A new FERC order, while ostensibly addressing energy storage resources, actually provides an important opportunity to create a universal data model for all grid resources. The traditional way of looking at generators and loads is no longer sufficient. We should take advantage of this opportunity.
FERC Order 841 requires electricity markets to create an energy storage participation model that allows a resource to “provide all capacity, energy, and ancillary services that the resource is technically capable of providing in the RTO/ISO markets, …be dispatched and set the wholesale market clearing price as both a wholesale seller and wholesale buyer, …and account for the physical and operational characteristics through bidding parameters or other means.”
I argue here that, if this is done correctly, this participation model should become the “universal participation model” for all resources – generators, loads, and even some transmission resources. And I believe that we need this universal model. Without it, our markets and systems will become increasingly convoluted and unable to deal effectively with the resources that we are already building today, and even more so with what we will come up with next. How do I offer “solar plus storage” plants, DER aggregated virtual power plants, or even “gas plus storage” plants into the market in a way that offers all of the capabilities to the market? What good is the next useful idea if the market system can’t use it?
First, what is a participation model? As FERC notes in the order: “The RTOs/ISOs generally have a set of tariff provisions that apply to all market participants. In addition, the RTOs/ISOs create tariff provisions for specific types of resources when those resources have unique physical and operational characteristics or other attributes that warrant distinctive treatment from other market participants. These distinct tariff provisions that are created for a particular type of resource are what we refer to in this Final Rule as a participation model.”
I argue that we need to flip this on its head. This definition suggests that participation models are created as an exception to the general tariff case, and the general case is essentially assumed to be a conventional generation resource, such as a traditional thermal power plant. But in the case of electric storage resources such as battery storage systems, the resource is more capable than the general case, albeit with some differences. It makes better sense to start with the most general and idealized conceptual resource as the general case and then turn off or adjust the parameters of this idealized model, otherwise we are constantly working to extend a hodgepodge of tacked-on exceptions. The unavoidable implementation delays are inherently discriminatory to new innovation and the RTOs are constantly operating in catch-up mode, with ongoing prodding from new entrants and from FERC.
In fact, if the RTOs do their job as FERC is requesting, I would argue that all other generation and load resources can be represented within the generalized storage participation model that is required by FERC Order 841. The storage participation model, perhaps with slight “idealization” in its design, becomes the universal model that can be used, simply by changing appropriate parameters, for all other resources.
Several major categories of descriptors are needed in this universal data model, allowing a resource to represent its various capacities, ranges, rates, limits, operating constraints, and operating interactions. For example, the capacity of a storage resource may be its nameplate value as either a generator or a load, and it may be able to vary real power continuously and rapidly through the full range, but it may be energy limited. A more traditional resource may have a limited operating range, perhaps with discontinuities across its range of possible power values, but it may be able to sustain a longer duration. Operating constraints must identify ramp rates and minimum times for starting, running, restarting and so forth. Operating interactions can describe the capabilities for providing reliability services and ancillary services, and whether or not the resource must currently be providing real energy or real load in order to provide the services, and the speed of such services under normal and emergency circumstances. Some of this information is static, while other parts are dynamic based on current conditions. But as a whole, the data model and associated price curves would fully represent the resource’s offer to the market in a way that is truly comparable and objective across all resources.
I’m not saying that designing the universal data model is easy. It’s complicated, and it will require our smartest and most experienced data architects to get it right. Each category contains dozens of descriptors and parameters, some of them quite complex. But I am saying that it is very important and it is possible.
Those of you with a background in software know why this is so important. Get the data model wrong and your software has limited capabilities and it is an expensive nightmare to code and maintain. But if you get the data model right, you have tremendous capabilities and code that is flexible and elegant. Data definitions literally change the way that you think about the problem. The data model affects what you can do and how you think about it.
It therefore follows that a well-designed universal data model would improve our market systems and commitment/dispatch systems in the long run. If all resources are viewed as subsets of a flexible, idealized model (rather than as tacked-on additions to a less flexible model), the next generations of our systems can be more elegant and more capable. It should also improve our ability to think about solutions to our power system needs, because it becomes easier to see how our available building blocks can fit together. For example:
- We will realize that we have hundreds of ways to respond to ramps and maintain system balance and reserves.
- When we need faster frequency response, we can identify all resources that can provide it and understand any interactions.
- For planning, because we can see both the current capabilities for all the resources and conceivably also know which of them have capabilities that can be adjusted, our planning process can be smarter about using what we have or building something new.
Finally, this universal model could work for more than loads and generators and storage; it could also work for high voltage DC (HVDC) transmission. The terminal of a HVDC system is an energy source behind a DC-to-AC converter, just like a large battery storage system. HVDC could participate in the markets using parameters in the universal data model that are like those of a battery storage system (but one that is capable of providing a very long, and potentially infinite, sustained duration). The possibilities for business models and interconnections across market seams gets interesting if you think about what this means.
The time has come to rethink our design, start with the most capable and idealized participation model that we can imagine, and then represent all real-world resources as subsets of that idealized case. A flexible battery storage resource is arguably the closest example to that idealized resource that we have today. Other generators and loads can be represented by varying the parameters in this data model.
Elegance is a very desirable and useful goal. The elegance of this model could change the way that we think about our resources, and it would allow us to operate our markets in a way that is technology neutral, economic and nondiscriminatory. Done right, it would largely eliminate the need for new programming (or new FERC orders like Order 841) when emerging technologies or novel combinations of technologies emerge. FERC is requiring the RTOs to develop a new model for electric storage resources, but we should take advantage of this chance to rethink how we look at all resources. This is a rare opportunity. Let’s use it.
Mark Ahlstrom is President of the Energy Systems Integration Group (www.esig.energy), a non-profit engineering, resources and education association that holistically serves the energy industry.