August 2016

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Just-In-Time Power and Water at the Edge.

Since water must be pumped, and pumped water can generate electricity, markets in transactive power and transactive water can work together.

Toby ConsidineToby Considine
TC9 Inc

The New Daedalus

Contributing Editor

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The future of infrastructure is just-in time. Just-in-time delivery of structures, ready to support people and business, customizable to the site, long lasting, ready for smart energy and water. Just in time delivery of distributed energy, ready to support structures, the people who live and work in them, and the services they need, and ready for smart grids. Just in time delivery of pure water, ready to support people and agriculture, able to work alongside smart power and smart grids.

Consider a simple building with only a refrigerator, air conditioning, a solar panel (PV) and a power storage system (battery). Each is represented by an autonomous market agent.

The refrigerator and the air conditioner are similar: each runs episodically to support some private purpose, prefers to run an entire cycle or not at all, can shift any cycle forward or back in time while still providing its service. To coexist within the power supplied by the PV, they must not run at the same time lest they exceed the power available. Each determines when it cycles by submitting time-based tenders, finding the minimum price, i.e., buying power when the other is not.

The PV is represented by an agent acting as a seller, able to make commitments based on its internal predictions of weather. When it is unable to meet commitments, say when a cloud passes over, it must go to the more expensive aftermarket, and buy power from the battery.

The battery is represented by a merchant actor, buying power low and selling high. In another model, it could operate as the “market specialist”, brokering market transactions and improving market liquidity through trading on its own account.

As we add more systems to the building, each represented in the internal power market by an agent, we do not need to add complexity to the control systems; we merely add participants to the market. The knowledge problem of specific system operations and controls is simplified through abstraction to the common transactions. If the building is able to connect to a grid of some kind, it does not expose its inner workings; the building exposes only the aggregate market position of the interior market.

In this model buildings may trade with each other using the same market services and interactions unused to manage the internal supply and demand. A community energy resource such as an independent wind generator or larger power storage system acts as a peer node within the neighborhood. A non-building entity such as a wastewater pumping station may participate in the local building-to-building (B2B) market.

In a similar way, the local B2B market can participate in a larger neighborhood market. Where transactions between particular market participants are limited by transmission capabilities, a parallel transport or congestion market can be introduced.

Inside any building, any system can potentially operate an internal market. For example, a multi-story building may choose to have its multiple air conditioning (HVAC) zones operating as their own market, with only the aggregate HVAC market participating in the building market. The underpinning for in-building markets in power are described in detail in the recently published ANSI/ASHRAE/NEMA Standard 201-2016, the Facility Smart Grid Information Model.

[an error occurred while processing this directive]This pattern of integration is sometimes referred to as fractal microgrids. With transactive integration, the market negotiations and transactions are identical at each level, and the underlying complexity of each market participant is hidden. Inside a building with a single owner, the complexity of block-chain as a transaction monitor may be unnecessary. At the largest scale, in the bulk power markets, transactions may require traditional financial instruments. In-between, where the transactions are many and small, where resources are flowing between systems with different owners, and where local settlement may be desired to achieve resilience goals, blockchain is of most use. Within any microgrid, systems may use blockchain to create and manage identity, to record contracts, and to settle transactions.

Blockchain is in essence a means to create a distributed database, with information shared between participants, so no one participant can change the information. Blockchain is in growing use from early power trading in the Brooklyn Microgrids project, to world-wide logistics management. Some codebases such as Open Ledger, look to bankable blockchain, wherein the net of transactions can easily flow into the world banking system. Others, such as IOTA, aim at lightweight models that are cost-effective for transactions a tenth of a cent and smaller, and that can run on very small chipsets.

New initiatives are extending the principles of transactive energy to water distribution. These models make sense today where there are tight restrictions on aquifer pumping shared between farms. Since water must be pumped, and pumped water can generate electricity, markets in transactive power and transactive water can work together. This scenario is particularly interesting in communities that are off the water grid and may be using energy intensive technologies such as Atmospheric Water Generation (AWG) to provide water for homes and hydroponics.

And now I have a question for my readers. Smart water meters that can support small transactions are hard to find. Most smart water meters are designed to update to legacy-utility systems to use the cloud without changing the fundamental business model. I am interested in finding more sources of small water meters able to support small transactions with open interfaces that enable development. If you know of such a product, let me know.


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