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rider
There seems to be great concern about battery life in these meters. In the case ...
Happy Heyoka
Smart meters wait on home net spec
Rick Merritt
5/26/2011 1:14 PM EDT
A separate committee under the Smart Grid Interoperability Panel is working on guidelines for how to migrate from SEP 1 to SEP 2 meters and home networks. It expects to release a first draft of its work as early as June.
"Millions of smart meters have been deployed that I would characterize as pre-standard, and we want to make sure people get full value of them," said George Arnold, national coordinator for Smart Grid standards, speaking at a conference here.
The SGIP group will deliver guidelines that address issues such as use of gateways and other migration strategies. It may also try to influence aspects of the SEP 2 standard still in progress, said Steve Widergren, head of the SGIP.
Concerns about the smart meter road map have delayed some smart grid projects. "This needs to stop being a blocking issue," said Widergren.
The SEP 2 effort is one of the most high profile of a broad range of standards for smart grids that extend from the home to back-end transmission and generation systems and networks that connect them. A recent report estimated the cost of upgrading to a smart grid could hit $476 billion.
The National Institute for Standards and Technology aims to publish before the end of the year an updated release of its January 2010 framework of smart grid standards. "A lot of work has gone on since then," said Arnold.
The update, a draft of which is now online, is the first to be reviewed by the SGIP, a broad industry and government collaboration set up in late 2009. The draft includes work on more detailed architectural concepts, smart grid test and certification processes and updates on a number of standards completed and still in progress.
A section on cyber-security for the smart grid will include a three year plan with milestones on the topic. A cyber-security group organized by NIST now includes more than 800 members in eight working groups.
"We are always looking for volunteers because the workload is extensive," said Marianne Swanson, who coordinates the smart grid security work at NIST. "We have looked at more than 25 standards just since September, and this is an area where we need the most help because we are almost drowning in standards to review--they just keep coming in," she said.
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LarryM99
5/26/2011 11:52 PM EDT
It doesn't surprise me that it is taking time to work out complex issues. It took me six months extra to get a smart meter because they had trouble making it run backwards to handle my solar panels. I suspect that they need to think in terms of incremental upgradability and backward compatibility rather than making it perfect out the gate.
Larry M.
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kinnar
5/27/2011 2:45 AM EDT
It something unbelievable that a meter will run for 15years on the local battery, also Zigbee being an open standard it will need extensive security if the technology is required to be used for metering application.
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rick.merritt
5/27/2011 11:02 PM EDT
@Kinnar: I suspect that meter does nothing the vast majority of the time and only wakes up on rare occasions to do work.
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Sanjib.Acharya
5/29/2011 2:23 AM EDT
@Rick, I've a couple of questions, might sound silly. Why is the requirement that the smart meters shall have 15 years battery life? Why not 10 or less?
Secondly, what is causing the TCP protocol being less energy efficient compared to UDP?
I believe data integrity is more reliable for TCP compared to UDP which, I think, should have higher priority compared to higher battery life.
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rick.merritt
5/30/2011 12:38 AM EDT
@Sanjib. I was told the requirement for some meters (a small subset of the smart meter group) is they can run 10-15 years on a battery, but I do not have more details. As for the software stack, the specifics of the stack were much more detailed than TCP and UDP, but at a high level that as one of the distinguishing features. I was told the UDP version allowed for less frequesnt updates or listening to the net and thus a less demanding battery workload.
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Happy Heyoka
5/30/2011 10:20 AM EDT
@Sanjb
The smart energy profile is also intended for water and gas utilities - hence the requirement for battery power (ie: not usual and possibly illegal to have mains connection, cabinets and other installation requirements make alternatives such as a solar panel difficult).
The usual operational life of a meter in a domestic or small business situation is 12 years (+/-); hence the 10-15 year battery requirement.
TCP is implemented using UDP; and UDP datagrams in themselves are checksummed. UDP is far less "chatty" than TCP. Guarantee of delivery (where TCP comes in) is not necessarily a requirement when the transmission can be retried periodically; provided there is no loss of data these systems are tolerant of a few hours of delay (ie: monthly or quarterly billing cycles).
@kinnar Zigbee has several provisions for encryption etc (it's effectively IPv6). That's not to say the system is totally secure (none is).
Although I am a fan of Zigbee, I really do think that they should also have a look at officially adopting support for Zigbee on 400 and 900 MHz ISM bands; 2.4GHz is really inadequate for metering... the currently deployed commercial alternatives use a blend of 400/900MHz and are successful in places a 2.4GHz solution would not work.
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Sanjib.Acharya
5/30/2011 12:22 PM EDT
Thank you and Rick for addressing my questions! From the 2nd sentence of the 2nd para of this article, I understand 15 years battery life could not be achieved with TCP and hence there is a requirement to change to UDP. Is it because UDP is less detailed than TCP. Could you please provide any numerical example to illustrate (20%/30% etc.)?
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Happy Heyoka
5/31/2011 2:17 AM EDT
@Sanjib the exact reduction in transmitter power required is not easy to calculate, but if you look at a diagram for a TCP "conversation" you will see that it is dependant on data length, errors and timing. The UDP version (I haven't seen the revisions to SE2) could at a minimum issue a single packet in a given time window once or twice a day.
As I mentioned, there is "plenty of time" to get any given meters data out, since a week of readings is a trivial amount of memory these days. The utility side software that I have seen has the ability to "catch up" on a meter that has been unavailable for a while.
Either way, the 15 years thing is all a projection from power consumption and battery life estimates. It assumes lots of things that may not actually be achievable in the real world.
The 15 years number also does not take into account "home displays" that directly query the meter (which will, IMHO, never work for battery-only gas or water meters).
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boblespam
5/31/2011 4:20 AM EDT
Happy Heyoka,
400 and 900 MHz ISM bands are not international. They are prohibited or require a licence in some countries of Europe.
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chanj
5/31/2011 1:11 PM EDT
The adaptation of TCP/IP is a good news. It is very important that smart meter consume less energy otherwise it wouldn't make too much sense. I don't quite believe TCP will consume significant more energy than UDP unless the smart meter has to listen to a TCP port consistently. Even so, energy use in listening to a UDP port and a TCP port shall not be much difference. The reliability of TCP will require the smart meter to send more bits than UDP. The chance of consuming more energy. To my experience, it shall never be significant though.
Adaptation of IP no doubt poses security challenges. Does anyone have further information w.r.t. security works done by NIST?
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Happy Heyoka
6/1/2011 1:11 AM EDT
@boblespam wrote "400 and 900 MHz ISM bands are not international."
it's interesting you say that - the particular competitor to the SE2 based meters I'm thinking of is (originally) European and uses an "open standard" in both 400/900 bands (so, maybe not ISM as such, but I was pretty sure 433 was available in Europe).
Incidentally, these units *just* cope in less dense housing situations as are found in places like North America.
My point was that the propagation of 2.4GHz Zigbee doesn't meet the requirements of the job; I know for sure there are a couple of devices that do Zigbee protocol on 900MHz bands (ie: only difference is the radio)
I realise this is a "branding" issue for Zigbee group - how do you make devices labelled "Zigbee" and differentiate between radios; not my problem.
All I'm saying is that it doesn't meet the requirements in the field for this task, and that successfully doing so would mean a market of what, several hundred million units?
(oh, and as a bonus, 900 or 400 would, afiak, mean less tx power and perhaps fewer retries so better battery performance)
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rider
6/8/2011 2:15 PM EDT
There seems to be great concern about battery life in these meters. In the case of electric meters, why not just harvest the relatively miniscule amount of energy required from the power being metered? The old fashioned disk type meters do just this to mechanically advance the gear train. For water or gas metering, a somewhat different energy harvester could be designed. Perhaps a turbine or positive displacement meter can do both the metering and energy extraction. However, this would not allow completely shutting off service for an extended time as the harvester would have no way to replenish it's energy source while flow is zero.
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