CADER/DPCA Symposium on Distributed Resources

[I’ll be attending the DOE Distributed Power Program Review and Planning Meeting in Washington next Monday September 27, followed by the IEEE working group session.]

San Diego Sept 13-14

(see program/agenda at

The meeting was very well attended, exceeding expectations, with roughly 400 registered. It included keynotes by notables (Larry Papay of Bechtel, Dan Reicher, Ass’t Secty, EE/DOE, and David Rohy, Calif Energy Commissioner) and two days of parallel sessions on “Policy”, “Technologies” and “Markets”. It was impossible to be in 3 places at once, however the 2″ thick binder provided copies of the vugraphs from most of the presentations.

A dominant theme: it is not a matter if, or even when, but only of how fast, distributed generation will be deployed on a major scale. In fact, DG is already here, and has been for a long time, in various forms and applications. If it truly is a “disruptive technology”, then we can expect it to lurk below the surface, serving in various niche applications, until a crossover occurs and it emerges an a major scale.

The biggest issue seems to be interconnection with the grid. Advocates see utilities as putting up strong resistance. One speaker, Edan Prabhu, explained it terms of distribution departments, at the low end of the totem pole in utilities, trying to protect themselves and their “turf” from this dangerous invasion of “their” system. He explained how the good guys meet the “nice guys”–DG advocates vs. the well-meaning protectors of the system.

There was considerable muttering in the back of the room as speakers from the California utilities claimed to be doing all they can. Repeatedly, we see instances where utilities can handle interconnections just fine, when they want to. In other situations, however, they seen as throwing up roadblocks and delays. Ironically, utilities are entirely comfortable with large motors, which feed back fault current when voltage disappears, but this same issue is seen as a huge problem for DG.

As Dan Reicher explained in his comments, nine states have now gone ahead to establish some kind of interconnection standards for small scale generation, while the long term answer is to have one new national standard. The IEEE work under Dick DeBlasio is key to this, and DOE also supports the development of advanced hardware and software for interconnection.

There was a very good summary of the remarkable events in Texas, where a process has moved with unprecedented speed to cut through the confusion and arrive at an interim set of workable policies. The proposed rules are available online:

A hearing is scheduled for October 25. The presentation was given by Nat Treadway, a former PUC analyst, who is now on his own. 713-669-9701,
New York state has a similar initiative for small DG (under 300 KVA). A commission staff proposal was issued in July, however timing of a decision is uncertain. Comments were due by September 20.
In California, the PUC took longer than expected to announce a decision on a staff recommendation to split their rulemaking proceeding into two parts — Distribution Competition, and DG Implementation Issues. A draft decision to do this was finally announced Sept 21, and is now available online (2 documents) at:
The California ISO presented an interesting comparison of technical requirements for large generators on the system with what might be needed for DG. Generators need to have sophisticated communications and control capabilities that the ISO can monitor and talk to directly. The ISO is implementing the “ANALOPE” system to do some of this over the internet (there is a strong need to certify bids and contracts–i.e. failsafe digital signatures). Once this is established, it may pave the way for the use of internet technology to communicate with DG’s and enable them to participate in the California energy and ancillary services markets.
(Contact: David Hawkins 916-351-4465
The Technology sessions featured presentations by makers of microturbines, fuel cells, reciprocating engines, dish stirling, storage, and renewables. Discussions on “Markets” ranged from the “sleeping giant” of international electric demand, to combined heat and power and the use of smart technology to capture market value. Selected items may be featured in future UFTO Notes.

Regensys Large Scale Utility Energy Storage

National Power (U.K.), has announced a new electricity storage technology – called Regenesys – in which a flowing electrolyte is charged and then and stored in tanks for later use. It has a high speed of response, supplies real and reactive power and is therefore suited to many different applications on a power system.

The Regenesysª system is based on regenerative fuel cell technology, (sometimes known as redox flow cell technology). Two electrolytes flow through the fuel cell on either side of an ion exchange membrane. By applying a voltage across the electrolytes they change state and become “charged”. The “charged” electrolytes pass out of the fuel cell to be stored in tanks. Just like a rechargeable battery, the process can be easily reversed. The “charged” electrolytes flow back through the fuel cell and electricity is produced.

The two electrolytes are concentrated solutions of sodium bromide and sodium polysulphide. The technology is environmentally benign, modular, comparatively easy to site, and separates the power rating from the energy storage capacity. These features make it suitable for energy storage applications in the 5 – 500 MW range which require storage times from fractions of a second to 12 hours or more.

Following successful trials of a Regenesys pilot plant at a power station in South Wales, the company will build its first full scale commercial plant at Didcot in Oxfordshire. Detailed designs are now complete for up to a 15 MW and 120 MWh utility scale energy storage plant. The plant would be housed in a low-rise building, occupying a compact site conservatively estimated at less than 0.5 hectare (1.2 acres). This generic design could be used for a number of applications within the power industry.

The total installed capital cost will be approximately $150/kWh. With continued technical improvements, National Power has set an eventual target price of US$80/kWh.

A storage plant with these cost and performance characteristics will provide significant technical and financial benefits in the operation of a network, from more efficient use of plant (generation, transmission and distribution), and from improved system performance. Storage can also significantly enhance the value of electricity produced by renewable generators, such as wind turbines.

The only available existing large-scale energy storage techniques are pumped hydro or compressed air energy storage, which have severe geographical limitations. Regensys would provide a real alternative. Other energy storage techniques such as batteries, flywheels, superconducting magnetic storage and supercapacitors have different capacity characteristics, and are not well suited to large scale applications.

National Power has formed a new business unit within its Commercial Division to develop the Regenesys technology in the UK and overseas.

Contact: Barry Davidson tel 011-44-1235-444-991

(I also have a PDF file of their brochure)

==== Some Additional Technical Details ===============

Regenerative fuel cells are a separate class of electrochemical device, which have inert electrodes acting only as an electron transfer surface. The electrodes do not take part in the electrochemical process and so do not limit the energy storage capacity of the regenerative fuel cell. This approach allows the complete separation of power, determined by the module’s electrode area, and energy, determined by the storage tank volume.

There are many electrochemical couples that have been assessed for use in flow battery systems. The Regenesys system uses electrolytes of concentrated solutions of sodium bromide and sodium polysulphide. These salts are readily soluble and present no adverse hazards in handling or storage. They are abundant and available at the necessary degree of purity at moderate cost. The use of other bromide and sulphide salts was investigated during the development phase, but the increased electrochemical efficiency would not necessarily repay the additional costs of the alternatives.

The simplified overall chemical reaction for the cell is given by:

3 NaBr + Na2S4 2 Na2S2 + NaBr3

The conversion of electrical to stored chemical energy and back again can be repeated indefinitely with high turnaround efficiency. There is no memory effect associated with the specific electrochemistry of the Regenesys system, and a full charge/discharge cycle can be completed without limitation of a theoretical maximum depth of discharge.

When commissioned the plant will have the ability to start up in less than 10 minutes or, if held in stand-by mode with the modules filled with electrolytes, in seconds. The plant will have a high rate of dynamic response. When running, the plant will be operated fully connected to the grid, capable of turning from a state of fully charging to fully discharging or any state in between in the order of 0.02 seconds. This performance makes the plant suitable for a number of ancillary service applications such as voltage control and frequency response. In stand-by or shutdown mode there is no self-discharge of the electrolyte stored in the tanks.

The Power Conversion System (PCS) provides the interface between the AC network electrical supply and the variable operating voltage of the DC modules. The four quadrant converter system is designed to transfer both reactive and real power simultaneously and independently from each other.

The PCS allows the operator to select from a wide range of operating modes.
– Pre-defined schedule
– Load following
– Voltage control mode
– Frequency regulation
– Power System Stabilisation
– Constant VAr
– Constant AC power
– Self-commutated to operate as a UPS, or to provide Black Start

And, practical peak shaving and dispatch optimization on networks, which has been limited by the availability of suitable technology.

CERTS Draft White Papers – Grid of the Future

Consortium for Electric Reliability Technology Solutions (CERTS)
Grid of the Future

White Papers — August 30, 1999

Prepared for the:
Transmission Reliability Program
Office of Power Technologies
Energy Efficiency and Renewable Energy, DOE

Attached are the six DRAFT white papers prepared for the CERTS program by the various participants (labs and others), which have been made available to UFTO for review and comment. These were presented at an invitational workshop last Friday Sept. 17. Apparently Hurricane Floyd dampened the attendance but not the enthusiasm.

Plans are to close the written comment period at the end of the month, finalize the white papers, and then use them to develop a multi-year research plan for DOE.

Comments should be directed to:
Joe Eto, LBNL, 510-486-7284,

(The six papers are together in a single zipped folder/directory. If you have trouble downloading or unzipping, I can supply them as word documents instead–total 2 MB)

1. scenario300899.doc

The Federal Role in Electric System Reliability RD&D During a Time of Industry Transition: An Application of Scenario Analysis; Joseph Eto, LBNL

2. integdr030999.doc

Interconnection and Controls for Reliable, Large Scale Integration of Distributed Energy Resources; Vikram Budhraja, Carlos Martinez, Jim Dyer, Mohan Kondragunta, Edison Technology Solutions

3. rcntevnt010999.doc

Review of Recent Reliability Issues and System Events;
John F. Hauer, Jeff E. Dagle, PNNL

4. bulkpowr070999.doc

Review of the Structure of Bulk Power Markets;
Brendan J. Kirby and John D. Kueck, ORNL

5. realtime300899.doc

Real-Time Security Monitoring and Control of Power Systems; G. Gross (UIUC), A. Bose (WSU), C. DeMarco (UWM), M. Pai (UIUC), J. Thorp (Cornell U) and P. Varaiya (UCB) PSERC

6. uncertai010999.doc

Accommodating Uncertainty in Planning and Operations;
M. Ivey, A. Akhil, D. Robinson, J. Stamp, K. Stamber, Sandia, K. Chu, PNNL


(Excerpt from:
UFTO Note – CERTS-New DOE Prog in Elec. Reliability, 01 Mar 1999)

FY 99 activities for DOE include work in five areas, the first of
which is:

“Grid of the Future”

The first year of a two year planning study to identify emerging gaps in reliability technology R&D. In the first year, CERTS will lay the groundwork for the development of a federal R&D roadmap by preparing six white papers, which will be the basis for industry-wide stakeholder workshops on:

(1) alternative scenarios for the future of the electric power system, including a detailed articulation of the technological assumptions underlying each of these futures;

(2) assessment of the technology and control R&D needs for widespread integration of distributed resources;

(3) recent reliability issues review, including in-depth analysis of technological and institutional aspects of recent reliability events (e.g., summer 1996 WSCC events; winter 1997 northeast ice storms; winter 1998 San Francisco outage, etc.);

(4) review and assessment of the current structure of U.S. bulk power markets and provision of reliability services (including 1998 price spikes in mid-west and west, and absence of meaningful opportunities for demand response);

(5) assessment of the technology and control R&D needs for real time system control;

(6) assessment of the treatment of uncertainty in planning and operational models.

NIST Workshop – Technical Implications of Deregulation

It’s been 5 years since the first UFTO visit to NIST, and we’ve had continuing contacts ever since. Our colleagues there have recently announced an upcoming workshop that may be of interest.

“Challenges for Measurements and Standards in a Deregulated Electric Power Industry”

A Workshop focused on the Technical Implications of Deregulation

–> For details, go to:
(ignore the password request–just click on “cancel”)

Key Bridge Marriott, Arlington, VA (near downtown Washington, DC)

December 6-8, 1999

Sponsored by:
-NIST (National Institute of Standards and Technology)
-EEEL (Electronics and Electrical Engineering Lab)
-Electricity Division

Technical Co-Sponsors: IEEE, DOE, NST, ERPI and NEMA

Deregulation promises to spur significant change in the electric power industry. To compete successfully and to provide the high levels of services that customers expect, companies will have to adapt to a new business climate, while effectively integrating emerging technologies into their operations. Thus, this historically regulated industry will be challenged to identify its technology needs in a changing and uncertain environment. To help the industry respond effectively, this workshop will address technical challenges related to measurements and standards that are needed to ensure continued reliable generation, transmission, and distribution of electric power.

The technical impact of deregulation on the industry’s measurement and standards infrastructure will be assessed from the perspectives of the electric utilities, power producers, electrical equipment manufacturers, meter manufacturers, federal and state regulators, government agencies, and standards-writing bodies. Sessions for this two-day workshop will focus on:

– measurement needs for transmission and distribution,
– international and voluntary standards needs of a deregulated
electric power industry,
– communication and control systems protocols and standards,
– competitive metering,
– distributed generation, and
– power quality.

The workshop will feature three or four plenary speakers each morning, and their comprehensive overviews of the technical topics will be complemented by panel sessions each afternoon. Panels will consist of recognized experts from all sectors of the electric power industry and relevant government agencies. The workshop’s published proceedings will identify key technical challenges facing the industry as it undergoes fundamental change, and it will discuss potential solutions. Copies will be distributed to all attendees.

Registration fee: $350 (includes reception, two lunches, and proceedings)

For questions and comments about this workshop, contact:

James K. Olthoff, 301-975-2431,
Electricity Division, NIST
Gaithersburg, MD

Technological and Economic Assessment of the Changing Measurement and Standards Needs of the Electric Power Industry

With restructuring of the electric power industry looming in all 50 states, NIST has initiated efforts to anticipate needs for measurements and standards that may arise as the industry transitions from a system of monolithic utilities to a diverse collection of firms competing to generate, distribute, and meter the power that goes to homes and businesses. In its role as the nation’s measurement authority, NIST has commissioned a study of technology and marketing trends in the transmission, distribution, and generation sectors of the electric power industry. Researchers will assess measurement and standards needs identified by power industry experts interviewed during the study.

The results of the study will be presented in a report, which will be distributed to the attendees of the workshop. An overview of the report and the conclusions therein will be presented in the first plenary talk of the workshop.

In May 1997, The Electricity Division at NIST published a planning document entitled:

“Measurement Support For the U.S. Electric Power Industry in the Era of Deregulation with Focus on Electrical Measurements for Transmission and Distribution”

It is available in “html” and “pdf” format.

A earlier draft of this document was offered to UFTO companies for comment.
(ref: UFTO Notes: 28Jan97 and 14Nov96)

The Division continues to seek input on its program to provide metrology support to the US electronic instrumentation and test equipment industry.

Gridcom Powerline Sensors

A remarkable new type of low cost and easily installed intelligent powerline sensors are nearing commercial readiness. They come in three flavors:

– Medium Voltage Single Phase Overhead (4 – 69 KV)
– Medium Voltage Single Phase Underground
– Low Voltage Single and Multi-phase Underground (e.g., 208 V)

The medium voltage devices simply clamp on the cable, and measure voltage and current without a connection to ground or a phase-to-phase connection. There is no penetration of cable voltage insulation. (It is not applicable to coax or multiple conductor configurations–only single unshielded cables.) The underground units are self-powered by the power line, and the overhead ones use batteries that will last 5 years or more.

They are said to be approximately ten times cheaper to buy and install, and offer far greater capabilities than anything else on the market. Measurement accuracies (I, V, P) are quoted at better than 3%, though the units invariably do much better. It is not a revenue meter, however.

Evaluation units are available now, and the first production units will be ready before the end of the year. Five utilities (including one or two UFTO companies) have been testing overhead sensors.

The sensors measure current and voltage and can be equipped to measure and/or detect a number of additional conditions or quantities including temperature, moisture, specific substances, light, acceleration, and vibration. Underground sensors utilize two-way powerline carrier communications over the existing lines and overhead sensors communicate through two-way low power RF systems.

Each sensor has its own local on-board intelligence to perform data processing and analysis. In typical applications the sensors calculate true rms voltage and current, power factor and harmonic content. Peak rms quantities and fault recognition capabilities can also be employed.

The sensors report by exception, when polled, or at determined times. Since data is processed at the sensors, communications bandwidth requirements are relatively low. Only processed data or observed data related events (like faults, voltage dips, or high current limits) are reported — not extensive strings of raw data.

Typical functions of these sensors (both overhead and underground) include:

– Detection and location of faults
– Measurement of power quality
– Identification of grounding and cable insulation issues
– Detection of non-technical losses
– Detection of unanticipated loads
– Confirmation of recloser, sectionalizer and other switch operations
– Support capacitor switching algorithms
– Monitoring distributed generation


Infrastructure Monitoring
– Distribution Automation
– Operations Support
– Fault Detection, Classification and Location
– Power-line losses
– Power Factor and VAR Monitoring
– Switch Operation Confirmation
– Planning Studies
– Circuit Design

Condition Based Maintenance
– Cable Burnout and Circuit Limiter Detection (low voltage U/G)
– Equipment Health Status (Fuse, Cutout, Transformer, Switch)
– Tree Trimming Effectiveness

Beyond the Meter Services
– Power Quality
– Sub-metering and Beyond-the-Meter Distribution Networks
– Harmonic Analysis

The underground sensors were initially developed for Consolidated Edison’s Secondary Underground Network Distribution Automation System (SUNDAS). The objective was to develop a comprehensive sensing system that would be relatively inexpensive to purchase, install, operate and maintain.

Con Ed has tested experimental versions of the low voltage underground sensors in their Battery Park City and Harlem networks. These tests demonstrated the capabilities of these sensors to monitor powerline conditions and to detect variations in line conditions associated with circuit limiter loss, arcing faults, changes in network protector relay status and unusual changes in power flow patterns. Based on the performance of the experimental sensors, Con Edison will install GridCom sensors throughout the Hunter network with installations beginning this fall.

US Patent No. 5,892,430: Self-powered powerline sensor
The company’s website has a lot of information and pictures:

Contact: Rich Wiesman, 781-684-4387