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

[ggunn]

Which fossil fuel subsidies are you referring to? I didn't know there were any for coal or gas. If there is, let me know, I tend to lose touch over the years.

The (as we say in Texas) the Ahl Bidness.

 

[PetrosA]

Which fossil fuel subsidies are you referring to? I didn't know there were any for coal or gas. If there is, let me know, I tend to lose touch over the years.

There are many - from various tax breaks that large corporations enjoy to the fact that the US government treats access to oil as a matter of national security and funds the protection of that access through armed conflicts. Whether or not it's intentional, the fact that we've had such a heavy military presence in the Middle East over the last 12-15 years has kept the price of crude from really skyrocketing.

 

[mivey]

That seems to be an entirely self centered view.

Non semper ea sunt, quae videntur - Phaedrus

There is a value to all of us on the planet to use less energy.

Well thank you Captain Obvious!

Does the Captain ignore that measures of value are not driven by energy alone? Who among us does not measure the value of actions by the financial consequences?

Return from your fanciful flight amongst the clouds of dreamy perfection and plant your feet once again upon firm earth where mere mortals tread the fields of reality.

 

[mivey]

I do not believe 'most' home PV systems will. Most system sizes are limited by available space.

Think about it. What is using energy when most people are at work and the home is in energy saving mode? When does the panel produce the most? Without reverse power relaying it is only common sense that energy will be pushed onto the grid at some point and that is indeed what we see, at least with the ones put in so far.

 

[Electric-Light]

Think about it. What is using energy when most people are at work and the home is in energy saving mode? When does the panel produce the most? Without reverse power relaying it is only common sense that energy will be pushed onto the grid at some point and that is indeed what we see, at least with the ones put in so far.

Lighting and machines that use motors that use three wires + ground like air conditioners, pumps, etc.

When the quantity of solar panel is small enough, they amount to something like strapping a dozen bottle rockets under your muffler. It gives an insignificant propulsion boost that asymmetry is no issue.

If you increase the thrust, you get to a point where a push from the left or right side starts to affect handling even if it's not anything close to enough to power the vehicle completely. Three phase motors don't like this. (phase balance..)

If the propulsion surges up and down, it judders or creates power quality issues (as faced by HECO now).

If the propulsion and demand don't line up, you'd have to flare it off with resistors or brakes.

 

[GoldDigger]

So, let's say you have some large three phase loads and you feed PV power into only one phase.
As long as the installation is designed for VD on the order of 5% or less on the service side, any load to PV imbalance may make POCO unhappy but will have little effect on the three phase loads, motor or otherwise.

 

[mivey]

So, let's say you have some large three phase loads and you feed PV power into only one phase.
As long as the installation is designed for VD on the order of 5% or less on the service side, any load to PV imbalance may make POCO unhappy but will have little effect on the three phase loads, motor or otherwise.

With that, you could have unbalanced voltage approaching 3.5%. That can be a problem with heavily loaded motors. I have seen chillers trip out on less unbalance than that.

 

[mivey]

If the propulsion surges up and down, it judders or creates power quality issues (as faced by HECO now).

Yes. A real concern when the PV sources become a significant size as compared to the load in their section of the system. You have any links to HECO reports on this issue?

 

[iwire]

Non semper ea sunt, quae videntur - Phaedrus

And yet ...... many times they are. - iwireus maxiumus

Well thank you Captain Obvious!

I was astonished you could not see it, but I if you want to explain what you meant without the Latin that would be cool.

Think about it. What is using energy when most people are at work and the home is in energy saving mode?

Sure some homes use very little during the day, just as some homes use a lot during the day.

'Energy saving mode'? What the heck is that, that must be a CA thing.

My issue was really with the context, EL grasps at every straw he can and in between very well documented points he tosses in vague unsubstantiated concepts like 'most home PV systems provide a large backfeed into the grid' etc.

When does the panel produce the most?

Roughly the same time the air conditioning load is most.

 

[iwire]

Straight up question that I really do not know the answer to.

If I understand EL correctly he has a problem with the imbalance that may be caused by single phase inverters back feeding into three phase distribution systems.

Here is where I am am lost.

If the three phase distribution system is stout enough to handle the imbalance of single phase home service to supplying home how is it not stout enough to handle the same or likely less current being back fed into it?

Second question.

Once more homes in the neighborhood become producers of energy won't that bring things back in balance?

 

[iwire]

Return from your fanciful flight amongst the clouds of dreamy perfection and plant your feet once again upon firm earth where mere mortals tread the fields of reality.

The reality is that all of us, like it or not are paying more for many things due to concerns about the environment. Some of those costs are justified and certainly some are entirely profit motivated.

Where the line is will be different for all of us.

 

[ggunn]

If I understand EL correctly he has a problem with the imbalance that may be caused by single phase inverters back feeding into three phase distribution systems.

If I understand EL correctly he has a problem with LED's and PV systems in general and trots out any arguments he can find to bash them whether they are real concerns or not.

 

[iwire]

If I understand EL correctly he has a problem with LED's and PV systems in general and trots out any arguments he can find to bash them whether they are real concerns or not.

I do not disagree but I also believe he does raise some valid points.

I wish he could present those valid points without the additional comments but at least he makes no attempt to deceive us about his feelings.

 

[Electric-Light]

Yes. A real concern when the PV sources become a significant size as compared to the load in their section of the system. You have any links to HECO reports on this issue?

https://www.greentechmedia.com/articles/read/How-Much-Solar-Can-HECO-and-Oahus-Grid-Really-Handle

Here are some keywords to use if you want to look around the web:
Shading, grid stability, PV, photovoltaic, Hawaii,

 

[Electric-Light]

The reality is that all of us, like it or not are paying more for many things due to concerns about the environment. Some of those costs are justified and certainly some are entirely profit motivated.

Where the line is will be different for all of us.

To defend my comment earlier, you volunteered that you're a lighting mercenary and you would gladly oblige to someone wanting to change it back to incandescent mogul.

So, I think it's reasonable to say that your concerns about environmental impact from solar or lighting isn't a genuinely held value.

Another way to say it... do you go to Church, because of genuinely held belief, or do you go because it's a good way to network with the community and advance your business? As you put it in the mercenary comment, I think the latter is a better illustration of your position.

 

[mivey]

if you want to explain what you meant without the Latin that would be cool.

Taking the Latin out takes out the fun but to put it simply: there is a value to all of us on the planet to not waste resources and money is a resource.

Sure some homes use very little during the day, just as some homes use a lot during the day.

In general, a solar panel output shape matches a commercial load shape better than a residential load shape. The residential load shape usually dips during the day. The general commercial load and solar panel output shapes are kind of bell-shaped.

'Energy saving mode'? What the heck is that, that must be a CA thing.

Thermostat changed to less A/C load during the day, washing clothes at night, cooking in the morning and at night, etc. happens all across the country. You do not need a passport to travel the country you know .

My issue was really with the context, EL grasps at every straw he can and in between very well documented points he tosses in vague unsubstantiated concepts like 'most home PV systems provide a large backfeed into the grid' etc.

Actually, that one happened to be a valid point.

 

[mivey]

Straight up question that I really do not know the answer to.

If I understand EL correctly he has a problem with the imbalance that may be caused by single phase inverters back feeding into three phase distribution systems.

Here is where I am am lost.

If the three phase distribution system is stout enough to handle the imbalance of single phase home service to supplying home how is it not stout enough to handle the same or likely less current being back fed into it?

We balance the loads on the system. Changing the loads require re-balancing. Varying the load pattern makes it difficult to balance the system.

Second question.

Once more homes in the neighborhood become producers of energy won't that bring things back in balance?

Ideally. But the loads aren't ideal as they can be more unpredictable. It definitely complicates system load control, generation dispatch, voltage control, power quality, etc.

 

[mivey]

The reality is that all of us, like it or not are paying more for many things due to concerns about the environment. Some of those costs are justified and certainly some are entirely profit motivated.

Where the line is will be different for all of us.

No doubt. Just some rough numbers: an LED lamp I tried costs ~3X as much as a CFL (~6X before estimated life adjustment) with only a 25% reduction in energy use. Just doesn't make sense for full deployment. Maybe they will get there but time will tell. For outdoor lighting they make more sense than HPS or MH for some applications. Indoors, not so much and they might make sense in limited application like cold areas. YMMV.

 

[mivey]

https://www.greentechmedia.com/articles/read/How-Much-Solar-Can-HECO-and-Oahus-Grid-Really-Handle

Here are some keywords to use if you want to look around the web:
Shading, grid stability, PV, photovoltaic, Hawaii,

Thanks

 

[mivey]

To defend my comment earlier, you volunteered that you're a lighting mercenary and you would gladly oblige to someone wanting to change it back to incandescent mogul.

So, I think it's reasonable to say that your concerns about environmental impact from solar or lighting isn't a genuinely held value.

Another way to say it... do you go to Church, because of genuinely held belief, or do you go because it's a good way to network with the community and advance your business? As you put it in the mercenary comment, I think the latter is a better illustration of your position.

I will agree that iwire has definitely been in the "I'll put in whatever the customer wants" camp, and has been critical of value-engineering at times. Perhaps there is some conflict between what he would like to do and what he has to do.