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Inconvenient Truths of Large Scale Solar and Wind Energy

image credit: Figures courtesy of https://www.biography.com/ and https://www.forbes.com/
Alan Rozich's picture
Alan Rozich
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Providing quantitative sustainability insights using sound technical analyses with a management consulting approach to craft strategies that address the mega-trends that are occurring in the...

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Al Gore famously coined the term, "​inconvenient truth,"​ to bring attention to man-made or anthropogenic carbon dioxide emissions and other related issues regarding societal functionality, the environment, and sustainability. Meanwhile, solar and wind energy are being touted with almost unbridled, messianic fervor by the main stream media as a sustainability panacea. Clearly, these technologies will play a significant role in a renewable economy. However, in the interest of hastening the ubiquitous and unquestioned deployment of these systems, their own sustainability baggage is often overlooked. These ignored "inconvenient truths"​ are subordinated in the interest of unquestioned deployment of solar and wind systems. Alarmingly, both of these platforms have major challenges that relate to sustainable land use which will only continue to worsen with the installation of larger, centralized systems.

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The Solar and Wind Juggernaut

Solar and wind power are projected to be the dominant energy sources as touted by mainstream media outlets such as Forbes who cite declining costs for both technologies as a major factor.

Forbes'​ "declining cost revelation"​ for solar and wind is somewhat pretentious considering that almost any manufactured system experiences hefty cost reductions with increased scale of production.

Others, such as climate zealots,  dutifully reaffirm these predictions and grant carte blanche approval for solar and wind in the absence of any critical thinking or value engineering analyses. Neither Forbes nor the zealots bother to understand, acknowledge, articulate, or analyze all the cogent factors impacting economics and overall sustainability.

It seems that vested stakeholders are recklessly pressing for larger and more massive installations in order to continue to drive down economics without analyzing for the potential of unforeseen and damaging consequences.

There is an alternative discourse that definitively shows that large scale solar and wind power are inherently less sustainable and, perhaps, even unsustainable, as system sizes increase. For example, there is tangible evidence that large scale solar farms are capable of causing unwanted and disruptive climate change. This prediction is not surprising because of egregious land requirements. The reality is that solar and wind require anywhere from 10 times to 1,000 times the land area that other fossil fuel or renewable energy technologies require.

Solar and wind energy systems must be players in a renewable economy. But they must be responsible players that are held accountable to the same stringent criteria as other energy sources. That is, they do not warrant a "free pass"​ simply because they are considered "renewable energy."​

Judicious Land Use Is A Vital Component of Sustainability

The United Nations defines sustainable land use as “the use of land resources, including soils, water, animals and plants, for the production of goods to meet changing human needs, while simultaneously ensuring the long-term productive potential of these resources and the maintenance of their environmental functions.”

Consequently, technologies or other human endeavors that displace thousands of acres of ecosystems egregiously compromise the Planet's ability to assimilate carbon dioxide. In the case of solar and wind, the amount of acreage displace can be orders of magnitude higher than other technologies as shown in the graph below.

Figure references: 1 Powerlink article; 2 Strata 2017; 3,4 AD, 45% & 90% conversion, repsectively; 5 NEI Report 2015

 

The data in the graph above are clear in that solar and wind systems rank at the bottom regarding sustainable land use. Consequently, there is a significant trade-off for using these technologies for large scale, centralized energy production. This information alone suggests that other alternatives merit serious consideration.

Comparison of Solar and RNG/LNG Systems Land Requirements

It is interesting to compare solar with an energy system such as RNG/LNG which has more favorable land use metrics. The graph shows the relative land requirements for solar and RNG/LNG systems for three different energy production scenarios: 10, 25, and 50 MW-Day.

  This graph and other information makes interesting points:

  • Because of the over 30 fold disparity in land area requirements of the two energy systems (Solar average = 21 and RNG/LNG = 685 from the first figure), the graph shows that for a 10 MW-Day of energy, a solar system will require a little over 100 acres more than an RNG/LNG system.
  • With high bioconversion ADs, the disparity in land area requirements of the two energy systems (Solar average = 21 and RNG/LNG = 1,300 from the first figure) climbs to 62 fold. For this case, it means that for a 10 MW-Day of energy, a solar system will require almost 200 acres more than an RNG/LNG system.

 

Summary

The need to decarbonize the global economy is considerable. Initiatives that reduce GHG emissions, particularly with respect to carbon dioxide production caused by fossil fuel energy sources, are important. However, implementing large scale solar and wind systems that have significant environmental and economic repercussions mandates the use of proven structured project development and implementation protocols that employ FEED methodologies. The FEED effort must also consider other technological alternatives. Other technological alternatives warrant consideration if only to ensure that the chosen solution is thoroughly scrubbed and not simply prejudicially pre-selected.

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Alan Rozich's picture
Alan Rozich on Jul 7, 2021

It is agreed that there is plenty of land. The question concerns whether there are other alternatives that ameliorate land sustainability challenges.

Some other commenters seem a bit over-sensitive. The point is not to dismiss solar and wind, but to refine criteria how these systems are configured into overall sustainability systems.

Michael Keller's picture
Michael Keller on Jul 7, 2021

Well, yes, I suppose we could cover the entire land area of the US with solar panels and all our energy needs would be met. Seem a bit harsh for the environment, however. Food production would also be a problem. Not sure where we would put the population.

My point is simplistic calculations decoupled from practical reality are useless. There is no one-size-fits-all solution. Advocates of zero carbon emissions are a classic example of the simplistic out of touch with reality.

Peter Farley's picture
Peter Farley on Jul 13, 2021

How many times do you have to told

1. If 25% of US electricity needs were sourced from fenced solar farms (a riduclously high share) they would need 2,100 square miles 0.1% of us agricultural land. At any one time 82,000 square miles of US agricultural land is held back from production

2. Around the world experiments have shown that horticulture orchards and small animal grazing productivity improves in colocated agri-solar installations.

3. The average 1 GW coal plant including mining uses 20GL of water per year, nuclear even more. That water freed up for irrigation would actually increase agricutural output

 In sum there is no threat to food production

Michael Keller's picture
Michael Keller on Jul 14, 2021

Depends on if the power plant uses evaporative cooling towers or once thru cooling from a river, lake or ocean. The later do not use much water because it is returned to the source.

Your calculations are suspect. To match a 1000 mW plant at 90% capacity, need about 55 square miles of desert for a typical solar power plant. The US uses about 3820 billion kWh of energy in a typical year. Need more like 25,000 square miles of desert. Gets worse in other parts of US with much lower incoming solar radiation. The area of California is nearly 165,000 square miles. Arizona is nearly 115,000 square miles. Utah is about 82,000 square miles. However, these states have a lot of mountains. Best guess is that the needed 25,000 square miles would take up a large part of the flat lands of the three states.

Peter Farley's picture
Peter Farley on Jul 15, 2021

1. Once through cooling is extremely destructive to aquatic life because it raises water temperatures by about 7-8 C, and nuclear plants draw up to 100 tonnes/second per GW so that is a lot of hot water to be rejecting into a river. That is why it is pretty much banned in California and those bans will spread.

2. Based on the area of Solar Star in California 5 square miles, to match the annual output of a 1 GW nuclear plant you would need about 25 square miles of solar not 55 square miles. The US has 1.8 million square miles of agricultural and scublands of which at least 80% is suitable for solar, so finding 2,500 square miles of that that can be optimised for solar use is not likely to be an issue

3. The power plant is a minor component of the area used by the nuclear industry. Fenced area of power plants in the US is less than 100 square miles but Hanford nuclear reservation is 586 square miles and mines mostly in other countries occupy at least another 100 square miles. 

So roughly 100 GW of nuclear needs 650 - 800 square miles not including water storages. 300 GW of solar would need 2,500 square miles.

So while it is superficially true that solar needs more land than nuclear, probably only 30-40% of solar will be located in solar farms, most will be on roofs, wastelands and floating

The NREL calculated in 2016 that the US could get 30% of its electricity from 14% of US roofs with 16% efficient solar panels. i.e. with an average 23% efficient solar panels which will be avilable in the next few years it could get 42%+ from roofs i.e. no net land area.

Peter Farley's picture
Peter Farley on Jul 7, 2021

This is complete rubbish. It is a rehash of an earlier completely misleading post. It neglects the land area of mines, railroads, coal and gas processing plants, pipeline ROW, ash pits, cooling and waste water storages, well pads etc etc. for coal gas and nuclear

1. About half of US electricity demand can be provided from either roof mounted or on adjacent structures such as carparks, hardstands and railway platforms. i.e zero effective land use. A further small share will be in unusable spaces such as road intersections, road and railway embankments and cuttings, worked out gravel pits, landfills etc. and floating solar, which will not only reduce evaporation but improve utilisation of existing transmission infrastructure on hydro dams,

2. Almost all the rest will be either agrivoltaic or at least pollinator friendly. It has been shown around the world that horticulture and pasture can not only co-exist with solar farms but the shading/and or wind break effects often improve agricultural productivity as well. Some farmers in Australia even report cleaner wool from sheep because of reduced dust. In Oregon pastures didn't dry out so fast in summer extending the grazing season in arid parts of India, horticulture production increased 200%

3. In any case if 25% of US electricity needs came from cleared lands under solar farms, they would need about 2,100 square miles. Cow grazing in the US takes up more than 1 million square miles. Bioethonol/biodiesel crops use 60,000 square miles. The US has more than 3,000 square miles devoted to golf courses and 4,700 square miles used by airports so it is clear land use by solar farms is trivial

4. Wind turbines use inconsequential amounts of land less than 300 square m per turbine, the rest of the windfarm continues as grazing land, forest or broad acre farming. The US will need about 150,000 land based turbines spread out over mostly low value grazing land (high wind areas are not usually the best places for growing grass). That means they will use 45 square km (18 square miles) to supply about 1,800 TWh/y of US energy demand. The Black Thunder/Jacobs Creek coal mine which supplies 8% of US coal i.e 2-3% of US electricity is 108 square km (42 square miles) for the production of 80-130 TWh per year. The Handford nuclear reservation is 586 square miles and the area used by the current nuclear power plants in the US is about 70 square miles to provide 20% of US electricity, not including uranium mines, water storages for cooling water supply. Again wind farms use far less land per MWh produced than either coal or nuclear.

5. Even gas is not as efficient. A 750 MW CC gas turbine on current US capacity factors will produce about 3,600 GWh per year. The plant itself will only use about 200 acres but over its lifetime it will need more than 100 gas well to supply it as well as gas processing stations, pumping stations, pipelines etc. for a total of 350-500 acres. 250 modern wind turbines would supply the same amount of energy using 18 acres. Even if you added a 750 MW/ 5,000 MWh battery installation that only adds another 10 acres

6. By way of comparison the US is 20 times as large as Germany. Germany already has 56 GW of solar and 63 GW of wind. If Germany replaced its wind and solar capacity 1 for 1 with modern solar panels and wind turbines it would have approximately 110 GW of solar and 180 GW of wind. Thus at the same density of wind and solar that Germany has today the US could install 2,200 GW of solar and 3,600 GW of wind. At current US capacity factors that would be approximately 4,200 TWh from solar and 13,000 TWh from wind. i.e a total of 17,000 TWh+. Coal gas and nuclear combined provide approximately 3,000 TWh today.

I don't know how you sleep at night when you claim to be a leader in energy analysis and you publish such complete and utter garbage.

 

 

Alan Rozich's picture
Alan Rozich on Jul 7, 2021

Two comments:

1. My calculations are based on the data listed in cited references which are provided.

2. Regarding your statement, "I don't know how you sleep at night when you claim to be a leader in energy analysis and you publish such complete and utter garbage.", I sleep pretty well.

Peter Farley's picture
Peter Farley on Jul 8, 2021

1. You are leaving out the areas for the mines etc, by far the vast majority of land used for fossil fuels.

2. You must be assuming that the entire area of a wind or solar farm is unusable for other activities. Again patently false

3. According to the NREL study from 2016 30% of US electricity could be supplied from 14% of US rooftops with 16% efficient solar panels. Now that 21% efficient solar panels are available and 25% will be available in the next 5-6 years, that means 40% could be supplied by rooftops. Add in carparks railway platforms hardstands floating solar etc. more than 50% of total electricity demand can be supplied from otherwise occupied land and as I pointed out 25% could be supplied from 2,100 square miles of grazing and farmland. The advantage of wind and solar is that much of it can be located at or near the loads, so that average transmission distances costs and losses can be reduced.

In the entirely likely event that I have made an arithmetic error somewhere please point it out

 

Michael Keller's picture
Michael Keller on Jul 7, 2021

Peter, you are absolutely and completely out-to-lunch. 25% of US energy needs came cleared lands beneath solar farms? That is patently absurd.
Your credibility meter is off-scale low and you simply cannot be believed. Therein lies a major problem for the green-energy movement. Trotting out complete rubbish is unhelpful to your cause and reinforces the view that the movement is infested with religious fanatics.

Joe Deely's picture
Joe Deely on Jul 9, 2021

Michael said:

Peter, you are absolutely and completely out-to-lunch. 25% of US energy needs came cleared lands beneath solar farms? That is patently absurd.

Did you see the IF ?

In any case if 25% of US electricity needs came from cleared lands under solar farms

Reading comprehension - its a wonderful thing.

Gene Nelson's picture
Gene Nelson on Jul 8, 2021

I believe you have never attempted to steer large powered farm equipment near solar panel supports. Furthermore, many crops require 100% Sun, not the partial shade caused by solar collectors.

Peter Farley's picture
Peter Farley on Jul 8, 2021

As I said, if 25% of US electricity demand came from solar farms it would use 2,100 square miles. The US uses 1,600,000 square miles for agricultural purposes, surely you can find 1 acre in 1,000 for solar

look up US Farmers are opting for solar leases and while you are at it look up agri solar and agrivoltaics you will find it quite enlightening

Joe Deely's picture
Joe Deely on Jul 9, 2021

Question for you Gene..Sounds like you are an agricultural expert.

The “many crops that require 100% sun” -do they die when a thunderstorm passes thru?

Gene Nelson's picture
Gene Nelson on Jul 9, 2021

Your comparison between a transient cloud and a stationary solar collector is not a valid comparison with regards to crop growth. Furthermore, solar power generation  demands huge areas because of the low energy density relative to dispatchable energy generation technologies.  Solar is also plagued by low daily capacity factors of on the order of 20% that are a consequence of the fact that the Sun does not always shine. That means solar needs five times the area to compensate for the intermittency. That is called "grid integration."  The task is typically accomplished by burning huge quantities of fossil fuels, which is what solar power is supposed to be reducing. For additional background, please search for the 2016 Washington Post article, "Turns out wind and solar have a secret friend: Natural Gas."  As noted elsewhere in the comments, batteries are a cost=prohibitive means to integrate solar into the grid.

Joe Deely's picture
Joe Deely on Jul 9, 2021

So perhaps you didn't really mean 100% when you said 100%. Fair enough.

A couple of more questions for you - you seem to keep saying that Solar capacity factor is 20% - however when I go to EIA report  - I see solar with a Capacity factor of 24.9%.  Is that wrong? Also, this is for US as a whole - wouldn't that mean that CA solar capacity factor is even more?

 

Also you said - 

That means solar needs five times the area to compensate for the intermittency.

Does that mean if I increase my solar farm from 100 acres to 500 acres I can "compensate for the intermittency"?

Wow that's big news.

Peter Farley's picture
Peter Farley on Jul 11, 2021

It is true that in the current US environment wind and solar require gas for backup. However in Germany, Australia and the UK, gas generation has fallen as wind and solar increase and coal falls. Gas has fallen from 124 TWh in 2016 to 95 TWh last year in the UK, 30 TWh in 2014 in Australia to 22.5 TWh last year and from 67 TWh in Germany in 2008 and 57TWh last year

Many crops actually fare better with partial shade and those that don't still have 99.9+% of US agricultural land available to them. Again solar power does not demand huge areas. In fact as Prof Blakers pointed out above the US could supply all its electrical energy from solar without a single acre of agricultural land being used.

A recent study of the Melbourne CBD, a city with many 20-60 storey buildings could supply 60% of its energy from rooftop solar.

You keep claiming that batteries are prohibitive without any evidence. The cheapest way of integrating wind and solar into the grid is to do what we always did in the past, have too much capacity. In 2010 with minimal wind and solar the US had enough coal gas and nuclear capacity to generate about 5,500 TWh, but they only supplied about 3,600 TWh. If you have enough wind and solar to generate 5,500 TWh and only use 3,000 TWh the rest coming from hydro, geothermal, waste to energy and remaining nuclear you will probably need the equivalent of 50% of demand on the worst day for 5-12 hours of storage. That will be split between thermal storage (the cheapest) pumped hydro, compressed air and batteries, Overall the battery fleet will cost less than 1/3rd of the replacement cost of the current nuclear fleet 

Michael Keller's picture
Michael Keller on Jul 9, 2021

You do realize you cannot farm under a solar farm? 

Joe Deely's picture
Joe Deely on Jul 9, 2021

Well I can't cuz I don't own a farm. But my cousin Jethro does...

Bob Meinetz's picture
Bob Meinetz on Jul 11, 2021

FYI that's not a farm, Joe, those are weeds. Tell Jethro he can stop waiting for his corn to come up, and sell the tractor. The guy who leased his land for solar was lying.

Joe Deely's picture
Joe Deely on Jul 13, 2021

Funny you should mention corn Bob.

My other cousin Ellie Mae has taken corn out in 2,000 acres of her farm in Iowa and replaced it with solar.

She was growing that corn for ethanol production but she saw the writing on the wall with EVs coming and made the switch.

Now she's buying farmland near old coal plants in Iowa.

Ellie always was smarter than Jethro.

Matt Chester's picture
Matt Chester on Jul 12, 2021

Agri-voltaics obviously doesn't work on every plot of land or with every crop, but to say blanket statement it doesn't work is ignoring the great study that's been going on for co-locating in specific successful use cases

 

Here are a few instances out of the much larger body of work into this topic

https://onlinelibrary.wiley.com/doi/full/10.1002/aenm.202001189

https://elk.adalidda.com/2017/07/5582-23376-1-PB.pdf

https://www.mdpi.com/1996-1073/13/18/4815

 

No doubt, where it works that you can get profitable crops and solar generation on the same land, farmers will be eager to learn how that can (and where it won't) work. T

Gene Nelson's picture
Gene Nelson on Jul 8, 2021

Your conflation of coal and nuclear power land use seems more akin to a propaganda technique.  Historically, Uranium mining and extraction yields a tiny footprint per terawatt hour of nuclear power production, in comparison with coal's mountaintop removal and massive coal ash pits. Nuclear power plants store their tiny volume of waste onsite.  The waste will be the fuel for the next generation of nuclear power reactors. Even if unused, spent nuclear fuel decays to the activity of a good grade of uranium ore in 300-500 years. All in all a nonissue.

Alan Rozich's picture
Alan Rozich on Jul 8, 2021

Gene, thanks for your input. Can you direct me to a website or PPT that provides some background on the green nuclear system you mentioned? Thanks.

Peter Farley's picture
Peter Farley on Jul 9, 2021

I agree nuclear uses less land than coal, but the nuclear industry still uses more land than wind.

The next generation nuclear plants that use old fuel for new generation have been 10 years away since 1960. Most of the prototype plants were closed and while China is having yet another try, there is a) no guarantee of success and b) even China's most optimistic forecast has no more than 15% of its energy coming from nuclear, almost all of that from Gen II and Gen III plants

Michael Keller's picture
Michael Keller on Jul 9, 2021

Incorrect. Wind farms remove huge land areas from habitation. 
The problem is the gigantic machines can throw objects (ice, parts of blades) quite a distance and that is why there are limitations on living near the machines. A I recall, is around 3 times the tower height. Throw in thousands of the machines and that works out to be a lot of land area.

As long as the machines are well removed from humans, the problem is relatively small, although the sheer size of the monsters make them monumental eyesores. While large farms (Western Kansas) are ostensibly OK locations, the impact on wildlife, including nearby sanctuaries is tough to figure. Prairie chickens are definitely impacted, but  farming has seriously threatened them in any case. Hawks and eagles as well as bats are victims of wind turbines.

Peter Farley's picture
Peter Farley on Jul 11, 2021

They don't some of the counties in the midwest that host windfarms have seen increases in population because the farmers hosting the wind farms can hire more hands, the counties have more tax revenues to spend on improving schools and services and the wind farms themselves need local maintenance technicians. Germany and Scotland with a population density higher than almost every state in the union manage to host 30,000 and 6,000 wind turbines respectively with no casualties caused by failing wind turbines.

Again even if you allow 500m radius around each wind turbine, wind farms would require less than 50,000 square miles out of the 3,800,000 square miles. 99% of that land will still be used for whatever it is being used for now

Bob Meinetz's picture
Bob Meinetz on Jul 16, 2021

Below, one of the 500,000 raptors killed by wind turbines in the U.S. each year.

If nuclear plants killed 500 eagles, hawks, or falcons each year we'd never hear the end of the wailing from renewables advocates.
To my knowledge, they've never killed one.

Michael Keller's picture
Michael Keller on Jul 9, 2021

Incorrect. Calculate land area based on energy output of 1000 megawatts x 1 year x 90% capacity factor for nuclear x say 200 acres. Wind turbine output of say 3 megawatts x 30% capacity factor x 1 year x exclusion area for missile protection.That works out to be a lot of wind turbines occupying a lot of land to match a nuclear unit. The equivalency calculation is left as a classroom exercise, but I will give you a hint. Your earlier claim is nonsense.

Peter Farley's picture
Peter Farley on Jul 11, 2021

Please show me a nuclear plant that has a fenced area of 200 acres, not to mention its share of Hanford, the water storage required to cool it, the share of the mine etc etc.

The alienated area of 600 GW of rooftop solar in the US which would supply the same energy as the entire nuclear fleet is exactly zero.

The area unusable for grazing under 50,000 wind turbines which will supply the same amount of energy as the entire nuclear fleet is about 5.5 Square miles. The fenced area around Palo Verde and its supporting infrastructure alone is 5.2 square miles. Plant Vogtle 2.3 square miles

Bob Meinetz's picture
Bob Meinetz on Jul 14, 2021

"...the nuclear industry still uses more land than wind."

You're only off by ~3 orders of magnitude. Wouldn't be the first time.

https://www.youtube.com/watch?v=zc7rRPrA7rg

Gene Nelson's picture
Gene Nelson on Jul 8, 2021

Your analysis apparently assumes the Sun always shines. The actual solar capacity factor or percentage on time is about 1/5, as I noted above. The remaining 4/5 of the time, natural gas is used to integrate solar power into the grid, calling into question both the environmental benefit and also the cost of the 100% solar approach you advocate. 

 

What about batteries? Their exorbitant cost, denominated in trillions of dollars, and short operational lifetime of 7 to 10 years means batteries can't be used for meaningful solar grid integration. Then there is the nasty tendency for batteries to catch fire and explode as happened a few years back at a 2 MW APS battery storage facility near Surprise, Arizona, USA. This also happened in South Korea, where most of these batteries are sourced.

Peter Farley's picture
Peter Farley on Jul 9, 2021

Please read what I wrote. There is no suggestion of a 100% solar system. I don't know what the final balance will be but it probably won't reach 50% for solar. Wind, hydro, geothermal, biomass, waste to energy will all play a part and maybe even 5% or so will still come from gas and and 10% from nuclear.

My analysis assumes that the sun shines for an average of 12 hours a day and tracking solar farms average 28-30% annual capacity factors. The majority of energy consumption occurs during the day and much of current nightime energy consumption, water heating, municipal water transfer etc can be transferred to daytime, particularly if the solar generation is onsite and therefore does not require transmission capacity. At night you will have hydro, wind, biomass, waste to energy, possibly some hydrogen as well as nuclear and possibly residual gas a few times a year. just like gas always operated. Perhaps you are unaware that peaking gas plants in the US have long had less than 5% annual utilisation. That will be the same or less with a balanced renewable system.

As it turns out the US will not need trillions of dollars worth of batteries because most of the storage will be existing hydro, thermal storage and smart charging of EVs. The combination of wind and solar across the country is never zero and just as the conventional grid had enough power plants to provide 40-50% more energy than the country ever used, a renewable system which had sufficient capacity to provide 50% more than you need will still supply at least 75% of requirements on any day 

Gene Nelson's picture
Gene Nelson on Jul 9, 2021

The late-afternoon and early evening load peak cannot be served by solar as the Sun is near the horizon or already set.  Furthermore, existing California natural gas generation is throttled back at mid-day. This leads to huge fossil-fired ramps, sometimes 20,000 MW over 10 hours.  That is the output of 10 Hoover Dams.  Your suggested workarounds would make minuscule contributions.  Running California's grid this way is very inefficient. However, natural gas interests support such inefficiency.

 

There is another problem. In order to prevent harmful over-voltage, California solar is being curtailed. Annual curtailment is over a gigawatt-hour.   A more rational grid is not dependent on the position of the Sun or the presence of temperature gradients that yield wind. Rational grid design depends on dispatchable energy sources under human control.

Peter Farley's picture
Peter Farley on Jul 11, 2021

The average capacity factor across combined cycle, combustion turbine and reciprocating gas generators in the US is approximately 33%. In other words allowing for maintenance some 60% of available gas capacity is curtailed. It has always been roughly the same because gas was secondary to coal and nuclear, now it comes second to wind and solar.

Did you complain that that was an inefficient way to run the grid when peaking gas plants in the US were turned off to prevent overvoltage and averaged between 2 and 5% capacity factor. The standing cost of an idled wind or solar plant is less than the standing cost of an idle gas generator so where is the problem

I agree California's early solar policies exacerbated the ramp rates for gas in the afternoon, but that is not a significant problem in other regions.  California does need much more tracking or west facing solar to minimise the ramp, it needs more offshore and near coastal wind to take advantage of afternoon sea breezes and it needs more storage, but all of this will cost less than replacing and operating its gas and nuclear plants.

Rational grid design always has excess capacity, see peaking gas plants and hydro plants that typically only have enough water for 20-40% annual capacity factor

Joe Deely's picture
Joe Deely on Jul 12, 2021

Hey Gene,

You said:

Furthermore, existing California natural gas generation is throttled back at mid-day. This leads to huge fossil-fired ramps, sometimes 20,000 MW over 10 hours. 

Can you help me out here? It seems you are saying that the CAISO grid regularly ramps NG by more than 20,000 MW.

I've looked around I can't find any of these days...

Perhaps you can share some of your inside knowledge about the CAISO grid and share an example day. Thanks in advance for your help on this.

Joe Deely's picture
Joe Deely on Jul 9, 2021

 The actual solar capacity factor or percentage on time is about 1/5, as I noted above. The remaining 4/5 of the time, natural gas is used to integrate solar power into the grid, calling into question both the environmental benefit and also the cost of the 100% solar approach you advocate. 

Gene -  based on what you said above would I be correct in saying:

If we implement a 100% solar approach - NG will we used for 4/5 of the remaining 0%.

Gene Nelson's picture
Gene Nelson on Jul 9, 2021

100 percent solar will not work because the Sun does not always shine. Modern society requires electric power 24/7.  I have raised this pair of points in several different ways in my responses to the article.

Peter Farley's picture
Peter Farley on Jul 11, 2021

1. No-one anywhere ever to my knowledge has suggested 100% solar, so therefore no-one has bothered to rebut your point.

2. We do have wind, hydro, geothermal, waste to energy and for the next 40 years some nuclear and some gas to cover most of night time demand. Then we will have flexible demand, cool stores, water heating, irrigation, municipal water transfer, industrial and consumer demand response as well as new storage to cover the rest

Michael Keller's picture
Michael Keller on Jul 9, 2021

Joe, are you familiar with the term “reducto absurdo”

Joe Deely's picture
Joe Deely on Jul 13, 2021

No Michael, I am not familiar with "reducto absurdo".   Is that from Harry Potter?

I am familiar with  "reductio ad absurdum" -  although I haven't done a lot of Latin work lately.

Joe Deely's picture
Joe Deely on Jul 12, 2021

Gene you said:

What about batteries? Their exorbitant cost, denominated in trillions of dollars, and short operational lifetime of 7 to 10 years means batteries can't be used for meaningful solar grid integration.

Denominated in trillions...Wow... I did not realize that. Learn something new every day.

Based on that - I came up with following costs:

  • 8 pack  batteries (Home Depot) - $1T
  • 100 kWh for car battery - $10T
  • 10MWh - small utility battery - $100T
  • 1,000 MWh - larger utility battery- $1,000T

Does that seem about right? Should I make any adjustments?

Dang - CAISO is already over 3,000 MWh. That would be like $3,000T

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If you have an experience or insight to share or have learned something from a conference or seminar, your peers and colleagues on Energy Central want to hear about it. It's also easy to share a link to an article you've liked or an industry resource that you think would be helpful.

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