Texas Power Outage Danger Until June 18th. Texans told to conserve energy!

[nsdp + 449]

21 minutes ago, turbguy said:

Power electronics "should" be able to emulate a rotating machine, almost precisely.

I guess "grid forming" inverters are more expensive?? 

Grid forming inverters have no inertial mass.   As we learned in Texas in February they are a bad joke. There was about 2500 mw on the Panhandle loop north of Lubbock that dropped off and could not restart despite 8.8m/s wind. Hydro quebec explains what went wrong  Can Synthetic Inertia from Wind Power Stabilize Grids? https://spectrum.ieee.org/energywise/energy/renewables/can-synthetic-inertia-stabilize-power-grids

Three years later NREL  figures out that that the Canadians do know what they are talking about. Research Roadmap on Grid-Forming Inverters

https://www.nrel.gov/docs/fy21osti/73476.pdf

Edited June 28, 2021 by nsdp
can't spell

[ronwagn + 6,290]

On 6/26/2021 at 11:34 PM, turbguy said:

 

When somebody says that without tax benefits, these systems don't make sense...

Somebody else is building a lot of them.

It ain't going to cease.

Taxes are typically imposed to extract revenue from social or market activity that causes social DAMAGE.  Such as alcohol, transportation fuels, consumption of just about everything, and property value.

If an "activity' causes less damage, should it not be taxed at a reduction?

Transportation fuels include alcohol and they do not cause social damage and are essential commodities!

[footeab@yahoo.com + 2,190]

2 hours ago, ronwagn said:

So how are the car batteries doing?

Did not buy the 2 wrecked nissan leaf's as the panels which had to be switched were too many for me to do.  I'll tackle doing 1 panel, but 3?  Ug, I hate body work and painting and the $$$ just keeps going up when talking body work even with ability to take body panels off one car to put on another.  I re upped my electric bike with LiPo, and they are doing great.  If only the thieves knew how much that brick inside my paniers on my ebike was worth...

[footeab@yahoo.com + 2,190]

2 hours ago, nsdp said:

Grid forming inverters have no inertial mass.   As we learned in Texas in February they are a bad joke. There was about 2500 mw on the Panhandle loop north of Lubbock that dropped off and could not restart despite 8.8m/s wind. Hydro quebec explains what went wrong  Can Synthetic Inertia from Wind Power Stabilize Grids? https://spectrum.ieee.org/energywise/energy/renewables/can-synthetic-inertia-stabilize-power-grids

Three years later NREL  figures out that that the Canadians do know what they are talking about. Research Roadmap on Grid-Forming Inverters

https://www.nrel.gov/docs/fy21osti/73476.pdf

What this is is Utopian foolery unless there is a massive government infrastructure to ENFORCE/fine said system on the populace  Why?  Because people aren't STUPID and demand to get paid for their reactive power.  What your link propose is millions of inverters on peoples houses tied to solar + batteries leading the grid instead of how all houses work today(lagging).

Can you easily program that into all of the inverters?  Sure, but any idiot can likewise download a slightly different firmware version, and have his grid tie inverter lag the grid or just stay even with the grid and increase amount of localized power by 1-->2% depending on how many power bricks, motors their home is using etc.

I can see the email headlines now, "Do you want to INCREASE your solar power SOLD to the grid, download our ap and SAVE today!"

It will not matter if you outlaw it, no one will ever enforce it unless legislation is passed requiring that all battery + solar grid tied inverters must frequency lead the grid by 'x' Hz and likewise provide 'x' trickle power to maintain said frequency by having EVERYONE's power meters replaced that can monitor and then tell on you that you are being naughty and not leading as much as you should be.

Possible, yes, Gargantuan Legislative hurdles, and everyone bypassing said laws, and why would it not be cheaper to just deal with the reactive power loads how we are doing so today? 

[NickW + 2,714]

On 6/24/2021 at 12:31 PM, Eric Gagen said:

@NickW I'm not sure what condensing mode, or condensing heating has to do with heating a house?  There isn't any water in any of the heating systems I am discussing.  If you are talking about radiator style heat, then I'll freely admit I know absolutely nothing about how those work - I am talking about combined HVAC systems where the heat is provided by a furnace heating air and then pumping it through the air conditioning ductwork during time periods when heating is required.  

It may be a US / UK terminology issue  - but gas boilers that achieve the sort of efficiencies you describe are condensing boilers*

*The point at which water vapour in the boilers exhaust condenses freeing up the latent heat of condensation - thats how you get to the efficiencies you describe. Any older conventional boiler won't get anywhere near this sort of efficiency as the exhaust gases are too hot. My domestic heating (and hot water) boiler is condensing - thats why it has a plastic flue pipe. 

Condensing boiler - Wikipedia

[Eric Gagen + 713]

16 hours ago, turbguy said:

A college with a 480 MW plant?

That's a LOT of money for a college.

No way could they "use" 480 MW.

Are you certain it wasn't just CHAP (Combined Heat and Power), instead of CC?

Yes it was a combined steam and electric plant - what you are calling CHAP.  I’m not an electric power industry expert so I don’t use and try to avoid fancy acronyms under the assumption that most other people don’t know them either.  This was at UC Berkeley with a campus population of 50,000 selling power to the grid also.  

[Eric Gagen + 713]

2 hours ago, NickW said:

It may be a US / UK terminology issue  - but gas boilers that achieve the sort of efficiencies you describe are condensing boilers*

*The point at which water vapour in the boilers exhaust condenses freeing up the latent heat of condensation - thats how you get to the efficiencies you describe. Any older conventional boiler won't get anywhere near this sort of efficiency as the exhaust gases are too hot. My domestic heating (and hot water) boiler is condensing - thats why it has a plastic flue pipe. 

Condensing boiler - Wikipedia

None of the systems I am discussing use a boiler, or use water in the system at all.  They are direct flame units - a flame burns,and heats up a grid/shell and tube in the furnace with no water in it, and the hot air is distributed by the air handler system.  No water, no boiler, no condensing, etc.  All that mess is for people living in cold places, where the primary purpose of a HVAC system is heating.  What I am describing is the add on heating system on an air conditioning and ventilation system.  

Edited June 28, 2021 by Eric Gagen

[Eric Gagen + 713]

9 hours ago, ronwagn said:

 It makes economic sense for you because you will not be taken advantage of like many people over the last ten years. You are very well informed and, I assume, young enough to benefit from your proposed system. It would not be wise for older folks to make that investment looking forward IMHO. I would go for a natural gas generator for backup purposes, and possibly, propane tank backup for my heating needs. 

Last time we built a house, it was in an area without pipeline gas service, so the cost of purchasing and running a diesel generator got sky high when you consider that it would have to run on diesel.  The property had propane service at one time, but delivery in that area was expensive - like $2 a gallon, everything out there was already all electric by the time we got there.  

I do expect it to take 10 years to pay for a solar setup, but even if we don't stay that long it helps to make the resale value of the property higher, so it pays off either way, either for me, or for my heirs.  

[Rob Plant + 2,756]

What do you guys think to these?

https://www.cleanenergysystems.com/zero-emissions-power-generation

https://netpower.com/

https://www.mcdermott-investors.com/news/press-release-details/2020/McDermott-Awarded-Pre-FEED-for-NET-Power-UK-Project/default.aspx

[NickW + 2,714]

2 hours ago, Eric Gagen said:

None of the systems I am discussing use a boiler, or use water in the system at all.  They are direct flame units - a flame burns,and heats up a grid/shell and tube in the furnace with no water in it, and the hot air is distributed by the air handler system.  No water, no boiler, no condensing, etc.  All that mess is for people living in cold places, where the primary purpose of a HVAC system is heating.  What I am describing is the add on heating system on an air conditioning and ventilation system.  

Ok - when you said furnace I assumed that was the American term for what we call a boiler and is used for heating and hot water

A vented warm air heating system with 95% efficiency? 

[Dan Clemmensen + 1,011]

2 hours ago, Eric Gagen said:

None of the systems I am discussing use a boiler, or use water in the system at all.  They are direct flame units - a flame burns,and heats up a grid/shell and tube in the furnace with no water in it, and the hot air is distributed by the air handler system.  No water, no boiler, no condensing, etc.  All that mess is for people living in cold places, where the primary purpose of a HVAC system is heating.  What I am describing is the add on heating system on an air conditioning and ventilation system.  

The water is a combustion product of the methane. In a high-efficiency ("condensing") furnace, this water condenses within the flue because the furnace is designed to extract enough heat that the exhaust temperature falls below the boiling point of water. This makes the furnace more expensive to build, because it must handle this hot (and therefore somewhat corrosive) water, and you need a drain for the water. Older furnaces were deliberately designed to keep the flue gasses above the boiling point to avoid this problem since gas was cheap and capital was costly.

[NickW + 2,714]

5 minutes ago, Dan Clemmensen said:

The water is a combustion product of the methane. In a high-efficiency ("condensing") furnace, this water condenses within the flue because the furnace is designed to extract enough heat that the exhaust temperature falls below the boiling point of water. This makes the furnace more expensive to build, because it must handle this hot (and therefore somewhat corrosive) water, and you need a drain for the water. Older furnaces were deliberately designed to keep the flue gasses above the boiling point to avoid this problem since gas was cheap and capital was costly.

I don't know about costs in the USA but the 15KW condensing boiler I installed last year was £800 with the flue system. 

Glow-worm Energy 15R 15kW Heat Only Boiler 10035905 | City Plumbing Supplies

 

[Eric Gagen + 713]

22 minutes ago, Dan Clemmensen said:

The water is a combustion product of the methane. In a high-efficiency ("condensing") furnace, this water condenses within the flue because the furnace is designed to extract enough heat that the exhaust temperature falls below the boiling point of water. This makes the furnace more expensive to build, because it must handle this hot (and therefore somewhat corrosive) water, and you need a drain for the water. Older furnaces were deliberately designed to keep the flue gasses above the boiling point to avoid this problem since gas was cheap and capital was costly.

Thank you! This is what I thought was being dicussed, but all the other descriptions everyone was giving involved the word 'boiler' and since I wasn't discussing usage of a system with a boiler, or any other method of intentionally introducing water to the system at all I assumed we were not on the same page, and I wasn't sure what I was missing.  

Edited June 28, 2021 by Eric Gagen

[Eric Gagen + 713]

25 minutes ago, NickW said:

Ok - when you said furnace I assumed that was the American term for what we call a boiler and is used for heating and hot water

A vented warm air heating system with 95% efficiency? 

A boiler boils water, without defining what the water is being heated for.  A heating system heats a structure.  A heating system may have a boiler in it, or it may not. The word boiler IS used for heating systems in the US, but ONLY if that heating system heats water as part of the expected and intended function of the system.  The furnaces I am referring to convert natural gas into heat for the heating system at  90-95% efficiency.  There is  loss in the ducting system which pipes the resulting heated air from one room to the next, but the furnace itself is extremely efficient.  

Edited June 28, 2021 by Eric Gagen

[NickW + 2,714]

1 minute ago, Eric Gagen said:

A boiler boils water, without defining what the water is being heated for.  A heating system heats a structure.  A heating system may have a boiler in it, or it may not, but it's not required.  the furnace converts natural gas into heat for the heating system at ~ 95% efficiency.  There is  loss in the ducting system which pipes the resulting heated air from one room to the next, but the furnace itself is extremely efficient.  

We have warm air heating systems which are effectively the same as you describe. I am not aware that they get anywhere near >90% in efficiency. 

The only way you achieve that is if the water in the flue gases condenses out (as Dan described) and I don't think this is possible with airs low specific heat capacity compared to water as the transfer medium. 

Happy to be proven wrong but would want to see the manufacturers spec. 

RE the previous point unless the ducting is outside the shell of the house there is no effective loss from this. The efficiency loss is in the flue gases as heat and unburnt fuel if the unit is performing poorly. 

 

 

[Dan Clemmensen + 1,011]

20 minutes ago, Eric Gagen said:

Thank you! This is what I thought was being dicussed, but all the other descriptions everyone was giving involved the word 'boiler' and since I wasn't discussing usage of a system with a boiler, I assumed we were not on the same page, and I wasn't sure what I was missing.  

Here is an article with pictures of a modern condensing furnace for a hot-air HVAC system. Note the two separate heat exchangers. The main one operates at above boiling and moves the bulk of the heat. The secondary exchanger  then extracts much of the remaining heat. It is made of stainless steel because the condensate is corrosive (water condensed an a high-CO2 environment forms carbonic acid). The resulting flue gas is cool enough to allow you to use a PVC flue.  The furnace requires forced air (a fan in the flue) because the gas is not hot enough to draw the intake air by convection alone. In many systems the intake air comes from a coaxial sleeve around the flue, which (among other things) extracts a little bit more of the heat from the flue gas.

https://www.thespruce.com/high-efficiency-condensing-furnace-1824740

Edited June 28, 2021 by Dan Clemmensen
add article link

[Eric Gagen + 713]

5 minutes ago, NickW said:

We have warm air heating systems which are effectively the same as you describe. I am not aware that they get anywhere near >90% in efficiency. 

The only way you achieve that is if the water in the flue gases condenses out (as Dan described) and I don't think this is possible with airs low specific heat capacity compared to water as the transfer medium. 

Happy to be proven wrong but would want to see the manufacturers spec. 

RE the previous point unless the ducting is outside the shell of the house there is no effective loss from this. The efficiency loss is in the flue gases as heat and unburnt fuel if the unit is performing poorly. 

 

 

The ducting is inside the attic space, which is not fully thermally connected to the rest of the house, because it is above the layer of insulation between the roof and the attic floor.  The roof has insulation also, but not nearly to the same degree, except in the very newest construction.  

 

So you prompted me to hike up to the attic, and see what we have, and you are correct  @NickW- we have a pair of  80% efficient, single stage natural gas furnaces  Honestly, I had heard the 'all new furnaces are 90-95% efficient' line so many times, that I assumed all of them were (you can tell I haven't ever lived in a place where heating is much of a concern).  I also looked up the cost, and they are about $800 or so each.  A 96% efficient gas furnace runs about $2,500, and I feel confident saying that in Houston TX where I live the increase of initial cost can't be justified.  Even this last winter when we had our crazy heavy snow storm leading to over 100 hours of consecutive below freezing weather, our winter heating for the whole heating season ran to something like $400.  Dropping that to $325 or so by spending an extra $4,200 would 'pay off' over the course of 50 or 60 years on a 0% discount schedule.  Not gonna do it! 

[NickW + 2,714]

12 minutes ago, Dan Clemmensen said:

Here is an article with pictures of a modern condensing furnace for a hot-air HVAC system. Note the two separate heat exchangers. The main one operates at above boiling and moves the bulk of the heat. The secondary exchanger  then extracts much of the remaining heat. It is made of stainless steel because the condensate is corrosive (water condensed an a high-CO2 environment forms carbonic acid). The resulting flue gas is cool enough to allow you to use a PVC flue.  The furnace requires forced air (a fan in the flue) because the gas is not hot enough to draw the intake air by convection alone. In many systems the intake air comes from a coaxial sleeve around the flue, which (among other things) extracts a little bit more of the heat from the flue gas.

https://www.thespruce.com/high-efficiency-condensing-furnace-1824740

As air temperature is cooler than water circulating in radiators this helps up the efficiency? 

[Eric Gagen + 713]

19 minutes ago, Dan Clemmensen said:

Here is an article with pictures of a modern condensing furnace for a hot-air HVAC system. Note the two separate heat exchangers. The main one operates at above boiling and moves the bulk of the heat. The secondary exchanger  then extracts much of the remaining heat. It is made of stainless steel because the condensate is corrosive (water condensed an a high-CO2 environment forms carbonic acid). The resulting flue gas is cool enough to allow you to use a PVC flue.  The furnace requires forced air (a fan in the flue) because the gas is not hot enough to draw the intake air by convection alone. In many systems the intake air comes from a coaxial sleeve around the flue, which (among other things) extracts a little bit more of the heat from the flue gas.

https://www.thespruce.com/high-efficiency-condensing-furnace-1824740

We have the forced air systems for intake air (must be more efficient even in a non condensing furnace) and we have the plastic water removal piping (so it must be doing something to cool it down) and the discharge blower is insulated (not what I would call super heavily, but it is insulated), but there is only one stage of heat exchangers, not two, and the combustion products discharge line is galvanized steel, not plastic or CRA, and I looked up the specifications on the furnaces.  

Edit @nickW the unit that Dan linked to is a two stage condensing furnace that only uses air - no water boiler, so it's definitely possible - it just takes a lot of surface area.  

Edited June 28, 2021 by Eric Gagen

[Dan Clemmensen + 1,011]

2 minutes ago, NickW said:

As air temperature is cooler than water circulating in radiators this helps up the efficiency? 

Boiler (hot water) systems and forced air systems must both move the same amount of heat to heat the same amount of house. In a forced air system, we just need a bigger heat exchanger and we need to move a lot of air, so that is how the system is designed. the cost tradeoffs end up being mostly about the amount of the home's volume that is occupied by the bigger furnace and the bigger ducts. If you already have the need for air conditioning, the incremental cost on volume is small.

[Eric Gagen + 713]

Just now, Dan Clemmensen said:

Boiler (hot water) systems and forced air systems must both move the same amount of heat to heat the same amount of house. In a forced air system, we just need a bigger heat exchanger and we need to move a lot of air, so that is how the system is designed. the cost tradeoffs end up being mostly about the amount of the home's volume that is occupied by the bigger furnace and the bigger ducts. If you already have the need for air conditioning, the incremental cost on volume is small.

That's exactly how ours is set up - the air handler, blowers, and furnace for the 5 ton downstairs system is about 15 ft x 3 ft x 4 ft and for the upstairs 3 ton system it's 10 x 3 x 4.  Moving it to a 'two stage condensing' furnace would only 3-4 ft to the length of each unit, and there's definately space to do it - it's just not justifiable based on the amount of use the furnaces get. 

[NickW + 2,714]

2 hours ago, Eric Gagen said:

That's exactly how ours is set up - the air handler, blowers, and furnace for the 5 ton downstairs system is about 15 ft x 3 ft x 4 ft and for the upstairs 3 ton system it's 10 x 3 x 4.  Moving it to a 'two stage condensing' furnace would only 3-4 ft to the length of each unit, and there's definately space to do it - it's just not justifiable based on the amount of use the furnaces get. 

I assume in Texas your energy demand is cooling led so it makes sense to focus the efficiencies in this area plus the factor cooling required electricity which is much more expensive than gas. 

[nsdp + 449]

13 hours ago, footeab@yahoo.com said:

What this is is Utopian foolery unless there is a massive government infrastructure to ENFORCE/fine said system on the populace  Why?  Because people aren't STUPID and demand to get paid for their reactive power.  What your link propose is millions of inverters on peoples houses tied to solar + batteries leading the grid instead of how all houses work today(lagging).

Can you easily program that into all of the inverters?  Sure, but any idiot can likewise download a slightly different firmware version, and have his grid tie inverter lag the grid or just stay even with the grid and increase amount of localized power by 1-->2% depending on how many power bricks, motors their home is using etc.

I can see the email headlines now, "Do you want to INCREASE your solar power SOLD to the grid, download our ap and SAVE today!"

It will not matter if you outlaw it, no one will ever enforce it unless legislation is passed requiring that all battery + solar grid tied inverters must frequency lead the grid by 'x' Hz and likewise provide 'x' trickle power to maintain said frequency by having EVERYONE's power meters replaced that can monitor and then tell on you that you are being naughty and not leading as much as you should be.

Possible, yes, Gargantuan Legislative hurdles, and everyone bypassing said laws, and why would it not be cheaper to just deal with the reactive power loads how we are doing so today? 

I have spent 30 minutes trying to make sense of what you have said.  I think you are wanting to get paid  for supplying SYNTHETIC reactive power from your solar inverter.   If so , you need to be aware that SYNTHETIC  reactive power destabilizes the grid.

"As penetration levels of inverter-based generation resources (e.g., wind, solar, batteries) that do not naturally contribute inertia to the system continue to increase and displace synchronous generators in a power system’s generation mix.  Additionally, it was determined that there is a critical inertia level below which existing frequency response mechanisms are not fast enough to arrest the frequency before it reaches UFLS after the largest generation loss, per NERC Standard BAL-003. If system inertia is expected to fall below this value, ERCOT system operators will follow procedures to start more synchronous generators in order to increase synchronous inertia online. Since these generators are not needed for energy, starting them is likely to result in power output reduction from lower cost resources, including curtailment of wind and solar generation. Currently, ERCOT’s all-time minimum inertia level is still about 30% higher than the determined critical inertia level., the synchronous inertia will inevitably decline, especially during operating conditions when system load is low and wind and solar power production are high. These conditions vary depending on the season and the time of day."   https://www.esig.energy/implementation-of-inertia-monitoring-in-er

Additionally, it was determined that there is a critical inertia level below which existing frequency response mechanisms are not fast enough to arrest the frequency before it reaches UFLS after the largest generation loss, per NERC Standard BAL-003. If system inertia is expected to fall below this value, ERCOT system operators will follow procedures to start more synchronous generators in order to increase synchronous inertia online. Since these generators are not needed for energy, starting them is likely to result in power output reduction from lower cost resources, including curtailment of wind and solar generation. Currently, ERCOT’s all-time minimum inertia level is still about 30% higher than the determined critical inertia level.

ERCOT did not make this change out of the goodness of their heart; they received a failing grade on their 2018 NERC Compliance Audit. This is as the audit report would be published by Pravda or Novy Mir.

I have not  decided which  of the following standards should apply to you.

1. You should take A Lincoln's advice to heart. "“It is better to be silent and be thought a fool, than to speak and remove all doubt.” – Abraham Lincoln or

2. You are a Russian/Chinese/Taliban/ISIS mole (pick one or more) intend on sabotaging the grid.   In this case the Smith Act should be immediately used to put you away for the safety of us all.

Edited June 28, 2021 by nsdp
proper emphasis of inverter failures

[turbguy + 1,543]

1 hour ago, nsdp said:

I have spent 30 minutes trying to make sense of what you have said.  I think you are wanting to get paid  for supplying SYNTHETIC reactive power from your solar inverter.   If so , you need to be aware that SYNTHETIC  reactive power destabilizes the grid.

"As penetration levels of inverter-based generation resources (e.g., wind, solar, batteries) that do not naturally contribute inertia to the system continue to increase and displace synchronous generators in a power system’s generation mix.  Additionally, it was determined that there is a critical inertia level below which existing frequency response mechanisms are not fast enough to arrest the frequency before it reaches UFLS after the largest generation loss, per NERC Standard BAL-003. If system inertia is expected to fall below this value, ERCOT system operators will follow procedures to start more synchronous generators in order to increase synchronous inertia online. Since these generators are not needed for energy, starting them is likely to result in power output reduction from lower cost resources, including curtailment of wind and solar generation. Currently, ERCOT’s all-time minimum inertia level is still about 30% higher than the determined critical inertia level., the synchronous inertia will inevitably decline, especially during operating conditions when system load is low and wind and solar power production are high. These conditions vary depending on the season and the time of day."   https://www.esig.energy/implementation-of-inertia-monitoring-in-er

Additionally, it was determined that there is a critical inertia level below which existing frequency response mechanisms are not fast enough to arrest the frequency before it reaches UFLS after the largest generation loss, per NERC Standard BAL-003. If system inertia is expected to fall below this value, ERCOT system operators will follow procedures to start more synchronous generators in order to increase synchronous inertia online. Since these generators are not needed for energy, starting them is likely to result in power output reduction from lower cost resources, including curtailment of wind and solar generation. Currently, ERCOT’s all-time minimum inertia level is still about 30% higher than the determined critical inertia level.

ERCOT did not make this change out of the goodness of their heart; they received a failing grade on their 2018 NERC Compliance Audit. This is as the audit report would be published by Pravda or Novy Mir.

I have not  decided which  of the following standards should apply to you.

1. You should take A Lincoln's advice to heart. "“It is better to be silent and be thought a fool, than to speak and remove all doubt.” – Abraham Lincoln or

2. You are a Russian/Chinese/Taliban/ISIS mole (pick one or more) intend on sabotaging the grid.   In this case the Smith Act should be immediately used to put you away for the safety of us all.

So,

Convert some synchronous equipment to be synchronous condensers.

Then you get some "thermal inertia" as well...

At times, I think it's an impediment that Tesla won the "current war".

 

 

 

 

Edited June 28, 2021 by turbguy

[turbguy + 1,543]

10 hours ago, Eric Gagen said:

Yes it was a combined steam and electric plant - what you are calling CHAP.  I’m not an electric power industry expert so I don’t use and try to avoid fancy acronyms under the assumption that most other people don’t know them either.  This was at UC Berkeley with a campus population of 50,000 selling power to the grid also.  

Wow!

They must need a lot of steam for 'something' locally.

Does Berkeley get THAT cold?