More energy on less land: The drive to shrink solar’s footprint
e360.yale.edu
e360.yale.edu
What we should be focusing on is transmission and distribution, those are the really hard problems. We could have all the power we want but if our grids can't handle the rapidly increasing demand it does nothing for us. And as more people go 100% electric for transportation, heating, and cooking the integrity of power distribution becomes even more important because we will have put all our energy eggs in the electricity basket.
The only place land use seems relevant is for smaller scale off-the-grid cases where someone's property is small but they want to generate all their own electricity.
I live in Oregon and slightly over 1/2 of the state is federal or state owned land which cannot be purchased. Even out in the middle of nowhere, there are still massive transmission lines carrying electricity from one part of the state to another through these areas. This is often in fairly mountainous terrain and dense forests. I'm often in awe at how much work they have to go through to keep the area immediately around these lines clear of trees and vegetation. I explore forest roads quite a bit. This is just to point out that we've been doing that type of thing for a long time and I don't think transmission itself is tremendously difficult. We just lack the will.
There are some challenges with transmission, but I think the bigger ones isn't necessarily building the infrastructure -- it's making the transmission lines themselves more efficient and reducing losses. We can't build all our solar in the southwest of the US and then distribute that all over the country; Our current transmission technology would produce too much loss over such distances.
1. In small(ish), densely-populated countries, land is in short supply, regardless of any socio-economic-political considerations.
2. In many countries, land is private, or has been fully "divvied up" in some form or another, despite being only sparsely used. In these countries, reallocating land is a headache - politically, economically and legally.
But I agree that storage, transmission and distribution are important things to focus on. Or rather - the important thing to focus on is to actually deploy lots of solar instead of fossil (which the recent US federal legislation makes even harder than before).
Why?
What do you think, expect or hope this will accomplish?
Because the technology is in good enough shape already to partially replace fossil-fuel-based production - at least in day-time. Some might even claim that it can replace fossil-fuel-based energy production in daytime entirely, and with existing storage tech, perhaps even mostly-replace it in night-time. But the first claim is sufficient and AFAICT pretty much in consensus.
> What do you think, expect or hope this will accomplish?
Significant reduction in greenhouse gas emissions by burning less coal and natural gas.
Secondary potential goals:
* A motivation to switch to synthesized car fuel / fuel cells / electric.
* Improvement in air quality around where coal-fired plants operate now.
Having and living with solar is very different from what people imagine solar to be. Here's a simple example from my 13 kW array:
https://i.imgur.com/SOr30bX.png
or
https://i.imgur.com/yvTdNX0.png
What are those massive dips sometimes causing a reduction of output of more than 50%? Clouds. Simple as that. This is what a "normal" clear-sky day looks like:
https://i.imgur.com/Fl8ARJd.png
Output like that is frequent but not the norm. Clear sunny days in Southern California. If you live somewhere with more weather than we have here, it will be more like the first example.
The consequences of weather are severe. Here's a look at January of this year:
https://i.imgur.com/bGuCH2F.png
And here's a look at all of last year:
https://i.imgur.com/EF2L3Hk.png
This is to say at least two things about the reality, vs. the fantasy, of solar:
First, the technology isn't reliable. Not inherently, of course, the power output reliability is a function of weather. And we can't control that. I can't think of a single place on earth where there aren't any clouds, rain, fog, storms, dust, etc. Note from the images I provided that my 13 kW array never really peaks out at 13 kW. I think the most I've seen is 11 kW. You would need an absolutely perfect day with perfectly clean panels to, maybe, reach a higher peak for a few seconds.
Also note where the annual production peak is located, May. Most people think solar peaks in the summer. Not so. Panels have a negative temperature dependency. Which means they make less power when they get hot. May, here, happens to be the balance point between incoming light and lower temperatures.
Having built and operated this system for a number of years, here's the biggest problem with solar as I see it (and this isn't something trivial):
A solar system built to deliver steady-state power 24/7 must be about
10 times the size of the required steady-state output.
I've done the math on this multiple times, it's undeniable. Some of it is very simple and some of it requires basic high-school calculus. Here's a couple of examples:
The area under the roughly parabolic shape of normal (ideal day) production is 2/3 of that of the rectangle that would represent steady-state power at the peak level for those 12 hours. In other words, you start to produce at, say, 10 kW at 8 AM and stay at that level until 8 PM.
That simple reality means that, in order to produce the same energy of a steady 12 kW power source you need to multiply your system size by 1.5. In other words, if you need 10 kW x 12 hours of energy, you need to build a 15 kW system.
The next easy to understand reality is that you need to double that system (at a minimum) in order to have that much energy available at night. Now we go from a 10 kW system to a 30 kW system plus the corresponding amount of storage.
Another easy one is inverter (and related components) average efficiency. I'll place that at 90%. That means you lose 10% just to make power you can use. It also means that we now need to add solar panels in order to achieve the required output. That means that we went from a 10 kW system to a 33 kW system. A multiplier of 3.3.
This super-simple analysis quickly got us to over 3x requirement for the system size. The way we get to 10x (or more in some cases) is to start including weather-related effects as well as time-of-year realities. Add to that efficiency calculations for large systems as well as statistical assumptions for failure rates (if you have tens of thousands or hundreds of thousands of anything, failures are an unavoidable reality) and it is easy to show that you need to install a system that is in the order of 7x to over 10x the desired steady-state power delivery.
This is the solar problem. And this is where the idea of "saving the planet" or even perhaps reducing CO2, etc. can start to quickly fall apart. One of the simple implications of this reality is that you need a massive amount of land in order to achieve output at scale. The next reality --something most people never think about-- is that you'll need, again, massive amounts of concrete, steel and other materials to build something like that. And, finally, we have to account for the energy and fuel burned not just in manufacturing and transporting all the required materials and components, but for the construction process itself. You can't build a 1000 acre solar farm without probably thousands of vehicles moving things, digging holes, delivering concrete, etc.
Anyhow, not coming down on solar, just pointing out that there is such a thing as understanding that it isn't some magical perfect technology that you install at no cost (environmental and otherwise) and produce perfect power 24/7. It's far more complex and, yes, dirty, than most people might imagine.
I guess what I am saying is that we really need honest assessments of these and other technologies before jumping head first into continental-scale projects that could be truly detrimental when viewed from a wholistic perspective.
After my analysis I came to understand that our clean future pretty much requires nuclear energy at a massive scale. I don't think we can do it without nuclear. Solar and wind cannot achieve what we need.
What do we need? In the US, if we want to go to a fully electric ground transportation system (cars and trucks included) we need to DOUBLE the current power system. That isn't trivial. Imagine creating a full duplicate of our current power production system. We need somewhere in the order of 1200 GW to support a full transition to electric vehicles. Our current power generation capacity sits at about 1200 GW, hence the need to double it. This, of course, will also require a doubling in capacity of our entire power distribution system. We cannot currently carry twice the power.
In other words, this is far more complex than just installing solar panels.
Wind is even a bit more space efficient in Germany. Land use is really not a problem for renewables.
1. Lobbying groups for fossils and nuclear trying to find disadvantages of renewables. The most bizarre thing I saw a while ago was arguing strongly for nuclear largely based on the fact that it's more space efficient (saying the importance of that outweighs cost), while completely ignoring the fact that nuclear plants require extensive nofly zones (note theybare not really a problem atm either but would affect how much we can build out nuclear).
2. A strong push for making large scale renewable installations. While it is true that large scale solar is more efficient than smaller scale, I think the prime motivation is that it benefits large operators and investors, not individuals or small communities. Hence the lobby efforts.
In reality just putting solar on most existing warehouses and parking lots would already cover a significant proportion of our electricity use. And others pointed out how solar (and wind) can often be used in dual use environments benifiting both.
We would get more GW for the buck by using subsidies to really accelerate the expansion of green power generation that is already cost effective without subsidies (solar/wind/pumped storage) rather than throwing money at a form of power generation that wouldnt even exist without subsidies.
If the subsidies were distributed on the basis of stability, GW output and availability then that would be efficient, effective and fair but that would kill off the nuclear industry entirely.
Only one of those choices feeds an exponentially increasing capacity to respond to the crisis.
There are plenty of much lower hanging fruit available than a nuclear plant. Insulation, residential thermal batteries, trains, cycleways, green hydrogen infrastructure, solar water heating, CAES projects, variable load upgrades to aluminium smelters, etc. etc.
I'm all for increasing public spend on green energy, but until there's enough money for the cost efficient things, then nuclear is just helping the fossil fuel industry
Or just do any of the other things on the list I mentioned. Getting 400 commuters out of cars and into a train is an instant 4MW saving.
Eminent domain is a common tool to solve this, and it is also used for mining. It is however not very popular.
just calling everyone a "NIMBY" is not a valid response to criticism of externalities.
The first video has pretty sound (pardon the pun) methodology.
Findings: Unless you're within 200m of a turbine, the background ambient sounds are louder than the sound of the turbine.
Do you have evidence to the contrary?
Their values and systems of belief/reality-building and trust networks are totally different. Successfully negotiating that doesn't mean "my numbers are more correct" but understanding the different subcultures, what's important to them, and being able to respectfully and empathetically communicate according to their needs, not yours.
My primary reason for sharing it was to avoid other (reasonable) people from walking away with some false belief that there might be something to the noise issue. There isn't anything to it.
I'm not trying to convince this person. However, there might be others who don't have the time to do the research. This comment is for them.
The exact blend depends on the location of course, but any sensible grid will likely include both of them (and mixes of distributed solar, onshore, offshore wind). Generally solar and wind should be about 80% of the generation mix, and the precise balance (after including the cost difference over the next few decades) globally leans towards solar being the dominant of the two in most plans and predictions.
edit: this has now made me wonder if anyone calculates the LCOE of 'optimal' solar/wind mix for the region.
Or are there examples of more intensive uses under wind turbines?
https://talkbusiness.net/wp-content/uploads/2018/02/Wind-Far...
https://static01.nyt.com/images/2016/07/19/world/windfarms-w...
Just what about these turbines makes farming / ranching more difficult?
People generally like making money with their land, and especially for wind it often doesn't impact the economics of current land use very much. (And even solar isn't necessarily exclusive)
The comparison with rail and highways also isn't very good since for those there are much stricter constraints to cover a useful and practical route in its entirety.
The biggest problem in those situation isn't that the actually land that get used, it is how the farmer get impacted by the rail road being there. If they got a lot of money for those 0.5% with no negative effect then naturally people would have no objection to sell that for huge profits.
I can't speak for your family members or the locations where they are involved, but I do know how much politics there is around where I live. There is a lot of resistance to place wind farms on farm fields, and farmers aren't exactly lining up to rent out their land (or at least not for the price people are willing to pay). Ocean farms are often cited as being easier to build because there is less resistance from land owners and local government.
One land location that does seem a bit easier for wind production are forests in mountain areas which is sparsely populated. The draw side is that the consumers isn't generally located there, so you get the situation where the best and easiest locations to install wind is also the worst location to utilize the production.
(And don't get me started on this, but most arrays are wired stupidly, ignoring what the telegraph and phone guys learned 125 years ago: you want to ground the positive leg, NOT the negative, so you can use cathodic protection via a sacrificial anode to prevent the wires corroding away. You would be shocked how many 10-15 year old arrays I've seen that have something rapidly approaching empty straws of insulation connecting the panels - the breakeven on a solar PV plant is around 20-22 years, so these will never break even!)
Land used for rail and roads is used up. Land used for solar may continue being used for whatever else it was doing already.
Please do not make up BS problems.
Solar and wind can be much more opportunistic in using small packets of land.
Researchers are experimenting with which plants do best under solar panels and even trying to grow tomatoes and potatoes between rows at existing utility-scale farms, Macknick says.
But most crops do not, and benefit both from reduced heat stress and reduced water loss. Livestock, likewise, benefit from shelter, and the grass grows not less, same reasons.
When you have all of cultivated land available to site solar in, you can choose places to put it where it is most beneficial.
Farm and pasture are not the only places that benefit from shade. Reservoirs and canals lose huge amounts of water to evaporation, and need constantly to fight biofouling.
Roofs, too, last longer in shade.
Maybe a specialized tractor could be built to go around the panels but really you’d want to grow laborious crops that are mostly hand-planted/harvested anyway.
On wheat you may not want to collect too much of the light anyway, because yield might suffer.
Corn is a little harder because it grows so tall. You would need high fencerows, or give up collecting much when the crop gets high.
One merit of these systems is that they produce revenue in fallow years and year-round, while the crops only produce revenue in a spike once a year.
https://www.reuters.com/business/environment/solar-panels-he...
For a certain number of hours in the day, yes. This always strikes me as an odd observation because storage and distribution have always been the more important challenges in our current implementation.
I'd also caution against any form of "monoculture strategy." The lessons from history are pretty clear on this.
Edit: They don't add it to the fuel because they want to. They do it because they are mandated to. Anti-knock properties are just a tiny silver lining that could be obtained through more efficient means were it not for the subsidized ethanol.
> Due to the phasing out of MTBE as a gasoline additive and mainly due to the mandates established in the Energy Policy Act of 2005 and the Energy Independence and Security Act of 2007, ethanol blends have increased throughout the United States, and by 2009, the ethanol market share in the U.S. gasoline supply reached almost 8% by volume
and
> In the U.S. MTBE has been used in gasoline at low levels since 1979, replacing tetraethyllead (TEL) as an antiknock (octane rating) additive to prevent engine knocking.[15] Oxygenates also help gasoline burn more completely, reducing tailpipe emissions and dilute or displace gasoline components such as aromatics (e.g., benzene). Before the introduction of other oxygenates and octane enhancers, refiners chose MTBE for its blending characteristics and low cost.
It is a farm subsidy program, but it also has an actual use. Oil companies went with lead in the first place, despite being well aware of the dangers, because ethanol is also a competitor to gasoline, being a fuel itself.
Yes, Archers Daniels Midland collects a monstrous undeserved federal subsidy.
But unleaded gasoline needs something to raise its octane rating. MBTE turned out to be a public health and ecological disaster. What we use now is ethanol. Probably some other alternative would be cheaper and not burn crop acreage, but wasting corn has been good politics: corn farming states have a preponderance of senators.
Probably naive, what does this mean? There are unleaded gases for sale that are ethanol free at some gas stations (typically only the premium / highest octane) which are often preferred for small motors / high end engines. I don't think they mix in lead, is MTBE what is added instead in those cases? I haven't heard of MTBE before.
ETA: I've been able to find a number of sites for WI gas stations saying "we have ethanol free," but none of them mention what is added in its place (if anything).
https://www.classicfuelsolutions.co.uk/products/classic-fuel...
That's a UK supplier but an answer on Quora suggests 'race' fuels are sold in the US with lead too. Not legal to use on the road though.
> Effective January 1, 1996, leaded gasoline was banned by the Clean Air Act for use in new vehicles other than aircraft, racing cars, farm equipment, and marine engines.
The only leaded fuel you can buy in the US is aviation fuel. You can't buy it at a gas station and the only reason it still exists with lead in it is because that is necessary for compliance with government rules that regulate what fuel can be sold for that specific purpose.
You do get alkylate gasoline, maybe that's what is being sold:
> The availability of alkylate petrol is limited. The actual alkylation process to produce Aspen is a much more advanced and expensive process which only a few refineries in the world can produce. Even if new ways of producing alkylate petrol is developed, regular petrol will still be the dominant type of motor fuel in the world.
https://www.buyrealgas.com/states.html
I found this website, that lists places that sell ethanol free gas, and the number of them that appear to be Marinas, combined with the bit above about lead being used for marine purpsose makes me think they're just using lead.
Somebody call Congress! Think of the children!
Pretty much nobody does this because on the high end race fuels as well as various alcohol fuels are more available and better supported by industry and on the low end ethanol free premium is substantially cheaper. If lots of people did it it wouldn't still be legal. Dumping 100LL into your boat or race car just isn't a good value way to solve a problem anyone has.
> I found several posts from people saying that they buy aviation fuel because they don't like ethanol for their lawn equipment, and presumably people informed enough about the issue to intentionally buy leaded avation fuel would know about other options available).
I hope I'm not the only one appreciating the schadenfreude here. It reminds me of when people unscrew the spout from their crappy compliant cans. Regardless, the overwhelming majority of these people just drag their butt to whatever local station has ethanol free premium rather than go to the airport because it's a faster/easier/cheaper way of accomplishing the same goal.
The current status quo is stupid but the rules are written by a bunch of jerks who either a) DGAF about what happens beyond the next election cycle or b) DGAF so long as they're not responsible and can collect their pension so it's no surprise that the things people do to compensate are non-optimal.
Large tanks are generally okay, but if you try to start a small carbouretted engine after 6mo and haven't drained the tank you'll need to clean the jets and replace the spark plug.
And the first primary or caucus state of the election season is Iowa. The state produces the most corn in the Union and by far the most corn per capita. Large corn subsidies will likely continue until this fact changes.
https://www.masterresource.org/political-capitalism/adm-etha...
> Thanks to federal protection of the domestic sugar industry, ethanol subsidies, subsidized grain exports, and various other programs, ADM has cost the American economy billions of dollars since 1980 and has indirectly cost Americans tens of billions of dollars in higher prices and higher taxes over that same period.
> At least 43 percent of ADM’s annual profits are from products heavily subsidized or protected by the American government. Moreover, every $1 of profits earned by ADM’s corn sweetener operation costs consumers $10, and every $1 of profits earned by its ethanol operation costs taxpayers $30….
It seems like a misunderstanding of both ag subsidies as they exist today and of ADM's business model
Probably because you took the time posting that you might otherwise have taken thinking. I suggest trying it the other way.
So the question is: Will you find enough locations that don't annoy the locals and once you found them will your project survive the inevitable intrigues amongst land owners over who gets to rent out their land for the lucrative PV installations?
Even though it's more expensive, I think that using rooftops and other already occupied spaces first is a more sensible route.
It’s quiet and doesn’t smell. It’s about as unobtrusive as you can imagine a thing to be.
If solar panels were more efficient and mass produced in the 1990s, I have to imagine solar farms would have replaced most tobacco farms after the buyouts.
Though maybe I’m biased by my feeling that solar panels are damn-near magic - you leave them outside, basically neglect them, and power just comes spilling out of them.
I spent six years in the utility-scale solar PV industry. You would be shocked to learn how many of the panels are not working in any given array. I've seen everything from almost 10% of the strings not even being connected to the inverters in a utility scale array, to a shocking number of rooftop arrays that were producing nothing. In my entire experience with the company and all its customers, we never encountered a single utility-scale array that was fully working when we arrived on site to add our monitoring or optimization systems, and many of those were brand new!
In one case of a sizable array on the roof of a Texas energy provider here in Austin, we discovered the inverter had died years before we discovered it! (This was field testing of of inverter bus noise effects, and the oscilloscope showed nothing but what the wiring picked up as antennas!) Turns out no one ever looks at the power bills in a power company... :-)
Solar PV actually requires a fair amount of maintenance for both prevention and remediation (cleaning and/or replacing panels, repairing connections/wiring, combiners, inverters, etc.) to ensure they are actually operating, but most owners are happier to cover their ears and eyes and sing, "La, la, la..."
It is extremely uncommon to site dedicated solar farms within 100m of residential areas.
So let them cultivate a perimeter of just enough forest to hide the panels if it really is a real issue and not a product of NIMBY OCPD.
This is stupid. The article leads with the solution to this non-problem. There is no shortage of pasturage to site solar in. Likewise, of reservoirs and canals. Both places get net benefit from the dual use, even discounting the extra revenue.
Personally I think they should be put to sea. Along with floating farmland. Just make concrete (or seacrete!) pontoons, connected together into 1000 km^2 islands. Leave the actual land to nature. I concede that is currently scifi though.
When you recognize you have plenty of land that is not being used up by placing panels in it, you can understand there is no need to try to pack panels as closely together as conceivably possible. You can leave room between for livestock and grass.
Open ocean has destructive waves. Panels do much better on calm reservoirs and ponds.
People greatly overestimate the footprint of solar power, and underestimate the footprint of oil and gas. Every oil and gas well in the nation sits on a 1-5 acre pad that has been scraped flat and denuded of all life. The area that has been sacrificed for this purpose in west Texas and Wyoming absolutely dwarfs the area that we would need to replace that production with PV.
I would probably agree if you are referring to USA. But I would be skeptical that the same is true in the UK.
It is true, that the amount of solar needed to power the entire US is about 0.5% of the land.
That doesn't mean there's no benefit in increasing the efficiency of panels and get dual use of the land. It also has the benefit of allowing for solar in more places where it's needed for more decentralized power.
> Solar energy is one example where the context and type of material matter a lot. Solar panels made from cadmium use less energy and materials than silicon panels, and therefore use less land per unit. It also matters a lot whether you mount these panels on rooftops or on the ground. Rooftop solar obviously needs much less additional land; we’re just using space that is already occupied, on top of existing buildings. However, they do need some land over their life-cycle because they still require mining of the materials to make them, as well as the energy (mostly electricity) used in refining the silicon. Finally, the density and spacing of the panels also makes a difference.
> Wind is the most obvious electricity source that we should consider differently when it comes to land use. You find it separated from the other sources, at the bottom of the chart.3 There are several reasons for this. First, offshore wind takes up space, but it’s marine, not land area. Second, onshore wind is different from other electricity sources because you can use the land between turbines for other activities, such as farming. This is not the case for a coal, gas or nuclear plant. This means the land use of wind farms is highly variable. I have calculated the land use of 22 of the world’s largest wind farms [you find my calculations here].
> Take the Roscoe Wind Farm in Texas, which uses 184 m2 per MWh. This is a large project, where farmers can generate additional income through electricity production while they continue their farming operations between the wind turbines. The wind farm is almost a secondary land use. This contrasts with much more dense wind farms, such as Fântânele-Cogealac in Romania, or the Tehachapi Pass in California, where energy production is the primary land use. These can have a small land footprint of just 8 m2 per MWh.
Seems pretty stupid to me. Though if someone get sucked in by the headline, reads the article and moves from thinking "we don't have enough room for renewables" to "there are lots of ways to dual use land with renewables" then maybe it's all for the best.
Pretending there is some sort of shortage of land to site solar in is not a valid reason to court efficiency. There are other, legitimate reasons.
The UK has a large amount of crop and pasture land, and quite a lot of reservoirs and canals besides. Most places do.
There's no need to be glib, and the GP was obviously talking about the availability of land on a much smaller and more densely populated nation than the comparatively massive and wide open country that is the United States.
It has, in fact, easily many, many times more of both than could ever be needed to share with solar and wind.
It seems like trying to make land do these two sunlight dependent things at once is not as efficient as having dedicated agricultural fields and dedicated solar farms.
I don't believe you are taking into account just how much location and transmission distance matters for such projects.
https://www.energy.gov/eere/solar/solar-futures-study
> Although land acquisition poses challenges, land availability does not constrain solar deployment in the scenarios.
> In 2050, ground-based solar technologies require a maximum land area equivalent to 0.5% of the contiguous U.S. surface area, which could be met in numerous ways including use of disturbed or contaminated lands unsuitable for other uses. The maximum solar land area required is equivalent to less than 10% of potentially suitable disturbed lands, avoiding conflicts with high-value lands in current use.
> Various approaches are available to mitigate local impacts or even enhance the value of land that hosts solar systems. Installing photovoltaic (PV) systems on water bodies, in farming or grazing areas, and in ways that enhance pollinator habitats are potential ways to enhance solar energy production while providing benefits such as lower water evaporation rates and higher agricultural yields.
> Expanding rooftop PV could reduce solar land use. Almost 200 GW of rooftop PV are deployed in the decarbonization scenarios by 2050 (10%–20% of total solar deployment). However, the technical potential for U.S. rooftop PV is greater than 1,000 GW, and efforts to promote rooftop PV could increase deployment beyond the modeled level.
Transmission distance matters when you are talking about sending power 1000s miles from the generation location. For that, you want something like HVDC. However, for anything else, HVAC is good enough.
If you have some transmission loss, you just add a few more panels.
What's your basis for this? Real-world power grids don't seem to be designed around transmission loss being a non-issue so long as they just 'generate more power' at the source.
Getting coal from a mine to a power station is a big task, so some grids are literally built around the locations of the coal. Hydro and nuclear have similar location needs.
This has changed more recently with gas and renewables where as they get cheaper other factors start to dominate, but the grid was not originally set up for that kind of distributed load and needed some tweaks to adjust I believe.
The issue is really mostly the difficulty of smoothing production over consumption. And transmission.
1) Heat kills PV efficiency, since, to a first order approximation, current is proportional to irradiance (deserts good), but voltage is inversely proportional to temperature (so deserts very bad). You make way more power on a clear winter day in Colorado (assuming no snow on the panels!) than you do on an Arizona summer day. If you don't like this, take it up with God, since it's just the way he built the universe and the quantum physics of semiconductor junctions.
2) Dust (and/or salt, if you're anywhere near the ocean) is a huge enemy of solar power production (so deserts bad, again). Dust or salt spray can easily cost you nearly half of your power output. PV panels are scarily susceptible to even small shading from leaves or even bird crap on them. I can throw a business card on most panels and take out 1/3 to 2/3 of that panel's output. If wired in a string, as is typical for utility scale PV, the loss of that single can take out the power production of that entire string (typically 12-22 panels worth), since it can no longer reach the inverter bus voltage set by the unimpaired strings.
Oh, and cleaning panels is really expensive - it was $0.50/panel a decade ago when I was collecting the largest database of DC solar panel data in the world - I don't imagine it's gotten any cheaper... (One of the big selling points of our software was that it could optimize cleaning and maintenance timing and intervals. This can actually make the difference between breaking even on the array cost or not!)
Wait, how does this shit even work at all, then? Are solar farms just perpetually functioning at <50% capacity because everything broken all the time?
Bonus if you use that heat to generate more power at night.
Some companies do Time of Use contracts which do this to a degree, but flat incentives (cut a one time check to the homeowner) seem much less complicated. The grid gets smoothing and the homeowner gets to keep the lights on when the power goes out and doesn't have to spend nearly as much on the install. The power company doesn't have to manage a big bank of batteries somewhere and saves on distribution costs. Plus the homeowners technically own the systems so when something goes wrong the power company doesn't have to roll a truck to fix it.
The only real problem with this scheme is that the battery market is already squeezed with so many companies jumping into the electric vehicle business and production lagging behind demand. However, this is likely to be a short term problem, so hopefully in the next couple of years something like this will be practical.
The batteries may be identical but installing them, monitoring them, doing AC>DC>AC conversions etc become much cheaper at scale.
A sharing program foists most of this complication off on homeowners.
https://www.greentechmedia.com/amp/article/from-pilot-to-per...
The general term is Virtual Power Plant, where software let's a bunch of distributed items act in concert as if they were a big powerplant.
From the gas and oil companies' perspective, with enemies like these, who needs friends?
Impacts to watersheds are the biggest environmental issues of any small or large scale building projects in my neck of the woods. I’m only allowed 12 percent of my land for impervious surfaces.
"EMLR allows solar panels associated with ground-mounted solar farms to be considered pervious if they are configured in accordance with the recommendations in this chapter. These recommendations promote sheet flow of stormwater from the panels and natural infiltration of stormwater into the ground beneath the panels."
...
"In general, the minimum disconnection length between two rows of solar panels is equal to the width of each row, as shown in Figure 1. However, some panel layouts include horizontal gaps between individual modules that allow stormwater to drip off the panels at intervals much smaller than the width of each row. In these instances, the solar farm can be designed with a smaller disconnection length, provided that they will not cause concentration of stormwater runoff."
Consider tokyo as an example of a space where area is at an absolute premium. There are around 7000 people per km^2
Shrink it down to a single block. Tokyo's blocks are a little smaller, but a common size is 100x200m for ease. At 0.7kWh/day/m^2 there are 14,000kWh/day available in this area shared between 140 people. This is about 100kWh/day each.
This isn't quite enough to be as absurdly wasteful as someone from Australia or the US, but it covers the total per capita energy consumption of people living pretty much anywhere else.
Note that this is just the net solar electricity available in a high density metropolis as an input vs all energy (including thermal) used everywhere.
As soon as you add in medium density towns or industrial areas there is an abundance of space for panels so long as we stop being exponentially more wasteful with the available energy.
Anyone bringing it up is a fossil fuel or nuclear shill.
https://arxiv.org/pdf/1905.08024.pdf
https://boeing.mediaroom.com/2010-11-01-Boeings-Spectrolab-P...
And, the important efficiency measure is W/$, where GaAs trails well back. Perovskites may exceed 40% conversion efficiency, and also have good prospects to offer much better W/$. Their endurance has grown encouragingly quickly.
W/$ goes down with manufacturing efficiency. Nobody has done large scale manufacturing of multi-junction GaAs cells.
Top-end GaAs technology wouldn't compete with bottom-end silicon technology (the below-16% panels that you mention). It would compete with top-end silicon technology, which is already commercially available at module efficiencies above 22%:
https://cdn.energypal.com/panels/spr-x22-370/energypal-solar...
Note that the upper cell efficiency limit for any single material under incident terrestrial sunlight is about 33.5%:
https://www.energy.gov/eere/solar/multijunction-iii-v-photov...
GaAs cells reported to operate above this limit are part of multi-junction cells and/or incorporate optical concentration systems to focus sunlight to higher intensities. The experimental record-holder of 47.1% uses a multi-junction cell plus optical concentration. Optical concentration only works with direct normal illumination; light that is scattered through haze or clouds can't be focused, so optical concentration systems are a good match only for sunny areas that have clear skies year-round.
That said, the National Renewable Energy Laboratory is researching ways to make GaAs cells at lower cost:
https://www.nrel.gov/news/video/building-low-cost-high-effic...
At low enough cost, GaAs modules could compete directly with premium silicon solar modules. They could conceivably be lighter as well as more efficient than silicon, since thinner layers of GaAs are needed than silicon layers, which in turn reduces the required module rigidity, thickness, and weight.
Certain uses place a premium on areal efficiency, notably aerospace.
But anybody who has maxed out their own collection area, whether a roof or reservoir, can get more revenue from using better cells. And, the more of that that is done, the faster their price falls. We may reasonably expect the price of multilayer perovskites to drop below cost of silicon panels. Sooner is better, which is driven by maxed-out demand.
I guess this makes sense given the hard bit is the substrate.
This would be good for everyone as second hand silicon cells for 10-30c/W will open up a bunch of new uses.
In the meantime, they are quite a lot cheaper to make, so in many uses it would not matter so much if they did fail faster. In some uses, like aerospace, their lighter weight and better areal efficiency are essential, and forgive a lot.
Hard disagree on that, their current longevity is comparably tiny so you'll have lots of overhead in installation costs. Not to mention the amounts of toxic lead trash you'll need to pay to dispose of, the thing is basically poison after all.
Makes far more sense to invest in multilayer tech even if it costs more since it'll last longer by an order of magnitude and use far less area to function which is a big benefit for vehicles too.
The thin films amount to very little mass, and in any case may be incinerated and the ash used as feedstock.
Longevity is already up to years. In many uses that is plenty, especially when you can just roll it out, instead of needing to bolt it up.
Well that's news to me, I thought that was part of the core functionality.
is an overview,
seems like for places where you could use silicon, but are limited by space and need high output then thy hybrids from Oxford PV seems ready, but I'd guess that's going to be a tiny share compared with people who just want it cheap and at scale.
https://www.oxfordpv.com/news/towards-better-understanding-l...
But hopefully that is enough for it to get proved out and scaled up.
Recall seeing a video of their factory printing solar cells.
Looked great but nothing on their site suggests they have a product unless anyone knows different?
They are listed on Warsaw stock exchange (and having a miserable time of it as the price would suggest).
Really the only downside is that people will crash their cars into the support structures. It is inevitable, and needs to be accounted for in the design.
Why is it that Trees can generate more energy via absorbing light than implied by the surface area of leaf coverage of the outer branches?
Hint, yes has to do with light spectrums and their behaviors and the benefits of chloroplasts using more than one light frequency
All the real estate there you could ever want. 9X the solar flux. Little or no "night". Direct delivery via lasers to any point in the hemisphere.
Where cost doesn't matter, everything gets easy.
The advantages of orbital are nearly 20X generation per panel to start with, even before considering support structures (none) and weather-proofing (none). That leaves lots of room in the cost equation.
Orbital power is a total nonstarter if we aren't building the panels in orbit. Launch costs will absolutely destroy any ROI, even before you get into the transmission losses beaming the power back to Earth. SpaceX has completely revolutionized the launch industry, getting costs down to around $1200/lb. A typical solar panel weighs about 40lbs, but aren't optimized for weight. Assuming you can reduce this to 20lbs per panel that's still $24,000 per panel not counting transmission equipment and the like. The panel itself costs maybe $2000 for a very high efficiency model. The launch costs dwarf the panel costs, even when accounting for the lack of weather in space. It just doesn't make sense, especially when you start adding in all of the additional costs like building the satellites, the ground stations, transmission losses, fuel to keep the orbits from decaying, the fact that you won't be able to send these to Geo Orbit without incurring crippling transmission losses, so you'll need a lot of ground stations, etc...
Compared to all of that, the problem of finding parking lots in the suburbs seems absolutely trivial.
Solar panels do not need to be "near major metropolitan centers". Modern transmission lines move power efficiently, silently, and reliably.
It would be impressive for your orbital panels to get out 4x as much energy as the light they intercept carries, but getting a patent on your perpetual-motion apparatus might be difficult.
Maybe do some elementary cost analysis. All the numbers are easy to find. Don't forget to figure in conversion loss from electric power on orbit to laser light emitted, losses scattering in the atmosphere, and conversion again from laser light received to electricity on the ground.
You would better loft many-square-km aluminized-mylar mirrors to reflect sunlight to solar farms on the ground. Keeping them pointing the right direction would be tricky.
Solar flux outside the atmosphere is 9X sea level. Go ahead, look it up. Then there's the periodic eclipse called 'night' that doubles orbital efficiency again. Look that up too.
Conversion losses of 20% seem normal? Both in orbit and on the ground. Which halves what you collect, well within the budget of 20X reducing it to around 10X.
Conversion losses of only 20% from electric to laser, and again from laser to electric again, would be miraculous. 20% scattering loss in clear weather would be unsurprising. 90% loss, total, would be admirable, not counting the original 60%+ loss off the top. So, even with 9x, and neglecting huge launch cost you still come out behind.
So about 75% of solar radiation reaches the ground. In the continental US, factoring in angle of the sun, average weather, night that comes to about 4-5KWh per day
In orbit you would have just 1.37KW X 24 hours (no weather, angle issues) which comes to about 33KWh per day. So that's 8-9X the collected energy per square meter in orbit vs ground level.
These folks https://www.allaboutcircuits.com/news/wireless-power-transmi... estimate 89% efficiency from orbit to ground.
So we're then at around 30KWh effective.
What am I missing?
So many things. The massive clear area around your receiver. Scattering induced by weather means you still don't have 100% capacity factor. With only radiative cooling available, cooling will take up as much space as the panels and make everything heavier. The atmosphere doesn't absorb light uniformly. Maintenance. You're comparing fixed panels at mid latitudes to rotating panels. Launch costs are still 10x the cost of a panel. UV and ionizing radiation will destroy your panels sooner. And a space borne panel will probably never reach net energy payback even before you add your laser boondoggle.
You're better off just burning the methane.
The land-based panels are 42lbs for 450W. The space-based ones are 6W per gram. Lots of room in the equation for cooling.
The 89% transmission already figured in weather and absorption; you don't get to count that twice.
Rotating panels get what? 25% better? Still an order of magnitude improvement.
Launch costs are dropping like a stone. Plan now; it'll be in the hundreds of dollars when you launch.
The slang about 'it'll never pay' is just talk. I'd hoped for some information, not just wet-blanket doubt.
Like the hot air about 9X being so far from the truth. Turns out, it's just about right. So I guess I'll have to look elsewhere for more information.
Somebody will make an orbital station, use it for space-based operations and all the hot air will disappear. And not that far in the future.
Land area is an absolute non issue for solar. With the exception of somewhere like luxembourg, just the roofs of the residential areas of a country have enough area to provide the total primary energy consumption. The singular and overriding factor is cost and cost of storing or moving the energy. Which brings me to
> The land-based panels are 42lbs for 450W. The space-based ones are 6W per gram. Lots of room in the equation for cooling.
You're not going to get nameplate capacity, and the weight is in the superstructure, cooling system, power delivery, and your 100s of metres aperture laser or maser. The actual panel for a terrestrial caravan system I installed recently weighed no more than the panels listed here https://www.spectrolab.com/DataSheets/Panel/panels.pdf (although it was bigger).
So you're proposing spending 10x as much on panels, another 10x as much on cooling, spending as much again on a transmitter, then as much again on a receiver. All to burn tens of kg of methane per watt in order to get the thing into a stationary orbit. Then you have a gigawatt death beam fucking up the atmosphere and making a square kilometer or so uninhabitable.
> Like the hot air about 9X being so far from the truth
Comparing like for like, you have about 1.3kW in space vs 1kW on the ground, and a tracking setup can get 6kWh/day out of a 1kW panel at low to moderate latitudes (where well over half of the world's population lives). This is a factor of 5 to 6 better, although your space based panel is vastly more expensive and a tracking system is pointless because cost is the limit, not area.
This is the most efficient high power long range wireless transmission system I can see mentioned: https://ietresearch.onlinelibrary.wiley.com/doi/full/10.1049... which brings the ratio to around 3-4. Except you also have to deal with losses due to clouds and dust so 2-3 is more likely.
At that point just build a nuclear plant. They're awful but they're better than this plan by every metric. Or do the sensible sane thing and build 100x the terrestrial solar for the same price (or 10x as much and enough storage) and save the space arrays for stuff in space -- once you're lifting megatons it makes far more sense to refine metals from asteroids and just leave 99% of them up there.
Or as I said, just burn the rocket fuel in a gas turbine. You'll get more energy out of it than you would from this utterly ridiculous machine in its lifetime.
If area was a constraint important enough to make space based solar viable we'd see water cooled triple junction cells as well as tracking on any utility scale installations near the equator (as this would reduce area by 2/3rds). We don't so it can be safely dismissed as more solar frickin roadways.
Also your design sounds suspiciously like a GDI Ion Canon from Command and Conquer[0]. Imagine having dual-use concerns like we do with nuclear power.
No matter what kinds of launch cost improvements you predict (including, of course, Starship-likes), it will always be orders of magnitude cheaper to just build an array here on earth that is 3-4x larger than to lob anything into orbit.
The Microwave/Laser power transmission schemes of orbital solar are also a huge problem, and in all likelihood would never make it through any kind of environmental impact study, much less an engineering effectiveness/reliability review. (Not to mention that, like the famous laser drive in Larry Niven's Man-Kzin wars, any laser/maser/microwave array that large is inherently a formidable weapon of mass destruction, with no modification other than repointing it....)
Technology moves on, but old wet-blanket excuses live forever.
But in reality, land use has never been a problem for Solar. It's great that lots of people are working on the issue and improving it. Just as lots of people are working on making them cheaper, or more environmentally friendly or easier to finance or a thousand other metrics.
But none of those were ever fundamental problems with the tech. Their own source of data about the 'problem' puts Ground-based PV at about the same land use as Coal.
They also missed out 'floatovoltaics' (PV on water) and building integrated PV as well as solar PV as a paving solution. Probably all of which are likely to be bigger than ground mount PV, given the trend to bifacial panels.
Better energy density will also help locate solar power closer to where it will be used, like on top of buildings in the city rather than in a large plant out in the middle of nowhere, thus saving on transmission costs.
Finally, IMO photovoltaic pavement is probably going nowhere.
> Sheep grazing under solar panels at farms in NSW's Central West have produced better wool and more of it in the four years since the projects began, according to growers.
> Local graziers have labelled the set-up a "complete win-win", with the sheep helping to keep grass and weeds down so as not to obscure the panels.
This is not something that works so well with open cut coal and down wind from city supplying coal burning power stations.
[1] https://www.abc.net.au/news/rural/2022-05-30/solar-farm-graz...
In fact, sharing improves efficiency of the panels, cuts water loss, and often increases yield.
When it is an issue there are countless solutions from sharing with livestock (already done in some areas) to providing partial shade for non energy crops like lettuce or capcicum that increase yield to covering parking.
For reference, there are about 2.5 billion parking spaces in the usa which take 20-50m^2 each, very little of which is more than three stories deep. This is room for between 1 and 5 TW of net (ie. averaged over the year including nights) capacity or roughly the USA's entire energy consumption. You could also replace a small fraction (about 5%) of corn used for ethanol (not the total corn) and get a similar result.
"Often" != "Always". Therefore you also agree that solar still competes for land use with crops.
Furthermore, land that has already been allocated to grid scale solar has already been taken away from possible crop use. Sometimes it's not arable land, but that isn't always the case, therefore solar is still ostensibly taking up land that could be used for crops.
Finally, I even disagree that somebody knew that solar and farming could use the same land. Someone had an idea that maybe they could coexist, then ran an experiment that succeeded. They certainly didn't know the outcome beforehand.
No. It just means that some places are better than others.
Since there is overwhelmingly more crop and pasture land than could ever be needed to satisfy power needs, solar may be placed exactly and only where it does the most good.
It has been known for centuries that most plants benefit from partial shade. It is an exceedingly tiny step of logic to go from "shade" to "shade provided by solar panels". In the past, providing shade just cost money. Now it yields direct revenue, year-round.
Again, "most plants" does not necessarily include "crops", most of which have been selectively bred over millennia while grown under full sun. The step is not from "plants do well under shade" to "plants do well under solar panels", it's to "crops we've never grown in partial shade might actually do better in partial shade too".
https://ourworldindata.org/land-use-per-energy-source
I'd assume coal uses much more land in absolute terms, since it's what 50% of global electricity vs 3-5% for solar at the moment.
Solar farms are often sited, stupidly, in deserts, not because it is a good idea, but because ignorant investors think it is a good idea.
Perhaps indulge our ignorance about deserts for a moment?
Siting panels on water and on farmland reduces operating temperature. Mounting vertically, in fence-rows, keeps off dust, collects more during morning and afternoon demand peaks, aids convective cooling, and protects crops from harshest afternoon sun.