Laminar Control and Transactive Energy

Laminar control is drawing a lot of attention from utilities today, and it may just clear the way be the basis for distributed transactive energy (TE).

The problem of smart grids boils down to adapting to intermittent power sources while reducing the operating margin. In power distribution, the operating margin is the amount of “extra” power available at any time. It is the operating margin that protects power delivery from unanticipated power consumption. This causes a volatility of power supply even while it reduces the ability of the traditional grid to adapt to consumers.

The intermittent power sources are distributed, meaning that they cannot supply any consumer not within the local distribution line unless that power travels between lines. For some users, these power sources will be local, and using them locally may not require permission from the grid. Some smart microgrids will not even be attached to the larger grid, so the model cannot rely on central control.

The power utilities have made heroic efforts to try to build a central control system that can manage this growing complexity and volatility with less margin for error. They still have little ability to provide an optimum solution to the knowledge problem of diverse technologies serving diverse purposes to support diverse activities. We are now seeing the beginning of a top-down re-architecting of the grid. 

Laminar Control manes an approach that layers the operation of power distribution. A lamina names a discrete adjacent layer, a term usually used for tissues in biology or for layers in rocks across a geological area. Laminar Control delegates decision-making to the Laminar Control Nodes within each lamina. Upper layers provide guidance based on strategic surveillance and offer situation awareness. Laminar Control nodes respond as best they can and provide telemetry up. Each node may itself have lamina underneath, with its own control nodes. At the lowest level, decision-making may use mechanisms such as traditional demand response (DR). This model pushes decision-making pushed down to the lowest layer, also referred to as the Edge. The Edge is where the local situation can be more clearly perceived and rapidly acted on. Even if there are disruptions in communications or power supplies from above, the elements at the edge can continue in semi-autonomy to complete the mission at hand.

Bottom-up re-architecting of the grid is getting to the same place. A FSGIM-aware facility is a facility ready to act as a Laminar Control Node. A FSGIM-aware node is also ready to negotiate with its peer nodes even in the absence of the higher lamina. A vehicle, then, acts as a mobile control node. Whether it is a peer node to the building systems, or it is a member of a lamina below the building or facility is an implementation decision.

Some early adopters of this edge-based decision-making are those interested in cybersecurity for their systems. For some, it is not enough to hide the internal mechanisms of their power generation and power management, but they want power cloaking as well. They have no interest in sharing any information of the internal workings of their FSGIM-aware facilities. They view the inside of a facility as a discrete security realm. The growing expectations are that a microgrid should cloak power signatures as well as controls. Clearly this model is not accepting of third party monitoring, let alone third party control.

Circling back to the electric vehicle, as a simple cartoon of these issues…

As a mobile control node it needs to understand, about itself, in information model conformant with FSGIM, or the CTS at least. As the EV drives around, it parks within different microgrids, which may opt to not share any information about this control node with the others. We can also imagine a charging station connected directly to the substation, allowing the car to act as a peer control node to the distribution microgrids.

Throughout, this car should be a car as any other. The V2B interactions and the V2G interactions should be the same. In either case, it should be laminar control node, acting autonomously with other nodes, to achieve directives from the lamina above….

The purpose of the Facility Smart Grid Information Model (FSGIM) (ASHRAE/NEMA/ANSI 201) is to prepare building-based systems to talk to the grid. Traditionally, such systems ignored power supply and demand, and simply assume it was there for them. It does not dictate what such a system does with that information. If could be merely to share its upcoming plans with its supplier, or it could negotiate changes to those plans.

The important part is the power *effects* of the activity, and not the details of the activity. There is far too much diversity in building systems and the business activities they support to expose direct control. One of the Regulated Environment facilities that Jim Butler’s company is known for could incur huge losses in dollars, and possible large health and safety risks by simply accepting a HVAC “nudge” from a far-away system operator.

This is exactly the information that an electric vehicle should have about itself. It should internally know those things that FSGIM describes, and use that information to share its upcoming plans with its supplier, or it could negotiate changes to those plans. That negotiation is properly with the facility it is plugged into, and we should not assume that is “the grid.” A car may be in an urban parking lot during the day a home at night, and at charging in an off-grid wilderness retreat on the weekend.

The Human Side of Energy Micromarkets

This post is part of the continuing Paths to Transactive Energy series. You can find them all listed by clicking on the matching metatag at the bottom of each post.

The Human Beings must have a say, or any model for transactive energy is doomed to failure. No model based on satisfying The Computers or The Grid will acheive prominence in the market. If optional, people will opt out. If mandatory, people will work around. The market is not a model for decision making, it is a pattern for interactions. In the abstract, semiotics does not determine meaning, only how meaning is conveyed. The interaction patterns do not determine the value of energy used at a particular place and time, they only determine how it is negotiated and conveyed.

Decision making must be local, driven by internal needs. Those decisions take place in the context of a larger market, but the larger market is not determinative of particular actions. People, whether at home or at work, will participate to the extent that it enhances their own satisfaction in some way, and transactive energy is, and must be, thoroughly agnostic about which layer of the Maslovian cake is driving decisions.

The occupants of the house, or of the business facility, determine the values of those systems that they use and how they negotiate. No one outside the house can know whether that spare refrigerator is deep storage or beer refrigerator, and if this weekend’s party makes the beer refrigerator and the ice-maker priority uses. (Note that I am not discussing the human interface that might make it useful or desirable to interact with the priorities of these systems—because these interfaces are outside the scope of transactive energy).

One system keeps things cool, within a range determined by biological safety or by personal preference, with limited flexibility over time of operation. One manages ice production, a pre-consumer that wants to acquire when power is cheap. Those two agents may have the same locus of interaction, let’s call it an IP address. They may be expressions of a single control system, of no open standard. They may not choose to share any temperature information with the EMS/BMS. The EMS/BMS does not care what protocols are used inside the refrigerator. In a similar way, a BACnet network with 5 AHUs may choose to represent itself as any number of agents (likely 1-5, but ventilation may come to market as a separate service than cooling) but not as a collection of BACnet points.

Transactive integration is the way to solve the problem of diversity of systems in the home. Developers of small microgrids aim to waste no energy, but struggle to develop drivers for every system. Energy device drivers for every CPAP? Every stereo system and television? Plate warming drawers? Expresso machines? In my home, the biggest energy user might be my well. The diversity of home systems is daunting. Each of them is valued for the service it provides, but each can have an economic profile, a meta-model, a prototypical pattern for its energy use.

This simplicity and abstraction is a benefit for the maker of the system or device as well as of the EMS/BMS. The owner can look at a device profile in a store or on-line and can say “yes, that is the way this device uses/stores/generates energy”. We can imagine heuristics, such as “you need some more pre-consumption devices to smooth your load.” The economic actor profiles become a way to discuss the systems as well as how they will interact when sharing resources.

DER systems in the house and small business

This post is part of the continuing Paths to Transactive Energy series. You can find them all listed by clicking on the matching metatag at the bottom of each post.

The purpose of an energy management system (EMS) or building management system (BMS) in a home or commercial is to serve the owner or occupants of the home or building. Only secondarily is its purpose to “serve the grid”—and then only to the extent that it is rewarded for doing so in a way that supports its owners or occupants.

Every system in a house or building is a legacy system from the moment it is installed (manufactured, actually). No matter what standard we may posit for future use in home systems and home integration, most systems managed by the EMS or BMS will be legacy for some time to come.

The makers of EMS and BMS will compete based on user (and system) interfaces as much as on performance. What is the easier-to-use interface? Which system gives me reporting that I like better? Which system can I connect to my corporate scheduling system? The inputs through these interfaces will inform the EMS/BMS as it responds to market signals from outside.

A common information model will make this market (interfaces) more competitive. The first draft of that information model was delivered last year by ASHRAE 201. Today’s EMS and BMS will work through local direct control and increasingly through a descriptive framework supplied by ASHRAE 201.

Early adoption of transactive services in the home and office will most likely to be for integrating DER inside the facility. The resource frameworks defined in the transactive energy specifications enable a device or system to express capabilities over time and to make forward commitments. The direct control system in the EMS/BMS can negotiate for future requirements without getting into the weeds of understanding a battery management system.

Battery management systems are increasingly supporting complex internal ecosystems of their own, embedded with integrated circuits and composed of hybrid technologies. These circuits manage battery life through creative monitoring of charge rates, temperature, and power factor. The BMS may take a cell off-line, recondition it over much of a day, and then restore the rejuvenated cell to full service. Flow batteries manage different chemistry and physics to manage dendrite development. Hybrid systems combine systems optimized for long slow charging and discharging with more nimble technologies able to take and provide fast charges.

No businesses will benefit more from virtuous markets for the rapid development and evolution of storage systems than those of the EMS/BMS developer. Rapid evolution and thriving markets could mean the unending development new drivers for new batteries. Even with drivers in place, batteries change in capabilities over time, and based on usage patterns; a full understanding of this year’s capabilities may not be adequate for optimum interaction with the same system after a year’s use. The solution is for battery management systems that are self-managing, can express their capabilities over time.

This requirement describes a transactive node able to describe its forward capabilities and make forward commitments. A battery system must be able to commit to service directives such as “be ready to provide a specific power curve for the 12 hours beginning at dusk”. A battery system must be able to communicate that if it commits to a transaction, it will needs six hours of charging to recover. It must be able to commit to standing requirements (“always have four hours available”) while fully discharging individual cells to maintain capability.

Renewable generation can pair with such systems, and will sometimes interact with a storage system to provide a single hybrid service. (This may well be structured as a transactive nanogrid interacting as a single node within the microgrid). Renewable generation, like battery management systems, is most likely to be part of a new installation. Such systems will likely follow the transactive model for behind-the-meter integration as soon as intelligent power controllers support integration by semi-skilled labor.

This describes a hybrid model, with the bulk of legacy and consumer equipment under direct control of the EMS/BMS, but informed by the transactive commitments of the newer systems. In this hybrid microgrid, the market is shallow, so the resource descriptions are useful.

Paths to Transactive Energy

Transactive energy uses markets to schedule the delivery of services over time. Each service is supplied by a node on a grid (or microgrid). Distributed energy resources and distributed energy resource aggregates can be such nodes. So can an entity that solely consumes power; consuming power at the right time is a market service just as power supply.

This post begins a series of ruminations based on conversations last spring that started in the OpenADR Alliance, and continued off-line with David Holmberg (NIST), Michel Kohanim (Universal Devices), and Gale Horst (EPRI). As usual, while people offer me wisdom, my mistakes are my own.

With the national Transactive Energy Conference coming up next week Portland, I am putting a series of posts together on the subject

Transactive Energy integration is based on Services

Transactive energy uses markets to schedule the delivery of services over time. Each service is supplied by a node on a grid (or microgrid). Distributed energy resources and distributed energy resource aggregates can be such nodes. So can an entity that solely consumes power; consuming power at the right time is a market service just as power supply.

1. All conversations with nodes on the grid should be conversations with black boxes. How those nodes choose to organize themselves internally is no affair of the larger entity. It’s a black box.
2. The purpose of each node / black box is to support the purposes of its owners / occupants / inhabitants, and not to support the things outside the black box.
3. Substantially all interactions with the black box can be transactive resource negotiations, i.e., transactive energy.
4. A node is its own operating environment. It may make sense for some nodes to organize some or part of their internal operations using transactive energy / transactive agents. A node box may choose to use an internal market to manage some or all of its energy use / generation / storage (/ pre-consumption (temporal shifting) / conversion / recycling)
5. If a “device” inside a node box operates through market interactions, those interactions are with the internal market, not the external one. There is no direct market interaction with things / markets / prices external to the black box. (see point 1)
6. Economic signals or availability from outside the node might influence the market, if any, inside the black box, but only as the market interface on the box relays that information. This may include markups / smoothing / discounts or any other means or mechanism that the owner of the black box chooses to use (or that the maker of the black box chooses to use so that the owner of the node will choose that black box).

And most important

7. Entities outside the black box should not use the possible existence of an economic entity inside the box as an excuse to penetrate the veil of the black box