Does a battery ever have a positive ROI with net metering

[GregBallantyne]

I disagree. If reliability is the number one goal, it's very hard to beat a quality diesel or natural gas/propane generator. They work when it's cold and overcast, and they work in the dead of winter when you have fewer hours of charging time available, and they work when you have a large house and a lot of energy demand (if sized properly), and if diesel they can even be refueled by you with a decent storage container.

Batteries depend on solar,, and even in CA where I live we had some pretty grey days with power outages this past winder. 3 days of power outage, and my diesel generator didn't even get to 60% of tank storage.

Now, I am not talking about some cheap home depot gas unit that needs oil or rebuilding after a couple days of runtime. You want a quality unit,. But if you have one, it's far better than depending on the sun always being there for your family.

My number 2 goal being get rid of fossil fuels. I have a generator, but have avoided using it since getting my solar system (10 months in). But it requires some batteries, for when the sun lets you down for a few days. 26 grid outages here in those 10 months.... longest was 3 days, quite cloudy days. Self powered right through, it could have gone longer. Generator stayed quiet. Car didn't get charged much. Would love another 2-3 PW, but if finding the ROI was hard on the first three the second 3 won't help.

 

[BGbreeder]

I meant that when _not_ using a heat pump, you use efficient heat exchange (air conditioning) for cooling, and combustion of fuel for heating.
So venting out the hot air just seems wasteful for those of us who live in cold climates.
I guess it's the humidity of the air that's the issue. Maybe it was more necessary to vent when drying laundry washed with low-efficiency washing machines that leave it more sodden.

(When people heat with wood here, they will sometimes _deliberately_ humidify because poor ventilation and the air pulled in by the wood stove lead to dry air.

That makes sense. Thanks for clarifying . When living in a cold climate, we used to vent the dryer inside. Yes it does add considerable moisture to the house, but that is often a good thing in the winter time, or at least was for us. The more challenging issue was designing a large, fine lint filter to keep the exhaust from spreading fine lint dust throughout the house. YMMV!

All the best,

BG

 

[GregBallantyne]

I'd like to see how that works for your specific case. In my scenario there are pennies to be had daily, but no ROI on the Batteries in >10 years

In my case, I considered the cost of the solar roof, the batteries, and the car as the number required to achieve ROI. I then used the avoided costs of the generated electricity at grid supply rates, the cost of avoided gasoline purchase, the cost of one avoided ICE vehicle purchase, and the cost of one avoided re-roof, all with an annual 4% increase factor. This resulted in ROI achieved in approx. 16 years, if I'm remembering right. A time period I stand a chance of being around for anyhow.
Trying to find ROI on batteries alone isn't a realistic exercise, but the ROI on the cost of an overall strategy in which the batteries play an enabling role is a better and more realistic approach.

 

[TacoGuy]

In my case, I considered the cost of the solar roof, the batteries, and the car as the number required to achieve ROI. I then used the avoided costs of the generated electricity at grid supply rates, the cost of avoided gasoline purchase, the cost of one avoided ICE vehicle purchase, and the cost of one avoided re-roof, all with an annual 4% increase factor. This resulted in ROI achieved in approx. 16 years, if I'm remembering right. A time period I stand a chance of being around for anyhow.
Trying to find ROI on batteries alone isn't a realistic exercise, but the ROI on the cost of an overall strategy in which the batteries play an enabling role is a better and more realistic approach.

Interesting approach. I think the battery return for me was a bit longer (~19-20years) based on the TOU rate differential and a peak shaving strategy. We just don't experience power outages here like other areas.

I charge the car during windows of opportunity when we're either producing MAX solar or in winter during cloudy days when super-off peak rates kick in to offset those costs. When I tracked the car charging I was at some number so low that it was > two zeros to the right of a penny (essentially free).

I'd like to have something off-grid for yard power, that offsets my pool pump and other things like outdoor lighting and irrigation system. This is where a smaller yet highly impactful battery system would make sense ~10-15kw per day, and put any surplus power in the car (top it off).

 

[mikesm]

My number 2 goal being get rid of fossil fuels. I have a generator, but have avoided using it since getting my solar system (10 months in). But it requires some batteries, for when the sun lets you down for a few days. 26 grid outages here in those 10 months.... longest was 3 days, quite cloudy days. Self powered right through, it could have gone longer. Generator stayed quiet. Car didn't get charged much. Would love another 2-3 PW, but if finding the ROI was hard on the first three the second 3 won't help.

There will never be a significant impact on greenhouse gas emission if the ROI for battery systems isn't positive. Some like you may make financial compromises as part of your economic calculation, but that is not going to be a significant number of households, not just in the US, but across the world.

That's why i think V2H will be key to making progress here. Cars seem to be a much lower cost of $/kWh of storage than powerwalls.

 

[Transformer]

BTW, I mentioned the LG dryer model number because there are few full size few heat pump dryers. Smaller dryers have been around a long time but won't keep up the pipeline with most U.S. washing machines.

There's a Samsung HP dryer that's pretty expensive and a Whirlpool dryer with a reputation for the lint clogging up the HP coils in a couple years.

Would love another 2-3 PW

Wow, that's a lot of watts! Oh, PowerWalls.

My number 2 goal being get rid of fossil fuels. ...

Your big picture approach is something like a verifiable carbon offset. Love it.

When living in a cold climate, we used to vent the dryer inside. Yes it does add considerable moisture to the house, but that is often a good thing in the winter time, or at least was for us. The more challenging issue was designing a large, fine lint filter to keep the exhaust from spreading fine lint dust throughout the house.

Apparently (this needs more investigating) dryer vents blow out a lot of microplastics. Future clothing materials might fix that. Meanwhile, it might be worth putting a very fine air filter on that.

 

[ucmndd]

Overall, as Solar gets cheaper and electricity gets more expensive, the number of situations where Solar will make financial sense will grow.

You're right, to the extent that you can store and consume it on site. As for grid-tied systems without storage, it seems we're already well past peak financial benefit and the economics are going to get worse.

California is grappling with a growing problem: too much solar

 

[Midpack]

You're right, to the extent that you can store and consume it on site. As for grid-tied systems without storage, it seems we're already well past peak financial benefit and the economics are going to get worse.

California is grappling with a growing problem: too much solar

Net metering isn't sustainable where homeowners view the grid as a battery, shouldn't be news to anyone. Net metering (without local system batteries) makes the demand curve for utilities worse, not better. The flatter the demand curve, the more efficient for traditional power plants, also not news to most.

 

[ucmndd]

also not news to most.

Not so sure I agree with that. Most people have little to no grounding in how electricity works (pun intended) and don't inherently grasp why they shouldn't be paid handsomely for their excess solar output in the middle of the day when the sun is shining.

 

[Midpack]

Not so sure I agree with that. Most people have little to no grounding in how electricity works (pun intended) and don't inherently grasp why they shouldn't be paid handsomely for their excess solar output in the middle of the day when the sun is shining.

You may well be right, I was trying to extend the benefit of the doubt. If people understood electricity daily demand curves and how large scale utilities have to respond to fluctuating demand, they might understand why net metering shouldn’t continue indefinitely. It was a gift incentive that couldn’t scale up extensively. It’s amazing how power plants micro manage capacity as it is, net metering is a lose-lose for utilities and consumers at large (beyond net metering direct beneficiaries).

 

[cali8484]

You're right, to the extent that you can store and consume it on site. As for grid-tied systems without storage, it seems we're already well past peak financial benefit and the economics are going to get worse.

California is grappling with a growing problem: too much solar

The link text looked reasonable but the actual article title ("Rooftop solar panels are flooding California’s grid. That’s a problem.") is misleading at best. The article conflates numbers for rooftop solar and the much bigger utility scale solar. The solar power curtailment mentioned in the article is almost certainly utility scale solar. To curtail rooftop solar the grid frequency would need to be shifted high which is rarely done. Rooftop solar certainly contributes to the duck curve problem but utility scale solar is the bigger culprit. By falsely highlighting rooftop solar as the problem cause the article plays into the POCO propaganda against rooftop solar.

 

[ucmndd]

The solar power curtailment mentioned in the article is almost certainly utility scale solar.

Of course.

But ultimately it doesn’t really matter. We have saturated the grid with solar to the point that prices are going negative during peak production. There’s very limited value to adding more without associated storage and utility rates are of course going to start reflecting that fact…

 

[cali8484]

But ultimately it doesn’t really matter. We have saturated the grid with solar to the point that prices are going negative during peak production. There’s very limited value to adding more without associated storage and utility rates are of course going to start reflecting that fact…

It does matter to know the correct main culprit if you want to choose the best solution to solve the problem. For example, utility scale systems have more energy storage options (e.g. mechanical, thermal) besides batteries that are simply impractical or impossible at residential scale.

 

[GregBallantyne]

Grid scale storage capacity needs to grow quickly. It actually is, but the required pace is slow compared to the pace that we need. Residential batteries can contribute to an over strategy ROI, as I've calculated. They never likely achieve it when considered as a separate expenditure and return, but being a goal-oriented person that scenario holds zero interest for me. Battery demand in the shorter term probably prevents price drop sufficient to change that in my lifetime, but again, no concern to me. If you want residential energy security, you will need batteries. As we move deeper into the effects of climate change, the value of this goal will become quite clear to more and more people. Batteries really help achieve goals. ROI should perhaps should include a few less quantifiable values, like quality of life, health, perhaps life itself, and others less easily identified.

 

[offandonagain]

One approach that should both help the grid and improve battery ROI is real-time/wholesale/dynamic pricing -- utility rates that change hourly or even more frequently, track wholesale prices more closely, and are generally announced 24h ahead.

These plans are not common in the US yet, but I've been following this in the UK. They have lots of renewable energy from wind and solar, and modern energy companies that support these "smart tariffs". When electricity prices go negative for part of the day (so you're getting paid to charge your battery), and then the battery gets you through peak pricing later in the day, the ROI starts looking much better. And utilities benefit from much stronger incentives for load shifting.

 

[GregBallantyne]

One approach that should both help the grid and improve battery ROI is real-time/wholesale/dynamic pricing -- utility rates that change hourly or even more frequently, track wholesale prices more closely, and are generally announced 24h ahead.

These plans are not common in the US yet, but I've been following this in the UK. They have lots of renewable energy from wind and solar, and modern energy companies that support these "smart tariffs". When electricity prices go negative for part of the day (so you're getting paid to charge your battery), and then the battery gets you through peak pricing later in the day, the ROI starts looking much better. And utilities benefit from much stronger incentives for load shifting.

I agree. I would really like to operate my system in a way that not only satisfies my own goals, but also helps the grid operator, other power customers, and accelerates the growth of renewable power generation. The past 3 weeks, I've moved solidly into the self powering season, sending nearly 300 kwh back to the grid. At exactly the wrong time of day, from the grid operator's perspective. I've been trying to operate in a manner that helps the grid, but have found few opportunities for success in that effort. Using my grid operator's TOU plan in the Tesla app has not done the trick.
If dynamic pricing plans were in place, and support for these plans were integrated into the Tesla app (or another 3rd part app) I would jump right in. That would be a move to drive markets in the direction of welcoming renewable energy sources rather than fighting them. Grid scale storage capacity installation could use some additional motivation, and dynamic pricing should motivate grid operators and residences to move in that direction.

 

[BGbreeder]

One approach that should both help the grid and improve battery ROI is real-time/wholesale/dynamic pricing -- utility rates that change hourly or even more frequently, track wholesale prices more closely, and are generally announced 24h ahead.

These plans are not common in the US yet, but I've been following this in the UK. They have lots of renewable energy from wind and solar, and modern energy companies that support these "smart tariffs". When electricity prices go negative for part of the day (so you're getting paid to charge your battery), and then the battery gets you through peak pricing later in the day, the ROI starts looking much better. And utilities benefit from much stronger incentives for load shifting.

The US has a more complex regulatory structure, but I hope that it will come to the US sooner rather than later. The UK has had time of use pricing for decades, historically largely for overnight heat and hot water. Texas has dynamic pricing for some plans for some time, and during the 2021 consumers who weren't aware of dynamic price got hit with huge bills, arguably deservedly so, but it does point to dynamic pricing not being something that every should use, even if it is permitted. (At least in my view.) Selling inexpensive dynamic power plan to an uninformed consumer without highlighting the downside risk is certainly not ethical.

All the best,

BG

 

[offandonagain]

Selling inexpensive dynamic power plan to an uninformed consumer without highlighting the downside risk is certainly not ethical.

I agree, to clarify I think dynamic tariffs make sense for homes with solar/battery, not everyone. Maybe I'd also include homes with EVs, heat pumps and other large loads that could be smart about when they pull from the grid.

 

[sunwarriors]

The US has a more complex regulatory structure, but I hope that it will come to the US sooner rather than later. The UK has had time of use pricing for decades, historically largely for overnight heat and hot water. Texas has dynamic pricing for some plans for some time, and during the 2021 consumers who weren't aware of dynamic price got hit with huge bills, arguably deservedly so, but it does point to dynamic pricing not being something that every should use, even if it is permitted. (At least in my view.) Selling inexpensive dynamic power plan to an uninformed consumer without highlighting the downside risk is certainly not ethical.

All the best,

BG

I wouldn't want dynamic pricing personally. Like with interest rates, unless you have easy access to get loans/refinance, it's risky (esp when rates "were" so low and what about job loss, or when markets completely freeze up like during the housing crash?). Just seems too risky for not much benefit. I saw some article about some T-Mobile user getting a 143k bill after a trip to Europe. Should have just bought an e-SIM and not assumed their in store rep enabled their global roaming.

Problem with variable pricing is most folks will never know if/when some crazy price is in like what happened in Texas freeze.

 

[ucmndd]

It does matter to know the correct main culprit if you want to choose the best solution to solve the problem.

I guess I fundamentally reject the idea that one is better than the other or that it’s somehow “big solar’s” fault and they’re ruining it for everyone like the word “culprit” implies. Grid-scale renewables would seem to have a very important part in the overall greening of the grid and it’s pretty easy to see why utilities might favor that approach based on the factors being discussed in this thread (for example the ability to quickly curtail production when necessary).

There’s also the obvious observation that utilities don’t have to pay commercial solar operators retail rates for their power during the day when spot prices might actually be negative like they do for the hundreds of thousands of residential customers on NEM 1 or NEM 2.

Homeowners have been spoiled by treating the grid as a year-round battery and the simple fact is that can’t scale any more. I suppose whether that’s “utility propaganda” or just simple facts can be left as an exercise for the reader.