1 – What is Greensmith’s product offering? 

Greensmith is a technology company providing turn-key, intelligent energy storage systems for distributed applications across the grid.  In addition to selecting, procuring, and installing the appropriate batteries, Power Conversion System, and other balance-of-system components for a customer’s system, Greensmith specializes in advanced control and optimization software to maximize the system-wide benefits of distributed energy storage. Moreover, Greensmith developed an active-balancing BMS (Battery Management System), as well as a set of end-use application programs including intermittency smoothing of renewable power generation, and a secure online portal for customers to manage their energy storage resources remotely. These data analytics and software make Greensmith energy storage units into intelligent energy control systems.

Greensmith is battery agnostic, meaning we support multiple battery manufacturers, and we are able to incorporate new battery innovations at lower prices as the market continues to evolve.

 

2 – What does it mean for energy storage to be “intelligent”?

Intelligent energy storage allows customers to optimize usage of their energy storage unit(s).  Greensmith is tapping into modern computing and communications to collect, analyze, and utilize data to maximize the value of their asset.  This “intelligent” energy storage can accept inputs from a variety of ancillary devices.  In addition, through the online portal, users can control all units in-sync as one large energy storage system, or they can allow each unit to do its own task, enabling multiple value-steams for the customer.

The batteries within each Greensmith unit are run with fleet control, such that batteries are arranged in a peer-to-peer local area network.  One assigned SuperNode receives instructions from the online user Portal and relays instructions to its peer batteries.  The system is built with redundant SuperNodes so that there is no one single point of failure.

3 – Who is purchasing these systems, and for what applications?

Since our founding in 2008, Greensmith has supplied its software and system integration services in over twenty installations.  Our customers are leading electric utilities (eight to date), renewable developers, academic/research institutions, and commercial developers working on sustainability initiatives.  These customers are primarily located in the US, but we are expecting to expand internationally during 2012.

Greensmith units can be deployed in the many applications of distributed energy storage, including renewable integration, load following/load management, peak shifting, ancillary services like frequency regulation, VAR control, and backup power.  We are also able to provide grid islanding and micro grid functionalities in cases like Community Energy Storage projects.  Because our customer portal provides visibility across all units in a customer’s system, the solution is highly modular, allowing customers to build their distributed energy storage system as their needs change over time.

 

 

4 – How are these systems used to integrate renewable energy into the grid?

When paired with renewable energy, the Greensmith PowerVault unit charges during periods of generation, and then discharges back into the grid as the customer sees fit.    Thus, by pairing renewable generation with energy storage, renewable developers can provide a firm, shaped resource instead of intermittent generation.  For commercial and residential sized systems, customers can store their own net generation on-site and use it during periods of high demand to reduce demand charge fees.  Our AMI-friendly software can accept data from residential and commercial buildings with smart meters.

5 – How do Greensmith systems improve power quality and maintain grid stability?

Greensmith units are distributed (AND portable in some units), so that they can be located directly next to the cause of a power quality or grid stability issue.   It’s a highly localized approach, which is not only more efficient, but also elongates the life of grid infrastructure.

Functionally, these distributed Greensmith units can provide load following, renewable smoothing, and/or VAR control at the source of the issue – at the transformer, on a customer site, or at the source of intermittent generation.  T&D utilities can also locate our units at strategic nodes on the grid to alleviate congestion problems. In markets like California with real-time congestion pricing mechanisms, strategic energy storage will reduce these congestion costs.

 

6 – How does your technology address grid stresses as related to distributed rooftop solar generation?

As more homes and businesses install solar energy on their rooftops, grid distribution stations become more stressed, especially in areas where panels are adopted in a high volume.  This is because the solar energy resources tend to generate during the middle of the day, when fewer people are at home to use up the electricity on-site.  Instead, the energy goes back into the grid (which is why solar owners need net meters), and back up the “food chain” of the distribution system. These systems were meant to carry power in one direction, not both, causing stress on distribution transformers.

To alleviate this issue, Greensmith’s distributed energy storage solution is installed near the stressed distribution feeder.  Rather than flowing into the distribution station, the distributed generation will flow into the Greensmith battery, where it can be stored and deployed later in response to demand in the evening.

 

7 – As solar energy installations continue to grow, world-wide, what does GS see as the future for your systems?

Solar is growing in the utility, commercial, and residential sectors, so Greensmith has solutions available for all three of these markets.  In the residential and commercial sectors, Greensmith can provide building energy balancing, which is a market we plan to enter internationally in the near-term with a partner company.  Residential balancing and grid-islanding is also possible via Community Energy Storage (CES), a specification which is currently in development at Greensmith.  Our AMI-friendly software can accept data from residential and commercial buildings with smart meters.

On the utility-scale side of the industry, Greensmith has a number of utility customers who have made recent orders for distributed energy storage systems (as described above in question 6) to manage stress on the grid and elongate the lifetime of critical grid infrastructure.  In particular, one major California IOU purchased a distributed 1.5 MWh system.  We anticipate more growth from the utility sector, especially as these utilities and their system operators continue to fulfill renewable energy procurement standards.  Similarly, we anticipate more renewable developers seeking solutions to shape intermittent generation and improve their bargaining position with utilities.

 

8 – As more electric vehicles enter the market, what role will GS technology play with EV charging stations?

Ten percent of Greensmith’s existing installations couple solar PV and EV charging.  In these projects, the Greensmith unit stores the solar energy for use in electric vehicle charging.  Without the energy storage unit, the solar energy would flow back into the grid as described before, and additionally the EV charge station would draw a lot of power when charging a vehicle.  By adding the energy storage unit, neither the PV nor the EV charging add greater load or stress to the distribution system, so we envision stationary energy storage as a critical element to sustainable growth in the EV sector.

 

KATE REIMER, Market Development Manager
Greensmith Energy Management Systems

Kate manages Greensmith’s marketing and outreach activities, sales pipeline, and policy development. Kate’s career has been focused on energy sustainability for seven years.

Kate holds an Honors BA in Economics from UC Berkeley and an MS in Management Science & Engineering from Stanford University.  As an undergraduate at Berkeley, Kate minored in Energy & Resources and City Planning.  From her sophomore year until graduation, Kate also worked part-time and over summers at the New Resource Bank, the Renewable and Appropriate Energy Lab, and the Transportation Sustainability Research Center.  

In 2008, Kate was recruited to join the PG&E Energy Procurement Rotation Program, where she focused on utility-scale renewable energy procurement and development in California. In this role, she performed modeling of PG&E’s renewable resource portfolio to inform the utility’s long-term procurement strategies.  In the Renewable Resource Development group, she wrote business cases on behalf of utility-scale renewable generation projects for PG&E’s BOD approval. In the Emerging Clean Technology group she worked directly in several energy storage projects: first in a DOE proposal for a Compressed Air Energy Storage project in PG&E service territory, and later in project management of a NaS battery installation at a customer site.

Kate completed her MS in Management Science and Engineering at Stanford.  Her Masters projects included life-cycle evaluation of a home energy monitoring device, market evaluation of peak-shaving building software, and the opportunities associated with low-cost sensing and controls as applied to water-saving demand response programs in California.  After graduating, she worked in Portland, OR as Program Manager at a small Automated Demand Response start-up company.  

Kate regularly makes presentations, including a recent Accenture Smart Grid Vendor Forum, and the CEATI forum on Managing System Impacts of the Renewable Portfolio in Santa Monica on Wednesday March 12.

About Greensmith Energy Management Systems

Greensmith Energy Management Systems can be contacted at: kreimer (at) greensmith.us.com.  The company’s website is: www.greensmithenergy.com.

Last month, the Department of Energy’s ARPA-E program put out a request for information (RFI)for new technologies to help solve a devilishly complex problem: managing today’s advanced battery energy storage systems.Today’s automotive or grid-storage batteries contain hundreds or thousands of electrochemical cells, all interacting in ways that are difficult, if not impossible to predict. To work around all that uncertainty, today’s batteries tend to be “built and operated well below their theoretical energy and power capacities,” the RFI states. Even when they are, “Many energy storage systems suffer from uncertain or inadequate lifetimes,” which increases costs and risks of deploying them.What’s needed is technology to monitor and manage the cell-to-cell charging, discharging, degradation and quality issues within the battery system as a whole, whether it’s new sensor technology, data modeling or battery system controls.

While ARPA-E notes how complicated the challenge is, it states that finding the right combination “would be a game changer — significantly accelerating the adoption and value of energy storage.”This isn’t news in the battery industry world. On the automotive side, we’ve seen General Motors and Nissan pour millions of dollars into battery management technology, both to squeeze maximum electrical efficiency out of the systems and to control temperatures to avoid thermal runaway. Tesla Motors is sharing its battery management system (BMS) with Toyota and Daimler.On the grid energy storage scale, we have hundreds of megawatts of lithium-ion batteries that are running some sort of hardware-software combination to charge and tap their warehouses full of cells, packs and racks of batteries. Companies like A123, Xtreme Power, Saft, AltairNano and Japanese giants like Mitsubishi, Panasonic and Hitachi are bringing their own battery management technologies to support the grid-scale storage units they’ve deployed. A123 has supplied more than 100 megawatts of grid storage using its own BMS, and Coda Automotive and BYD Motors have launched grid storagelines that take what they’ve learned in automotive battery management to apply to grid scale.But the ARPA-E call for technology makes it clear that there’s still a lot of work to be done to get the industry into new realms of efficiency and reliability. So do reports of “bricked” Tesla Roadster batteries, Chevy Volt battery fires, exploding grid-scale wind power storageunits in Japan, and other such bad news.I recently spoke to two startups, Sendyne Corp. and GreenSmith Energy Management Systems, that said they’re working on solving ARPA-E’s battery management problem. Each has its own techniques, and each is tackling the market, such as it is, in a different way. Each also has its work cut out for it, if it’s to meet ARPA-E’s definition of a “game changer” in the battery management space.Sendyne Seeks Active Balancing for Better PerformanceSendyne, a New York-based semiconductor developer that also works on portable fuel cell power management, unveiled its battery management plans in February when it announced a partnership with the University of Toronto. The company is providing “patented technology as well as access to intellectual property, development tools and scientific expertise” for the partnership, according to its announcement.

Ellen Gooch, marketing director for Sendyne, wouldn’t disclose details on the company’s funding to date, or which battery cell makers it may be partnering with. Nor did she get into too many details on Sendyne’s technology during a February interview, though she did say it’s based on semiconductors that can accurately measure voltage, temperature and other states within battery cells.

“We are addressing what we believe to be fundamental issues with respect to battery pack management. Among these are accurate measurement and accurate modeling,” she said. Today’s battery systems suffer from a lack of visibility into cell status, as well as the complexity of lining hundreds or thousands of strings of cells together, she added — “No matter how well you match them, no two cells are exactly alike.”

That means that, over time, certain cells become stronger or weaker than others. Because a battery pack’s overall performance is limited by its weakest cells, battery systems today use a technique called passive balancing, which actually bleeds off power, to try to manage that variation, Gooch said.

Sendyne, on the other hand, is working on active balancing, where power isn’t bled off, she said. Instead, the startup manages relative state of charge at the cell level, sharing charge between cells to balance out weak-strong cell differences. That process can be as much as 15 percent more energy-efficient than the passive process, she said.

Active balancing isn’t a new concept, of course, and there’s active research underway. Tesla buys battery cells from Panasonic and stacks them in the thousands for its Roadster and Model S batteries. Since 2010 it has used power management chips from Infineon in its BMS, which could support active balancing.

Beyond better-balanced cell charging, Sendyne’s system can warn when certain weak cells are about to drop below a critical state of discharge, typically about 15 percent or so, that essentially ruins the cell, Gooch noted. That’s important in preserving the overall life of the battery pack, which can degrade beyond usefulness if too many cells end up failing.

GreenSmith: From Cell Management to Smart Grid Integration

Bethesda, Md.-based GreenSmith is also working on active balancing technology, targeting the control of cells within individual battery packs, CEO John Jung told me in a February interview. The startup was founded in 2008 and has raised $6 million in angel and early-stage financing.

So far, GreenSmith has done demonstrations that show its active balancing system can improve round-trip efficiency of battery systems from the high-70 to low-80 percentage range all the way up to 88 percent, Jung said. Its firmware can also check battery nameplate performance against real-world performance and spot weakening cells and capacity degradation issues, he noted.

In GreenSmith’s case, however, its cell-to-cell management is tied up in a larger Distributed Energy Storage System offering, which includes the industrial servers and underlying software that allows batteries to interact with smart grid, solar panels that deliver power, or plug-in vehicle charging stations that want to tap the power, he said.

GreenSmith is managing a bunch of smaller-scale (100-kilowatt or so) energy storage units that add up to about 4 megawatt-hours of storage in projects with San Diego Gas & Electric, Hawaii Electric Co., Duke Energy and solar manufacturer Amonix, among others, Jung said. The main goal is to make grid-scale storage systems “as easy as distribution transformers” to deploy onto the grid, he said.

The Challenge Ahead: A Comprehensive Set of Solutions

Importantly, neither Sendyne nor GreenSmith are planning on building batteries themselves. Sendyne is aiming at providing components and software for battery management system makers to use for consumer, automotive and grid storage applications, Gooch said. GreenSmith is talking with OEMs interested in partnering with the startup to license its technology or to bring it to market with battery system channel partners, Jung said.

They’re not the only startups targeting battery management. RockPort Capital Partners and Terawatt Ventures have backed Newark, Calif.-based Qnovo, which has promised a next-generation electronic management system for lithium-ion batteries, without providing any details on its technology.

Anyone tackling the challenge will have their work cut out for them, on a number of fronts. Let’s take accurate measurements. ARPA-E’s request for information acknowledges that technology exists today to solve the problem, but that it’s very expensive: “The idea of embedding a third reference electrode into a commercial battery has captivated the imagination of battery developers,” but that solution “remains an elusive goal.”

Likewise, getting down to cell-level monitoring in complex battery systems containing up to thousands of cells “is not practical. Series and parallel cell configurations couple the states of groups of cells, and the cost of highly parallelized wiring or sensing is prohibitive,” ARPA-E wrote.

Even when sensors at the individual cell are available, today’s simple voltage, current, and temperature measurements only go so far in giving a true picture of what’s happening inside it. To wit: “Voltage provides a composite measure of changes in potentials, but does not provide critical information on the individual state of either electrode. Temperature measurements in today’s systems only probe the surface temperature of a cell, not sensing localized temperatures that internally drive degradation and failure.”

All in all, ARPA-E sees a need for a comprehensive set of technology solutions, “combining data from novel sensors with advanced models, system designs, and control paradigms.” Any combination of solutions, of course, will need to “provide system level benefits (e.g., increased battery utilization, lifetime, safety, and/or applicability), which far exceed the cost of implementation.”

It’s important to note that there’s no funding attached to ARPA-E’s request, though law firm Wilson Sonsini Goodrich & Rosati noted that it could tap a portion of $100 million in anticipated future funding opportunities at the agency. No doubt the agency will be poring through the submissions to its RFI to see if anyone has come up with persuasive proposals for solving all these problems — or, more likely, just one of them. In the alchemical world of battery science, any insight into the inner workings of operating cells may be worth investing in.