# US solar power generation for 2014-17

## Main Question or Discussion Point

Solar generation results for US are out for 2017.
Year over year:

http://www.eia.gov/electricity/annual/html/epa_01_02.html
https://www.eia.gov/electricity/annual/pdf/epa.pdf

US: Net Generation (Thousand Megawatthours) 2014
Solar: 17691 (that's 0.43%)
All sources: 4093606

US: Net Generation (Thousand Megawatthours) 2015
All sources: 4077601
Solar utility scale: 24893 0.61%
Solar all (estimated): 39032 0.95%

US: Net Generation (Thousand Megawatthours) 2016
All sources: 4076627
Solar utility scale: 36054 0.88%
Solar all (estimated): 54866 1.34%

US: Net Generation (Thousand Megawatthours) 2017
All sources: 4034268
Solar utility scale: 53286 1.32%
Solar all (estimated): 77276 1.92%

Fisherman199, russ_watters and OmCheeto

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anorlunda
Staff Emeritus
Thanks for sharing. The public confuses the soaring growth rate of solar (and wind) with the very low starting point (sub 1%). The public also finds it hard to comprehend an industry that requires 20-40 years to make big changes.

A very interesting development is that utility-scale contracts for energy futures have been bid and won by solar or wind including storage.

russ_watters
russ_watters
Mentor
Yes, thanks for pointing to this. This is an issue I've been tracking and I have a spreadsheet and some analysis I'll share later.

We've previously discussed growth rates and scalability, and I have commented largely on two benchmarks:
1% (passed in 2016) was my threshold for considering solar power "relevant", meaning prior to that it was just too low to affect the grid or make realistic predictions about its growth. Opening one plant would skew a year's growth rate. We've passed that and growth rates have settled down.

10% is suspected to be the limit of practical exploitation based on Germany's model. We're about 5 years from that based on the current growth rate trend (about 40% now, and dropping pretty much every year).

Obviously the industry climate has a big impact on what happens next.

Fisherman199
Solar utility scale generation
growth 2014 to 2015: 24893 / 17691 = 1.407, or ~41%
growth 2015 to 2016: 36054 / 24893 = 1.448, or ~45%
growth 2016 to 2017: 53286 / 36054 = 1.477, or ~48%

mfb
Mentor
10% is suspected to be the limit of practical exploitation based on Germany's model.
The US has places with more sunlight, but it doesn't feature the ridiculously high subsidies Germany has.
The US needs more electricity in the summer, that works nicely with solar power.

russ_watters
phyzguy
Storage is the key. Sunny places like Hawaii and California are already facing problems where generation exceeds demand on sunny summer days. Until we have efficient utility scale storage, it will be hard to have solar power go beyond 10% or so.

Fisherman199, berkeman, russ_watters and 2 others
OmCheeto
Gold Member
... problems where generation exceeds demand ...
What a horrible problem. This has also been an intermittent "problem" with wind farms, also.

Storage is the key.
I agree with this.
Until we have efficient utility scale storage, it will be hard to have solar power go beyond 10% or so.
I disagree that "utility" scale storage is the only solution.
Being a northerner, I could really use some "thermal" storage, similar to the Drake Landing type of system.
My annual heating requirements are 3 times that of my base load.
Reducing my heating bills to zero, I could get by easily with a single Tesla Powerwall.
Powerwall: 13.5 kwh

That sure is a fun page to ogle. I've created countless interesting graphs from it.

Quite the impressive reduction in SO2 over the last 10 years.

I'm guessing that's mostly because of a shift from coal to natural gas.
It will be interesting to see what it is in another 10 years, as solar increases.

And imagine what the following graph would look like, if everyone followed the Drake Landing example:

Per wiki; "In the USA, HVAC systems account for nearly half of the energy used in residential buildings."
[edited for brevity]

As I've mentioned before, I will do what I can, when I can afford it*. Commercial and Industrial customers can figure it out for themselves.

----
* Coincidentally, on the day California senate bill 100 passed(Aug 28th), a rep from from my electric company showed up on my doorstep and talked me into signing up for 100% renewable energy. According to them, it will cost me an extra 5.5%. I still have no idea how they are going to provide me with 100% renewable energy, when such a thing doesn't exist, as far as I can tell, but, I did it anyways.

Also, by this day in 2021, I should be able to afford to both cut my neighbors trees down, and install a thermal sump.
Amazing what you can do, when the house gets paid off.

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phyzguy
phyzguy
What a horrible problem.
It is a problem. Without a way to store the energy being generated, what is the utility supposed to do with it? Also there is a problem in that the grid, as currently designed, works well when power is flowing from the utility to homes and businesses, and can fail when power begins to flow back the other way.

I disagree that "utility" scale storage is the only solution.
By "utility scale", I just mean enough energy storage to store several days of demand, if it is cloudy or raining, etc. I don't mean it has to be at the utility. It could be many Tesla Powerwalls or some other form of local storage distributed across millions of users. But if you look at the numbers, it is a daunting challenge. California uses about 800 GWh of electricity per day. If we want to store 2 days of this usage, we need 1600 GWh of storage. A Tesla Powerwall stores 14 kWh. So we would need 114 million of them. This is a tall order.

Tom.G
This site, from ca.gov, says 10.2% in 2017, not 16%.
Ahh, well, it WAS from a newspaper; ( must have been 'Good Enough.')
Thanks for the correction! Appreciated.

1600 GWh of storage. A Tesla Powerwall stores 14 kWh. So we would need 114 million of them. This is a tall order.
Sure is tall. There are only:
California
Total housing units: 13,911,737
Number of Companies: 3,548,449
(and another order-of-magnitude creeps in )
That's 8+ Powerwalls each. Ouch.

source: https://factfinder.census.gov/faces/nav/jsf/pages/community_facts.xhtml?src=bkmk

By "utility scale", I just mean enough energy storage to store several days of demand, if it is cloudy or raining, etc. I don't mean it has to be at the utility. It could be many Tesla Powerwalls or some other form of local storage distributed across millions of users. But if you look at the numbers, it is a daunting challenge. California uses about 800 GWh of electricity per day. If we want to store 2 days of this usage, we need 1600 GWh of storage. A Tesla Powerwall stores 14 kWh. So we would need 114 million of them. This is a tall order.
Tesla Powerpack is more appropriate product to consider for mass storage. 210 kWh per fridge-sized box. You'd need "only" 7.6 millions of those.

mfb
Mentor
Tesla Powerpack is more appropriate product to consider for mass storage. 210 kWh per fridge-sized box. You'd need "only" 7.6 millions of those.
At $80,000 per piece that would cost$600B, or $15,000 per capita - if anyone could build so many batteries. Tesla's Gigafactory 1 is expected to reach 150 GWh/year production. We need 10 years of full production to be able to store 2 days worth of California's electricity. If the batteries last 10 years the factory has to run continuously just to keep up with aging batteries. OmCheeto Gold Member It is a problem. Without a way to store the energy being generated, what is the utility supposed to do with it? I'm not a utility, but when I don't need energy from my solar panels, I just unplug them. I do understand that there are "contractual" problems, with the "utilities". Also there is a problem in that the grid, as currently designed, works well when power is flowing from the utility to homes and businesses, and can fail when power begins to flow back the other way. Sounds like a problem to be solved. By "utility scale", I just mean enough energy storage to store several days of demand, if it is cloudy or raining, etc. I don't mean it has to be at the utility. It could be many Tesla Powerwalls or some other form of local storage distributed across millions of users. But if you look at the numbers, it is a daunting challenge. California uses about 800 GWh of electricity per day. If we want to store 2 days of this usage, we need 1600 GWh of storage. A Tesla Powerwall stores 14 kWh. So we would need 114 million of them. This is a tall order. Huge numbers divided by lesser huge numbers = manageable numbers, IMHO. Fortunately for me, I have a mole(my sister) who lives in a region(San Diego metro area) that recently(last year) provided me with her utility bill history. Her average "electrical" consumption (16 kwh/day) is quite close to your 19 kwh/day, so I'm going to call her a good source of empirical data. And as far as I can tell, more than half (22,000,000) of Californians live the the Los Angeles and San Diego statistical areas. Now, I may not be a genius, but if it's hot enough that you have run your a/c, then the sun is probably shining. Hence, no need for "electrical" storage. And given that "solar thermal" is 10 times as efficient as "solar pv", I'm going to guess that heating is 10 times less a problem, area and cost wise. At$80,000 per piece that would cost $600B, or$15,000 per capita
This kind of brings my sister's next door neighbor into the equation.
He paid umpteen thousands[aka bazilions!] of dollars to install a 5 kw solar pv array, 20 years ago. Why should he have to subsidize those who couldn't afford it?

ps. My sister installed insulation in her attic this year. I'll ask her next year, in March, what happened to her utility bills.
Yay science!

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mfb
Mentor
And given that "solar thermal" is 10 times as efficient as "solar pv", I'm going to guess that heating is 10 times less a problem, area and cost wise.
What does "10 times as efficient" mean? The sunlight->useful energy conversion can't be 10 times better, solar PV has more than 10%.
He paid umpteen thousands[aka bazilions!] of dollars to install a 5 kw solar pv array, 20 years ago. Why should he have to subsidize those who couldn't afford it?
It is probably the opposite: Your neighbor got thousands of dollars as subsidy.

CWatters
Homework Helper
Gold Member
I'm not a utility, but when I don't need energy from my solar panels, I just unplug them. I do understand that there are "contractual" problems, with the "utilities".
People get unhappy paying the utilities not to generate. If you don't pay them why should they build the plant?

It's not a problem if they only have to curtail generation infrequently but the problem with solar and wind is the variability. You have to install lot more peak capacity than you need on average.

Storage is the key.
I too used to think that, but by now... Well, I think the actual key is the equipment price falling so low that PV could be curtailed (remotely) without suffering noticeably loss (and gaining by the ability to curtail).

All that storage business - the numbers are just horrible.

phyzguy
I too used to think that, but by now... Well, I think the actual key is the equipment price falling so low that PV could be curtailed (remotely) without suffering noticeably loss (and gaining by the ability to curtail).

All that storage business - the numbers are just horrible.
If you rely on PV without storage, where will your power come from at night?

If you rely on PV
I don't want to rely on PV: I just want the mid-day consumption peak being mostly transferred to PV.
That's big enough goal for my lifetime

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phyzguy
I'm not a utility, but when I don't need energy from my solar panels, I just unplug them. I do understand that there are "contractual" problems, with the "utilities".
I have solar panels on my house also. Averaged over the year, I generate more electrical energy than I use. But I don't have any energy storage, so I get power from the utility at night and in the winter. How do you deal with this? Do you have energy storage in your home, and if so, what kind?

phyzguy
I don't want to rely on PV: I just want the mid-day consumption peak being mostly transferred to PV.
That's big enough goal for my lifetime
That's a good goal, but I don't think it transitions us off fossil fuels fast enough to meet climate change goals.

What about the economics of non-electrical power storage like deep underground caverns pumped with air and converted with turbines or some such? Of course that would not be a solution for home owners but utilities could do it. The question is the cost compared to Tesla batteries?

OmCheeto
Gold Member
What does "10 times as efficient" mean? The sunlight->useful energy conversion can't be 10 times better, solar PV has more than 10%.
I rounded.
It is probably the opposite: Your neighbor got thousands of dollars as subsidy.
My sister's neighbor. Solar pv would not work at my house.
And anyways, solar pv is so cheap now, I don't see any reason to continue the subsidies.

People get unhappy paying the utilities not to generate.
This is a media problem, IMHO. From my recollection, the amount of time wind utilities are required to shut down, is trivial. Haven't really looked into solar, as fall/winter/spring solar potential is kind of nil where I live.
If you don't pay them why should they build the plant?
Why I said; "I understand the 'contractual' obligations."
It's not a problem if they only have to curtail generation infrequently but the problem with solar and wind is the variability. You have to install lot more peak capacity than you need on average.
I agree.

I have solar panels on my house also. Averaged over the year, I generate more electrical energy than I use. But I don't have any energy storage, so I get power from the utility at night and in the winter. How do you deal with this?
As I alluded to above, I don't. My panels are just a hobby.
Do you have energy storage in your home, and if so, what kind?
If I did have access to southern California levels of sunshine, I'm sure I'd figure it out. But since I don't, I haven't.
We have stretches of MONTHS without sunshine.
Hence, why that solar thermal installation in Canada, so intrigues me.
My "off base" requirements mostly involve the "heating" portion problem of "HVAC".

Refrigeration will require a new refrigerator. Mine is actually quite old, and the nameplate data on new ones indicates and I could cut my base load down to 2 kwh/day with a very small investment.

ps. Got rid of my "tropical" fish.
pps. Hey! That reminds me. I never solved how much energy my back porch light was costing me:
3958 hours ≈ 165 days
5.62 kwh
yields 0.034 kwh/day. (2.8 watts continuous)​
Quite a bit higher than my estimated 0.0083 kwh/day. (0.7 watts continuous)
But still, quite reasonable.
I love my Kill-A-Watt [hour] meter.

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mfb
Mentor
And anyways, solar pv is so cheap now, I don't see any reason to continue the subsidies.
As an example, Germany subsidizes new installations with 12 cent/kWh. That is about three times the typical market price of electricity. In addition you are guaranteed that you can sell it - even if there is more production than demand on a sunny summer day. The government will still happily give you 12 cent/kWh for pushing electricity into a grid where the prices get negative, i.e. switching off your solar panels would actually be better for the grid. In addition you get some tax benefits and potentially local incentives for PV installations.
Sound great, right? Everyone must install PV like crazy! Well, turns out new installations have been dropping a lot over the recent years. New installations peaked in 2012 (when the subsidies were much higher than today), we are now below 20% of this peak.

The US has areas with much more sunshine and often area itself is more easily available, but the modules and their installation still cost a lot of money. In exchange you get something that is available most days, but not all of them. You still need conventional generation as backup. If this conventional generation is based on fossil fuels then solar power saves CO2 emissions - that is great - but it doesn't save the money needed to install and run these power plants. Just dividing the cost of solar power by its power output is misleading, it hides the costs of keeping a backup in case the Sun doesn't shine. The owner of the installation might make money, but overall it makes electricity more expensive because the operators of the power plants will charge more in a scenario with a lot of solar power.

russ_watters, OmCheeto and NTL2009
tech99
Gold Member
There seems to be a growing public view in Europe that we are heading for an extinction if fossil burning continues. This thread does not give much confidence! The 40 year time scales alone seem to be cause for great concern as the window is closing.