let's talk about battery banks- I reckon the "they aren't worth it" thing is wrong

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Solar cannot be dependably used to avoid demand charges. One cannot be sure that a PV system will be running at high output during every 15 minute period of high demand, and it only takes one to incur the charge.

http://energystorage.org/energy-sto...harge-avoidance-prudent-energy-vanadium-redox

Check out the ¶ right above Results.
One of the main advantages of BESS is peak shaving.
That's not rich people with jacuzzis - well the people that own the plant probably are, but that's an onion processing plant.
You have lots of onions in TX, I don't see any reason for a company there not to save money the same way.

Not sure why the onion folks charge from the grid at night. I'd think they'd use PV if it was possible and was cheaper (probably is...)
 
Co-generation is where it is at.
http://cumminsengines.com/dual-fuel

Cummins are nice. Perkins are better.
http://www.centralmainediesel.com/order/Perkins-10-kW-Diesel-Generator.asp?page=Perkins10

Honestly, dude/lady/person, whichever of the first two you are...Stirlings are where it's at for co-G.
This is not MY caps-lock below.

The key concept here is stirling engines require FAR LESS mainnance then a typical gas (internal combustion) engine used to run a generator. The MAIN reason of course is that you don’t mix the fuel (heat source) with the internal moving parts and working fluid (in this case air or helium). Thus such engines are sealed, and run for years on end – just like your refrigerator.
The stirling engine runs ABSOLUTE CIRCLES around the internal combustion engine in terms of maintains and trouble free operation.
The cost of building such a durable engine is more then a “cheap” internal combustion engine, but not more then something that needs to be durable (run 24/7).
You don’t see small sterling engines on the end of a say a “weed eater” because the power to weight ratio in a sterling engine is LOWER then a typical small gas engine. However the efficiency of stirling engines can easy compare or even exceed internal combustion engines.

The BECON 10 is DESIGNED exactly for operating 24/7 and MORE important the exhaust output can be vented directed to the room. And it is QUIET – no muffler is required. And the TARGET IS residential.

The burner (used) in such a system is much the same as a typical stove top burner which also does not need venting to the outside.
http://www.e-catworld.com/2014/12/2...-home-electricity-generation-albert-d-kallal/
 

GoldDigger

Moderator
Staff member
Location
Placerville, CA, USA
Occupation
Retired PV System Designer
One very small problem with your "free" energy from a wood stove and the -20 degree outside is that any heat engine works by moving heat energy from a hot area to a cold area. You burn more wood as a result.
Second problem is that theory aside Stirling engines are not economical with current materials and construction.
 
One very small problem with your "free" energy from a wood stove and the -20 degree outside is that any heat engine works by moving heat energy from a hot area to a cold area. You burn more wood as a result.
Second problem is that theory aside Stirling engines are not economical with current materials and construction.

Not sure what you mean by "burn more wood". You'd just use some "extra" heat from the wood stove.
You can get a fan that splices small pipes into/through the chimney and blows out hot air, those don't change the draft of the chimney or amount of wood burned.

Plus, there's no exchange of air between inside/outside- Stirlings work by...
Heat exchanger
Also known as the regenerator, the heat exchanger sits in the closed chamber between the heat source and the heat sink.
http://www.explainthatstuff.com/how-stirling-engines-work.html
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The important thing is the difference between hot and cold- so a wood stove chimney for instance, already wasting a bunch of heat, would be the hot side and there's a closed chamber between inside the house and 20 below outside.

If you wanted to build a solid Stirling based system you could actually use to crank out multiple kWh, you'd want a machine shop, sure.
Just for the engine itself, really, the heat exchange part is a lot simpler.

Mr. Stirling did invent them in 1812, so...you don't really need space-age materials, it's more precise construction to reduce friction/balance properly, etc.

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quote_icon.png
Originally Posted by PVfarmer
Onion Processing

gg-

Storage, yes; PV, no.

Both- why not? :D

Trivia fact:
The original diesel engine was invented by Rudolf DIESEL in 1880-something or so- but it ran on...
Peanut oil!!
True story.
 
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mivey

Senior Member
less water delivered in the same pipe = bigger pipe / gallon
You must mean "more empty pipe per gallon"?
Nope. Meant what I said. bigger pipe / gallon. You see, its a ratio.

You can't have a smaller pipe.
I've never heard of a POCO installing smaller feeders.
It happens. Either smaller than before or smaller than would be needed otherwise.

If you are paying 20 cents for kWhs and you can get your kWhs for 10 cents from solar panels, to do so would be absurd?
If it is the same product then you would be compelled to do so.

How about you go ahead and do that. Don't forget to call the POCO and have them remove the service and transformer from your house. Have fun with that.

Glossed over?
A 6 watt hour battery sure is useless for running a house- what about the right size? 6kW? 12kW? k?
You are still missing his point.

Generators only run when there is fuel, which costs money, and cost a LOT more in Alaska, so....?
Remind me not to buy fuel in Alaska.
 

mivey

Senior Member
When someone is putting out MORE energy than they use, it is going into a neighbor's house and taking strain off of the grid
What strain? The grid plan is to size it to handle the load. To take strain off the grid, the DG has to be reliable and available otherwise we have to size the grid as if the DG is not there. If the reliability and availability is not the same as the grid resources, then the DG does not bring the same value.

I'm not saying DG has no value, just a different value. Too often DG suppliers want to pretend it is a 1:1 swap when they make financial calculations. In a small area POCO grid that is prone to cloud cover, solar would have a smaller reliability & availability factor as compared to a large area POCO system where the risk of cloud cover is spread over a larger number of square miles. Same goes for comparing a dry zone with a rainy zone.
 
quote_icon.png
Originally Posted by PVfarmer

less water delivered in the same pipe = bigger pipe / gallon
You must mean "more empty pipe per gallon"?

Nope. Meant what I said. bigger pipe / gallon. You see, its a ratio // That means the kWh charges no longer cover the pipe & pump cost.

If you are paying 20 cents for kWhs and you can get your kWhs for 10 cents from solar panels, to do so would be absurd?
If it is the same product then you would be compelled to do so.
How about you go ahead and do that. Don't forget to call the POCO and have them remove the service and transformer from your house. Have fun with that.

Glossed over?
A 6 watt hour battery sure is useless for running a house- what about the right size? 6kW? 12kW? k?

You are still missing his point.

Generators only run when there is fuel, which costs money, and cost a LOT more in Alaska, so....?
Remind me not to buy fuel in Alaska.

I still don't get it- the feeders are built, and the cost is established to cover them.
How does the pipe get bigger when someone's PV is putting power into someone down the street's house during the day?
The person with PV is not paying a bill, and the person down the street is paying the POCO retail for any extra PV. The POCO gets paid for the extra energy generated, if there isn't any extra at least there's one less house drawing from the grid during the day.
Things like AC and water heaters are the problems- PV can help with those loads, and batteries help balance out fluctuating demand even more.

The POCO around here in fact wants people to install DG, to in fact reduce demand and avoid new substation(s), so why would anyone disconnect their PV?

Yes, I am missing the point- no idea what a 6 watt hours in an iPhone has to do with PV battery storage.
People don't use lead acid AGM batteries in iPhones, they're lithium so...
And people don't use iPhones to power homes- is he saying that lithium batteries don't discharge fast enough? :huh:
The value of car battery is in its ability to deliver 1.78Wh in *four seconds*. A battery that delivers 6Wh over one day is completely useless.

I have no clue where you are from, but internal combustion is noisy and pretty expensive no matter where you are.
Yep, noise ordinances...you can't just say "I'm gonna run a diesel gen"...in Alaska, yes, in the suburbs no, where I live maybe, but it would bother me so...why bother...myself?
 
What strain? The grid plan is to size it to handle the load. To take strain off the grid, the DG has to be reliable and available otherwise we have to size the grid as if the DG is not there. If the reliability and availability is not the same as the grid resources, then the DG does not bring the same value.

I'm not saying DG has no value, just a different value. Too often DG suppliers want to pretend it is a 1:1 swap when they make financial calculations. In a small area POCO grid that is prone to cloud cover, solar would have a smaller reliability & availability factor as compared to a large area POCO system where the risk of cloud cover is spread over a larger number of square miles. Same goes for comparing a dry zone with a rainy zone.

Well, aren't new grids and old grids completely different things then?
That's one of the main advantages of BESS with PV- it balances out the availability for grid AND consumer.

That stuff about clouds and voltage drops, etc is pretty interesting...quick question- it's the voltage fluctuation which is the biggest problem, so grid people must prefer these newer, fancier inverters that can actually help balance drops and such?
Reactive power, right? You can't get an inverter with a better power factor than 1, so...why not get the best?
 

mivey

Senior Member
I still don't get it- the feeders are built, and the cost is established to cover them.
How does the pipe get bigger when someone's PV is putting power into someone down the street's house during the day?
Again, it is a ratio.

The person with PV is not paying a bill, and the person down the street is paying the POCO retail for any extra PV. The POCO gets paid for the extra energy generated, if there isn't any extra at least there's one less house drawing from the grid during the day.
More correctly: during some days.

Things like AC and water heaters are the problems- PV can help with those loads, and batteries help balance out fluctuating demand even more.
Now we have added to the 10 cents/kWh you proffered.

The POCO around here in fact wants people to install DG, to in fact reduce demand and avoid new substation(s), so why would anyone disconnect their PV?
Then put the extra PV on a separate meter connected for grid sales. Put a separate PV unit just for your house load and let your house be free and clear of the grid. Go ahead. I dare you. No, I double-dog dare you!:D

Yes, I am missing the point- no idea what a 6 watt hours in an iPhone has to do with PV battery storage.
People don't use lead acid AGM batteries in iPhones, they're lithium so...
And people don't use iPhones to power homes- is he saying that lithium batteries don't discharge fast enough? :huh:
The value of car battery is in its ability to deliver 1.78Wh in *four seconds*. A battery that delivers 6Wh over one day is completely useless.
His point was an illustration about how demand works and how it gets overlooked in PV financial calcs.

I have no clue where you are from, but internal combustion is noisy and pretty expensive no matter where you are.
Yep, noise ordinances...you can't just say "I'm gonna run a diesel gen"...in Alaska, yes, in the suburbs no, where I live maybe, but it would bother me so...why bother...myself?
Then run something quieter. Simple isn't it?
 

mivey

Senior Member
Well, aren't new grids and old grids completely different things then?
In one sense, but they both have to be managed and are part of the continual planning process.

That's one of the main advantages of BESS with PV- it balances out the availability for grid AND consumer.
No doubt storage is one of the big hurdles for PV systems.

That stuff about clouds and voltage drops, etc is pretty interesting
Did I mention voltage drops?

...quick question- it's the voltage fluctuation which is the biggest problem
Is that a statement or question? I'm guessing a statement.

, so grid people must prefer these newer, fancier inverters that can actually help balance drops and such?
Certainly those that will integrate with the grid better. Not sure if that problem is solved yet though, at least to any appreciable degree.

Reactive power, right?
That is an issue as well.

You can't get an inverter with a better power factor than 1, so...why not get the best?
In what world do you think 1 is the best? Actually it is not so good from a DG standpoint.
 

Electric-Light

Senior Member
Uncontrollable is a very creative description of solar panels, would you like to expand on that one?

You have total control over an engine by adjusting the fuel feed until you run out of fuel. Solar panels are like sail boats. If cloud goes over, you'll drop the load. Something HECO (Hawaii Electric Co) has been experiencing problems with. You'll need an expensive UPS system to provide ride through capacity and if the capacity doesn't return within a few minutes, you're screwed.

When solar is a small percentage, a variation is not a big deal. If a bus gets over crowded, people might experience a bit of an uncomfortable ride. But what if a bunch of people are waiting at the stop and the bus doesn't show up?

And if a cost of under a dime (perfectly realistic) per kWh of output for solar is "absurd", then...that's weird, it looks like you currently may be paying more than that to your own grid.

No, because solar industry arithmetic assumes 20 miles of one seat on Sunday night is worth the same as one mile of 20 seats in middle of downtown at 8AM on Monday morning.
 
1 Again, it is a ratio.

2 The POCO gets paid for the extra energy generated, if there isn't any extra at least there's one less house drawing from the grid during the day.
More correctly: during some days.

3 The POCO around here in fact wants people to install DG, to in fact reduce demand and avoid new substation(s), so why would anyone disconnect their PV?
Then put the extra PV on a separate meter connected for grid sales. Put a separate PV unit just for your house load and let your house be free and clear of the grid. Go ahead. I dare you. No, I double-dog dare you!:D

4 The value of car battery is in its ability to deliver 1.78Wh in *four seconds*. A battery that delivers 6Wh over one day is completely useless.
His point was an illustration about how demand works and how it gets overlooked in PV financial calcs.

5 internal combustion is noisy and pretty expensive no matter where you are.
Then run something quieter. Simple isn't it?

6 Well, aren't new grids and old grids completely different things then?
In one sense, but they both have to be managed and are part of the continual planning process.

7 That's one of the main advantages of BESS with PV- it balances out the availability for grid AND consumer.
No doubt storage is one of the big hurdles for PV systems.

8 That stuff about clouds and voltage drops, etc is pretty interesting
Did I mention voltage drops?

9 so grid people must prefer these newer, fancier inverters that can actually help balance drops and such?
Certainly those that will integrate with the grid better. Not sure if that problem is solved yet though, at least to any appreciable degree.
In what world do you think 1 is the best? Actually it is not so good from a DG standpoint.

1 What I'm hearing about this ratio thing is really "less $ for the POCO coming out of the pipe". When someone produces more energy than they use, there is a little more energy in the pipe, and one less person paying a bill.
Around here there's a limit- total kw of DG on a feeder must be < 6.7% of the "peak draw" on that feeder. In my neighborhood that would be over 500kW, and there's currently <100kW.
So we could just say the ratio is around 6.7% then.

2 Yes, some days, but isn't "some months" more accurate? There are a lot of variables there. For instance, a system which doesn't quite cover usage in the winter will cover 2x usage in summer due to longer days.

3 That is actually an option, as far as I can tell. As long as the two systems <= 10kW or 25kW, depending on service. They do set you up with a meter for PV ouput and a meter for usage even for one system.
Pretty sure two "separately derived" systems are ok.

4 Ok, but he didn't really expound on how calcs should be done...so what's the "right" way then?

5 Ok, so diesel gens aren't always the best way! Glad we agree.

6 Right, the 6.7% thing could end up being even higher on a new feeder, conceivably.

7 Going from 14 cents to 2 cents is a pretty big hurdle to clear!
“Using conservative assumptions and no incentives, our model indicates that the incremental cost of storage will decrease from ~14c/kWh today to ~2c/kWh within the next five years,” the report says.
http://cleantechnica.com/2015/03/04/energy-storage-could-reach-cost-holy-grail-within-5-years/

8 You mentioned clouds moving across PV arrays affecting the grid- they do that by causing voltage drops...or is it drops and then spikes? Or...?

9 Why is a power factor of 1 not the best? From what I've read about reactive power, the closer to 1 the better.

You have total control over an engine by adjusting the fuel feed until you run out of fuel. Solar panels are like sail boats. If cloud goes over, you'll drop the load. Something HECO (Hawaii Electric Co) has been experiencing problems with. You'll need an expensive UPS system to provide ride through capacity and if the capacity doesn't return within a few minutes, you're screwed.
When solar is a small percentage, a variation is not a big deal. If a bus gets over crowded, people might experience a bit of an uncomfortable ride. But what if a bunch of people are waiting at the stop and the bus doesn't show up?
No, because solar industry arithmetic assumes 20 miles of one seat on Sunday night is worth the same as one mile of 20 seats in middle of downtown at 8AM on Monday morning.

Right off the bat, Enphase was able to prove its microinverters were accurate as sensors, by showing that they had recorded past voltage spikes that correlated to HECO’s system-wide voltage readings. “That gave them confidence that the data is accurate,” he said. Interestingly enough, Enphase's data indicated that voltage fluctuations on the circuits showed little correlation to how much solar PV was installed on each circuit.
The primary issue for solar-heavy circuits, instead, had to do with the age and quality of the power-conducting cables and transformers on each circuit, he noted. “A 50-year-old network can act very different than a brand-new network,” he said, with older equipment showing more propensity for problems caused by out-of-range voltages.
http://www.greentechmedia.com/artic...g-enphase-data-to-open-its-grid-to-more-solar

(the bus ride analogy)
To be fair, a vast number of residential rate structures assume the same thing for ratepayers without DG.

Exactly. Unfair would be the POCO paying residential customers the same amount for their personal PV generation as they pay the coal or gas plants.
Anyone who dumps a bunch of $$ into PV should be able to make it back in a timely fashion.
Utilities are a public service- so is a house with PV, just a lot smaller.
 

ggunn

PE (Electrical), NABCEP certified
Location
Austin, TX, USA
Occupation
Electrical Engineer - Photovoltaic Systems
Utilities are a public service- so is a house with PV, just a lot smaller.
No. Utilities do not have to buy your power. Household PV is great for reducing your electric bill, but for turning a profit, not so much. Many utilities have disincentives in place to discourage homeowners from building PV systems which produce more than the home uses. For example, Austin Energy will credit your account at their Value Of Solar (VOS) for your surplus energy, and they roll it over month to month, but they will never write you a check.
 
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No. Utilities do not have to buy your power. Household PV is great for reducing your electric bill, but for turning a profit, not so much. Many utilities have disincentives in place to discourage homeowners from building PV systems which produce more than the home uses. For example, Austin Energy will credit your account at their Value Of Solar (VOS) for your surplus energy, and they roll it over month to month, but they will never write you a check.

They sure will write you a check here.
But what they will NOT do is make the process obvious to or easy for anyone who isn't capable of deciphering legal-ese, accounting, and taxes.
Or even easy for professionals who are paid to do those things!

If the customer is in need of a new electrical service (e.g. there is no existing electric account at the proposed project location) or upgraded electrical service (e.g. proposing to install a three-phase DG system on a single-phase service), request it before proceeding!
If the customer is in need of a new electrical service (e.g. there is no existing electric account at the proposed project location) or upgraded electrical service (e.g. proposing to install a 200kW DG system behind an existing residential meter), request it before proceeding!

Um, thanks guys...the exclamation points make it seem like a "fun time for everyone"!
It ain't.

Ok, it's weird. POCOs are private for-profit companies, yes, but they are providing a public service via public property- they own the poles and lines, but the state/town/or even customer owns the property that POCO requires to deliver the for-profit public service.
So they can't *really* just do whatever they want- yes, the majority of them probably do, but the "property owner" has a say.
They also can't force you to buy power- nobody can say "hey, you can't go off grid", although I believe the insane person who is also Governor of Florida is currently trying to pull that scam. Now there's a can of worms.

Obviously, the for-profit people are going so see the "we give you money for PV" thing as a threat.
BUT- it isn't, really. The trick is setting it up so it's win-win.

The Problem with Contracts
But a problem with these renewable energy contracts makes them undesirable for utilities. In fact, this problem has been one of the main reasons that utilities all over the country have been deeply reluctant to sign up renewable energy projects. The problem is this: when a utility has long-term contracts for renewable energy, the contract has adverse effects on the utility’s balance sheet, credit rating, and cost of borrowing. These adverse consequences are mandated by Generally Accepted Accounting Principles (GAAP). The contracts show up on the utility’s balance sheet as a liability; the additional liability affects the utility’s credit rating, and can raise the cost of borrowing for the utility. This costs the utility (and its stockholders) money – and, of course, affects the utility’s openness to renewable energy.
The Solution to the Problem
The new DG Bill in Rhode Island addresses this problem in a way that we believe may prove to be a model for the rest of the country. It gives renewable energy developers a guaranteed 15- to 20-year tariff instead of a contract. Once a developer qualifies for the tariff, the bill stipulates that it cannot be rescinded or taken away. This new system for paying owners of renewable energy projects would (if enacted) be a classic win-win. The developer gets what she needs: a stream of payments, guaranteed by law, that can be used to collateralize a loan to build her project. The utility gets what it wants: no pesky contracts showing up on its books or hurting its credit rating. And, perhaps best of all, those of us who care about climate change and reducing our dependence on fossil fuels get something very important, too: a new model designed to remove one of the oldest, and longest-standing obstacles to building a robust renewable energy future.
Meeting Renewable Energy Goals in Innovative Ways
Rhode Island’s new DG Bill sets a very(!) ambitious goal: 160 MW of new DG renewable energy in five years. We believe that this ambitious goal is achievable thanks in part to this new model substituting tariffs for long-term contracts.
http://www.clf.org/blog/clean-energy-climate-change/distributed-generation-in-rhode-island/
 

ggunn

PE (Electrical), NABCEP certified
Location
Austin, TX, USA
Occupation
Electrical Engineer - Photovoltaic Systems
...nobody can say "hey, you can't go off grid"
But they can and they do. Many municipalities will not issue a building permit if a connection to the grid is not part of the project. They cannot make you buy power but they can make you have a grid connection.
 
For example, Austin Energy will credit your account at their Value Of Solar (VOS) for your surplus energy, and they roll it over month to month, but they will never write you a check.

They do that here too, but the options are:
1. Net metering. No check, bye-bye credits at end of year. (POCO loves that one of course)

2. Net metering. No check, give excess credits to "other accounts", other accounts meaning...a person or....NOT a person who may be defined as a company OR person or town OR farm....5 MEGAwatt limit on net metering!?!? Just....whoa.

3. Residential tariff. you pay your bill, they pay you (with a check) for excess- limited by "previous 3 year average bill OR predicted future bill OR...blah blah!

4. Non-residential. Same as 3, no limit!

But! For #4, request before proceeding!
Oh, non-residential means "you have a commercial account", and comm. accts are "available for all purposes".

You kind of need to go a little big to make up for the "tax break" you lose by not net metering. Option #3 can be a real stinker, to put that another way.

Random theory- they get nailed on taxes if they don't meet their..."REC quota"? Ya know? So option #4 or option 2 are the best, depending on...a dozen other things!
 
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