Will Solar Power Outshine Oil in the Near Future?

[Blank_Stare]

Cost is the key factor. A cell which is 4 times heavier, but twice as cheap as car battery, (and all other parameters are same), would win hands down for utility storage.

Car battery which needs replacement in 5-10 years is okayish for cars. Utilities would want to install them once and run them for as long as possible.

Car battery needs to be able to provide spiky output. Utility storage does not need that. This means that batteries which have many good params, but require only slow discharge can be suitable for utility but useless for cars.

Thank you for the clear reply.

 

[nitsuj]

Tesla's Powerwall is not optimal economically (it's too costly, and I have doubts about longevity). Tesla is just repackaging and selling excess production originally designed for cars. They are, as a business, certainly justified in doing so, but we as consumers need storage tailored for non-mobile, large scale storage.

?? The cells are panasonic, at least the first gen powerwall was. They (tesla) do make and have installed "utility" sized power storage and market it as the powerpak.

I'm missing the point of "made for mobility" So because the cell has a much better energy density it's made for mobility? imo important factors for a battery is energy density, voltage curve, resistance, c rating and ease of use

As far as non-mobile installations and cost what beats flow batts? The energy department is supporting/funding both flow batts and Li for energy storage.

Tesla is making batts already?? news to me. I thought that was why they (Tesla) partnered with Panasonic.

 

[gleem]

Tesla is making batts already?? news to me. I thought that was why they (Tesla) partnered with Panasonic

https://www.usatoday.com/story/tech...gafactory-begins-battery-production/96133342/

 

[nitsuj]

https://www.usatoday.com/story/tech...gafactory-begins-battery-production/96133342/

That's awesome! Though that article says initially the batts will be used in the powerpak and powerwall. and that eventually they will be in the model 3...not that the excess of batts from the car production are being "repacked" into the powerwwall/pak

 

[Ken Fabos]

So, using these numbers, I would spend $23,000 on these batteries; they would last 10 years; and in those 10 years I'd use 10 * 365 * 30 = 109,500 kw-hr.

Then the battery cost is $23000/109500 = $0.21 per kwhr. That's more than I pay for my grid power (even where I live, and the power cost is high here).

Or, say you took a loan for the battery; 10 years at 4%, the monthly payment is ~$235, and that's just for the battery. That's more than my monthly power bill.

So, there's plenty of room for improvement in the numbers before I can see widespread adoption of solar.

The true value of storage for anyone with PV is a lot higher than the average kWh price. As the cost of the PV drops and users have greater supply in excess of usage that value will become more apparent.

I realize there are large differences in how electricity is sold dependent on where you live. Here we pay a Service Availability Charge on top of usage, so a close to self sufficient PV and battery fitted home effectively pays much more per kWh than a home totally reliant on the grid. Many are on time of use tariffs, where the evening usage can be double the daytime price - for those it can be financially sensible right now. Note that predictions here are for significant retail electricity price rises, as much as 30% this year, and if that is mostly SAC rises it will shift the balance yet further in favour of battery installations. Most batteries will be still working after 10 years, albeit with reduced capacity that, for a lot of households, will still be adequate. Expect both working life and price to continue to drop as the battery industry develops and expands.

We are moving beyond renewables being used because of subsidies and other policy support into circumstances where market forces sustain it. Those market forces, combined with shortsighted responses like offering very low prices for PV sold back to the grid or forging ahead with Time of Use metering (both on the face of it, expected to reduce attractiveness of PV - batteries not much figuring into those decisions) continue to strengthen rather than weaken demand for PV and storage.

The service the grid provides to PV and battery using customers is in provision of backup supply, with ongoing improvements decreasing the frequency and depth of dependence on that backup. Equitable arrangements are needed for accommodating that and make best use of the excess such installations tend to produce; higher prices during weather affected periods where existing fossil fuel plant has to ramp up is reasonable, but again will make improved storage options more attractive. If equitable arrangements are not introduced going off the grid will begin looking increasingly attractive; personally our household is very close to the point where additional batteris and the occaisional use of a generator would be cheaper than paying for an ongoing grid connection. We are borderline for gaining any financial advantage from our PV and batteries installation, but if that price rise does go ahead it will no longer be borderline.

 

[NTL2009]

Good point. I checked again from what I could glean it seems you can count on at least 90M single family house with another 16M being occupied only part of the year (second homes?) 18M households are apartments. and may include multi family dwelling.

And yes some may not be suitable for solar or minimally. Example. A neighbor of mine had Solar City install panels. I believe these are leased not purchased. The array was installed on an east facing roof among significant shade from nearby trees a real stupid installation. He is lucky to get two hours of sun each day.
So houses with north south orientations a roof installation is not very good.

Solar panels on residential rooftops is the worst way to utilize solar panels. It ought to be frowned upon by anyone who is pro-solar.

As you mentioned, a residential install can have shading issues. And few of them will have rooftops in the optimal direction/slope, requiring additional resources for the racks, or just limiting how many panels you can place there.

Plus, every single installation has to be reviewed, permitted, inspected and have it's own transfer switch. And workers will go to a new site every few days, deal with different roof slopes, gutters, dogs, fences, and on and on. Solar is responsible for more deaths/injuries than nuclear, maybe even coal (on a MW-hr generated basis) - I can dig up the link if needed, from US BLS, IIRC.

Much better to have an industrial/commercial scale installation. A big-box store, warehouse, and/or large public building (school, library, etc). There's is no shortage of large, flat rooftops in populated areas where the grid is available and energy is needed. A crew goes to one site for an extended period of time, instead of a hundred or thousand individual sites. They work on one flat roof - much safer. Easy to get to for maintenance also. Economy of scale in so many ways.

I'd consider buying into 'shares' of solar farm like that, long before I would put panels on my roof. I wouldn't need to worry about getting my investment back if I moved. I could buy a share of panels in a locality that had the best combination of available sun, high kWh prices, and the dirtiest grid. That would put those panels to the best use, and provide the best financial and environmental ROI. Everything is so far in favor of solar 'farms', that any talk of residential solar is just silly and counterproductive (exception for the rare off-grid requirement).

 

[Blank_Stare]

Much better to have an industrial/commercial scale installation. A big-box store, warehouse, and/or large public building (school, library, etc). There's is no shortage of large, flat rooftops in populated areas where the grid is available and energy is needed. A crew goes to one site for an extended period of time, instead of a hundred or thousand individual sites. They work on one flat roof - much safer. Easy to get to for maintenance also. Economy of scale in so many ways.

I'm not so convinced that putting all of the eggs in one basket is the way to go.

Every four or five years we have a storm that knocks out the power to tens of thousands of people (Michigan, USA), and lasts for as long as several weeks, before everyone is back up and running. The usual reason for the failure is the infrastructure, namely poles and wires that get knocked out by either wind, snow, or ice, or a combination thereof.

I definitely am sick of extended blackouts. Aside from the regional occurrences, I have had, on average, a local blackout lasting more than 48 hours, about every 30 months over the past 15 years where I live. Now, a simple battery back-up would have taken care of most of those, but installing a system of batteries to last more than 3 days, is a pretty expensive proposition, and it doesn't take long to start justifying some solar panels, instead of a few more batteries, especially when you consider the potential for the regional blackouts of extended duration.

If I had the coin, I'd be talking about my solar system, not discussing the merits of having one, wistfully.

From a purely "economy of scale" stand point, your argument is clearly bullet-proof. On a practical level, there are at least some people who would be better served if the power generation was not super-centralized.

I live on a "spur", not a grid, when you look at how power gets to me. A few years ago, some automobile driver hit a pole 2 miles from me , at 2 in the morning. Everyone on a line between that pole and the stop sign 5 houses past my house, went without power for almost two days, except folks with the means to generate their own, because the power company has not seen fit to cross-connect our end to the grid a few blocks away from me, where there is another "spur".

I guess what I am saying is that there is no "one size fits all" solution for Solar infrastructure. In my case, I'd rather be self-dependent, than rely on some bean counters to decide if building the infrastructure properly is "cost effective".

Also, I would hate to think of what would happen if a big-box store that was providing the real estate on their roof caught fire, and the solar farm was lost. We'd be talking about a lot of people with no lights, for an extended period. If it took an extended period of time to build in the first place, imagine how long it will take to clean up the site, and then remove the damaged portions of the farm, or all of the farm, and rebuild it... the red tape alone would be a nightmare.

...and that's an awfully large basket of eggs, I think.

 

[mfb]

Plus, every single installation has to be reviewed, permitted, inspected and have it's own transfer switch. And workers will go to a new site every few days, deal with different roof slopes, gutters, dogs, fences, and on and on. Solar is responsible for more deaths/injuries than nuclear, maybe even coal (on a MW-hr generated basis) - I can dig up the link if needed, from US BLS, IIRC.

Coal is worse.
US coal is ~25 more deadly than rooftop solar, which is 4000 times (sic!) worse than US nuclear power. All per kWh of course.
If we take the global average and include all accidents, coal kills 250 times more people, while nuclear power has 5 times lower death rates than rooftop solar.

 

[russ_watters]

I'm not so convinced that putting all of the eggs in one basket is the way to go.

Every four or five years we have a storm that knocks out the power to tens of thousands of people (Michigan, USA), and lasts for as long as several weeks, before everyone is back up and running. The usual reason for the failure is the infrastructure, namely poles and wires that get knocked out by either wind, snow, or ice, or a combination thereof.

I definitely am sick of extended blackouts.

That's definitely a problem, but unfortunately, residential rooftop solar won't solve it; The vast majority of residential rooftop solar installations are not allowed to operate during a blackout.

 

[NTL2009]

I'm not so convinced that putting all of the eggs in one basket is the way to go.

Every four or five years we have a storm that knocks out the power to tens of thousands of people (Michigan, USA), and lasts for as long as several weeks, before everyone is back up and running. The usual reason for the failure is the infrastructure, namely poles and wires that get knocked out by either wind, snow, or ice, or a combination thereof.

I definitely am sick of extended blackouts. ...

There are other ways to get residential backup power, they might (probably?) be more cost effective than solar and batteries every few years (natural gas/propane generator). But that's an individual situation for you to make the call on. I was really talking more about regular day-day power generation, not back up power.

From a purely "economy of scale" stand point, your argument is clearly bullet-proof.

Thanks!

Also, I would hate to think of what would happen if a big-box store that was providing the real estate on their roof caught fire, and the solar farm was lost. We'd be talking about a lot of people with no lights, for an extended period.

Nah. There are two large installations near us, on large school buildings, LOTS of roof space covered with panels. There are 1,760 panels on the roof, yet it has a peak capacity of ~ 440 KW. That's KW, not MW. A typical coal plant in Illinois has a capacity of ~ 800 MW. So losing one building like that would be like losing 1/2000th the capacity of a coal plant (and only when the sun is shining).

The eggs would be in thousands of baskets.

 

[mheslep]

They (tesla) do make and have installed "utility" sized power storage and market it as the powerpak.

The 80 MWh Mira Loma battery facility is for grid transients. It does not qualify as utility 'storage' in the sense of pumped hydro storage plants. Twelve Mira Loma plants would be required to back up *one* large (GW) sized thermal plant or wind farm for *one* hour. There are no battery based utility scale storage facilities anywhere the world, nor any planned, that could back up one middling 500 MW power plant for a day.

 

[mheslep]

The eggs would be in thousands of baskets

All the eggs are crushed every night.

 

[mheslep]

...a local blackout lasting more than 48 hours, about every 30 months over the past 15 years where I live. Now, a simple battery back-up would have taken care of most of those, ...

So far as I can tell, there are no common residential homes in the US (typical sq footage, not a woodland shack) that can run off the grid for 2 to 3 days anytime of the year using just batteries, no combustion generator behind the curtain.

Off the grid doesn't work with solar. And, once you need the grid, some 3/4 of its cost is just the maintenance of the infrastructure. Actually shipping power is an afterthought. So, those with residential solar and net metering plans who avoid those costs are simply pushing the grid costs on to their neighbors. That practice is beginning to end in the US.

 

[nikkkom]

I'm not so convinced that putting all of the eggs in one basket is the way to go.

Every four or five years we have a storm that knocks out the power to tens of thousands of people (Michigan, USA), and lasts for as long as several weeks, before everyone is back up and running. The usual reason for the failure is the infrastructure, namely poles and wires that get knocked out by either wind, snow, or ice, or a combination thereof.

This does not happen in Europe since a lot of electrical lines here are underground and thus are well-protected against weather. I'm guessing it's used more in a denser-populated areas where cost of land is relatively more important, and also in places expanding grid capacity at some point forced it underground because above-ground expansion was not possible.

I take it this is economically unattractive for sparsely populated areas of US, since lines are longer while customers are fewer?

 

[nitsuj]

The 80 MWh Mira Loma battery facility is for grid transients. It does not qualify as utility 'storage' in the sense of pumped hydro storage plants. Twelve Mira Loma plants would be required to back up *one* large (GW) sized thermal plant or wind farm for *one* hour. There are no battery based utility scale storage facilities anywhere the world, nor any planned, that could back up one middling 500 MW power plant for a day.

Some semantic work there on "utility storage". A journey of a thousand miles begins with a single step, "According to market research firm IHS, the energy storage market is set to “explode” to an annual installation size of 6 gigawatts (GW) in 2017 and over 40 GW by 2022 — from an initial base of only 0.34 GW installed in 2012 and 2013."

Comparing the energy production of a traditional power plant to the storage capacity of current tech batts. Why must a battery be able to support a days worth of energy from said power plant? Such storage could be done locally, even down to a per person...this flexibility is appealing.

There are a number of MW storage facilities being built and running all over the world. China, Japan & California seem to be throwing money at this...presumably to further improve/demonstrate the technology.

I suspect the reason the industry is not planning to build a storage facility capable of backing up one middling 500 MW power plant for a day is because it makes MUCH more sense to scale up...such a bizarre argument. "There are no manned space ships capable of traveling to Titan nor are any planned...ergo not possible."

Once government funded projects demonstrate the economics the industry grows...and grows and grows.

 

[gleem]

Much better to have an industrial/commercial scale installation. A big-box store, warehouse, and/or large public building (school, library, etc). There's is no shortage of large, flat rooftops in populated areas where the grid is available and energy is needed. A crew goes to one site for an extended period of time, instead of a hundred or thousand individual sites. They work on one flat roof - much safer. Easy to get to for maintenance also. Economy of scale in so many ways.

Rooftop installations on big box stores ,warehouses and public buildings will most likely only provide power for those structures. facotries that may have access to adjacent land will probably only produce a fractions of their needs. As a example a factory near me just built a solar facility 1.57 MW, producing about 2.3MWhrs per year on 6 acres (4992 panels) produces only about 12 % of their needs. One MW of power will meet the need of only about 70- 100 residences.

One could consider municipal solar farms. A community with 5000 houses would need about 60 MW of panels for just the residential requirements add to that commercial and municipal needs. The area needed would be similar to say an additional land fill. It could be funded by bonds and

I definitely am sick of extended blackouts. Aside from the regional occurrences, I have had, on average, a local blackout lasting more than 48 hours, about every 30 months over the past 15 years where I live. Now, a simple battery back-up would have taken care of most of

those, but installing a system of batteries to last more than 3 days, is a pretty expensive proposition, and it doesn't take long to start justifying some solar panels, instead of a few more batteries, especially when you consider the potential for the regional blackouts of extended duration.

If I had the coin, I'd be talking about my solar system, not discussing the merits of having one, wistfully.

I don't think solar is a good option for blackout in a place like Michigan especially when many will be in the winter when output is minimal. You can go for weeks without significant sun. Better with a standby generator 16kW about $3500 https://www.electricgeneratorsdirect.com/power/generac-11kw-16-kw-home-standby-generators.html

The 80 MWh Mira Loma battery facility is for grid transients. It does not qualify as utility 'storage' in the sense of pumped hydro storage plants. Twelve Mira Loma plants would be required to back up *one* large (GW) sized thermal plant or wind farm for *one* hour. There are no battery based utility scale storage facilities anywhere the world, nor any planned, that could back up one middling 500 MW power plant for a day.

Did a quick calc for a 1 GW, 4GW-hr storage facility using Tesla POWER PACK batteries. it would take 20,000 POWERPACKs occupying a building roughly taking up 4 acres and 5 stories high. From pictures of the Mira Loma facility it looks like the batteries take up about 0.25 acres with the transformers and other equipment taking up another and the power lines towers taking up ? all this fits on a 1.5 acre site.

The Mira Loma plant provides 2500 houses back up for 24 hours producing 20 MW of power (50kW x 396 bat) with an energy storage of 83,000 kW-hrs. which for 2500 houses is about 33kWhr which is reasonable. A 1 GW facility which is 50 times greater would provide those same houses with 50 days of power. or
125,000 homes 24 hours. and take up at most 75 acres probably significantly less. However such a facility might cost as much as $900M .

 

[NTL2009]

Rooftop installations on big box stores ,warehouses and public buildings will most likely only provide power for those structures. facotries that may have access to adjacent land will probably only produce a fractions of their needs. As a example a factory near me just built a solar facility 1.57 MW, producing about 2.3MWhrs per year on 6 acres (4992 panels) produces only about 12 % of their needs. One MW of power will meet the need of only about 70- 100 residences. ...

It's not clear to me what your point is?

What difference does it make who is "using" the output of the solar panels, or what % of their usage those panels represent? An installation of X MW will offset that much grid power, regardless of who is using it.

BTW, I think you meant 2.3GWhrs (not 2.3MWhrs) per year. 1.57 MW * ~ 5 hours/day * about 300 sunny days/year is about 2.3 GWhrs/year.

 

[gleem]

It's not clear to me what your point is?

I got the impression that there was a thought of using the large roof areas of large area commercial buildings to produce excess power which could be diverted to residential use.

 

[NTL2009]

I got the impression that there was a thought of using the large roof areas of large area commercial buildings to produce excess power which could be diverted to residential use.

The thought is to use the large roof areas of large area commercial buildings to produce (solar) power (period). It just goes into the grid, there's essentially no difference to the grid and the power plants between 1,000 panels on a big flat roof in the neighborhood, or 2 panels on 500 houses in the neighborhood.

The important difference is that it will be cheaper, faster and safer to do one install on a big building, and very likely to get more power from the same number of panels, because they will all be at the optimum angle on a big flat roof, with no shade trees. Economy of scale will come into play at all levels (fewer transfer switches, optimally sized inverters, etc). Maintenance on one site is far easier (and likely to be noticed and repaired quicker) on one big install versus 500 small ones. And over 10-20-30 years, guess how many trees will grow and shade some of those panels installed earlier?

 

[gleem]

The important difference is that it will be cheaper, faster and safer to do one install on a big building, and very likely to get more power from the same number of panels, because they will all be at the optimum angle on a big flat roof, with no shade trees. Economy of scale will come into play at all levels (fewer transfer switches, optimally sized inverters, etc). Maintenance on one site is far easier (and likely to be noticed and repaired quicker) on one big install versus 500 small ones. And over 10-20-30 years, guess how many trees will grow and shade some of those panels installed earlier?

I got that and you are correct. Many large local facilities obviate a number of problems.

 

[mfb]

This does not happen in Europe since a lot of electrical lines here are underground and thus are well-protected against weather. I'm guessing it's used more in a denser-populated areas where cost of land is relatively more important, and also in places expanding grid capacity at some point forced it underground because above-ground expansion was not possible.

In towns, the lines are typically underground, but the big distribution lines between towns are in the open air as everywhere in the world. We just don't have so many bad ice storms and probably more redundancy in the network.

 

[NTL2009]

I got that and you are correct. Many large local facilities obviate a number of problems.

But what point were you trying to make about the commercial building using all (or most?) of the energy the panels would produce?

 

[gleem]

But what point were you trying to make about the commercial building using all (or most?) of the energy the panels would produce?

.That the panel arrays takes up all the available space for their own needs and they cannot produce any excess power to sell to the utility.

 

[NTL2009]

.That the panel arrays takes up all the available space for their own needs and they cannot produce any excess power to sell to the utility.

And again, what difference does that make?

A) If a set of panels on a commercial building produce exactly 1 MW at noon, and the building is consuming exactly 1 MW at that time, the power plants on the grid produce 1 MW less to feed that grid than if there were no panels.

B) If those same panels are scattered across hundreds of houses, and we assume (maybe incorrectly), that the houses are not consuming all that is produced, the net effect is the same. The power plants on the grid produce 1 MW less to feed that grid.

I see essentially no difference between the power being consumed at the point of solar generation, or consumed by others nearby on that grid. I say "essentially", because consuming it close to where it is generated will reduce transmission losses somewhat, another plus for commercial installations.

You seem to think there is some advantage to it being scattered across many homes. But I do not get your point.

Other than the losses I mentioned, there is no connection between the roof used to generate the power, and how much consumption is under that roof, they are just separate things. The grid doesn't 'care' if the solar panels were put over land where no electricity was being used, or put on the roof of a manufacturing plant that uses more power than the panels produce. The end result is the same.

 

[gleem]

You seem to think there is some advantage to it being scattered across many homes. But I do not get your point.

If the panel where scattered and only half of the power generated where used the panel owners put that on the grid and get paid the going rate for electricity generators. So when you are not home your panels are making money.

 

[NTL2009]

If the panel where scattered and only half of the power generated where used the panel owners put that on the grid and get paid the going rate for electricity generators. So when you are not home your panels are making money.

AFAIK, no utility pays a homeowner more (per kWh) for excess power than they charge that homeowner for consumption. It's a wash.

 

[gleem]

AFAIK, no utility pays a homeowner more (per kWh) for excess power than they charge that homeowner for consumption. It's a wash.

Suppose I normally use 40 kwhr per day my meter reads 10000 kwhr. at the beginning of the day. I use 25kWhrs. during the daytime when my panels produce 60 kwhrs. during this period. producing 35kwhrs of excess energy. At the end of the day my meter reads 9965kWhrs. I produced enough electricity myself so no charge for electricity that day plus I sent to the utility for their use 35KkWhrs for which they credit my account via the meter. At least that's the way I understand it and the reason people spend big bucks to put in these panels. and then there's the tax breaks on top of it.

 

[mfb]

AFAIK, no utility pays a homeowner more (per kWh) for excess power than they charge that homeowner for consumption. It's a wash.

The German government did that for a while (and continues to do so for old installations), now the rates are lower.
Various governments do that for wind energy, this plus the equivalent for solar power can make electricity market prices negative - it makes sense to "sell" electricity and pay for it if the government pays you more than that. An odd situation.

At least that's the way I understand it and the reason people spend big bucks to put in these panels. and then there's the tax breaks on top of it.

Everything is heavily subsidized. Directly, and indirectly - because you still need the grid with your solar panels (even more than before: you now use it in both directions!), but now you pay less for it. Which means others have to pay more for it.

 

[gleem]

Everything is heavily subsidized. Directly, and indirectly - because you still need the grid with your solar panels (even more than before: you now use it in both directions!), but now you pay less for it. Which means others have to pay more for it.

I do not know in fact that they pay the total cost per kwhr. because it includes the charge for generation and the charge for transmission which for me are about equal. If the meter reads less than the previous day then they know your sold them power and they might credit your account for the generation charge only and not the total charge. So everything is copacetic.

 

[mfb]

That's not what I meant. Let's ignore taxes for now:

Producing 1 kWh typically costs something like 4 cent in big power plants. The distribution, logistics and so on cost about the same, so you pay 8 cents per kWh in total. That is the system with big power plants only.
Now you install a small solar panel on your roof. On some days you don't need to buy electricity. You don't pay the 4 cent/kWh for the production naturally, but you also don't pay the 4 cent/kWh used to maintain the grid. But the grid still has to be maintained, because you want to be able to use it at any time. To get the same money to operate the grid, the electricity price has to rise. The effect from your local solar panel is tiny, of course, but summed over all residential solar power it can matter. While you save 8 cent/kWh, summed over all customers we only save 4 cent/kWh.

It gets worse. Electricity demand is quite predictable and follows daily and weekly cycles. Production from solar panels is not that predictable, and has a different pattern every day. The grid operators have to match production to demand, which means regulating down some power plants. Power plants that are idle still cost money but suddenly no money flows in when the sun shines.. What does the power plant operator do to recover these losses? Increase the price per kWh. Your electricity company guarantees that you get power even if the sun doesn't shine - the power plants will have to stay as long as we don't have a better storage solution.

A production/demand pattern that changes frequently can also mean the transmission lines need more capacity, increasing distribution costs. And handing down these costs to the customers, of course.

For you as customer solar power can be worth the investment - you save 8 cent per kWh, and even more if we add taxes. You might even get subsidies if you produce more power than you need, to increase the use of solar power for you even more. That is the calculation you see solar power proponents make. The overall economic use is much smaller: It is the difference between running or not running an existing power plant, something like 1-2 cent per kWh. And I don't see how solar panels are supposed to get that cheap - installation costs alone are at this price level.
If it helps to reduce emissions from coal and gas power plants, I think it is worth the investment, but we wouldn't need solar power to do that.
A reliable method to store electricity would improve things a lot.

 

[NTL2009]

Suppose I normally use 40 kwhr per day my meter reads 10000 kwhr. at the beginning of the day. I use 25kWhrs. during the daytime when my panels produce 60 kwhrs. during this period. producing 35kwhrs of excess energy. At the end of the day my meter reads 9965kWhrs. I produced enough electricity myself so no charge for electricity that day plus I sent to the utility for their use 35KkWhrs for which they credit my account via the meter. At least that's the way I understand it and the reason people spend big bucks to put in these panels. and then there's the tax breaks on top of it.

Yes, yes, yes, I understand how the numbers 'work'. But you are looking at the micro-level, and I'm looking at the macro-level. At the macro level, physics and economics and common sense say residential rooftop solar makes no sense, compared to large industrial scale installations. At the micro-level, Congress (with few if any physicists or engineers) has warped the market.

Please read the excellent post above from mfb. I'd summarize that by saying - the utility is currently paying residential solar generators retail cost for something they normally buy at wholesale, and everyone else on the grid is going to pay extra for that. That is not reasonable and it is not sustainable.

Anyone who really wants to promote solar for environmental reasons (or any other reasons I guess) should be against residential installations and in favor of large scale installations. If someone just wants what they can get from the government and their fellow taxpayers, well, I think that's outside the realm of a physics forum.

 

[Physics_Kid]

Fossil fuel generators like a GE 2000KVA model produces an AC terminal voltage of 26kV which is stepped up to 67kV to 765kV for transmission. The max voltage I've found for a panel is 48 VDC. How do you produce 1Gw at 26kV AC.

a lot of panels, inverter(s), step up xfmer. as the efficiency of panels get better the number of panels needed will go down. i don't know what the quantum limit is, that's the real stickler.

 

[nikkkom]

Residential solar is less economically efficient - well known "economies of scale" reasons apply here. The cost of installation, for example. The same worker can install maybe 20-50 times more panels in the same time span when he is installing them at the solar farm, not on a smallish roof.

This will be somewhat alleviated when integrated solar roofing becomes mainstream. If you need to build a roof anyway, then ordering a solar roof only costs more than ordinary roof, but the same workers do about the same amount of work and it takes about the same amount of time.

 

[NTL2009]

... It is beginning to seem to me the current idea of using residential and commercial installations and tying into the grid locally to augment the power grid may be the more efficient way to incorporate this energy source (thoughts?). No additional transmission lines, no storage facilities, power disruption is minimized. ...

Getting back to your earlier post, here are my thoughts... Using the large roof of schools, big-box stores, etc does not require any additional transmission lines, storage facilities (no more than residential), or significant power disruption either. Here's some numbers:

I mentioned the large school install near us. 440 KW, 1760 panels. So let's put that in perspective. When converted to 120 V, that would be 3667 Amps. A typical NA home has 200 Amp capacity wiring, so we could think about one of these buildings as needing the same wiring capacity as about 18 homes (or 9 homes if that is 200 Amps capacity per each branch of two phases, I'm not sure on that). Off hand, I would think any big building would have that much wiring capacity (large A/C systems). Since the panels offset usage first, we never exceed the panel power amperage, it is always subtractive. We would have full panel amperage on the wiring only if the building was shut down to zero. As long as the panel peak power does not exceed the wiring capacity of the building, no upgrades to any of the distribution system is required. In fact, the panels reduce loading on the distribution system, on average.

You might be picturing solar farms that are the size of present thermal power plants, ~ 1 GW. But there is no need for that. We don't need to have solar distant from homes, as there is no smoke or other need for separation. Better to distribute 2000 large roofs of 1/2 MW each distributed throughout the area consuming it.

There is talk of large solar farms in the desert, and those would need large transmission lines. I haven't seen the numbers, but offhand, I wouldn't think that added % of sunshine would offset the cost of transmission lines, when smaller, distributed local installations would need little/no infrastructure changes.

 

[nitsuj]

AFAIK, no utility pays a homeowner more (per kWh) for excess power than they charge that homeowner for consumption. It's a wash.

This whole thread has pointed out the higher cost of solar to traditional. http://energyrates.ca/ontario/green-energy-ontario/

Another point is personally owning the electricity / installation. A very attractive feature that makes economic sense...sometimes (smelting, pulp) making your own coal / hydro plant makes economic sense. "Soon" it will "make sense" even for jane doe consumer.

Who on Earth thinks that paying to get electricity from here to there, a profit margin, supporting billions in infrastructure, at the mercy of market pricing is better economically than simply owning your own power generation equipment and having it on your own property?

 

[nitsuj]

Residential solar is less economically efficient - well known "economies of scale" reasons apply here. The cost of installation, for example. The same worker can install maybe 20-50 times more panels in the same time span when he is installing them at the solar farm, not on a smallish roof.

This will be somewhat alleviated when integrated solar roofing becomes mainstream. If you need to build a roof anyway, then ordering a solar roof only costs more than ordinary roof, but the same workers do about the same amount of work and it takes about the same amount of time.

This would vary greatly from jurisdiction, Some places the homeowner could install and hook up the panels, others may require the permission of neighbors to even have them in the first place. Some may ban (Texas?) their use all together.

 

[nikkkom]

There is talk of large solar farms in the desert, and those would need large transmission lines. I haven't seen the numbers, but offhand, I wouldn't think that added % of sunshine would offset the cost of transmission lines, when smaller, distributed local installations would need little/no infrastructure changes.

I suspect large installations are significantly cheaper per kW. When you plan and install 1 km^2 of PV, there are significant economies of scale.

 

[gleem]

This would vary greatly from jurisdiction, Some places the homeowner could install and hook up the panels, others may require the permission of neighbors to even have them in the first place. Some may ban (Texas?) their use all together.

This has to do with homeowners associations (in Texas) who you agree to abide by their rules which can vary anywhere from forcing you to garage your car every night to regulating your landscape and color of your house. We lived in one that required approval of the architecture of the house before building it. The advantage I guess is that you have the same taste as your neighbor.

And as far as the unsightliness? is concerned Tesla is manufacturing roof tiles with the solar electric capabilities.

 

[nitsuj]

This has to do with homeowners associations (in Texas) who you agree to abide by their rules which can vary anywhere from forcing you to garage your car every night to regulating your landscape and color of your house. We lived in one that required approval of the architecture of the house before building it. The advantage I guess is that you have the same taste as your neighbor.

And as far as the unsightliness? is concerned Tesla is manufacturing roof tiles with the solar electric capabilities.

With Texas I was leaning on their ban of Tesla dealerships...not sure of any details. For all I know Texas is big on solar for electricity (fine with there being a solar industry there.

 

[mheslep]

Residential solar is less economically efficient...

Yes, far less. Residential is 4X more expensive than utility solar PV.
https://www.lazard.com/media/2390/lazards-levelized-cost-of-energy-analysis-90.pdf

 

[mheslep]

Who on Earth thinks that paying to get electricity from here to there, a profit margin, supporting billions in infrastructure, at the mercy of market pricing is better economically than simply owning your own power generation equipment and having it on your own property

You have not made the case from running entirely off "your own power equipment", but rather for using your own installation part time, and then when it doesn't work, and often it won't, receiving the benefit of a trillion dollars worth of reliable electric grid almost for free.

 

[mheslep]

A journey of a thousand miles begins with a single step

Many things begin with a single step, like getting lost the forest.

 

[NTL2009]

... Who on earth thinks that paying to get electricity from here to there, a profit margin, supporting billions in infrastructure, at the mercy of market pricing is better economically than simply owning your own power generation equipment and having it on your own property?

Hello - from your fellow Earthling!

We have so many examples where it is worthwhile to purchase the end product rather than DIY. Electricity is a fantastic example of that.

Even with the present situation where you get to use the grid for zero, or near zero cost, solar PV has a pretty long payback (and subsidies don't really count, that is still a cost, it is just someone else paying for it). With all the uncertainties, I'd rather get what I need at ~ $0.11/kWh.

As @mheslep pointed out, it isn't as 'simple' as you say ("simply owning your own power generation equipment and having it on your own property"). You are still very reliant on that big, old, bad, profit seeking utility and their billions of infrastructure. If you really want to disconnect from the electrical grid, be my guest. But please let me know how much it will cost for batteries and inverters to store enough kWh to get you through a cloudy, snowy Canadian winter, or how people would do it with large A/C needs?

The economy of solar PV you see is because we have a grid available for you to use at night, in bad weather, and to pull from anytime your instantaneous power demand exceeds your system capacity. The grid is your storage system, and you are getting it almost for free. You deride it, but I bet you won't give it up!

 

[nitsuj]

lol the grid is free,

Who's still reliant on "still very reliant on that big, old, bad, profit seeking utility"? What's more in my province ultimately the populace owns the infrastructure, well apparently just a controlling share at this point...they sold 60% to those big bad stakeholders. teeheee hee the infrustrure was failing apart, repair greatly increasing the cost...of electricity, hmmm...

 

[NTL2009]

lol the grid is free,

Who's still reliant on "still very reliant on that big, old, bad, profit seeking utility"? What's more in my province ultimately the populace owns the infrastructure, well apparently just a controlling share at this point...they sold 60% to those big bad stakeholders. teeheee hee the infrustrure was failing apart, repair greatly increasing the cost...of electricity, hmmm...

?

You didn't answer the question. What would it cost you to disconnect from the grid?

 

[gleem]

Now you install a small solar panel on your roof. On some days you don't need to buy electricity. You don't pay the 4 cent/kWh for the production naturally, but you also don't pay the 4 cent/kWh used to maintain the grid. But the grid still has to be maintained, because you want to be able to use it at any time. To get the same money to operate the grid, the electricity price has to rise. The effect from your local solar panel is tiny, of course, but summed over all residential solar power it can matter. While you save 8 cent/kWh, summed over all customers we only save 4 cent/kWh.

It sound like people with solar panels should feel guilty for not paying their fair share of the transmission cost. How is that different from a person who has a second home which is used for 4-5 months and turns off the power when not in use. In the US 15 million residences are occupied part time.

It gets worse. Electricity demand is quite predictable and follows daily and weekly cycles. Production from solar panels is not that predictable, and has a different pattern every day. The grid operators have to match production to demand, which means regulating down some power plants. Power plants that are idle still cost money but suddenly no money flows in when the sun shines.. What does the power plant operator do to recover these losses? Increase the price per kWh. Your electricity company guarantees that you get power even if the sun doesn't shine - the power plants will have to stay as long as we don't have a better storage solution.

A production/demand pattern that changes frequently can also mean the transmission lines need more capacity, increasing distribution costs. And handing down these costs to the customers, of course.

I don't get it. One user putting power on the grid is the same as one user reducing his pull from the grid by the same amount. The fluctuations of demand from the grid from solar at least currently is small the great fluctuations occur in the morning as household and commerce awake and at night when they wind down.

Except as new solar installations come on line the solar effect on fluctuations should be predicable but new solar usually comes on line in very small negligible capacities. As new solar comes on line so do new houses without solar which increase the demand on the grid which must be accommodated. I can't see where solar is particularly bad for the power companies.

 

[nitsuj]

?

You didn't answer the question. What would it cost you to disconnect from the grid?

That's a good question, I'll try and measure-calculate it. It'll take me some research and stuff but will do it as I'm interested to know myself.

I have played with measurements from a single solar panel, I can't remember exactly but think it farmed maybe 0.10$ over a day (not straight /kwh cost, our billing includes fixed recurring costs). So maybe 30 panels , let's add a 1/3 for bad weather, so 40 panels for 90$ (assumed cost of current elec use - $3*30days) of electricity. $5000 just for the panels (40*$100+$tuff).

then there's the batts...

super rough guess is $10k per person per 15yrs. looking for to getting it from a measurement perspective.

1kwh for 0.08 - 0.16$ is SO CHEAP, it'll be bad lol

 

[NTL2009]

...I don't get it. One user putting power on the grid is the same as one user reducing his pull from the grid by the same amount. ...

No, it is very different.

Take the simple case where a solar home nets to zero, they have a very low bill (connection fees vary), but they used the grid for most of the day. If they are able to net to zero, they had an excess around noon (so used the grid to absorb the excess), and then they used the grid to pull what they need for ~ 18 hours/day. Yet they pay almost nothing. Their solar system would not function w/o the grid, they ought to pay for it's use, the same as anyone.

If I reduce my consumption through efficiency, I'm using the grid less, and it's reasonable for me to pay a lower share of its support.

 

[mfb]

It sound like people with solar panels should feel guilty for not paying their fair share of the transmission cost.

I don't say people should feel guilty, but keeping it in mind is certainly not a bad idea.
As long as it replaces coal or oil, I think it is a great thing, and I happily pay for it.

How is that different from a person who has a second home which is used for 4-5 months and turns off the power when not in use.

That house won't suddenly need power if it is cloudy, and the owners use electricity and pay elsewhere for the grid infrastructure.

The fluctuations of demand from the grid from solar at least currently is small the great fluctuations occur in the morning as household and commerce awake and at night when they wind down.

The daily cycles are highly predictable, and changes occur over a timescale of about an hour. The overall fluctuations from solar power can be faster and they are less predictable. They are small today, sure, but the fraction of solar power is small as well.

 

[OCR]

So maybe 30 panels , let's add a 1/3 for bad weather, so 40 panels...

You added a 1/3 (10 panels ) for bad weather on your initial 30 panels... did that estimate include bad weather for the 10 added panels ?