Chapter: kW DEMAND vs kWh consumption. How LEDs and solar PVs are rather ineffective

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Electric-Light

Senior Member
In this thread, I will talk about how solar photovoltaic is a huge money pit It is only done to meet regulations on renewable energy and when it is used in moderation, it can have reasonable positive effect, but in excess it's just lining up the pockets of solar installers using tax money without a proportional public benefit.

Airlines, buses, solar photovoltaic owners all have one thing in common. Demand capacity is costly. They want to make best utilization of existing demand capacity.

Solar PV cost is measured in $/kW, which is demand capacity. The cost of system depends on the kW capacity. Energy sales companies like solar installers have huge vested interest in selling the most kW size and lobby to generate demand for the energy created to justify debauchery in status symbol clean energy luxury.

Power companies would rather have 50kW of on-call solar power and call 50kW in ten 6 minute segments and purchase 10kWh than have a 10kW supplier providing 10kW for 5 hours rather. The benefit provided by the first example far exceeds the value of the second example. The solar owner that bought 50kW system wants to dump the entire output into the grid during the entire duration and expects to get paid at retail price and whine about removal of welfare that lowers the payment to cost-avoided basis or competitive wholesale pricing.

Ok, so you own a bus with 15 seats. Your dream is of course, all 15 seats are filled every time you drive it. If you book 17 with calculation that two will cancel, but all 17 ends up showing up, you would find it very valuable to have a service allies who will take your two passengers even if they keep the full ticket revenue + you have to pay a 10% fee, because you do not want to refuse service and have these passenger be angry at you which will affect future business.

That's the idea behind how solar photovoltaic can provide a relief. If you had four applicants show up each wanting two passengers and full fare payment, it gives you no advantage whatsoever. You will then only collect seat revenue for 9 seats and create 7 seat revenues at 110% the prevailing fare for the government bus. Be assured, the .Gov helps you pay for a portion of the fare paid to the government bus using tax money :lol::lol::lol::lol::lol:


What about net metering?
It's day time. A government subsidized bus offers to take your passengers during daytime even when you don't need the relief/forcing you to purchase from them. In exchange, they want to place seat credits for those who already rides in your bus and have been paying night time fare and force you to lose night time passenger revenue which helps you cover fixed cost.

Now, how about kWh conserving light emitting decoration street lights? does the cost advantage from 5-7PM demand offset surpass the revenue loss from kWh sold throughout the night? Oh no problem, this can be overcome in the long run by increasing the off peak rates.

Solar Photovoltaic in general have been a horrible waste of tax money.


Rolling blackouts and such are not due to shortage of electricity. It's a due to congestion in the network somewhere. If hot weather and demand locally causes one of the lower blocks to shut down, a bunch of ACs will run at full duty cycle which increases load on the next upper tier. When that one overloads, all three lower tiers can lose power. The purpose of rolling black is to prevent black outs from propagating upwards.

Jk7qZDJl.png


Some eco liberation front funded solar covered data center that is upstream of the demand constraints have no helpful effect whatsoever in mitigating black outs. Injection power into the far lower right section with residential solar would reduce the load on the substation above it, but if the power shortage was to occur locally at the lower left substation due to system capacity issue, it's a branch circuit shortage, not a main panel shortage.
 

coop3339

Senior Member
Location
NJ
I believe the grid gets a large share of power by burning gas, coal and oil. The government also gives tax breaks to the companies extracting these from the ground and importing them from our enemies. I would rather see the "welfare", tax breaks you talk about, go to the middle class solar installer rather than the huge corporations.

Have you ever heard of demand response and frequency stabilization. As inverter technology improves, there are many advantages to having multiple distributed generators capable of providing these services. Add a few batteries and the inverters can help stabilize the grid day or night.

I think peak demand is most likely to hit between 12PM and 5PM, during this time the solar is producing lowering the need for additional power company resources.

Solar had to be subsidized to start out or it may never have been developed. The large companies that are capable of developing it would not have done it if it wasn't for the demand caused by profitability. As the cost of solar panels continues to drop, it will become viable without the subsidies.

As for LEDs, the more we lower our power usage the better. How can this be a bad thing? Like solar they will also become cheaper as technology improves.
 

ActionDave

Chief Moderator
Staff member
Location
Durango, CO, 10 h 20 min from the winged horses.
Occupation
Licensed Electrician
In this thread, I will talk about how solar photovoltaic is a huge money pit It is only done to meet regulations on renewable energy and when it is used in moderation, it can have reasonable positive effect, but in excess it's just lining up the pockets of solar installers using tax money without a proportional public benefit.

Airlines, buses, solar photovoltaic owners all have one thing in common. Demand capacity is costly. They want to make best utilization of existing demand capacity.

Solar PV cost is measured in $/kW, which is demand capacity. The cost of system depends on the kW capacity. Energy sales companies like solar installers have huge vested interest in selling the most kW size and lobby to generate demand for the energy created to justify debauchery in status symbol clean energy luxury.

Power companies would rather have 50kW of on-call solar power and call 50kW in ten 6 minute segments and purchase 10kWh than have a 10kW supplier providing 10kW for 5 hours rather. The benefit provided by the first example far exceeds the value of the second example. The solar owner that bought 50kW system wants to dump the entire output into the grid during the entire duration and expects to get paid at retail price and whine about removal of welfare that lowers the payment to cost-avoided basis or competitive wholesale pricing.

Ok, so you own a bus with 15 seats. Your dream is of course, all 15 seats are filled every time you drive it. If you book 17 with calculation that two will cancel, but all 17 ends up showing up, you would find it very valuable to have a service allies who will take your two passengers even if they keep the full ticket revenue + you have to pay a 10% fee, because you do not want to refuse service and have these passenger be angry at you which will affect future business.
Doing good here.

That's the idea behind how solar photovoltaic can provide a relief. If you had four applicants show up each wanting two passengers and full fare payment, it gives you no advantage whatsoever. You will then only collect seat revenue for 9 seats and create 7 seat revenues at 110% the prevailing fare for the government bus. Be assured, the .Gov helps you pay for a portion of the fare paid to the government bus using tax money
I'm still interested.
:lol::lol::lol::lol::lol:
Hmmmm, now I'm thinking there is an agenda at hand.
What about net metering?
It's day time. A government subsidized bus offers to take your passengers during daytime even when you don't need the relief/forcing you to purchase from them. In exchange, they want to place seat credits for those who already rides in your bus and have been paying night time fare and force you to lose night time passenger revenue which helps you cover fixed cost.

Now, how about kWh conserving light emitting decoration street lights? does the cost advantage from 5-7PM demand offset surpass the revenue loss from kWh sold throughout the night? Oh no problem, this can be overcome in the long run by increasing the off peak rates.

Solar Photovoltaic in general have been a horrible waste of tax money.


Rolling blackouts and such are not due to shortage of electricity. It's a due to congestion in the network somewhere. If hot weather and demand locally causes one of the lower blocks to shut down, a bunch of ACs will run at full duty cycle which increases load on the next upper tier. When that one overloads, all three lower tiers can lose power. The purpose of rolling black is to prevent black outs from propagating upwards.

Jk7qZDJl.png
Interesting. Tell me more.

Some eco liberation front funded solar covered data center that is upstream of the demand constraints have no helpful effect whatsoever in mitigating black outs. Injection power into the far lower right section with residential solar would reduce the load on the substation above it, but if the power shortage was to occur locally at the lower left substation due to system capacity issue, it's a branch circuit shortage, not a main panel shortage.
Now you've lost me. When the name calling starts I check out.
 

Haji

Banned
Location
India
One way to increase the power handling capacity of transmission lines is to use power electronics. However, the power electronics devices may lack two way power flow with adverse effect on distributed power generation including solar panels.
 

mivey

Senior Member
I believe the grid gets a large share of power by burning gas, coal and oil. The government also gives tax breaks to the companies extracting these from the ground and importing them from our enemies. I would rather see the "welfare", tax breaks you talk about, go to the middle class solar installer rather than the huge corporations.
If you go along with that then you would have to support income tax refunds for people who don't pay income tax. All corporations get tax breaks as it is one of the benefits of incorporating in the first place.

Show me where we are paying to install small coal units or small diesel units and we have a basis for discussion. Subsidizing a technology that is otherwise not a market player is shoring up one technology over the other, plain and simple. We know that is what is happening so pointing hollow fingers at some non-related tax breaks is not a good argument.

We know ECs with a corporate structure get tax breaks. So if we start giving monies to Handy-Andys to help them compete because we feel sorry for them, it is hard to justify that just because the legitimate ECs get tax breaks. I think we would say let the Handy-Andys run a legitimate business in the market place and the market will decide who has the best product.

Not saying solar is not legit but just trying to illustrate (there are probably better illustrations) that a product should sell itself without the government trying to force the issue like they did with CFLs. Also reminds me of the AFCIs that were forced down our throats before they were ready.

Have you ever heard of demand response and frequency stabilization. As inverter technology improves, there are many advantages to having multiple distributed generators capable of providing these services. Add a few batteries and the inverters can help stabilize the grid day or night.
Have you looked at that cost? Energy storage is the holy grail that will make solar a legitimate alternative.

I think peak demand is most likely to hit between 12PM and 5PM, during this time the solar is producing lowering the need for additional power company resources.
In a perfect world it is producing. In a real world it is not dependable enough unless you have a large group of them. When the group covers a big enough area, many times you either fall outside the control area or you are outside the constraint area.

Also, don't forget that peak demand is only part of the story. Part of the value is the off-peak demand as well.

Solar had to be subsidized to start out or it may never have been developed. The large companies that are capable of developing it would not have done it if it wasn't for the demand caused by profitability. As the cost of solar panels continues to drop, it will become viable without the subsidies.
But at what cost? We will have run off cheaper alternatives and at the end the cost goes up for everyone.

As for LEDs, the more we lower our power usage the better. How can this be a bad thing? Like solar they will also become cheaper as technology improves.
I like the lower usage, however the money I spend on the lamp wipes out the value from the energy savings.
 

Bugman1400

Senior Member
Location
Charlotte, NC
One way to increase the power handling capacity of transmission lines is to use power electronics. However, the power electronics devices may lack two way power flow with adverse effect on distributed power generation including solar panels.

Can you elaborate? There are numerous ways of increasing the capacity of a T-line. Power electronics are typically not considered. I know they are used for system stabilization and are very costly to implement. They are also sources of numerous failure points.
 

Electric-Light

Senior Member
Look beyond photovoltaic system. Grid tying privately owned petroleum fuel burning generators that can go online immediately provide a much greater kW as well as reactive demand per $1,000 real cost. They can operate as an on-demand turbocharger for the grid. The available on-demand kW per $1 capacity is extremely valuable and this is something solar proponents ignore.

kWh is kW multiplied by hours. A Toyota will probably provide more hp-hr than a Lambo, because of higher usage. 50 hp for a minute provides the same kWh of delivered energy as 500 hp for six seconds.This is what we mean when we say "demand" and by now, the value of demand should be very obvious. Solar systems are prohibitively expensive to breakeven under privately negotiated price without subsidies. This means kWh buyback at cost-avoided basis.

Ability to produce a steady demand regardless of sudden weather change or cloud passing, which requires a flywheel or large battery UPS.


http://www.netl.doe.gov/File Librar...neration-08-29-08-AZ--2-_APPROVED_2008_09.pdf
"
While new guidelines and regulations such as IEEE (Institute of Electrical and Electronics Engineers) 1547 have come a long way in addressing interconnection standards for distributed generation, utilities have largely overlooked the untapped potential of these resources. Under certain conditions, these units (primarily backup generators) represent a significant source of power that can deliver utility services at lower costs than traditional centralized solutions. These backup generators exist today in large numbers and provide utilities with another option to reduce peak load, relieve transmission congestion, and improve power reliability.
Backup generation is widely deployed across the United States. Carnegie Mellon?s Electricity Industry Center reports that there are about 12 million backup generators in the United States with over 200 GW of generating capacity (growing at ~5 GW per year)1. Today, Smart Grid technology can integrate these resources into the grid in an intelligent way, allowing utilities to effectively deploy them in a fully coordinated manner. For example, Portland General Electric (PGE) has engaged more than 40 MW of standby generation at customer sites to address peak load.2 Using these resources could reduce required installed capacity and would increase the operating reserve margins for the network, resulting in lower electricity prices."


As for LEDs, the more we lower our power usage the better. How can this be a bad thing? Like solar they will also become cheaper as technology improves.
The bus example again. Replacing your 15 seat bus with a 20 seat bus is a very costly decision, so day-time only service ally that absorbs passengers that exceed your seats during commute hours make sure your bus operates at full capacity, and the 2-3 people that don't fit on your bus still get to work and home as planned and remain happy.

You provide a bus service that's essential to community and you need to continue operating it at night. Some, but not many people ride off peak. So, you provide an attractive fare to increase seat revenues during off peak. If something changes that cause most of night customers to stop riding, you're still going to drive the bus around the route, but your cost do not reduce proportionately with the dropping seat revenue, therefore you will have to overcome this by raising the fare.

So, LED street lights are good for demand reduction when there's an overlap between dusk and peak demand, but once it goes into off peak, street lamps currently on metered service will lower revenue which will likely get compensated in the long run by increasing rates.

Data centers are massive power hogs, but they're good customers, because, they provide a good utilization of transmission resources and provide a steady source of revenue.


Doing good here.

Interesting. Tell me more.

There has been a huge cultural change since the time power systems were installed. Here's a smaller model of demand shortage, kWh surplus. Uploading kW x hours right there is not going to address the demand shortage
at the receptacle. To make sure both loads operate, you would need to supply power right at the point of shortage throughout the duration of demand and you probably need a large battery or flywheel UPS to coast through clouding.
BivF7Oh.png


Real life constraints prevent supplemental power source from providing power at the point of shortage due to geographic, real estate or climate limitations. If the capacity constraint is due to landlocked substation building, you'd have to inject additional power into secondary side at the distribution voltage. You might not find the space to set up solar.


One way to increase the power handling capacity of transmission lines is to use power electronics. However, the power electronics devices may lack two way power flow with adverse effect on distributed power generation including solar panels.
I believe a lot of shortage is localized at sub-transmission or distribution level rather than regional or national grid level. A power electronics based substation with enough redundancy to provide the same level of resiliency as existing equipment at small sites would cost a lot of money.
 

jglavin427

Member
Location
Denver, CO
Back in college, one of my friends wanted to install a large grid-tied diesel genset in his back yard and collect waste vegetable oil from local restaurants. I always thought that was an intriguing (albeit labor-intensive) idea.
 

gadfly56

Senior Member
Location
New Jersey
Occupation
Professional Engineer, Fire & Life Safety
Back in college, one of my friends wanted to install a large grid-tied diesel genset in his back yard and collect waste vegetable oil from local restaurants. I always thought that was an intriguing (albeit labor-intensive) idea.

This is the sort of thing that may work well for the first two or three players who get in the game, but in the end, Americans don't eat enough fried foods to keep all the players in waste vegetable oil. Pretty soon, the local McDonald's is going to be auctioning their used oil to the highest bidder, rather than paying someone to cart it away.
 

Electric-Light

Senior Member
I'd say it's more effective to tie into a medium voltage distribution voltage unless it is added into a very large capacity utilization voltage grid and you push a fair amount of power into all three phases.

A residential service is limited to uploading onto one phase and limited by the service size.
 
In this thread, I will talk about how solar photovoltaic is a huge money pit It is only done to meet regulations on renewable energy and when it is used in moderation, it can have reasonable positive effect, but in excess it's just lining up the pockets of solar installers using tax money without a proportional public benefit.

Im kinda sick of these type of arguments. Sure PV is subsidized. Many many other things are too, get over it and stop picking on PV. Your coke is subsidized, trucking is subsidized, milk, petroleum - both directly and indirectly through our massive military spending. Have a cold coke or glass of milk and stop worrying about it.
 

Electric-Light

Senior Member
Im kinda sick of these type of arguments. Sure PV is subsidized. Many many other things are too, get over it and stop picking on PV. Your coke is subsidized, trucking is subsidized, milk, petroleum - both directly and indirectly through our massive military spending. Have a cold coke or glass of milk and stop worrying about it.

Which form do you you submit for your expenses for those items other than PV and get a 30% tax credit?
 

Bugman1400

Senior Member
Location
Charlotte, NC
Look beyond photovoltaic system. Grid tying privately owned petroleum fuel burning generators that can go online immediately provide a much greater kW as well as reactive demand per $1,000 real cost. They can operate as an on-demand turbocharger for the grid. The available on-demand kW per $1 capacity is extremely valuable and this is something solar proponents ignore.

kWh is kW multiplied by hours. A Toyota will probably provide more hp-hr than a Lambo, because of higher usage. 50 hp for a minute provides the same kWh of delivered energy as 500 hp for six seconds.This is what we mean when we say "demand" and by now, the value of demand should be very obvious. Solar systems are prohibitively expensive to breakeven under privately negotiated price without subsidies. This means kWh buyback at cost-avoided basis.

Ability to produce a steady demand regardless of sudden weather change or cloud passing, which requires a flywheel or large battery UPS.


http://www.netl.doe.gov/File Librar...neration-08-29-08-AZ--2-_APPROVED_2008_09.pdf
"
While new guidelines and regulations such as IEEE (Institute of Electrical and Electronics Engineers) 1547 have come a long way in addressing interconnection standards for distributed generation, utilities have largely overlooked the untapped potential of these resources. Under certain conditions, these units (primarily backup generators) represent a significant source of power that can deliver utility services at lower costs than traditional centralized solutions. These backup generators exist today in large numbers and provide utilities with another option to reduce peak load, relieve transmission congestion, and improve power reliability.
Backup generation is widely deployed across the United States. Carnegie Mellon?s Electricity Industry Center reports that there are about 12 million backup generators in the United States with over 200 GW of generating capacity (growing at ~5 GW per year)1. Today, Smart Grid technology can integrate these resources into the grid in an intelligent way, allowing utilities to effectively deploy them in a fully coordinated manner. For example, Portland General Electric (PGE) has engaged more than 40 MW of standby generation at customer sites to address peak load.2 Using these resources could reduce required installed capacity and would increase the operating reserve margins for the network, resulting in lower electricity prices."



The bus example again. Replacing your 15 seat bus with a 20 seat bus is a very costly decision, so day-time only service ally that absorbs passengers that exceed your seats during commute hours make sure your bus operates at full capacity, and the 2-3 people that don't fit on your bus still get to work and home as planned and remain happy.

You provide a bus service that's essential to community and you need to continue operating it at night. Some, but not many people ride off peak. So, you provide an attractive fare to increase seat revenues during off peak. If something changes that cause most of night customers to stop riding, you're still going to drive the bus around the route, but your cost do not reduce proportionately with the dropping seat revenue, therefore you will have to overcome this by raising the fare.

So, LED street lights are good for demand reduction when there's an overlap between dusk and peak demand, but once it goes into off peak, street lamps currently on metered service will lower revenue which will likely get compensated in the long run by increasing rates.

Data centers are massive power hogs, but they're good customers, because, they provide a good utilization of transmission resources and provide a steady source of revenue.




There has been a huge cultural change since the time power systems were installed. Here's a smaller model of demand shortage, kWh surplus. Uploading kW x hours right there is not going to address the demand shortage
at the receptacle. To make sure both loads operate, you would need to supply power right at the point of shortage throughout the duration of demand and you probably need a large battery or flywheel UPS to coast through clouding.
BivF7Oh.png


Real life constraints prevent supplemental power source from providing power at the point of shortage due to geographic, real estate or climate limitations. If the capacity constraint is due to landlocked substation building, you'd have to inject additional power into secondary side at the distribution voltage. You might not find the space to set up solar.



I believe a lot of shortage is localized at sub-transmission or distribution level rather than regional or national grid level. A power electronics based substation with enough redundancy to provide the same level of resiliency as existing equipment at small sites would cost a lot of money.

Your points are interesting and both quite wrong and quite right. You paint with a very broad brush over this topic and do not address the details that need to be addressed. There are so many facets to this subject that cannot be ignored. For example, power shortages are definitely at the grid level, in California, and not at the local level. You can't deny that but, what you say has merit in other regions. Another example is, that most privately owned generation (new generation) is not fuel burning.....its wind. That government subsidy ran out in Dec 2014 but, was a program that worked as it allowed a large portfolio of a renewable energy to connect to the grid. It has also provided thousands of jobs. There is little to no doubt that solar has its drawbacks but, tell that to all the residents that live in Hawaii that have PV on their roofs. Go ahead Goole Map Hawaii and see. Why do these folks have PV. Its because kW prices in HI are the highest in the country for obvious reasons and PV makes perfect sen$e. However, for residents in the Eastern US where kW prices are much cheaper, PV is not an economical alternative.
Another example of where your analysis falls short is the use of backup generation. I think you need to define what backup generation is. Is it the 5500W backup generator I have in the garage I keep for emergencies? If so, am I supposed to keep that connected to my house at all time now and burn my gas that may be at a high price at the time just to use for peak shaving. I don't think this is an efficient method of generating power. A regulated generation plant is much more efficient at producing power to your house, even if you include all the transmission and distribution losses.

Not sure how long ago that linked paper was written but, you don't have to read very far into to it to see that the EPRI study it references is wrong. Its 2015 and hardly any new generation is distributed generation. The previous reference it sites is from 2001.....geesh.

Now I am starting to see where the tirade begins. It seems to be based on a graduate paper or thesis.......insert favorite emoticon here.
 
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DarylH

Member
Location
San Marcos, CA
I for one am pleased to get the 30% tax credit.

I'm moving a 3 kW system from my previous house and adding another 3 kW to it.

The new house has a pool and a bit more lighting and other loads that make it desirable to add the additional panels. The tax credit helps make it easier to afford to put the system in and I certainly have a large enough tax bill that I'll still owe plenty of money to Uncle Sam.

But besides saving on my monthly bill and eventually paying back the cost of the PV system I do have the additional comfort in knowing that I'm adding some power to the grid and helping to offset a bit of my footprint on the world.

This new property has enough room to add more ground mounted panels and I'm currently weighing the option of adding some more PV over time and switching my water heater over to electric to save on propane. We have enough sun here in San Diego that a solar water heater system would work fine, but seems like it's just one more system I'd have to maintain so why not just size up the PV system.

As for the tax credit itself, I pay a lot of tax and every year some portion of it goes off to subsidize other things I'm not particularly in favor of, so for once it's nice to see a tax credit work for me :)
 

Electric-Light

Senior Member
Your points are interesting and both quite wrong and quite right. You paint with a very broad brush over this topic and do not address the details that need to be addressed. There are so many facets to this subject that cannot be ignored. For example, power shortages are definitely at the grid level, in California, and not at the local level.


You can't deny that but, what you say has merit in other regions. Another example is, that most privately owned generation (new generation) is not fuel burning.....its wind. That government subsidy ran out in Dec 2014 but, was a program that worked as it allowed a large portfolio of a renewable energy to connect to the grid. It has also provided thousands of jobs. There is little to no doubt that solar has its drawbacks but, tell that to all the residents that live in Hawaii that have PV on their roofs.

Go ahead Goole Map Hawaii and see. Why do these folks have PV. Its because kW prices in HI are the highest in the country for obvious reasons and PV makes perfect sen$e. However, for residents in the Eastern US where kW prices are much cheaper, PV is not an economical alternative.
Another example of where your analysis falls short is the use of backup generation. I think you need to define what backup generation is. Is it the 5500W backup generator I have in the garage I keep for emergencies? If so, am I supposed to keep that connected to my house at all time now and burn my gas that may be at a high price at the time just to use for peak shaving. I don't think this is an efficient method of generating power. A regulated generation plant is much more efficient at producing power to your house, even if you include all the transmission and distribution losses.

You're not separating kWh and kW completely. Hawaii has the highest kWh price, but I don't think there is kW demand charge there. I am talking about generators at retail locations, schools and such and setting them up to utility addressable grid tie systems that can automatically start and operate as grid tie on an on-demand basis, not steady payment of added prices on kWh basis.

1kw solar at someone's house for 5 hrs a day x for 7 days produces 35kWh and solar sales people only calculate this as 35kWh x $0.35/kWh = $12.25 but it can be worth at the most $10/month for demand.

A 750kW generator at a facility that can turn down their own usage to 200kW and start contributing 550kW for as little as 15-30 minutes at a time is worth a rent of $5,500/mo if demand is $10/kW. I am talking about fair sized generators that are already installed, but not setup for grid tying and only start up for routine tests. If it gets called 3 times a month for 400kW of capacity 3 times a month and paid at-cost for fuel use + demand, the on-demand rent would be worth $4,000 @ $10/kW.

A reliable "reserve demand" contract that can provide 500kW with a five minute notice and feed right into distribution voltage is of great value even if they don't get deployed for much kWh capacity.

PoCos don't need supplemental power if it can be booked in advance unless there's an infrastructure based shortage. Large backup generators can produce three phase, reactive power capable, semi bulk quantity power with minutes notice and can contribute much more to avoided cost.

It's about time they stop paying inflated kWh pricing and push cost avoided or wholesale rate which is only logical. This has the solar PV owners sales people fuming.
 

Bugman1400

Senior Member
Location
Charlotte, NC
I appreciate the examples but, I am quite familiar with demand rates. I used to read meters back in the day and would have to reset them every month and then place a tag on it.

In short, there is a reason that industrial customers don't have there own way to offset their demand requirements even though they know they are being charged more. There is also a reason why PoCos don't build distributed generation, if they can help it. It all has to do with $$. But, I guess you already know that.

And, I guess you already know that excess demand on a distribution grid cause more losses and more wear and tear than the normal base load. This is why there is a surcharge. The exact same principle applies to customers that use a lot of reactive power. I don't understand your idea of using backup generation to offset the demand rates. To me, that is six of one to half a dozen of the other. The implementation of backup generation would also cost the PoCo more money and thus, invoke a surcharge. And, it would be less reliable and less efficient than the grid.

Perhaps you should lay off the copy and paste for a while and talk about something you know.
 

ggunn

PE (Electrical), NABCEP certified
Location
Austin, TX, USA
Occupation
Consulting Electrical Engineer - Photovoltaic Systems
I'd say it's more effective to tie into a medium voltage distribution voltage unless it is added into a very large capacity utilization voltage grid and you push a fair amount of power into all three phases.

A residential service is limited to uploading onto one phase and limited by the service size.

In the first place, that is not true for residential systems. In homes with 240 split phase service, virtually all PV inverters feed both phases, and I know of some homes with 208 three phase supply where a PV inverter could (and should) feed all three phases.

In the second place, the limit on a PV system size imposed by the size of the service is really beside the point; residential systems function mainly to reduce the consumption from the grid by the homeowner, not to supply power to the grid. In most jurisdictions there is no benefit in building a residential PV system which produces more energy than the home consumes.

In the third place, there's no reason besides economy of scale why injecting power at medium voltage would be more efficient than doing so at 480V (or whatever); there are transformer losses involved no matter which way the power gets from the inverter(s) to the medium voltage supply lines.
 
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Electric-Light

Senior Member
In the first place, that is not true for residential systems. In homes with 240 split phase service, virtually all PV inverters feed both phases.
It's not a two phase service.

and I know of some homes with 208 three phase supply where a PV inverter could (and should) feed all three phases.
Why do those homes have a three phase service?


In the third place, there's no reason besides economy of scale why injecting power at medium voltage would be more efficient than doing so at 480V (or whatever); there are transformer losses involved no matter which way the power gets from the inverter(s) to the medium voltage supply lines.

The transformer doesn't get in the way as the road block.
 
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