Almost Plausible Solar Takeover Plan

[anorlunda]

This article:
Overbuilding solar at up to 4 times peak load yields a least cost all renewables grid.

I'm normally among those who think that renewable advocates lack realism when they advocate 100% wind+solar grid. This article is the first I've seen that comes close to being plausible. I do doubt the article's numbers for storage and for wind, but the basic idea of massively overbuilding solar is in the right direction.

The basic idea is this. Actual solar generation depends strongly on the season and the weather. But even on the worst case day (winter solstice, thick clouds, and heavy snowfall), solar panels produce a fraction of their rated power. If there is enough overcapacity, then even that fraction will be big enough to supply the demand on that day plus recharge the batteries for that night. No heroics, special tricks or cleverness are necessary. Simplicity and reliability are the keys to successful power.

The article says 400% overcapacity is enough. I say 800% for the sake of argument and to allow for contingencies like hurricanes and ice storms. That is roughly 8 Terrawatts for the USA. At $1/watt installed, that's $8 Terradollars investment we need for the generation part (plus ? for storage). That's nearly 40% of the pre-COVID USA GDP. Big numbers, but conceivable when spread over a number of years.

Side issues:
Terrestrial wind in some regions is subject to 2-4 consecutive weeks with winds <15 knots, so wind production would be nearly zero. That makes terrestrial wind overcapacity less attractive than solar overcapacity. Offshore wind is more dependable, and thus more attractive, but it is only close to the coastline by definition. This whole idea is much easier to visualize with solar.

Solar capacity could be distributed across the continent close to the load centers. Therefore, massive new investments in power transmission or distribution would not necessarily be needed with this change.

What to do with the massive solar overcapacity in summer? The article says "curtailment" meaning shut down portions so we don't generate energy that we can't use. But the excess capacity could be used to produce hydrogen or fresh water production by desalinization. Hydrogen and desalinization are not economical in most circumstances, but if the alternative is curtailment of excess capacity, we might reconsider their economy.

Others have proposed use rather than curtailment before, but they weren't thinking on the scale of 700% of peak demand. The economies of scale would be very significant.

The required overcapacity would be less in southern states than northern states. Fresh water is more scarce in southern states.

We already have the technology (called synthetic inertia) to make solar panels behave transiently like old fashioned steam turbine generators. That allows a non-disruptive transition with respect to grid operations and control. No matter what the ratio of solar to conventional generation, the dynamics of the grid would remain nearly constant.

Of course it would take lots of engineering to study the actual feasibility of this plan. Perhaps 50 engineering-man-years to do the study. If I was not retired, I would bid for the study contract myself I know exactly the team to do it. It is a study that I believe should be funded.

p.s. It's fun to have something other than COVID-19 to think about.

 

[Svein]

You argue from the viewpoint of someone who assume that the sun is shining "most of the time". Some of us live in countries where that is not true. Try to calculate the solar energy hitting Alaska in the winter months - and then remember that parts of the Nordic countries and parts Russia lies north of Alaska.

 

[256bits]

At 1000W per meter squared solar irradiation, for 1 TW that is about a square 30 x 30 km each side if the collection was all in one concentrated localized area.
Of course, solar panels do not collect 1000W per square meter, so the land area required increases substantially. There might be some "not in my backyard" issues to overcome, just because. ( elimination of the sun shining on my spot of land ).
But the amount of land used presently for particular endeavors such as transportation road network, golf courses, mining, just to name a few, usually isn't an issue most people contemplate. But I still suspect location of the solar farms, or panel placements ( such as rooftop or roadway right of ways ) might spark some discussion.

 

[anorlunda]

You argue from the viewpoint of someone who assume that the sun is shining "most of the time". Some of us live in countries where that is not true. Try to calculate the solar energy hitting Alaska in the winter months - and then remember that parts of the Nordic countries and parts Russia lies north of Alaska.

That's true. I was thinking about the lower 48 states in the USA. Obviously, it won't work near or above the arctic circle. I mentioned that in #1.

The required overcapacity would be less in southern states than northern states.

 

[Windadct]

The upfront and operating costs for renewables continues to fall and despite the 20+ years of naysayers claiming it will destroy the economy and is a fools errand.

However - whenever I see an "argument" regarding the economic feasibility of renewables that does not account for environment cost of the status-quo, then I simply have to assume the motivation of discussion is purposely ignoring the driving issue.

You can agree or disagree with my opinion (based on educated experts) that we are in an environmental crisis that is due to human activity. To address this we need to make many changes in order to reduce the amount of carbon converted to CO2, by a staggering amount, and to do this we need to shift our source of energy, but also use (consume) less.

No scientist, study, or solution is perfect - and constantly knocking them for being imperfect (sniping), meanwhile the alternative being "let's do nothing until we have a perfect solution" is what? Irresponsable.

I feel like we are driving on the highway towards an accident, and refusing to slow down because : "There is no accident", "I don't feel the accident.", "That accident will slow me down - I can't stop now" "There is no way around that accident, so why slowdown."

If you went to see 100 doctors and, 97 of them say you have cancer - guess what, you get the {expletive] chemo / surgery / radiation...or what ever it takes to fight it.

Sorry for the rant - but we NEED solar today because it is an effective part of trying to fix a serious problem that will not just go away "like a miracle" tomorrow. Yes there are many challenges and nothing can do is perfect, all we can do is work on the problems and keep fighting. If you do not believe we have a crysis and that we need to change, then please, just say that, so we can see where you are coming from.

 

[anorlunda]

Sorry for the rant -

What in this thread are you ranting about? It is pro solar.

Or do you mean today literally, only 13 hours left?

 

[russ_watters]

I haven't read it yet, but I will say from an aesthetic point of view I like the take. Too many solar advocates ignore/gloss-over the capacity factor issue, so it's refreshing to see one plow throw it head-on. The conclusion is a surprising one, but at least I know they've gone to the effort to attack that difficult problem and find a potential solution.

My concern that I'll need addressed when I get a chance to read is is how they'll deal with the marginal cost vs output of the installations. It's one thing to say that the average cost gets paid back in production in X years, but if the marginal payback of the last few solar plants is 50x, it won't make sense to do it. As an academic exercise it might be an interesting scenario, but I expect it would still be cheaper to run the baseload on something else.

 

[mfb]

$8T over 20 years (by that time you probably start replacing cells) is $400B per year. Divided by 4 trillion kWh we get $10 cent/kWh. That's quite expensive for the raw production, it doesn't include additional storage cost that comes with this option, it doesn't include maintenance, and it needs $1/W solar, a factor 3 improvement over today, at a time where installation costs (=people working on site) are already significant. 4-10 days of storage is going to cost a lot, even with hydrogen (the low conversion efficiency is probably acceptable with the big overproduction).
Where do you get 1 TW from? Average demand is about half of that.

 

[anorlunda]

As an academic exercise it might be an interesting scenario, but I expect it would still be cheaper to run the baseload on something else.

We use marginal costs to allocate between competing sources of power. If there is only one kind of source, there is no competition. More important, I think the reliability engineers would argue the case for solar on simplicity and reliability rather than strictly cost. Here are some of the non-cost factors:

• There are few things in this world more complex than a steam power plant or as simple as a solar panel. Simplicity and reliability go hand in hand.
• The solar panels would be more thoroughly distributed and geographically closer to the loads than central power pants are. That reduces the MW*miles of power transmission. That has a powerful benefit to reliability.
• Solar panels require little or no smarts or Internet connections, thus offering immunity to cyber attacks. Considering cybersecurity, it would be wise to resist the temptation to add any kind of digital monitoring or control.
• Panels could self-dispatch using only the local information of grid frequency. That's the way we controlled distributed power grids since the 1880s, long before remote communication and central controls. See this Insight. No remote communications needed. No economics or costs considered, only frequency.
• A solar farm should exhibit incremental degradation rather than total failure when components start failing.
• On the minus side, the magnitude of panel snow/ice/dust removal efforts is hard to imagine. If done by robotics or automation, we would sacrifice some of the simplicity.

 

[anorlunda]

Where do you get 1 TW from? Average demand is about half of that.

Generating capacity is determined by peak demand, not average. EIA.gov says that the installed generating capacity of the USA is 1050 GW. (I don't know if that include Alaska and Hawaii), but they're small anyhow.

and it needs $1/W solar, a factor 3 improvement over today,

The numbers change rapidly. See this news from last week. $1B for 690 MW including storage. That's $1.44/watt including storage.
https://www.smithsonianmag.com/smart-news/solar-energy-project-nevada-will-be-biggest-us-180974862/

 

[trurle]

My concern that I'll need addressed when I get a chance to read is is how they'll deal with the marginal cost vs output of the installations. It's one thing to say that the average cost gets paid back in production in X years, but if the marginal payback of the last few solar plants is 50x, it won't make sense to do it. As an academic exercise it might be an interesting scenario, but I expect it would still be cheaper to run the baseload on something else.

Current state of solar generation is "cheap, but not cheap enough". Business (at least in Japan) is ready to operate solar plants for 0.165$/kWh, while baseline costs for fossils is 0.1$/kWh. Any solar over-capacity requirement will be devastating for solar power generation with the current economics. In brief, we simply still have too much cheap oil.
https://www.power-technology.com/comment/japan-solar-pv-subsidies/

Sorry for the rant - but we NEED solar today because it is an effective part of trying to fix a serious problem that will not just go away "like a miracle" tomorrow. Yes there are many challenges and nothing can do is perfect, all we can do is work on the problems and keep fighting. If you do not believe we have a crysis and that we need to change, then please, just say that, so we can see where you are coming from.

Then the "accident" will be avoided if perceived future cost of the carbon volatilization will translate into something like "carbon tax". Current risk perception is $6-$60 per ton of carbon, or 0.007-0.07$/kWh for oil burning or 0.018-0.18$/kWh for coal. The upper end of perceived cost range provide just enough incentive to switch from oil to solar. The coal is already in the process of being phased out as mainstream power source though.

 

[mfb]

Generating capacity is determined by peak demand, not average. EIA.gov says that the installed generating capacity of the USA is 1050 GW. (I don't know if that include Alaska and Hawaii), but they're small anyhow.

I assumed the x% safety factor was above the average load, as the plan is to average across a day or multiple days anyway.

The numbers change rapidly. See this news from last week. $1B for 690 MW including storage. That's $1.44/watt including storage.

Wait, are the numbers installed power now? If you take installed power then 400% "overcapacity" is barely covering the average, and will let you freeze in winter. Well, if installed capacity is 400% of the peak demand then it might work somewhat if demand is lower in winter (->US, not Europe).
And the 1440 MWh storage won't last long, that's not even enough to cover the night.

 

[Svein]

Some random thoughts:

• Solar panels are high technology. It needs a highly sophisticated manufacturing process. From where do you get the power to manufacture the panels?
• Solar power - almost all the power we use is solar power when you look behind the curtain. Hydroelectric power is solar power. Fossil fuels are stored solar power. Trees are a result of solar power. Atomic power is - not.
• To get very physical: One of the laws of thermodynamics (https://en.wikipedia.org/wiki/Laws_of_thermodynamics) states that you need a hot source and a cooler "drain" in order to get energy out of a thermodynamic system.
• "Heat death": There are about 7.5E9 human beings on this planet. A human being produces about 600W when sitting still. That is 4.5TW of "heat pollution".

 

[artis]

The argument made here earlier about the low solar capacity due to climate in far north , I think by @Svein doesn't seem valid to me , one of the obvious reasons being that in the North there is very little sun but there are also very few people living there and very low electricity demand.
Scandinavia might be an exception but Russian far north is so scarcely populated that if you ran out of fuel there on a road you might die before finding the nearest home.
I don't know about Alaska but I think Alaska is also mostly empty land.

My summary being that, humans tend to live where the sun also shines , alot.

 

[anorlunda]

I assumed the x% safety factor was above the average load, as the plan is to average across a day or multiple days anyway.

We are more sophisticated than that. We have lots of software to predict the absolute highest peak load. The public demands that there is enough power to meet demand always, not almost always. On top of that, we typically require 20% reserves. That's the safety factor. But for installed capacity, it is 20% of peak, not average. Average doesn't enter the calculations anywhere. Also, for installed capacity, there's an additional factor for the percent that might be out of service for maintenance, repair, or upgrade.

Well, if installed capacity is 400% of the peak demand then it might work somewhat if demand is lower in winter (->US, not Europe).

Yes, the idea is 400% of peak demand. It can also be expressed more simply if we use a different definition of the rating of a solar panel. Instead of rating it by how much power it makes in the best case instantaneously, rate it by the power it makes in the worst case 24 hours. A conservative rating rather than an optimistic rating. Then using that conservative rating, you need to satisfy 100% of the peak demand.

Using the conservative definition, today's panel advertised to have a rating of 1000w, would need to be redefined as rated at perhaps 100w. Of course that has practical problems because of latitude differences, but it makes the idea simpler.

From where do you get the power to manufacture the panels?

From the same sources that you manufacture anything. Why is that important? We are not discussing free energy, or climate change, or the end of energy angst, but rather a way to spend money and resources to satisfy our electric demand.
---
I should emphasize that the operating costs of 100% solar are not zero, despite the fact that they do not consume fuel. Snow/ice/dust removal is one thing. Rodent damage, random failures, and vandalism are all significant. Technological obsolescence will motivate upgrades once in a while. Hurricane/tornado/earthquake/landslide/fire/volcano will destroy some percentage of the panels every year, and force replacements. We even need to think about the wartime vulnerability. Estimating all that stuff is one of the major tasks of the study.

Just to hazard a wild guess, 10% replacement per year is credible. If capital costs are spread over a number of years, then operating costs will overtake capital costs at some point. Accurate forecasts of operating costs are non-trivial. In #1, I guessed 50 man-years to do the engineering study.

 

[Svein]

My summary being that, humans tend to live where the sun also shines , alot.

Well, I prefer some chilly weather to heat-related fatalities (every year media tells us that hundreds of people die in the south of Europe due to "exceptional" high temperatures).

And if people prefer living "where the sun shines a lot", why the large demand for air conditioners and the power need to run them?

 

[anorlunda]

My summary being that, humans tend to live where the sun also shines , alot.

I should have put it in the title, that my thoughts and numbers cites are specific to the lower 48 US states. I prefer not to expand the discussion to global scope.

 

[eq1]

We have a natural experiment in California that’s testing this thesis. In 2017 it was big news that we had to pay neighboring states to take our power because our solar farms generated so much of it. That incident convinced me that the political problem is way harder than the engineering problem.

https://www.latimes.com/projects/la-fi-electricity-solar/

 

[Lord Crc]

A human being produces about 600W when sitting still.

Surely that isn't correct. That would mean sitting still for 12 hours would be 7.2kwh = 6.2 kcal. I'd be skin and bones if that was true.

 

[Lord Crc]

The analysis modeled meeting current uses of electricity, based on projected technology costs for 2030.

But by 2030 electric cars, busses and trucks should be a significant factor. So any semi-realistic plan needs to factor in that.

 

[Lord Crc]

Substantial battery capacity would be needed in regions with the highest percentage of solar generation. In the Southeast, batteries would store up to 36% of annual generation for delivery after the sun goes down.

I'm confused. They say annual generation, but isn't the main issue with batteries their capacity? If they mean production, then 36% of annual production seems substantial in light of the Hornsdale Power Reserve.

 

[anorlunda]

I'm confused. They say annual generation, but isn't the main issue with batteries their capacity? If they mean production, then 36% of annual production seems substantial in light of the Hornsdale Power Reserve.

You have a good eye. I reacted to the same sentence when I read the article. My conclusion is that it is a plain error. They should have said "daily".

 

[bhobba]

We have all sorts of claims and counter claims floating around in Australia. Some people say Australia has an inconsistent policy, personally I would describe it as a 'robust' debate. But anyway one state, Victoria, is going gung ho on renewables, and what results will, IMHO likely, in the medium term, determine its viability:
https://www.theage.com.au/politics/...-victoria-pulls-the-plug-20200217-p541nj.html

Long term I am unsure what will happen as I think eventually Fusion power may happen - but that has been promised for a long time.

Thanks
Bill

 

[essenmein]

So I wonder if they also worked out the land area we'd have to destroy for this environmentally friendly endeavor?

Topaz (https://en.wikipedia.org/wiki/Topaz_Solar_Farm) is 550MW peak. It covers an area of about 19km^2.

If we use that as a reference, 19km^2 for 550MWpk, then to produce 8TW peak results in about 276000km^2.

The entire US has an area of about 10million km^2 (including water).

Are you really suggesting that covering about 2.7% of the entire United States with solar panels is somehow a good idea? For the "environment"?!

Then, a slight issue: TPES.

In the US, quick google didn't give me recent numbers, but even old numbers tell a tale.

TPES, per capita in USA, = 9200W (https://en.wikipedia.org/wiki/List_of_countries_by_energy_consumption_per_capita)
Electricity consumption per capita in the US is 1300W (https://en.wikipedia.org/wiki/List_of_countries_by_electricity_consumption)

Which is to say, covering 2.7% of the entire USA in solar panels only solves 13% of the problem, so to really get "environmentally friendly" we'd only have to cover about 20% of the US in solar panels.

Sounds totally reasonable to me.

So then, in 2013 (again sorry about old numbers, but it gives you a reference), USA consumed 91000PJ TPES (PJ = peta joule), or, given there are about 3.154e7 seconds in a year, 3TW continuously.

That 8 terra dollars could off course completely make the USA carbon free for all of its energy without having to cover 20% of the country in solar panels, but instead, let's all continue on this wind and solar feel good loony train.

 

[essenmein]

Keep in mind, only about 3% of the total land area of the US is "developed"...

 

[anorlunda]

This thread is a good opportunity for me to make a pitch for power system planning, and national energy planning. It is a vital, yet largely unrecognized and unsung profession.

It's sad and dangerous that these planning activities have become politicized to the point where they are either not done, or done in semi-secret obscurity. The last public attempt to do that in the USA was in 2001, and release of the report caused a political storm. There are plenty of people ready to label a plan as "not green enough" or "too expensive" or "includes too little of my favorite or too little for my state", but neither the public nor the media is interested in risk as the number 1 planning criterion.
There are also plenty of people with ideas and opinions on energy policy. (Me for example, in this thread and this post.) Unfortunately, the media, politicians, and especially Presidential candidates, don't understand why a consensus of Reddit users (or PF users) is not better than a plan developed by career professional planners.

Just one small example: The premise in this thread is 100% solar. That would be anathema to planners because of lack of diversity. If we have N kinds of power production (just for simplicity assume equal capacity), we then hypothesize that 1 of the N fails for unspecified reasons. They require the remaining N types, have the installed capacity to increase their output by $\frac{N}{N-1}$ to make up for the loss. We don't put all our eggs in one basket. It is very difficult to make that work with less than 4 baskets.

Diversity of supply was a dirty word in earlier decades because it included coal as one of the N baskets. Among planners, diversity in supply has never diminished in importance.

There's much more to it. The planners must look at the geographical and electrical realities to assure that the power can be delivered to every corner of the country, despite random or weather related failures. In this Insight, I discussed evaluation of up to 1 million what if contingencies per hour of CPU time for just one region. A national 10 year plan would need to evaluate 10⁹ or more hypothetical failure cases to assure deliverability of the power despite adversities.

It is easy to shoot arrows in the backs of the planners. They necessarily must use extrapolations of demographics, prices, economics, and supply trends, and future technology. Their demographic assumptions include estimates of future poverty versus affluence. They also need to assume carbon tax or no tax. Their calculations determine not only the optimal distribution of funds, but the fraction of GDP devoted to energy; a decision comparable in magnitude to health care . They usually rerun all calculations with combinations of high/low/mid estimates of the most important unknown parameters. 10 or 20 year plans are also typically updated annually.

After 2001, some of the US planners even feared death threats. It is no wonder that plans are no longer public. Also, the raw data supporting the plan's model is now classified because of fears that terrorists might exploit it. NGOs are no longer able to independently verify the plans.

Why plan 10-20 years into future? Because large scale power projects take so long to plan, design, get approval, and construct. Think transmission as well as generation. Small scale projects like wind farms or solar farms are easier and more rapid.

But it is vital that this planning is done and done right, whether in public or private. South Australia is a good recent example, of a massive failure in planning. They almost brought down on their heads a financial catastrophe of a severity comparable to a COVID-19 lockdown. Only a last minute injection of money, a heroic rescue from Elon Musk, and luck saved them (at least temporarily). As @bhobba points out, the topic is now highly political in Austrailia.

 

[anorlunda]

this environmentally friendly endeavor?

The OP never mentions the words "environment", or "climate". Let's keep it that way.

 

[essenmein]

The OP never mentions the words "environment", or "climate". Let's keep it that way.

What other reason is there then for pursuing solar and wind if the ultimate goal is not related to the e word, or c word? (ahem a different c word...)

FYI, I'm no c change denier, or anti e, I'd actually rather we keep both in good shape.

If this is just an academic exercise to see if solar or wind can replace the current energy supply then the answer is easy, off course it can with enough of it.

But IMO its foolish to lose sight of the whole reason we are pushing this, because then small issues like land use and resource consumption can't really be ignored.

 

[anorlunda]

What other reason is there then for pursuing solar and wind

For the same reasons we explore any form of power generation. Because they may prove useful and valuable.

Please stay on topic.

 

[essenmein]

For the same reasons we explore any form of power generation. Because they may prove useful and valuable.

Please stay on topic.

Odd that the last thing is only there when I hit reply, is that a hint?

"Almost Plausible Solar Takeover Plan" is the name of the thread, and if "almost plausible" includes covering around 3% of the worlds third largest country in solar panels, then all good.

The last thing I'll add before graciously bowing out is we've had solar PV for 50+ years, it shouldn't take that long to figure out if its useful. The fact that we are here in 2020 still trying to convince ourselves it *could* work should tell you something.

 

[Lord Crc]

Here in Norway grid-scale direct solar PV is a non-starter, due to climate and terrain. We rely heavily on indirect solar power though, in the form of hydro.

In an effort to reduce spending on infrastructure upgrades, residential installations will soon have to pay a "power fee", which depends on the maximum instantaneous power draw. The industry has been charged this since way back but now regular citizens will have to pay this as well.

In addition they will introduce hourly prices for electricity.

The wanted effect is to move more load to night time, reducing the peak demand on the grid.

Something like that would be contrary to a 100% solar grid though it seems to me, then you'd want the load concentrated when the sun's out. So seems it might also require more infrastructure investments to handle higher sustained near-peak loads?

 

[bhobba]

What other reason is there then for pursuing solar and wind if the ultimate goal is not related to the e word, or c word? (ahem a different c word...)

Out here in Aus, because we have a lot of sun, it is relatively easy to reduce your power bill to zero via solar panels and solar heated hot water systems. They are very popular and becoming even more popular as batteries become cheaper, and the panels themselves become cheaper. The issue we are finding is not that in a number of niches solar power makes perfect sense, its that when excess power is fed back into the grid may be causing fluctuation problems that need fixing:
https://www.abc.net.au/news/2018-10...-warn-excess-solar-could-damage-grid/10365622

Regardless of other issues such as peoples attitude toward CC, I think, due to advancing technology, we will have a greater mix of power sources. Exactly what that mix will be will depend on many factors, some of which will be political, and the public's view of sources such as coal, nuclear etc.

Thanks
Bill

 

[Lord Crc]

I mentioned it already, but I reiterate that I find it disappointing that such studies does not take electric vehicles into account.

They will add a lot of additional demand on the grid. However they potentially could also provide a lot of flexibility by acting as grid batteries.

In a 100% solar grid you'd want the electric car charging at work, but it could then provide power for the home during evening and night.

For us with a majority of hydro you'd want the car charging at night, but it could then also provide power for cooking, reducing that peak load.

There are probably a lot of other interesting and important interplay effects I've not considered.

 

[anorlunda]

I mentioned it already, but I reiterate that I find it disappointing that such studies does not take electric vehicles into account.

No no. It's not true that they don't take EVs into account. In fact the switch to EV means that the electric sector demand will increase very substantially. But when discussing how to meet the total demand, it is unnecessary to mention each of the uses that contribute to the demand. From an earlier thread:

The power grid may have problems expanding fast enough to meet the demand for electric vehicles. The figure below is from

https://www.eia.gov/energyexplained/?page=us_energy_home
As you can see, to totally shift the transportation sector onto the electric sector means nearly doubling the electric capacity. But some transport such as ships and planes do not switch to EV, so let's say in round numbers 50% more electric power.

That is more than just power plant capacity, but also the transmission lines, distribution, and perhaps even upgrading the electric service entrance to every house and building. That can be done, but not overnight and not at zero cost.

View attachment 246642

 

[mfb]

Topaz (https://en.wikipedia.org/wiki/Topaz_Solar_Farm) is 550MW peak. It covers an area of about 19km^2.

It is built in a desert where area doesn't matter. It would be possible to make it more compact, but why bother? At ~20% efficiency you need ~5 km² per GW, let's be conservative and double that for tracking panels, that's still a factor 4 more compact than the total Topaz site area.

Keep in mind, only about 3% of the total land area of the US is "developed"...

I don't know where that number comes from, but that suggests plenty of undeveloped area to use. The US has large deserts, so everything close to a desert won't have any issue with area.