Ow. I just had a bad idea.

Cariboocoot

GTI + line side tap + "smart" meter = utility control of your solar power production.

Yes, it would have to be a smarter smart meter than what is now available. But in theory the utility could measure your system's potential and regulate its output as-needed the way they do major power plants. Might require different GTI's but possibly not; could have "load testing" built in to the solar meter. Micro-managed solar installs.

Please don't kill me for thinking of this. I probably need my medication adjusted.

inetdog

Re: Ow. I just had a bad idea.

Cariboocoot wrote: »

GTI + line side tap + "smart" meter = utility control of your solar power production.

Yes, it would have to be a smarter smart meter than what is now available. But in theory the utility could measure your system's potential and regulate its output as-needed the way they do major power plants. Might require different GTI's but possibly not; could have "load testing" built in to the solar meter. Micro-managed solar installs.

Please don't kill me for thinking of this. I probably need my medication adjusted.

Medication works for me too.

Question is just how the meter would feed control information back to the GTI. Changing the voltage will not change the GTI output in any way. Changing frequency like the SunnyIsland is not an option. Might actually be easier to put a "SmartControl" addressable unit into the GTI. (Can I take credit for that one?)

NorthGuy

Re: Ow. I just had a bad idea.

IMHO, it would be easier for the utility to measure the combined net (consumption - production) of thousands of customers somewhere at the central location. That would automatically adjust for wire/transformer losses too.

But having the smart meter that telegraphs your production to Ottawa would be a great idea. This way they could tax it the same whether you consume it at home or sell it to the grid. This would also help cell phone companies who would be able to collect their fees for the transmission of the information :D

Cariboocoot

Re: Ow. I just had a bad idea.

You have two power control options that I can see:

External skewing of Voltage/frequency to shut down the GTI via existing anti-islanding circuitry which would be an on/off choice. Each unit would have to be powered at least occasionally to test for potential. Compared to a full-size plant it would be miniscule increments turning each one on/off.

Internal control of current function of the GTI. This would require different units than are already available, so would be more costly and difficult to implement. But it would allow almost linear power output control (possibly unnecessary - again we're talking drop-in-the-bucket changes).

I got on to this thinking about utilities complaints that they have no way of knowing or controlling GTI production so it represents an unknown factor to grid management. With the few that are in place now it is not an issue, but with solar becoming more prevalent (as in Germany's 25% production goal) it has to be dealt with somehow. You could not have 25% of your power potential going up and down like a yo-yo without any ability to predict or control it.

But yes, they would probably see it only as a way to tax and charge production - after the homeowner/business makes the capital investment. Supposedly BC Hydro has a plan for small-scale inclusion, but at the rates here it probably isn't worth the investment. Economies of scale and all that.

NorthGuy

Re: Ow. I just had a bad idea.

Cariboocoot wrote: »

External skewing of Voltage/frequency to shut down the GTI via existing anti-islanding circuitry which would be an on/off choice.

That mechanism is in place in many inverters. Utility company has the ability to shut down all the susceptable GTI inverters by simply alerting frequency. Do people who installed such inverters are aware of that?

Cariboocoot wrote: »

With the few that are in place now it is not an issue, but with solar becoming more prevalent (as in Germany's 25% production goal) it has to be dealt with somehow. You could not have 25% of your power potential going up and down like a yo-yo without any ability to predict or control it.

Even if you achieve 25%, most of it will be used at household who generated it.

Then it will not be like a yo-yo when averaged over a big territory. When you look at a single place, you see a clouds moving inverter's output up and down, but clouds are relatively small and hold their shape rather well. When a cloud shades your inverter, someone else's inverter on the other size of the cloud gets uncovered. As a result, it will be relatively smooth, same as with loads.

Cariboocoot

Re: Ow. I just had a bad idea.

NorthGuy wrote: »

That mechanism is in place in many inverters. Utility company has the ability to shut down all the susceptable GTI inverters by simply alerting frequency. Do people who installed such inverters are aware of that?

All legal GTI's have this anti-islanding function. Installers/AHJ's/Utilities should be aware of this. Sometimes we see indications that they are not. And yes a utility can shut them down in the manner you describe, but that would be blanket turn-off not individual management. That lack of control of production is one of the companies' complaints against solar.

Even if you achieve 25%, most of it will be used at household who generated it.

Then it will not be like a yo-yo when averaged over a big territory. When you look at a single place, you see a clouds moving inverter's output up and down, but clouds are relatively small and hold their shape rather well. When a cloud shades your inverter, someone else's inverter on the other size of the cloud gets uncovered. As a result, it will be relatively smooth, same as with loads.

Not necessarily. A home may be empty during peak production times so its usage could be quite small compared to production.

Clouds do tend to be a passing thing, but in my neck of the woods it can be sunny in one neighbourhood and dark in the next. However I don't believe small-region weather variations would be a major problem.

Whether or not it really would be smooth isn't the issue either; it's the companies complaints that solar installs on a large scale would create unmanageable fluctuations. I'm just thinking out loud about how those complaints may be addressed and eliminated.

Of course if you take away one cause for complaint they'll find another. :roll:

westbranch

Re: Ow. I just had a bad idea.

I see the answer as distributed storage, ie Flow Batteries, on site, capable of taking up to a days PV production at one go, this assumes that the array is designed for powering a house for a day+-, so that if the grid power goes down the battery can take over from the grid..

Cariboocoot

Re: Ow. I just had a bad idea.

westbranch wrote: »

I see the answer as distributed storage, ie Flow Batteries, on site, capable of taking up to a days PV production at one go, this assumes that the array is designed for powering a house for a day+-, so that if the grid power goes down the battery can take over from the grid..

That's somewhat of a different issue: storage for independence against grid failure rather than controlled distribution of surplus.

It's also along the lines of the (hopefully) defunct utility plan of rationed distribution. You don't want to know how ugly that is!

It should be interesting to see how Germany's increase in solar production works with distribution management. But don't hold your breath waiting for USA plans to follow suit; seems more and more they are working against solar everywhere.

gww1

Re: Ow. I just had a bad idea.

I still don't see how solar production based on weather is any differrent then when rains and cools down air conditioners don't run as much. Why is this more then just a revenue loss issue to power companies?

Big factory closures or temporary shut downs would seem to have a larger effect then people going solar. It would seem they could plan as well for solar as those types of situations. Now power companies are getting people to allow them to control their air conditioners. Maby they will start paying us to not plant our fields.

Cheers
gww

solar_dave

Re: Ow. I just had a bad idea.

Cariboocoot wrote: »

GTI + line side tap + "smart" meter = utility control of your solar power production.

Yes, it would have to be a smarter smart meter than what is now available. But in theory the utility could measure your system's potential and regulate its output as-needed the way they do major power plants. Might require different GTI's but possibly not; could have "load testing" built in to the solar meter. Micro-managed solar installs.

Please don't kill me for thinking of this. I probably need my medication adjusted.

Yes this is a bad idea! Your a bad bad man, get those meds adjusted ASAP.

Oh and block this tread from the bots so the utility doesn't pick up on this. :D:D

NorthGuy

Re: Ow. I just had a bad idea.

solar_dave wrote: »

Oh and block this tread from the bots so the utility doesn't pick up on this. :D:D

Don't be afraid. If your electric company gains control of your power generation equipment, that's only for your own good. You won't need to worry about chosing payment plans any more, because no matter what plan you choose, they always can tweak your inverter to make you pay more.

BB.

Re: Ow. I just had a bad idea.

We already have addressable power control via remote control relays for Electric Water Heaters and A/C systems... You pay less per kWH for power if you install one of these power switches--And let the utility turn off the power for ~30 minutes at a time during a (usually) summer power emergency (as I recall).

If the power company had their way, they would probably like to see the GT Inverters output at 0.75 Power Factor--It does not use any more solar power (need a "larger inverter" output stage to handle the lower power factor)--That would reduce the amount of current flow in their lines (and generator loading) for not too much cost.

-Bill

westbranch

Re: Ow. I just had a bad idea.

But Bill, they can make them cheaper, eh? so more people will buy them, and with engineered in obsolescence, what a gold mine... Start up those presses!

petertearai

Re: Ow. I just had a bad idea.

So something like this being offered by my lines company ,. http://vector.co.nz/solar

peakbagger

Re: Ow. I just had a bad idea.

Germany is developing a new feed it tariff for solar system owner that have battery backup. The reason is so that when there is a sudden demand on the grid (like a power plant kicking off line) rather than ramp up inefficient reserves, the utility would island the house for a short period. If the utility can get 15 minutes to ramp up more efficient production, it makes a big difference.

Blackcherry04

Re: Ow. I just had a bad idea.

peakbagger wrote: »

Germany is developing a new feed it tariff for solar system owner that have battery backup. The reason is so that when there is a sudden demand on the grid (like a power plant kicking off line) rather than ramp up inefficient reserves, the utility would island the house for a short period. If the utility can get 15 minutes to ramp up more efficient production, it makes a big difference.

If the price is right this might actually be a win/win for everyone. Offsetting the cost of the batteries during their useful life span would sure lower the costs of having them, kind of like having your cake and eating too. Where do I sign up ??

Cariboocoot

Re: Ow. I just had a bad idea.

peakbagger wrote: »

Germany is developing a new feed it tariff for solar system owner that have battery backup. The reason is so that when there is a sudden demand on the grid (like a power plant kicking off line) rather than ramp up inefficient reserves, the utility would island the house for a short period. If the utility can get 15 minutes to ramp up more efficient production, it makes a big difference.

Uh-oh.
Remember that "rationed distribution" plan I mentioned? Sounds like somebody thought it was a good idea after all; that is alarmingly similar to it.

stephendv

Re: Ow. I just had a bad idea.

Blackcherry04 wrote: »

If the price is right this might actually be a win/win for everyone. Offsetting the cost of the batteries during their useful life span would sure lower the costs of having them, kind of like having your cake and eating too. Where do I sign up ??

Indeed! Looks like the subsidy will be linked to the solar capacity installed, not the battery capacity (unless the media got it wrong): 660 Euros per kW of PV to add battery storage. That would pay for a nice set. http://www.bloomberg.com/news/2013-04-17/germany-to-support-solar-backup-batteries-with-subsidy.html

solar_dave

Re: Ow. I just had a bad idea.

stephendv wrote: »

Indeed! Looks like the subsidy will be linked to the solar capacity installed, not the battery capacity (unless the media got it wrong): 660 Euros per kW of PV to add battery storage. That would pay for a nice set. http://www.bloomberg.com/news/2013-04-17/germany-to-support-solar-backup-batteries-with-subsidy.html

per KW of storage capacity:

The government will pay 660 euros a kilowatt of storage capacity under a program that begins May 1, the trade group said today in a statement. The systems will also stabilize the flow of electricity into the grid.

stephendv

Re: Ow. I just had a bad idea.

solar_dave wrote: »

per KW of storage capacity:

The google translated german version says kW of solar capacity (which makes more sense because kW is not a unit of energy): http://translate.google.com/translate?sl=auto&tl=en&js=n&prev=_t&hl=en&ie=UTF-8&eotf=1&u=http%3A%2F%2Fwww.solarwirtschaft.de%2Fpresse-mediathek%2Fpressemeldungen%2Fpressemeldungen-im-detail%2Fnews%2Ffoerderprogramm-fuer-solarstrom-speicher-startet-im-mai.html

NorthGuy

Re: Ow. I just had a bad idea.

solar_dave wrote: »

per KW of storage capacity:

What is a kW of storage capacity?

If they mean kWh, the subsidy would be 4-6 times the cost.

ggunn

Re: Ow. I just had a bad idea.

NorthGuy wrote: »

That mechanism is in place in many inverters. Utility company has the ability to shut down all the susceptable GTI inverters by simply alerting frequency. Do people who installed such inverters are aware of that?

I don't think utilities would want to putz with the frequency just to do this. They would incur all sorts of liability for the failures of customers' timing functions which rely on tight control of line frequency. It would make my Strobotuner go out of calibration and make me play out of tune!

BB.

Re: Ow. I just had a bad idea.

I am not sure that the utilities would be too worried about taking the grid +/- 0.6 Hz to knock GT based systems off line if they ever needed too. This Wiki article seems reasonable:

http://en.wikipedia.org/wiki/Utility_frequency

Long-term stability and clock synchronization

Regulation of power system frequency for timekeeping accuracy was not commonplace until after 1926 and the invention of the electric clock driven by a synchronous motor. Today network operators regulate the daily average frequency so that clocks stay within a few seconds of correct time. In practice the nominal frequency is raised or lowered by a specific percentage to maintain synchronization. Over the course of a day, the average frequency is maintained at the nominal value within a few hundred parts per million.^[17] In the synchronous grid of Continental Europe, the deviation between network phase time and UTC (based on International Atomic Time) is calculated at 08:00 each day in a control center in Switzerland. The target frequency is then adjusted by up to ±0.01 Hz (±0.02%) from 50 Hz as needed, to ensure a long-term frequency average of exactly 50 Hz × 60 sec × 60 min × 24 hours = 4,320,000 cycles per day.^[18] In North America, whenever the error exceeds 10 seconds for the east, 3 seconds for Texas, or 2 seconds for the west, a correction of ±0.02 Hz (0.033%) is applied. Time error corrections start and end either on the hour or on the half hour.^[19][20]

Real-time frequency meters for power generation in the United Kingdom are available online - an official National Grid one, and an unofficial one maintained by Dynamic Demand.^[21][22] Real-time frequency data of the synchronous grid of Continental Europe is available at mainsfrequency.com. The Frequency Monitoring Network (FNET) at the University of Tennessee measures the frequency of the interconnections within the North American power grid, as well as in several other parts of the world. These measurements are displayed on the FNET website.

Smaller power systems may not maintain frequency with the same degree of accuracy. In 2011, The North American Electric Reliability Corporation (NERC) discussed a proposed experiment that would relax frequency regulation requirements for electrical grids^[23] which would reduce the long-term accuracy of clocks and other devices that use the 60 Hz grid frequency as a time base.

Frequency and load

The primary reason for accurate frequency control is to allow the flow of alternating current power from multiple generators through the network to be controlled. The trend in system frequency is a measure of mismatch between demand and generation, and so is a necessary parameter for load control in interconnected systems.

Frequency of the system will vary as load and generation change. Increasing the mechanical input power to a synchronous generator will not greatly affect the system frequency but will produce more electric power from that unit. During a severe overload caused by tripping or failure of generators or transmission lines the power system frequency will decline, due to an imbalance of load versus generation. Loss of an interconnection, while exporting power (relative to system total generation) will cause system frequency to rise. Automatic generation control (AGC) is used to maintain scheduled frequency and interchange power flows. Control systems in power plants detect changes in the network-wide frequency and adjust mechanical power input to generators back to their target frequency. This counteracting usually takes a few tens of seconds due to the large rotating masses involved. Temporary frequency changes are an unavoidable consequence of changing demand. Exceptional or rapidly changing mains frequency is often a sign that an electricity distribution network is operating near its capacity limits, dramatic examples of which can sometimes be observed shortly before major outages.

Frequency protective relays on the power system network sense the decline of frequency and automatically initiate load shedding or tripping of interconnection lines, to preserve the operation of at least part of the network. Small frequency deviations (i.e.- 0.5 Hz on a 50 Hz or 60 Hz network) will result in automatic load shedding or other control actions to restore system frequency.

Smaller power systems, not extensively interconnected with many generators and loads, will not maintain frequency with the same degree of accuracy. Where system frequency is not tightly regulated during heavy load periods, the system operators may allow system frequency to rise during periods of light load, to maintain a daily average frequency of acceptable accuracy.^[24][25] Portable generators, not connected to a utility system, need not tightly regulate their frequency because typical loads are insensitive to small frequency deviations.

-Bill

Cariboocoot

Re: Ow. I just had a bad idea.

If you alternated pushing the Hz up and down for equal amounts of time it would "correct itself" in terms of end-usage.

ggunn

Re: Ow. I just had a bad idea.

Cariboocoot wrote: »

If you alternated pushing the Hz up and down for equal amounts of time it would "correct itself" in terms of end-usage.

That's what a Sunny Island does.