8 ms·

Also many municipalities don't allow battery 'grid-tie' with the option of 'off the grid' living. For example, Connecticut has laws which don't allow houses to

Also many municipalities don't allow battery 'grid-tie' with the option of 'off the grid' living. For example, Connecticut has laws which don't allow houses to have batteries that would allow a house to be self sustaining and have a connection to the grid. This is because if you have batteries which cause a back flow during a power outage to the power station, an electrical worker could get shocked down the road. The fact that lithium batteries aren't the greenest combined with the fact that you can't even live 'off the grid' in a grid tied system is a big uphill for these batteries.

Cthulhu_ 12y ago
Then that electrical worker would have to take precations (like disconnect the system), no? Sounds like it's just something that can be held in account. Plus the battery could not flow back to the grid in case of power outage (but instead power the own house first)
fche 12y ago
A properly wired transfer switch fully cures that risk.
- spydum 12y ago
  True, but bewary of automated transfer switches. I have seen DC's fail due to ATS's not doing their job. This can be pretty dangerous for a lineman/fire rescue if your particular ATS fails to switch...
- danielweber 12y ago
  And even though the solution is right there, power line worker remains the ninth deadliest job in America. http://www.businessinsider.com/most-dangerous-jobs-in-america-2014-12#9-electrical-power-line-installers-and-repairers-2 http://www.businessinsider.com/most-dangerous-jobs-in-americ...
  - maxerickson 12y ago
    On trip through Minnesota, I watched a helicopter ferry guys up onto the towers to work (they dangled from the helicopter and then transferred over to the tower: http://www.capx2020.com/ http://www.capx2020.com/ ). They were building the type of infrastructure the news says America doesn't know how to build anymore. I wonder if energized lines are the big problem.
    - tlrobinson 12y ago
      Workers can safely work on live high voltage lines, if they're wearing a Faraday cage "hot suit" and not grounded: http://youtu.be/LIjC7DjoVe8 http://youtu.be/LIjC7DjoVe8
      - lutorm 12y ago
        That video is awesome. I've seen a version with much better quality that really gets my acrophobia going... ;-)
  - fche 12y ago
    (It's likely there are many -other- hazards to power line working, beyond presence or absence of transfer switches at on-site generators.)
    - danielweber 12y ago
      If you are a lineman, you are three times more likely to die from electrocution than from a fall. (They die from electrocution at 35x the normal population rate, while the death from falls is 5x the normal population rate.) http://www.ncbi.nlm.nih.gov/pmc/articles/PMC1568699/pdf/envhper00445-0284.pdf http://www.ncbi.nlm.nih.gov/pmc/articles/PMC1568699/pdf/envh... That's just fatalities, ignoring the other dangers like getting your arms blown off.
- brudgers 12y ago
  A couple of my architect friends -- and they are good competent architects who spend the proper portion of their fees to hire competent consulting engineers -- designed an emergency services center a few years ago. The hurricane came - the project was in Florida - the utility cut grid power per protocol and the automatic transfer switch didn't flip to onsite power. Neither did the backup automatic switch. The person trained to operate the manual switch was on a scheduled vacation (hurricane season in the US is six months it ain't reasonable to prohibit vacations). It took over an hour to get the system back online. Now keep in mind that all of this was with emergency services grade equipment trained professional staff and regular inspections and testing. And everybody wasn't away on vacation by policy. Proper wiring is a necessary, but not sufficient condition. Power grid failures are many sigma events.
  - warfangle 12y ago
    > The person And there's the problem.
    - brudgers 12y ago
      The HIL was the backup to the backup. [HIL]: https://en.wikipedia.org/wiki/Human-in-the-loop https://en.wikipedia.org/wiki/Human-in-the-loop
vetler 12y ago
> This is because if you have batteries which cause a back flow during a power outage to the power station, an electrical worker could get shocked down the road. Surely there is some safe way of preventing this?
- TallGuyShort 12y ago
  I would think so, and I would hope they would implement it. Especially considering the benefits to society of having people who are more prepared and self-sufficient, I would hope that safety would be only one of the reasons they wouldn't rely on people obeying some regulation for their worker's safety.
- ceejayoz 12y ago
  There is. The same issue is present with home generators, and most cities require they be installed by a licensed electrician who will ensure it doesn't power the grid in an outage.
Igglyboo 12y ago
>This is because if you have batteries which cause a back flow during a power outage to the power station, an electrical worker could get shocked down the road. If I were an electrical worked I'd treat a power line like it was live regardless of whether there is a power outage or not.
shiggerino 12y ago
Any reasonable grid company should not only not prohibit this, but welcome it and pay for energy people feed back into it. I can call mine any day and have a bi-directional meter put in so I can charge for it, should I ever choose to install solar panels.
- shillster 12y ago
  In some states, it is required by law that the power company pay for home generated electricity that is fed back into the grid.
rplnt 12y ago
Why is this not an issue if you have solar cells or wind mill or whatever?
lsaferite 12y ago
This is an issue even without battery storage. Solar and wind generation that is set up to feed excess back to the grid already has to have a way for the utilities to shut it off. This is why you have to have your setup vetted by the utility if you are feeding the grid.
engendered 12y ago
>you can't even live 'off the grid' in a grid tied system I can't find any references for your stated claim about Connecticut, however it seems deeply illogical given that a generator (which surely aren't banned), solar panels, wind, etc, all have the potential of feeding energy back to the grid in an outage. Which is why there are regulations and home inspections and all of that, to ensure that the appropriate safeties and switches are in place. Simply banning one of many possible mechanisms of generating power would be very short sighted. Many regions that offer feed-in time-of-day tariffs are rightly trying to figure out how to accommodate battery systems, where some users are trying to game the system by charging a big battery array during low cost hours, and then "selling" it back to the grid during peak hours (at inflated, subsidized prices). EDIT: As a reply to msandford, given that I can't reply lower -- the reason they have this limit is that the tariff price paid to home solar/wind generators is way above the bulk, "wholesale" price of power. It was created as an incentive to encourage green energy. So when you feed back their own power to them, it does them no favor given that now they're paying 2x+ what they would pay on the normal power market for power, and simply undermines the entire incentive program.
- msandford 12y ago
  > where some users are trying to game the system by charging a big battery array during low cost hours, and then "selling" it back to the grid during peak hours (at inflated, subsidized prices). The idea that a utility wants a heads-I-win-tails-you-lose kind of situation is annoying at best and downright infuriating at worst. If they're willing to sell power for $X now and willing to buy it later for $Y, what does it matter the method? I mean, there are people working on grid-scale storage batteries to do precisely that because utilities desperately NEED additional peak capacity when it's a hot day and everyone's A/C is on in the late afternoon. Why would it be OK for the UTILITY to utilize grid storage, but not an INDIVIDUAL? http://en.wikipedia.org/wiki/Grid_energy_storage http://en.wikipedia.org/wiki/Grid_energy_storage
  - michaelt 12y ago
    If they're willing to sell power for $X now and willing to buy it later for $Y, what does it matter the method? In the UK, to encourage adoption of residential solar panels there is a scheme of "feed in tariffs" where you can generate renewable energy and receive a guaranteed, above-market-rate price for it. The goal of this is to reduce carbon emissions. For example, you can buy residential electricity for 15p/kWh [1] but sell energy from your small hydro installation for 19p/kWh [2]. Obviously, the goal of reducing carbon emissions would not be achieved if people simply charged batteries at 15p/kWh and sold it back at 19p/kWh! Of course, this issue only arises because feed in tariffs are subsidised. [1] https://www.gov.uk/government/uploads/system/uploads/attachment_data/file/388121/qep_dec_14.pdf https://www.gov.uk/government/uploads/system/uploads/attachm... [2] http://www.fitariffs.co.uk/eligible/levels/ http://www.fitariffs.co.uk/eligible/levels/
davegardner 12y ago
The same issue exists with grid connected solar panels. My solar panels are designed to stop working whenever there is a power outage. This is a legally mandated requirement here and is very annoying when it happens on a beautiful sunny day. A solar panel installer told me that if I add a battery backup to my installation, then at least it'll still charge the batteries during a power outage.
- jacquesm 12y ago
  There are some ways around that limitation. The reason it exists in the first place is so that the power company can safely power down their lines without installations such as yours feeding power back into the lines that are supposedly safe. This on the off chance that you'll end up electrocuting a line-man, which makes good sense. Of course, since your puny little solar installation is incapable of powering a substantial portion of the grid this usually only really becomes a problem when the section that is islanded is small enough. Some electrical codes allow you to resume powering your own circuit if you physically lock-out your connection during such an outage, and re-configure your inverter to non-grid connected mode. You will also require a battery in such a case since the stabilizing properties of the grid (it's a very large load and acts as a huge flywheel or capacitor with basically endless capacity from the point of view of your installation). And of course when the grid outage has been dealt with and you wish to feed power back into the grid again (or consume when the sun is down) you're going to have to undo all of this. When I built a solar / wind power installation in Canada I decided that the net metering laws and price of power produced by renewables was so low that I scrapped the whole grid connectivity portion and invested the surplus into a much larger battery. It felt pretty good to have power when the island was down which happened many times every year.
  - davegardner 12y ago
    Yes it's not such a problem when it's just my 5 KW system. However here in Perth, Western Australia there are a lot of sunny days, so domestic rooftop solar systems are very commonplace now. In my case there's some significant financial incentives to stay connected to the grid (I actually get a cheque from my power company for most of the year). That'll change in another 6 years time when this higher buyback rate expires, so I'll be looking very closely at whether I want to remain grid connected at that point.
brudgers 12y ago
Such regulations provide several types of protection to the public commons. Another group of people who are protected are firefighters. In a typical residential installation the power meter also serves as the service disconnect. Response protocols include pulling the meter before many other life saving and property preserving operations. Live equipment and conductors operating from a second source downstream of the meter are a serious hazard to fire fighting personnel. Solar panels are a particular hazard because the sun doesn't have a disconnect, many firefighting operations involve working on the roof, and fire burns upward. A collapsed roof may bring a tangle of live electrical parts down into the building and create a hazard that persists long after the fire has been suppressed. In addition, miscellaneous loads applied to a grid can bring it down. In the Northeast US, much of the infrastructure is old and therefore less robustly engineered than elsewhere.
- jacquesm 12y ago
  And last but not least: when disconnected solar panels are 'open circuit' and the voltages will rise very rapidly. You can arc-weld with two fully illuminated 48V panels in parallel.
  - spydum 12y ago
    that is an interesting fact! wonder if there is a simple solution like a chemical blinder, that could be integrated into something sort of like a "EPO" button, making the panel inert in terms of voltage when hit? Just like the fire rescue folks can pull a breaker or service disconnect for traditional mains?
  - mtrimpe 12y ago
    It's also not a theoretical concern for disconnected panels either; my late father was consultant in a lawsuit where a small mechanical design flaw in the solar panel connector boxes combined with rough installation procedures caused farms all across France to go up in flames. It's also not that strange considering the farms would often have 20+ panels generating multiple kVs worth of electricity. Afterwards he refused to put any panels on our home without having a proper micro-inverter installed.
rasz_pl 12y ago
> because if you have batteries which cause a back flow during a power outage to the power station, an electrical worker could get shocked What is the difference between Battery backup and a wind turbine/solar? Somehow you are allowed to have solar and pump back to the grid, but not battery, geee wonder why that is.
IgorPartola 12y ago
Living in CT, is my gas generator considered a battery?
higherpurpose 12y ago
I'm not an electrician, but that sort of thing seems trivial to prevent? Surely there are ways to stop the current from passing through the cables where the outage happens, or somewhere near it?
GregBuchholz 12y ago
For people who are more interested in these topics, you'll want to investigate "anti-islanding", UL-1741, and IEEE-1547. http://en.wikipedia.org/wiki/Islanding http://en.wikipedia.org/wiki/Islanding http://en.wikipedia.org/wiki/IEEE_1547 http://en.wikipedia.org/wiki/IEEE_1547 https://www.google.com/?gws_rd=ssl#q=ul1741+pdf https://www.google.com/?gws_rd=ssl#q=ul1741+pdf ...if you wanted to power your house from a battery-fed inverter you'd have to install an automatic transfer switch, just like if you had a back-up generator. http://en.wikipedia.org/wiki/Transfer_switch http://en.wikipedia.org/wiki/Transfer_switch http://powerequipment.honda.com/generators/connecting-a-generator-to-your-home http://powerequipment.honda.com/generators/connecting-a-gene...
deeviant 12y ago
That may be the reason why the law was made, but that situation simply does not exist in reality. Any 'off-grid enabled' battery system that's worth anything at all would isolate the house from the grid when it kicks on, else all manner of bad things could happen, including having your battery drained on somebody else's load or the aforementioned electrical worker zappage. It's also trivially easy to accomplish said isolation.

Cthulhu_ 12y ago

Then that electrical worker would have to take precations (like disconnect the system), no? Sounds like it's just something that can be held in account. Plus the battery could not flow back to the grid in case of power outage (but instead power the own house first)

fche 12y ago

A properly wired transfer switch fully cures that risk.

spydum 12y ago
True, but bewary of automated transfer switches. I have seen DC's fail due to ATS's not doing their job. This can be pretty dangerous for a lineman/fire rescue if your particular ATS fails to switch...
danielweber 12y ago
And even though the solution is right there, power line worker remains the ninth deadliest job in America. http://www.businessinsider.com/most-dangerous-jobs-in-america-2014-12#9-electrical-power-line-installers-and-repairers-2 http://www.businessinsider.com/most-dangerous-jobs-in-americ...
- maxerickson 12y ago
  On trip through Minnesota, I watched a helicopter ferry guys up onto the towers to work (they dangled from the helicopter and then transferred over to the tower: http://www.capx2020.com/ http://www.capx2020.com/ ). They were building the type of infrastructure the news says America doesn't know how to build anymore. I wonder if energized lines are the big problem.
  - tlrobinson 12y ago
    Workers can safely work on live high voltage lines, if they're wearing a Faraday cage "hot suit" and not grounded: http://youtu.be/LIjC7DjoVe8 http://youtu.be/LIjC7DjoVe8
    - lutorm 12y ago
      That video is awesome. I've seen a version with much better quality that really gets my acrophobia going... ;-)
- fche 12y ago
  (It's likely there are many -other- hazards to power line working, beyond presence or absence of transfer switches at on-site generators.)
  - danielweber 12y ago
    If you are a lineman, you are three times more likely to die from electrocution than from a fall. (They die from electrocution at 35x the normal population rate, while the death from falls is 5x the normal population rate.) http://www.ncbi.nlm.nih.gov/pmc/articles/PMC1568699/pdf/envhper00445-0284.pdf http://www.ncbi.nlm.nih.gov/pmc/articles/PMC1568699/pdf/envh... That's just fatalities, ignoring the other dangers like getting your arms blown off.
brudgers 12y ago
A couple of my architect friends -- and they are good competent architects who spend the proper portion of their fees to hire competent consulting engineers -- designed an emergency services center a few years ago. The hurricane came - the project was in Florida - the utility cut grid power per protocol and the automatic transfer switch didn't flip to onsite power. Neither did the backup automatic switch. The person trained to operate the manual switch was on a scheduled vacation (hurricane season in the US is six months it ain't reasonable to prohibit vacations). It took over an hour to get the system back online. Now keep in mind that all of this was with emergency services grade equipment trained professional staff and regular inspections and testing. And everybody wasn't away on vacation by policy. Proper wiring is a necessary, but not sufficient condition. Power grid failures are many sigma events.
- warfangle 12y ago
  > The person And there's the problem.
  - brudgers 12y ago
    The HIL was the backup to the backup. [HIL]: https://en.wikipedia.org/wiki/Human-in-the-loop https://en.wikipedia.org/wiki/Human-in-the-loop

vetler 12y ago

> This is because if you have batteries which cause a back flow during a power outage to the power station, an electrical worker could get shocked down the road. Surely there is some safe way of preventing this?

TallGuyShort 12y ago
I would think so, and I would hope they would implement it. Especially considering the benefits to society of having people who are more prepared and self-sufficient, I would hope that safety would be only one of the reasons they wouldn't rely on people obeying some regulation for their worker's safety.
ceejayoz 12y ago
There is. The same issue is present with home generators, and most cities require they be installed by a licensed electrician who will ensure it doesn't power the grid in an outage.

Igglyboo 12y ago

>This is because if you have batteries which cause a back flow during a power outage to the power station, an electrical worker could get shocked down the road. If I were an electrical worked I'd treat a power line like it was live regardless of whether there is a power outage or not.

shiggerino 12y ago

Any reasonable grid company should not only not prohibit this, but welcome it and pay for energy people feed back into it. I can call mine any day and have a bi-directional meter put in so I can charge for it, should I ever choose to install solar panels.

shillster 12y ago
In some states, it is required by law that the power company pay for home generated electricity that is fed back into the grid.

rplnt 12y ago

Why is this not an issue if you have solar cells or wind mill or whatever?

lsaferite 12y ago

This is an issue even without battery storage. Solar and wind generation that is set up to feed excess back to the grid already has to have a way for the utilities to shut it off. This is why you have to have your setup vetted by the utility if you are feeding the grid.

engendered 12y ago

>you can't even live 'off the grid' in a grid tied system I can't find any references for your stated claim about Connecticut, however it seems deeply illogical given that a generator (which surely aren't banned), solar panels, wind, etc, all have the potential of feeding energy back to the grid in an outage. Which is why there are regulations and home inspections and all of that, to ensure that the appropriate safeties and switches are in place. Simply banning one of many possible mechanisms of generating power would be very short sighted. Many regions that offer feed-in time-of-day tariffs are rightly trying to figure out how to accommodate battery systems, where some users are trying to game the system by charging a big battery array during low cost hours, and then "selling" it back to the grid during peak hours (at inflated, subsidized prices). EDIT: As a reply to msandford, given that I can't reply lower -- the reason they have this limit is that the tariff price paid to home solar/wind generators is way above the bulk, "wholesale" price of power. It was created as an incentive to encourage green energy. So when you feed back their own power to them, it does them no favor given that now they're paying 2x+ what they would pay on the normal power market for power, and simply undermines the entire incentive program.

msandford 12y ago
> where some users are trying to game the system by charging a big battery array during low cost hours, and then "selling" it back to the grid during peak hours (at inflated, subsidized prices). The idea that a utility wants a heads-I-win-tails-you-lose kind of situation is annoying at best and downright infuriating at worst. If they're willing to sell power for $X now and willing to buy it later for $Y, what does it matter the method? I mean, there are people working on grid-scale storage batteries to do precisely that because utilities desperately NEED additional peak capacity when it's a hot day and everyone's A/C is on in the late afternoon. Why would it be OK for the UTILITY to utilize grid storage, but not an INDIVIDUAL? http://en.wikipedia.org/wiki/Grid_energy_storage http://en.wikipedia.org/wiki/Grid_energy_storage
- michaelt 12y ago
  If they're willing to sell power for $X now and willing to buy it later for $Y, what does it matter the method? In the UK, to encourage adoption of residential solar panels there is a scheme of "feed in tariffs" where you can generate renewable energy and receive a guaranteed, above-market-rate price for it. The goal of this is to reduce carbon emissions. For example, you can buy residential electricity for 15p/kWh [1] but sell energy from your small hydro installation for 19p/kWh [2]. Obviously, the goal of reducing carbon emissions would not be achieved if people simply charged batteries at 15p/kWh and sold it back at 19p/kWh! Of course, this issue only arises because feed in tariffs are subsidised. [1] https://www.gov.uk/government/uploads/system/uploads/attachment_data/file/388121/qep_dec_14.pdf https://www.gov.uk/government/uploads/system/uploads/attachm... [2] http://www.fitariffs.co.uk/eligible/levels/ http://www.fitariffs.co.uk/eligible/levels/

davegardner 12y ago

The same issue exists with grid connected solar panels. My solar panels are designed to stop working whenever there is a power outage. This is a legally mandated requirement here and is very annoying when it happens on a beautiful sunny day. A solar panel installer told me that if I add a battery backup to my installation, then at least it'll still charge the batteries during a power outage.

jacquesm 12y ago
There are some ways around that limitation. The reason it exists in the first place is so that the power company can safely power down their lines without installations such as yours feeding power back into the lines that are supposedly safe. This on the off chance that you'll end up electrocuting a line-man, which makes good sense. Of course, since your puny little solar installation is incapable of powering a substantial portion of the grid this usually only really becomes a problem when the section that is islanded is small enough. Some electrical codes allow you to resume powering your own circuit if you physically lock-out your connection during such an outage, and re-configure your inverter to non-grid connected mode. You will also require a battery in such a case since the stabilizing properties of the grid (it's a very large load and acts as a huge flywheel or capacitor with basically endless capacity from the point of view of your installation). And of course when the grid outage has been dealt with and you wish to feed power back into the grid again (or consume when the sun is down) you're going to have to undo all of this. When I built a solar / wind power installation in Canada I decided that the net metering laws and price of power produced by renewables was so low that I scrapped the whole grid connectivity portion and invested the surplus into a much larger battery. It felt pretty good to have power when the island was down which happened many times every year.
- davegardner 12y ago
  Yes it's not such a problem when it's just my 5 KW system. However here in Perth, Western Australia there are a lot of sunny days, so domestic rooftop solar systems are very commonplace now. In my case there's some significant financial incentives to stay connected to the grid (I actually get a cheque from my power company for most of the year). That'll change in another 6 years time when this higher buyback rate expires, so I'll be looking very closely at whether I want to remain grid connected at that point.

brudgers 12y ago

Such regulations provide several types of protection to the public commons. Another group of people who are protected are firefighters. In a typical residential installation the power meter also serves as the service disconnect. Response protocols include pulling the meter before many other life saving and property preserving operations. Live equipment and conductors operating from a second source downstream of the meter are a serious hazard to fire fighting personnel. Solar panels are a particular hazard because the sun doesn't have a disconnect, many firefighting operations involve working on the roof, and fire burns upward. A collapsed roof may bring a tangle of live electrical parts down into the building and create a hazard that persists long after the fire has been suppressed. In addition, miscellaneous loads applied to a grid can bring it down. In the Northeast US, much of the infrastructure is old and therefore less robustly engineered than elsewhere.

jacquesm 12y ago
And last but not least: when disconnected solar panels are 'open circuit' and the voltages will rise very rapidly. You can arc-weld with two fully illuminated 48V panels in parallel.
- spydum 12y ago
  that is an interesting fact! wonder if there is a simple solution like a chemical blinder, that could be integrated into something sort of like a "EPO" button, making the panel inert in terms of voltage when hit? Just like the fire rescue folks can pull a breaker or service disconnect for traditional mains?
- mtrimpe 12y ago
  It's also not a theoretical concern for disconnected panels either; my late father was consultant in a lawsuit where a small mechanical design flaw in the solar panel connector boxes combined with rough installation procedures caused farms all across France to go up in flames. It's also not that strange considering the farms would often have 20+ panels generating multiple kVs worth of electricity. Afterwards he refused to put any panels on our home without having a proper micro-inverter installed.

rasz_pl 12y ago

> because if you have batteries which cause a back flow during a power outage to the power station, an electrical worker could get shocked What is the difference between Battery backup and a wind turbine/solar? Somehow you are allowed to have solar and pump back to the grid, but not battery, geee wonder why that is.

IgorPartola 12y ago

Living in CT, is my gas generator considered a battery?

higherpurpose 12y ago

I'm not an electrician, but that sort of thing seems trivial to prevent? Surely there are ways to stop the current from passing through the cables where the outage happens, or somewhere near it?

GregBuchholz 12y ago

For people who are more interested in these topics, you'll want to investigate "anti-islanding", UL-1741, and IEEE-1547. http://en.wikipedia.org/wiki/Islanding http://en.wikipedia.org/wiki/Islanding http://en.wikipedia.org/wiki/IEEE_1547 http://en.wikipedia.org/wiki/IEEE_1547 https://www.google.com/?gws_rd=ssl#q=ul1741+pdf https://www.google.com/?gws_rd=ssl#q=ul1741+pdf ...if you wanted to power your house from a battery-fed inverter you'd have to install an automatic transfer switch, just like if you had a back-up generator. http://en.wikipedia.org/wiki/Transfer_switch http://en.wikipedia.org/wiki/Transfer_switch http://powerequipment.honda.com/generators/connecting-a-generator-to-your-home http://powerequipment.honda.com/generators/connecting-a-gene...

deeviant 12y ago

That may be the reason why the law was made, but that situation simply does not exist in reality. Any 'off-grid enabled' battery system that's worth anything at all would isolate the house from the grid when it kicks on, else all manner of bad things could happen, including having your battery drained on somebody else's load or the aforementioned electrical worker zappage. It's also trivially easy to accomplish said isolation.