Penny Wise and Rand Foolish
In the RSA, regulators and utilities are focused on “smart meters.” However, without providing customers with smart price signals, it is doubtful that the purported benefits of smart meters will accrue. Much of the policy debate over smart meters thus far appears to focus on how to get the meters installed and who should pay for them.
However, there are many applications that smart grids must employ to create this major investment’s benefits.
Advanced Metering Infrastructure (AMI) requires high-bandwidth communications to allow large quantities of data to be transferred every now and then. Smart grid sensors require high latency to allow small quantities of data to be moved from the location where it is captured to another where a tool will perform an analysis. Failure to keep the end game in mind is likely to result in substantial increases in overall capital outlay, which will ultimately undermine the business case benefits of the smart-grid initiative.
How Much Is Enough Bandwidth?
“A survey of the 15 most recent experiments conducted in the U.S. Canada, Australia, and France has been conducted with the dynamic pricing of electricity. We find conclusive evidence that residential customers respond to higher prices by lowering their electricity usage. The magnitude of response depends on how much prices increase, the prsence of central air conditioning, anad th availability of two-way programmable communicating thermostats and always-on gateway systems that remotely control multiple end-uses – that is, ‘enabling technologies’.
“…Time-of use rates induce a drop in peak demand that ranges between 3% and 6%. Critical-peak pricing rates induce a drop in peak demand of between 13% and 20%. When accompanied with the above-described ‘enabling technologies’ the later set of rates lead to a drop in peak demand from 27% to 44%.
“..These results have big impacts on reliability and least cost operation of a power system facing escalating power demand and capacity costs.
“Smart Meters and Smart Pricing – Survey of the Experimental Evidence”, Ahmad Faruqui and Sanem Sergici, The Brattle Group [http://www.hks.harvard.edu/hepg/Papers/2009/The%20Power%20of %20Experimentation%20 01-11-09_pdf]
“…There were two main objections to the conclusions I reached and in the substantiation of the data I used. The first was based in existing utility practices: A meter read only contains basic information about the identity of the power meter, the time stamp, and the meter reading itself: around 14 bytes per read, resulting in a belief that such a small amount of data would never amount to anything like the avalanche previously described. The second objection was that there was little likelihood that such data was going to be stored for long, meaning, I guess, that we could design the system as though it had never arrived at all. Many of the questions came from individuals with strong/long histories in utilities, so I felt it my responsibility to validate my data.
While I consider myself to be relatively well-versed in the core of these topics, I decided to go back to Austin Energy, and understand better the reality of the situation from the folks who are actually doing the job, and who are considering these concerns as fundamental parts of their planning for successfully serving their clients on the new grid in the years to come. We called Andres Carvallo and Karl R. Rábago at Austin Energy, and they helped us understand the world and the Smart Grid that they are planning for.
“Smarter Grid vs. Simpler Meter Reading — … These gentlemen expect to coax rich two-way data communications from the new grid infrastructure. While time, location, and power used are at the heart of a meter read, there is much more to be learned. Some examples are:
“Device Health Information – Watch for varying temperature, periods from outage, battery power, heartbeat, and other variables, the system can better predict and recover from failures.
“Real-Time Monitoring – Real-time monitoring may be in demand almost immediately, as customers recognize there is now more information with which they can manage their energy.
“Energy Services Provision Trumps Energy Provision Services – Newly informed and empowered customer base will spawn new requirements for functionality that is logically delivered by the provider. Power providers are now actively thinking about services that they can offer over the new and smarter infrastructure. Things like profiled energy use: “I am going away, manage my power” or “There is a spike in prices, manage me down by 10%” or “I only want to use power that is generated from renewable resources.” These all require data, new interfaces, and a channel over which all of the control and monitoring information can be passed.
“Networking Overhead – Given the complexity, regularity, and importance of this data, a protocol (like IP) will be adopted to package up and send all of this data to central systems for analysis, aggregation, storage, and action. Protocols generate their own overhead and two-way data communications.
“Other Factors – We are only just beginning to see the potential for Smart Grid and Soft Grid enablers — even my estimates are likely to be low, particularly with real-time monitoring and data analysis.
“Based on this analysis, the numbers are far from a simple 14-byte read, and are more likely in the range given by Andres of 4,000 to 16,000 bytes (128,000 bits to be transmitted) per reading. If we estimate the maximum case, the numbers are even higher than I had referenced in the earlier article. Let’s not think about real-time (the numbers are mind-numbing), but instead look at a simple check every 5 minutes:
“12 (reads/hr) X 24 (hrs/day) X (365 days/yr) X 16K (bytes/read) yields roughly 1.7GB/meter/year
“Multiply that by the number of meters you deploy in your footprint, the challenge is clear. For more reality, take that number and multiply by 5 for readings every minute, or by 300 for readings every second.
This is a problem because rushed, tactical, and incremental hardware additions will not make that data secure. It has to be expected that as organizations run out of room for data, they will simply rush to add more. Caught in a flood of data, the pressures for survival and successful operation will naturally trump any meaningful consideration of re-architecting data storage for adequate and appropriate security.
“For utilities that recognize the Smart Grid will need data, will need security, and will likely grow to fill whatever space is available, the call is clear. Plan for an avalanche, plan for a flood. Create systems and segregations that will allow for managing these flows reliably. The data surge is coming, and you can either surf it, or be pounded by it. You certainly will not be able to ignore it.” — “That Smart Grid Data Surge We Mentioned Earlier? You Can’t Ignore It”, 3 Nov 2009, Jack Danahy, SmartGridNews.com
The municipal energy company views the utility of the smart grid system as first and foremost operational cost mitigation, second energy demand management (i.e., moving demand to off-peak rather than limit the amount of energy available), and then third, customer-end user benefits.
But it is clear that for a smart grid system to deliver sufficient benefits to justify its cost, all these applications must be deployed. To date, very little is understood about the bandwidth utilization profiles of smart grid applications, since so few have been implemented.
Silver Spring Networks sells a 19,600 bits per second radio mesh network of smart meters. But GE thinks that while 100 kilobits per second might be fine for reading electric meters’ gross usage statistics, 1 to 2 megabits per second is required to have enough information and communications to automate the distribution grid in real time.
Says Larry Solecito, CEO of GE Digital Energy, “if you’re doing distribution automation, you require very fast response times. You cannot miss a read on a communication. With that speed and reliability, you will damage a transformer, you’ll break a generator, and you may even have a customer safety issue.”
The Pacific Crest Mosaic Smart Grid surveyed 20 industry leaders with budgeting or technology selection responsibilities from 1-23 July 2009. They listed and ranked smart grid applications in the order of of their importance to the utilities, as follows:
- Advanced Control (real-time)
- Fault Detection and Isolation (real-time)
- Substation Automation and Diagnosis (real-time)
- Demand Response (smart pricing)
- Firming and Integration of Variable Renewable (distributed energy sources)
- Asset Management
- PHEV (Electric Vehicle) Integration with the Power Grid
- Load Forecasting and Capacity Planning
- Workforce Management (reading meters remotely)
- Voltage Monitoring
- Carbon Compliance
Analysis of a Utility’s Description of its Smart Grid Usage Profile
“…Austin Energy’s CIO Andres Carvallo says that Phase 1 of his company’s smart-grid project completed in July 2009, when a half-million smart-meter devices were implemented across the company’s footprint. “Our total information online was 20 terabytes (20,000,000,000,000 bytes).
“But right now, we are capturing data from the smart meters every 15 minutes – that requires 200 terabytes of storage space, since we’re doubling up with a second disaster recovery site. (This 100 terabytes of transmission to the smart grid management system over the network occurs over 1 year, every year, with each year’s data records having to be protected, retained, and readily accessible on-line for at least seven years to address potential dispute resolutions).
“If we move to reporting the meters once every five minutes, that 200 terabytes becomes 800 terabytes of storage space (or 400 terabytes transmitting in from the meters to the system over the network).
“If we move the reporting frequency to once every minute, this then requires 1.5 petabytes of storage space (or 750 terabytes transmitting in from the meter to the system over the network)…” — “That Smart Grid Data Surge We Mentioned Earlier? You Can’t Ignore It”, 3 Nov 2009, Jack Danahy, SmartGridNews.com
What is the throughput capacity required on the network for 500,000 meters to transmit their reports every 15 minutes?
At 30 megabits per second dedicated capacity, 500,000 meters can transmit their reports in 12.68 minutes, so they can be ready to retransmit during the next 15 minute reporting increment.
What is the throughput capacity required on the network for 500,000 meters to transmit their reports every 5 minutes?
At 100 megabits per second dedicated capacity, 500,000 meters can transmit their reports in 3.81 minutes, so they can be ready to retransmit during the next 5 minute reporting increment.
What is the throughput capacity required on the network for 500,000 meters to transmit their reports every 1 minute?
At 400 megabits per second dedicated capacity, 500,000 meters can transmit their reports in .95 minutes, so they can be ready to retransmit during the next 1 minute reporting increment.