Will Solar Power Outshine Oil in the Near Future?

[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 ?

 

[zoobyshoe]

So, the key to viable wind and solar is not in direct generation of electricity, but in using them to create a storable form of energy that can be used as needed by big power plants. Most are looking at hydrogen gas.

According to this wiki article, storage of hydrogen gas for stationary power plants (as opposed to the mobile car engine) is not especially problematic:

Unlike mobile applications, hydrogen density is not a huge problem for stationary applications. As for mobile applications, stationary applications can use established technology:

• Compressed hydrogen (CGH2) in a hydrogen tank[61]
• Liquid hydrogen in a (LH2) cryogenic hydrogen tank
• Slush hydrogen in a cryogenic hydrogen tank

Underground hydrogen storage[edit]
Underground hydrogen storage is the practice of hydrogen storage in underground caverns, salt domes and depleted oil and gas fields. Large quantities of gaseous hydrogen have been stored in underground caverns by ICI for many years without any difficulties.[62] The storage of large quantities of liquid hydrogen underground can function as grid energy storage. The round-trip efficiency is approximately 40% (vs. 75-80% for pumped-hydro (PHES)), and the cost is slightly higher than pumped hydro.[63] The European project https://en.wikipedia.org/w/index.php?title=Hyunder&action=edit&redlink=1[64] indicated in 2013 that for the storage of wind and solar energy an additional 85 caverns are required as it can't be covered by PHES and CAES systems.[65]

By this scheme, the grid and all its power plants remain intact, but they would burn hydrogen instead of natural gas and coal. Wind and solar farms would not be directly connected to the grid: all their output would be used to split water, and the resultant hydrogen conveyed to power plants much like natural gas is now.

Power to gas is a technology which converts electrical power to a gas fuel. There are two methods: the first is to use the electricity for water splitting and inject the resulting hydrogen into the natural gas grid; the second, less efficient method is used to convert carbon dioxide and hydrogen to methane, (see natural gas) usingelectrolysis and the Sabatier reaction. The excess power or off peak power generated by wind generators or solar arrays is then used for load balancing in the energy grid. Using the existing natural gas system for hydrogen Fuel cell maker Hydrogenics and natural gas distributor Enbridge have teamed up to develop such a power to gas system in Canada.[66]

Pipeline storage of hydrogen where a natural gas network is used for the storage of hydrogen. Before switching to natural gas, the German gas networks were operated using towngas, which for the most part (60-65%) consisted of hydrogen. The storage capacity of the German natural gas network is more than 200,000 GW·h which is enough for several months of energy requirement. By comparison, the capacity of all German pumped storage power plants amounts to only about 40 GW·h. The transport of energy through a gas network is done with much less loss (<0.1%) than in a power network (8%). The use of the existing natural gas pipelines for hydrogen was studied by NaturalHy[67]

https://en.wikipedia.org/wiki/Hydrogen_storage

 

[mfb]

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

I don't know when you did your measurements and cents are a problematic unit for electricity production, but with $6000 minus installation costs in batteries and solar cells that just barely cover your average demand you'll have no power frequently.

 

[nikkkom]

Wind and solar farms would not be directly connected to the grid: all their output would be used to split water, and the resultant hydrogen conveyed to power plants much like natural gas is now.

Not connecting PV farms to the grid is obviously wrong. That would waste energy on conversion even at times where it is not necessary.

The right way is to connect all energy sources to the grid, and also connect all storage to the grid. When other demand is low (e.g. night), generation does not dial down, it continues to run and this energy goes to storage. When peak comes, storage puts additional power to the grid. This way, generation does not need to be built up to support peak load alone.

Utilities have already figured out this elementary logic and are going with it.

 

[Algr]

I'm not sure if I should start a new thread for this.

I heard this from a questionable source, and trying to fact check it myself did not make clear results. Can anyone here help me? Someone said:

One trillion dollars in windmills and solar panels would generate more power then we get from the middle east. Add a half trillion for power lines and storage and we can forget [the middle east] ever existed.

This was in the context of the Iraq war costing $6 trillion, and "accomplishing nothing". That part probably doesn't belong on PF, but the quote above ought to be demonstrably true or false.

 

[gleem]

I checked out the process for selling power back to the utilities in my area and from it I am lead to believe that the user gets charged for the line at his rate of usage like everybody but get paid for his generation of power because they know what is used and what is and going out.. Check it out.

https://www.renewableenergysolar.net/blog/can-i-sell-electricity-from-solar-energy-to-bge-and-pepco/

It looks like no freebies.