_662601190.jpgAs the grid’s reliance on distributed energy resources continues to expand – and as the number of assets feeding into the DER mix grows with it – we believe that sub-second responses will be required. A good rule of thumb for assessing whether a Distributed Energy Resource Management System (DERMS) is fast enough for modern grid balancing needs is to ask one fundamental question: can it respond at the rate of the traditional power system, i.e., can it respond instantaneously?

Our experience, combined with a bit of prognosticating about the future, indicates that the imminent success of DERMS will be measured by their ability to respond to grid events at least every two seconds, along with their ability to achieve real-time forecasting and optimization control.

It’s All About the Mix – and the Problem to be Solved

The optimal mix of DER assets is dependent on the current state of hundreds of thousands – and potentially MILLIONS – of connected distributed energy devices at any given moment in time. It is thus very important that a DERMS platform be able to accurately optimize all of these assets quickly enough to ensure that power is moved to the right places at precisely the right time. If it can’t, it will quickly face limitations in what it is able to accomplish, the benefits it is able to achieve and the ROI it generates.

To solve a peak capacity problem, hour-ahead speed may be adequate, but to solve a real-time frequency or voltage reliability problem, sub-second optimization and control are required, particularly with challenges like voltage excursions, where thousands of different problems might be simultaneously occurring at numerous locations on the grid. 

Ask Yourself ‘What If?’

Utilities base numerous business decisions around forecasts founded on best-guess assumptions about what’s most likely to happen on the grid. Consider, however, how much more accurate and sound these business decisions could be if planning forecasts could be replaced with real-time optimization and control enabled by sub-second data feeds from millions of distributed energy assets extending to the furthest edges of the grid.

Instead of coming up with potential solutions to forecasted scenarios, could we instead act in real time to solve actual problems as they are occurring, thereby achieving a much better solution? For example, instead of forecasting how best to leverage traditionally slow, low-resolution, day-ahead or hour-ahead demand response programs to balance renewable resources like wind or solar, what if we could simply respond immediately to clouds covering a solar array by leveraging DER assets that can balance solar energy drops with second-to-second balancing that maintains an optimal balance of supply and demand.

These are just some of the reasons why speed of response is so important today in the DERs world. 

We’ve written a new white paper about the new normal in leveraging DERs for optimal grid balance and invite you to download that paper for a more in-depth discussion of the concepts we’ve discussed here. 

 Get the paper

Stay tuned for blogs on tenets 2 and 3 for DER success: accuracy and scalability.  They are coming soon.


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