More  solar roadways  B.S. - "Solar panels replaced tarmac on a motorway" - Page 1
Forum section: electronics / general

author: johnlsenchak
author_rank: Frequent Contributor
timestamp: September 23, 2018, 05:04:04 pm
content: Solar panels replaced tarmac on a motorway. Here are the results.Several factors work against this oddly popular idea.Dylan Ryan / The Conversation - 9/23/2018, 12:30 PMhttps://arstechnica.com/science/2018/09/solar-panels-replaced-tarmac-on-a-motorway-here-are-the-results/"While the road is supposed to generate 800 kilowatt hours per day (kWh/day), some recently released data indicates a yield closer to 409 kWh/day, or 150,000 kWh/yr. For an idea of how much this is, the average UK home uses around 10 kWh/day. The road’s capacity factor—which measures the efficiency of the technology by dividing its average power output by its potential maximum power output—is just 4 percent."

author: nctnico
author_rank: Super Contributor
timestamp: September 23, 2018, 06:01:17 pm
content: The piece of solar roadway in France has already been discussed at length. In short: the are two big flaws in the article:1) is that the author assumes solar panels on roofs are actually going to happen. WITH the required grid upgrades to handle all the power which people tend to forget about.2) is that the piece of road in France is a test and not a commercial installation so it makes no sense to compare it with a commercial installationStill let's forgot about the 'solar roadway' in Sandypoint. That is just a gimmick. An author of a serious article about solar roadways wouldn't have mentioned it.

author: vk6zgo
author_rank: Super Contributor
timestamp: September 24, 2018, 09:16:33 am
content: Quote from: nctnico on September 23, 2018, 06:01:17 pmThey have already happened in Australia.Roof top solar is normally used where it is produced, with only a small amount returned to the grid, so upgrades are not essential.In any case, solar roadways would definitely require grid upgrades, & even new construction, as the grid is not always next to a road.Quote

author: glarsson
author_rank: Frequent Contributor
timestamp: September 24, 2018, 10:04:42 am
content: Quote from: vk6zgo on September 24, 2018, 09:16:33 amBut the contribution from the solar roadways are so small that a grid upgrade would not be necessary.

author: coppice
author_rank: Super Contributor
timestamp: September 24, 2018, 10:35:48 am
content: Quote from: nctnico on September 23, 2018, 06:01:17 pmWhat do you mean by "going to happen"? Quite a lot of the existing solar panels are already on roofs. The sensible question is at what level of roof utilisation will solar plateau out? There is only so much roof that faces the right way, has an area big enough to be worth covering in panels, isn't in a conservation area, etc.The grid infrastructure issue is as true for using road surfaces as for using roof top panels. The very distributed nature of road surface generation means it will almost certainly require numerous grid injection points, similar to the situation with roof top generation.Quote from: nctnico on September 23, 2018, 06:01:17 pmIt makes no sense to look at how much a prototype road cost. It does, however, make sense to look at the inherent complexity, which will give an indication of likely volume installation costs, and robustness, which will affect lifetime. I agree that the article does a poor job in this area.Quote from: nctnico on September 23, 2018, 06:01:17 pmI agree that the Sandy Point setup has no place in a serious discussion about solar roads. What people should include in these articles is things like the German installations of solar panels along Autobahn verges. They look so much saner than paving the driving surface with solar panels.

author: PlainName
author_rank: Super Contributor
timestamp: September 24, 2018, 11:12:49 am
content: QuoteThat's a hell of lot better than 0kWh, isn't it?The issue is cost vs power and whether you get more out (in power) than you put in (in resources). But the figures aren't clear on that - you cannot compare it to the Cestas solar plant since they are doing different jobs. The roadway may cost £14K/kWh but I bet the Cestas plant would cost a HUGE amount more than that to transport cars and trucks over it. Don't forget that the solar roadway's primary job is NOT to generate power, where it certainly is for Cestas.Also, the cost of the solar part of the roadway shouldn't include the normal cost of providing a traditional road (or the cost of maintenance if it's a conversion rather than new build). Again the primary job, and cost, is not for electricity generation.So, take all the factors into account and see what the numbers say then. If you don't you're effectively just trolling from a position of ignorance.

author: nctnico
author_rank: Super Contributor
timestamp: September 24, 2018, 03:38:48 pm
content: Quote from: coppice on September 24, 2018, 10:35:48 amThe biggest problem I see is that roof solar panels don't have a very good economy of scale because each home owner will have to hire a company to do the installation. Also for a lot of home owners the investment may not be worthwile (especially if you'd have to borrow money). I don't see governments making solar panels mandatory on existing buildings either. That would be political suicide.QuoteIt is much easier to put an extra cable next to a road (especially when it is renewed) compared to opening up all the streets in a neighbourhoud to upgrade the cables and reconnect each single home.I fully agree with dunkemhigh. You have to look at the entire picture and see the cost versus benefit before writing solar roadways off.One bird in hand is better than ten birds on the tree. The pieces of solar roadway in China and France wouldn't have been build if there is absolutely no business model in which they are profitable.

author: coppice
author_rank: Super Contributor
timestamp: September 24, 2018, 04:15:51 pm
content: Quote from: nctnico on September 24, 2018, 03:38:48 pmThe cost can be a lot lower when things are done in bulk. For example, there are a few rows of terraced houses near here which were clearly covered in solar panels as a single exercise. I don't know if they are rental houses, or if the owners all got together and obtain a good deal. I expect the deal would have been pretty good, though.

author: nctnico
author_rank: Super Contributor
timestamp: September 24, 2018, 04:28:07 pm
content: Quote from: coppice on September 24, 2018, 04:15:51 pmThe problem is that seperate home owners doing things together is quite rare. My guess is that those houses are rentals or have a home owners association in which a majority vote counts. There are always those who don't see the need and/or don't have the money. For example: a block of houses across the street where I used to live had a problem with the pilings causing the entire block to sink into the ground (unevenly ofcourse). Because one of the owners didn't want to have it fixed the problem became much worse and ended up costing 10 times more to fix.

author: coppice
author_rank: Super Contributor
timestamp: September 24, 2018, 04:31:26 pm
content: Quote from: nctnico on September 24, 2018, 04:28:07 pmSo, the world isn't perfect. Whoda thought?

author: rstofer
author_rank: Super Contributor
timestamp: September 24, 2018, 05:13:49 pm
content: Quote from: nctnico on September 24, 2018, 03:38:48 pmResidential payback for a single installation usually runs out to 20 years - not especially attractive. OTOH, there are companies that offer a Power Purchase Agreement (PPA) and they bear all the costs and the homeowner pays something like $0.15 per kWh. This in comparison to $0.35 or more for utility costs at top tier pricing. This works for the installer because they have huge volume discounts and it works for the homeowner because they don't have any money tied up in the installation.Around here, utility customers can not be net generators. The electric bill is handled on an annual settleup basis where the customer pays only the meter charge ($5) per month and at the end of 12 months the total amount of kWh bought or sold is settled. But there's a gotcha! Utility customers can not be net generators! The utility pays just $0.04 for any net generation and that's a loss of $0.11 for the energy purchased under the PPA. So, it doesn't pay to oversize the array.Bottom line: Rooftop solar, at least under the PPA arrangement, makes all the sense in the world.FWIW: In the last house we owned, we had an 8 kW array that covered every bit of our usage and not enough extra to be a factor. Our utility bill was simple 12 monthly meter charges and the net cost to us was about half what it was without solar.Unfortunately, our new house has a style of roof construction that is not consistent with solar installation. Re-roofing the house is pretty much out of the question.

author: In Vacuo Veritas
author_rank: Frequent Contributor
timestamp: September 24, 2018, 05:59:21 pm
content: Let's start Roadway Roofs, getting cars to drive on house roofs. I want to see how far we can push late industrial absurdity before it all collapses.

author: russ1669
author_rank: Newbie
timestamp: September 26, 2018, 03:38:36 pm
content: Maybe slightly off topic... But has anyone looked at the Swedish project which has electrified a short stretch of road to allow electric cars to charge while they move.https://www.theguardian.com/environment/2018/apr/12/worlds-first-electrified-road-for-charging-vehicles-opens-in-SwedenRuss

author: Bassman59
author_rank: Super Contributor
timestamp: September 26, 2018, 08:35:35 pm
content: Quote from: nctnico on September 24, 2018, 03:38:48 pmExcept,not so!And consider that the cost of putting panels on the roof of a house designed for those panels, and at the time the house is constructed, should be significantly less than the cost to retrofit the system onto an existing house.From the article: "The requirement is expected to add $8,000 to $12,000 to the cost of a home."We don't know how much power is expected to be generated by these systems. Round number would be 10 kW. But consider that $10,000 for the panels is an adder for a $500,000 house, which is to say, nothing, and less expensive than a granite kitchen or some shit.

author: nctnico
author_rank: Super Contributor
timestamp: September 26, 2018, 09:04:04 pm
content: Still the ROI needs to be kept in mind. Saying $10k on a $500k house is insignificant is just fooling yourself. Worse if you take a mortgage because you likely pay more interest on the solar panels than they earn.

author: Red Squirrel
author_rank: Super Contributor
timestamp: September 28, 2018, 12:10:11 pm
content: Quote from: In Vacuo Veritas on September 24, 2018, 05:59:21 pmWould make a fun project to come up with something absurd like that just to see how many investors you can get.

author: Red Squirrel
author_rank: Super Contributor
timestamp: September 28, 2018, 12:20:38 pm
content: Quote from: Bassman59 on September 26, 2018, 08:35:35 pmI imagine that would make a big difference too. I started putting panels on my shed roof but it was not really designed as part of the build and it was particularly tricky as I found out stud finders don't work over shingles so needed access to the attic to put blocking for the mount bolts. Basically drill hole first, go inside and add blocking where hole ended up, then go back to drill into blocking. Lot of back and forth. Not a big deal for a shed but for a house would not be very fun. For a new house then if you do it as part of the build, like put mounts before shingles go up so you can see where rafters are (the sheathing screw location) it would be easier.Getting the actual equipment such as PV modules and mounts was hard though, seems so many sites don't really have a buy option, and it's still too niche for anyone to bother selling it locally. Ended up finding the solar panels on Amazon and mounts on another site. Hopefully this stuff will become easier to buy as it gains popularity.

author: Bassman59
author_rank: Super Contributor
timestamp: September 28, 2018, 05:13:13 pm
content: Quote from: Red Squirrel on September 28, 2018, 12:20:38 pmWe contracted with a local well-regarded solar-power installer. They know the sort of construction used in houses in our city and they know how to put the systems on the roof. The install took two days, day one was building the support structures and the electrician set up the inverter and the meter and the disconnects, and on the second day they installed the panels and connected it up and verified it was all working.The best part about hiring the company to do it was that they deal with all of the permits. They drew up the plans, they dealt with presenting same to the city and ensured that it would all be approved. The process went as smooth as one could hope.

author: Bassman59
author_rank: Super Contributor
timestamp: September 28, 2018, 05:16:39 pm
content: Quote from: nctnico on September 26, 2018, 09:04:04 pmInterest rates on a first mortgage are still lower than a loan for a post-construction install. And the interest on $10k on a $500k mortgage isn't much of an adder. You can do the math. Especially when we know that a solar installation improves resale values. (My real-estate agent friends confirm this.)As for ROI? Here in Arizona, and certainly it's the same in southern and central California, the ROI on the panels is quick. Especially when you consider that the price of utility-supplied power will always go UP, while the cost of payments for panels will not.

author: Red Squirrel
author_rank: Super Contributor
timestamp: September 28, 2018, 06:18:26 pm
content: Quote from: Bassman59 on September 28, 2018, 05:13:13 pmOh that sucks never even thought about that, probably do need permits for panels on a house. My city is ridiculous when it comes to building bureaucracy so they probably require one too. For the shed I'm ok as any structure under a certain size does not require a permit to build so don't imagine I need a permit to do anything to it either. But that got me wondering what happens if I want to do the house... I think I would just play dumb and do it anyway. Would be on side of house so not that visible from the street. Technically, it's an electrical installation, and those don't require permits here, so maybe I'd actually be ok. Hard to tell. Sometimes it's easier to ask forgiveness than permission.The hardest part is getting the mounts in though. Would need to go in attic to add blocking after I drill holes, though it would be a good excuse to buy a FLIR gun... they are great for locating rafters.

author: nctnico
author_rank: Super Contributor
timestamp: September 28, 2018, 07:02:50 pm
content: Quote from: Bassman59 on September 28, 2018, 05:16:39 pmA mortgage runs much longer than a consumer loan so in the end you really have crunch some numbers to make a good comparison.

author: madires
author_rank: Super Contributor
timestamp: November 11, 2018, 03:17:10 pm
content: Sadly I have to announce that Germany got one too:http://www.solmove.com/en/home-2-2/.There's an article (in German) about a test installation near to Cologne:http://www.spiegel.de/wirtschaft/unternehmen/erftstadt-bei-koeln-deutschlands-erster-solar-radweg-oeffnet-a-1237681.html.

author: denial
author_rank: Newbie
timestamp: November 12, 2018, 11:22:50 pm
content: Also saw it on tv today. Must be somewhere around here:https://www.openstreetmap.org/#map=16/50.8122/6.827690m, 150 modules. Each module appears to consist of 144 10x10cm² tiles. The four corner tiles of each module look like they are dedicated to interconnection. So we've got 210m² of solar cells.They expect to generate 16MWh per year. A blog post on the Solmove site talks about 5-8€ payback and 100kWh per m² per year in Germany and a lifetime of about 25 years.The modules are said to heat up to remove ice.

author: Pluscrafter
author_rank: Regular Contributor
timestamp: November 13, 2018, 07:48:51 pm
content: Quote from: denial on November 12, 2018, 11:22:50 pmWhere there getting the energy to melt snow? From another power plant?Gesendet von meinem G8341 mit Tapatalk

author: Neilm
author_rank: Super Contributor
timestamp: November 13, 2018, 08:50:50 pm
content: Quote from: Pluscrafter on November 13, 2018, 07:48:51 pmThey store all the energy they capture during the summer and use it to melt the ice in winter.

author: Bassman59
author_rank: Super Contributor
timestamp: November 13, 2018, 10:27:18 pm
content: Quote from: nctnico on September 28, 2018, 07:02:50 pmA coworker made an observation yesterday about the extra $10k on the $500k property. "Wait a month and the value of the property will have increased more than the extra cost for the solar panels."

author: nctnico
author_rank: Super Contributor
timestamp: November 13, 2018, 11:02:20 pm
content: But the $10k will still be lost. It is the little things which add up to the most. That is the danger on buying expensive items. Everything else suddenly looks cheap.

author: PlainName
author_rank: Super Contributor
timestamp: November 13, 2018, 11:19:37 pm
content: QuoteDoes it matter? Suppose there were no solar panels but, instead, the company had proposed a road with built-in heating to melt ice and snow so hundreds of tons of salt wouldn't need to be spread over winter. Wouldn't that be a decent thing to do? Not only do you save the salt (and the manpower to spread it) you save the corrosion of vehicles and other stuff too. The big reason we don't see that kind of thing is because we can't do it, not because we wouldn't want to do it.So here we have not just the ability to keep roads ice-free but also to do it with less power than would otherwise be required. I'd say that's a win, yet there is determination to paint it as a massive fail.

author: Bassman59
author_rank: Super Contributor
timestamp: November 15, 2018, 04:46:12 pm
content: Quote from: nctnico on November 13, 2018, 11:02:20 pmDon't forget that the people buying these houses are blowing $25,000 on the kitchen accessories and furnishings. At least solar panels provide value -- and electricity!

author: vk6zgo
author_rank: Super Contributor
timestamp: November 15, 2018, 11:19:33 pm
content: Quote from: dunkemhigh on November 13, 2018, 11:19:37 pmIn countries with snowy winters, the amount of sunlight arriving on the solar road is going to be reduced during snowstorms, so there will be less power available to remove the resultant ice & snow.In Australia, it only snows in the mountainous areas in the SE of the country, so there is little advantage in "the ability to keep roads ice-free".In this, & other countries with similar climates, the things must stand & fall on their electricity generation ability.And why do you say "less power than would otherwise be required"?The heating system is unlikely to be highly efficient, & heavy snowfalls will still have to be removed mechanically, so most of your perceived advantage is lost, before even factoring in the energy used installing the solar panels

author: PlainName
author_rank: Super Contributor
timestamp: November 16, 2018, 02:36:12 am
content: QuoteYes, yes. I think you missed the drift (sorry!) of my comment. Assume the panel get no light at all. Nothing. Nada. It's still a snow melter.A bit like the airport around this way. They have heated runways to keep them clear in inclement weather, but periodically they get such a fall that they have to close. Doesn't negate the benefit those times it does work.In regards roadways, there has to be some thinking involved at some point. You don't need to keep twenty zillion miles of it ice-free: you can concentrate just on junctions and still reap a benefit.QuoteHey, maybe you could use them just for generating electricity threre! A novel thought, but...Sometimes a jack of many trades, master of none, can be more useful than a tightly focused genius. However, let me think a moment... tell you what, you could have panels aimed more at heating in icy locations and drop that bit in the sunny locations. I don't recall anywhere they said you had to use the exact same component regardless of where in the world it's going.QuoteSkip to the first para above: we assume there is no light at all. It's pure heating. We also assume that some heating is better than none (remember, doesn't have to be perfect, just usable). OK, not it might be a surprise but on some days it won't actually be night, and there will be a leetle bit of electricity generated. Not a lot, but some. Feed that back to the heaters and wouldn't you agree that you are suddenly usinglessexternal power than if you didn't?QuoteIt's heating. The inefficient part of the energy is going to disappear as... well, I'm sure you don't need me to point it out. Feel free to correct me (yes, really) but ISTM the two questions are: 1. Is the heat going to go up or down, and 2. depending on insulating properties of the panel surface, how early do you need to turn it on to have the heat leak through in time to be useful?Actually, that does raise another thing: could the heat from the daytime sun be used as well as light? being embedded in a huge heatsink, I'm sure you could arrange for a temperature gradient across them (even if that meant, say, a borehole of an inch across and a few m deep under each). Maybe, if that worked, you could do the reverse for the snowy locations.