Utilities, Commercial Building Owners Win With Distributed Energy Storage

by Doug Staker, Demand Energy Networks Inc.

The idea behind smart grids is to use information to improve the efficiencies and effectiveness of electrical power generation, transmission and distribution resources.

It’s easy to see why this makes sense for utilities.

By reducing electrical demand during times when resources are heavily taxed, the existing grid infrastructure can be used more efficiently, controlling costs for all while maximizing usable power for energy consumers.

Accomplishing this and getting the greatest return from smart grid investments require active involvement from energy users and suppliers. Conservation is important, but fulfilling the promise of the smart grid is not just about reducing the energy consumption by power customers.

Building owners can partner effectively with utilities to control and schedule their power demands to serve their operational needs while helping utilities achieve their goals.

Installing intelligent distributed energy storage systems at the load center on the customer side of the meter that interact with utility controls and local building controls and other systems such as EV charging stations and distributed renewable sources unifies distributed resources with the rest of grid operations.

Smart buildings that incorporate intelligent energy storage enable smarter grids. With local storage capability, a building can become part of the generation resource that helps support grid demands.

An intelligent energy storage control system monitors building loads and market pricing in real time and intelligently decides how to operate. If energy is inexpensive during off-peak periods based on the hourly market price, it will draw power from the grid and store the energy for when the hourly price is high, which is typically in the afternoon.

If the storage system is connected with on-site solar panels, it can store the solar energy based on the same rules and release the energy when it has the highest economic value.

With the ability to draw on local storage, the demand charges that utilities impose on large consumers at peak times can be reduced (see Figure 1).

demand profile

As more commercial users install local storage systems, the power grid begins to look like a network of virtual power plants. With local power generation such as solar arrays or on-site natural gas generation added to the mix, each customer-owned energy system can function as a microgrid and disconnect from the utility during high use (see Figure 2).

Browser-Based Interface   2
Joule.System browser interface
Using the Joule.System browser interface, building owners can configure the system and monitor its operation from anywhere that Internet access is provided. They also can aggregate the information from multiple properties.

Utilities must consider these distributed microgrids as part of the overall power infrastructure and be able to rely on their operation as part of the utilities’ overall power supply strategies.

There are big benefits in this for utilities. Working with building owners, utilities can deploy and manage distributed storage to solve crowded feeders and lower the peak power demand. In addition, distributed architectures composed of consumer microgrids are more reliable than centralized supply networks, with no single point of failure and components and communication paths that are replicated throughout the system. They are easily scalable by bringing additional local power sources online or instituting load reduction programs as required to maintain a high-performance system.

But there are technical problems that need to be solved. The barriers of traditional meter demarcation that isolate consumers from their utilities must be broken down.

Traditional building energy management systems focus on managing building loads, but they don’t have the capability to reach out and interact with utilities to monitor and react to real-time power market factors such as changing demand charges. And typically they don’t provide for the integration with local renewable energy sources, electric vehicle (EV) charging, energy storage and other load or generation assets.

Further, the software architecture that supports the decision-making and data management and storage functions that are required to implement the microgrid infrastructure must be extensible, reliable and secure.

Integrating a smart building into a smarter grid requires a next-generation control platform.

Demand Energy of Liberty Lake, Wash., offers this next-generation software platform.

The company’s Joule.System is built around an open interface and control architecture that allows utilities and building owners to participate together in the operation of a system that can integrate with existing building management systems as master or slave to provide total control over buildings’ energy flow. The system operates in real time to centralize and tightly integrate all of the functions needed to aggregate and manage distributed energy storage resources independently of their locations, capacities or ownership.

The control platform incorporates a cloud-based control system called Grid.DNA (where DNA stands for Distributed Network Architecture) that applies advanced algorithms with dynamic learning capabilities to automate and optimize decisions about energy use.

The system integrates a massive data store with device control, back-office support software, business logic and security services using a distributed messaging system. The software tracks and predicts the price of power to identify savings opportunities and measures of real-time energy demand at the building level. Controls ensure stored energy can be deployed immediately to respond to demand, either from increased needs locally or driven by utilities’ demand response programs, with no impact to the buildings’ operation or living conditions for those working inside them. The system’s big data analytics leverages cloud-based data storage that is scalable and highly reliable. Data is replicated throughout the system and secured via encryption.

The browser-based, graphical user interface (see Figure 3) also is a cloud-resident application that provides an intuitive, convenient way for facility managers to configure the system and monitor its operation. Operating strategies supported include demand-capping, where stored energy is used to reduce or eliminate power usage that would subject the facility to special charges for demand above a certain level, and arbitrage mode, where energy storage is used to capture and store lowest-cost energy from one of a set of possible sources for use when rates are highest.

Future Microgrid   3
smart buildings can function as local microgrids
With local energy storage, smart buildings can function as local microgrids with their own virtual power plants.

At the core of the hardware architecture (see Figure 4) is the Grid.Balancer hardware platform, including a power conversion and energy storage system that accepts and conditions power from multiple DC and AC input sources and manages the energy storage battery array.

Hardware architecture   4
Demand Energy's Joule.System
Demand Energy’s Joule.System architecture optimizes the capture, storage and generation of energy while shaping and time-shifting renewable energy such as solar power to minimize the electric utility bill.

The system is battery technology agnostic and can adapt to future advances in battery chemistries and power conversion technologies.

Future enhancements to the system include predictive analysis of day-ahead usage and energy pricing based on previous data and integration of weather forecasting data into the system’s self-adaptive algorithms.

In addition, the system will be able to shop for best rates from various energy service companies and wholesalers on a real-time basis. Buildings that have excess energy can sell their capacity into the wholesale energy market or put the power onto the grid and have another building load absorb the excess energy and pay a transfer tariff known as a wheeling fee into the market for further energy distribution.

Building owners can aggregate their loads and generation into market metrics that allow them to become real-time participants in the deregulated energy markets.

Capabilities such as these give new meaning to smart buildings because the intelligence of the energy storage system will be a major part of the overall intelligence of the building.

But energy storage advances also represent a net benefit for utilities as they drive to resolve technical issues associated with the implementation of the smart grid and the issues associated with meeting peak demands. As more intelligence is installed at the edge of the grid, so grows the ability for utilities to interact with power consumers to better serve everyone’s needs.

Just as the telecommunications industry evolved to leverage technology to serve consumers’ needs for enhanced features and options at an economical cost, intelligent energy storage will help provide consumers with access to the energy that they need when they need it with a degree of independence from their power utilities.

The future of the utility industry will be influenced by smart buildings that incorporate customer-owned energy management and production systems (micro-utilities with real or virtual power plants).

The enablers of demand response programs for the utility industry will be distributed energy storage solutions installed at the local facility level.

Doug Staker is vice president of International Sales and Business Development at Demand Energy Networks Inc. Involved in the energy business worldwide for 30 years, Staker joined Demand Energy in early 2009. Prior to joining Demand Energy, he was a vice president of Itron. Staker has a Bachelor of Science in Mechanical Engineering from the University of Idaho.

More PowerGrid International Issue Articles
PowerGrid International Articles Archives
View Power Generation Articles on PennEnergy.com
Previous articleIntelligent Load Management – The Future of Demand-side Management
Next articleExpectations of a Utility Outage Management Website

No posts to display