LMG wants to add solar power, what a professional roofer has to say.

[Commodore Sim]

So a few weeks ago (floatplane calender) a video was posted where @LinusTech mentioned that solar might be a project LTT/LMG could engage in. While I'm generally lukewarm at best on the cost effectiveness of solar.  I'll put those opinions to the side now and focus only on the building integration side of adding solar.

I'm a commercial flat roof installer with over 10 years experience, I'm also well learned in most external building systems.

When adding something like solar to your building there's a bad way, a good way, and a best way.  Not surprisingly the price is proportional. Though this is only the install price, down the lifespan it's back to front.

There are two ways to mount solar.  To the side of a building or onto the roof.  Greater latitude means more angle on the panels as well.  Likely we can assume that LMG would opt for the roof install.  There are a few areas of consideration:

Building Integration:

LMG studio has a single ply ballasted EPDM rubber roof.  This means that the water is basically kept out by fully cured inner tube rubber (EPDM).  And the 1-1_1/2" inch stones spread across the roof are ballast to hold the roof in place against wind tear off.  Though they also have the effect of blocking UV rays from the membrane, which is always handy.

This type of roof is relativity inexpensive but performs extremely well against the forces of nature.  Unfortunately it performs poorly against the meddling of humans, more on this later.

Any solar array will be build onto a metal skeleton, the point we want to look at today is how that framework installs to the building.  The simplest method is to simply place said framework upon the roof and weigh it down. This is the dumbest idea ever, just ask the Canadian Tire store in Kenora Ontario who did exactly this on a roof identical to LMGs roof.  They spent a lot of money hiring my classmates to repair many holes after water leaked into the building then more reinstalling the framework properly.

The proper way would be to use rubber mats or rubber bricks (C-Port is a popular choice).  This method also would use some variety of ballast weight. However while being somewhat less expensive it takes up more space.

My personal choice is to fully anchor the framework to the building itself.  There are a couple of ways to do this but both would have you hiring a roofing company to "tie in" the structural mounts to the roof.  This method would not require a structural engineer assuming your panels aren't too heavy. If done properly this is the cleanist looking install, and you're not relying on ballast to secure your panels.  Technically this method can be done DIY as there aren't any expensive special tools needed however your roof is the first line of defence keeping the weather out of your building so if DIY, best not make costly mistakes.

Electrical integration:

Simply put the power needs to entry the building.  This can be done through the exterior walls or through the roof.  I recommend going through the roof as it's less external electrical.  Again same warning about messing with roof applies. Roofers aren't the cheapest but far less than mistakes.

Maintenance:

I'll be honest I don't know how well rain cleans solar but one must consider dirt and possibly snow buildup.  Regardless at some point you will need to access and service. LMG already has an advantage since their building already had a roof access ladder.  Some thought may want to be put into providing a rooftop walkway, this would essentially be rubber mats or patio stones with a protective layer between stone and roof.  Don't worry I'm not saying you need a metal gantry way or anything so fancy. Another possible feature would be an external water tap. There are special kind that have their value inside the building so water won't freeze in the pipes.

Safety:

This is part of the maintenance section.  Working at heights is regulated by each province through their workplace safety administration.  And an uncontrolled rooftop requires special training of a worker who is on the roof. Yes that remote access video LTT just made is a workplace safety violation though I can't imagine they'll get trouble over it.

IMO the easiest solution is to turn your roof into a controlled workspace.  This is easily done by having maker lines that show the worker where the safe areas of the roof are.  Essentially a series of posts with cables strung between them forming a corridor from the ladder to the solar and creating a perimeter around the solar.

They could of course ignore this safety portion, and have a fair chance to get away with it.  However an once of prevention, saves a pound of cure.



 

[BuckGup]

Knowing Linus he’ll be like I ordered these 50 solar panels off Aliexpress and wired them up and we are making enough to power 1 PC. The title would be HOW TO POWER YOUR PC WITH FREE ENERGY!!

 

Really though you sound like you know what you are talking about and @LinusTech should have a read before considering 

[Jtalk4456]

9 minutes ago, Commodore Sim said:

1. There are two ways to mount solar.  To the side of a building or onto the roof.

2. My personal choice is to fully anchor the framework to the building itself.  There are a couple of ways to do this but both would have you hiring a roofing company to "tie in" the structural mounts to the roof.  This method would not require a structural engineer assuming your panels aren't too heavy. If done properly this is the cleanest looking install, and you're not relying on ballast to secure your panels.  Technically this method can be done DIY as there aren't any expensive special tools needed however your roof is the first line of defence keeping the weather out of your building so if DIY, best not make costly mistakes.

3. Electrical integration:
Simply put the power needs to entry the building.  This can be done through the exterior walls or through the roof.  I recommend going through the roof as it's less external electrical.  Again same warning about messing with roof applies. Roofers aren't the cheapest but far less than mistakes.

4. Maintenance:
I'll be honest I don't know how well rain cleans solar but one must consider dirt and possibly snow buildup.  Regardless at some point you will need to access and service. LMG already has an advantage since their building already had a roof access ladder.  Some thought may want to be put into providing a rooftop walkway, this would essentially be rubber mats or patio stones with a protective layer between stone and roof.  Don't worry I'm not saying you need a metal gantry way or anything so fancy. Another possible feature would be an external water tap. There are special kind that have their value inside the building so water won't freeze in the pipes.

First off, I know some basic carpentry, but my field of study in college was appropriate tech (solar, wind, efficient building practices, etc). I'm curious why you say solar isn't very cost effective.

1. I know it's possible for a wall install, but in your experience is this actually common?

2. I definitely agree, and I would personally imagine the wall extends up past the floor of the roof a few feet at least, and I would imagine something like this would be cheap and effective with no compromises to the structure, though that can depend on the size of the roof.

3. Would you not be more worried about creating an extra point for leaks in the roof vs a hole in the wall somewhere?

4. I've only worked with residential roofing, so I may be very wrong here, but I thought that was still structural enough to walk on?

 

[Commodore Sim]

30 minutes ago, Jtalk4456 said:

First off, I know some basic carpentry, but my field of study in college was appropriate tech (solar, wind, efficient building practices, etc). I'm curious why you say solar isn't very cost effective.

1. I know it's possible for a wall install, but in your experience is this actually common?

2. I definitely agree, and I would personally imagine the wall extends up past the floor of the roof a few feet at least, and I would imagine something like this would be cheap and effective with no compromises to the structure, though that can depend on the size of the roof.

3. Would you not be more worried about creating an extra point for leaks in the roof vs a hole in the wall somewhere?

4. I've only worked with residential roofing, so I may be very wrong here, but I thought that was still structural enough to walk on?

 

I'll answer the bit about cost effective in another reply.

 

1. It is common enough though often this is planned with new construction.  I really only meantion it to signify I've accounted for the option. And don't recommend it for LMG.

 

2. Parapet: a wall that extends above a horizontal surface but is not enclosed.

 

Roof deck: the rigid structural component of a roof.

 

I think you're suggesting a horizontal beam that bridges the the entire roof resting on the parapets. While such things exist(see photo) this would not be a good application for this purpose.  I'll mostly file them in the 'trust me' category. But one reason is that the parapet for the LMG building isn't all that strong, especially against the added wind sheer.  While the parapet in the photo is atop a much stronger concert parapet.

 

3. Atop the roof works directly against gravity, mounting to a wall puts the stress at an angle.  Roof leeks are definitely a concern but I've that can be migrated.

 

4. You've missassumed the hazard.  The risk is falling off the roof. Not roof collapse.  As a roofer I play cat and mouse with occupational health and safety on a constant basis.

 

[Jtalk4456]

1 hour ago, Commodore Sim said:

I'll answer the bit about cost effective in another reply.

 

1. It is common enough though often this is planned with new construction.  I really only meantion it to signify I've accounted for the option. And don't recommend it for LMG.

 

2. Parapet: a wall that extends above a horizontal surface but is not enclosed.

 

Roof deck: the rigid structural component of a roof.

 

I think you're suggesting a horizontal beam that bridges the the entire roof resting on the parapets. While such things exist(see photo) this would not be a good application for this purpose.  I'll mostly file them in the 'trust me' category. But one reason is that the parapet for the LMG building isn't all that strong, especially against the added wind sheer.  While the parapet in the photo is atop a much stronger concert parapet.

 

3. Atop the roof works directly against gravity, mounting to a wall puts the stress at an angle.  Roof leeks are definitely a concern but I've that can be migrated.

 

4. You've missassumed the hazard.  The risk is falling off the roof. Not roof collapse.  As a roofer I play cat and mouse with occupational health and safety on a constant basis.

 

Fair enough

[Commodore Sim]

47 minutes ago, Jtalk4456 said:

First off, I know some basic carpentry, but my field of study in college was appropriate tech (solar, wind, efficient building practices, etc). I'm curious why you say solar isn't very cost effective.

 

 

My words were that I was lukewarm at best about the cost effectiveness.

 

What you must understand is that present solar integrations are completely biased and uselessly unrepresentative of the cost model.

 

There are almost always subsidies so you never pay the actual price, selling to the grid won't scale.

 

Right now basically nobody has solar, were you to round off to the nearest whole number 0% of the population had their own solar.  That's how few actually have solar.  So when power grids do buy solar from residential systems it's strictly a PR move.  Similar subsidies are also PR expenditures.

 

Were solar to go mainstream then those subsidies will disappear or be hugely reduced.  While power companies simply won't buy it at that scale.  The price is too high, the power is electrically dirty which damages the grid, it's too unreliable, and the administration costs would be obcene.

 

Without subsidies and grid purchase the residential solar integrator pays the real price and while in theory they will pay less than buying from the grid.  The break even point is at the 15-20 year mark.  And you have to pay up front or get a mortgage loan for your solar, which raises the total.

 

The big issue is that a solar system lasts only about 15-20 years before it must be replaced and the output deminshes over the lifespan too.  Further extending the payoff period.

 

So basically in a general deployment of solar you don't save any money, the lifespan of the system affects your home sale price.  The only positive outcome is that you are living on reduced carbon, though solar production is extremely toxic, as is recycling old panels.

 

[TechyBen]

Supply and demand.

If it has a 10-20 year payoff, then the supply will cost 10-20 years of budget to the end user/consumer (commercial prices will be different).

If this was not the case, you could remortgage a few trillion, buy all the panels, and become Apple.

 

The economy fights such things.

[Commodore Sim]

10 minutes ago, TechyBen said:

Supply and demand.

If it has a 10-20 year payoff, then the supply will cost 10-20 years of budget to the end user/consumer (commercial prices will be different).

If this was not the case, you could remortgage a few trillion, buy all the panels, and become Apple.

 

The economy fights such things.

I have no idea what you're saying.

[Yoinkerman]

We have some 25 yr + solar installs, they're very very low maintenance, we've only replaced panels if they fall over or are shot or something of that nature. Lmg won't have to deal with snow load where they are, but what we do is make the panels as vertical as possible.  Works great.  The output doesn't diminish nearly as bad as people claim.  The real magic is in the controllers, new mppt controllers are so much better than old ones.

[Jtalk4456]

15 hours ago, Commodore Sim said:

1. There are almost always subsidies so you never pay the actual price, selling to the grid won't scale.

Were solar to go mainstream then those subsidies will disappear or be hugely reduced.  While power companies simply won't buy it at that scale.  The price is too high, the power is electrically dirty which damages the grid, it's too unreliable, and the administration costs would be obcene.

2. And you have to pay up front or get a mortgage loan for your solar, which raises the total.

3. The big issue is that a solar system lasts only about 15-20 years before it must be replaced and the output deminshes over the lifespan too.  Further extending the payoff period.

4. Though solar production is extremely toxic, as is recycling old panels.

 

1. I will agree to this point, though I believe that by the time they have grown enough for subsidies to disappear, the price will have come down proportionally or even more than the increase in price due to loss of subsidies. This is just my assumption though.

2. Yes and no. The way this is typically made cost effective is that in paying the extra $X/month on loan for the panels, you save having to pay $X+/month in electricity bills. And once that loan is done, it's just profit at that point. Having said that, I will admit this makes less sense in the case of retrofitting old construction. I still think it CAN make sense in many situations, but the ideal is new construction, where the upfront cost will just be part of the whole mortgage and the actual installation doesn't involve making holes and replacing walls

3. I would beg to differ on this one. Most last far longer than that

Quote

For monocrystalline silicon, the most commonly used panel for commercial and residential PV, the degradation rate is less than 0.5% for panels made before 2000, and less than 0.4% for panels made after 2000. That means that a panel manufactured today should produce 92% of its original power after 20 years, quite a bit higher than the 80% estimated by the 1% rule.

further someone in the comments extrapolated further:

Quote

With 0.2% degradation, the panel will still produce 81.8% after 100 years.

https://www.engineering.com/DesignerEdge/DesignerEdgeArticles/ArticleID/7475/What-Is-the-Lifespan-of-a-Solar-Panel.aspx

Quote

As a general solar industry rule of thumb, solar panels last 25-30 years. However, this doesn’t mean that they stop producing electricity after 25 years – it just means that energy production has declined by what manufacturers consider a significant amount. Solar panels can continue to work for many decades, given they aren’t physically damaged by wind, debris, or any other factors. This is primarily because solar panels don’t have any moving parts – they rarely break from within and are only ever damaged by outside forces like poor racking or bad weather.

https://news.energysage.com/how-long-do-solar-panels-last/

4. While there is some mining required as with anything, the result is still far less toxic than burning coal or oil. 

Quote

You don’t need to worry about the carbon footprint of your solar panels, either. The 25 to 30 year lifespan of a solar panel is significantly longer than its “energy payback time,” or EPBT. EPBT is the amount of time it takes for a solar panel to produce enough clean electricity to “pay back” the energy that was used to manufacture it in the first place. A 2010 analysis from Brookhaven National Laboratory found that the EPBT of a solar panel is just six months – a number that has surely fallen in the past six years as panel manufacturing becomes more efficient.

https://news.energysage.com/how-long-do-solar-panels-last/

Quote

 

The panels themselves, like any other electrical appliance, may also contain a number of toxic materials (to name a few, cadmium telluride, copper indium selenide, and sulfur hexafluoride). These materials are used in the manufacturing process for many other electronics, like your cell phone or laptop.

While many of these chemicals are hazardous, they aren’t so while the panels are on your roof. The concern for their toxicity comes into play during the manufacturing process, as well as disposal process from by products during the manufacturing process, and at the end of the panel’s lifetime. 

Responsible solar panel manufacturers will ensure that the chemicals used in the manufacturing process are handled properly.

 

https://news.energysage.com/solar-panels-toxic-environment/

[TechyBen]

15 hours ago, Commodore Sim said:

I have no idea what you're saying.

Supply and demand. If you supply solar at cheap rates, everyone wants it, so demand goes up, so pricing goes up because of shortages of stock.

If you up the price, demand goes down, so you tend to get forced to reduce price to meet sales, or keep a high price and no one buys it.

 

If Solar panels cost 50c/p each, and made $/£100 electricity a day, then the price of panels would skyrocket to meet the demand, or the price of electricity would plummet because of oversupply.

 

That means, unless some magic comes along, diesel, petrol, gas, electric, wind, solar, etc of the same difficulty/supply demand will cost and perform similar. With the exception of really expensive systems (nuclear etc), or really "free" (hydro electric in the main), the pricing will stabilize.

 

Which means you can only play the strengths of the system. Petrol for easy storage and delivery. High density and performance. Solar/electric for less logistics (no longer need to drive to a petrol station ), or "off grid" systems. Low maintenance (vs generators) or tax/price guarantees (unlike petrol prices that fluctuate, the sun outpt is rather steady state).

 

Early adopters can get in before others, use that benefit to gain a foothold in the market, or take early gains on price/supply. But generally things balance out. For example, over the life of the car, a diesel or petrol can work out the same costs, even though the fuels have different prices/performance on MPG. It depends how long you use each, how large the vehicle. It's not as simple as "A is cheaper than B". It is only "A is cheaper than B when C applies".

[Jtalk4456]

17 minutes ago, TechyBen said:

Supply and demand. If you supply solar at cheap rates, everyone wants it, so demand goes up, so pricing goes up because of shortages of stock.

If you up the price, demand goes down, so you tend to get forced to reduce price to meet sales, or keep a high price and no one buys it.

 

If Solar panels cost 50c/p each, and made $/£100 electricity a day, then the price of panels would skyrocket to meet the demand, or the price of electricity would plummet because of oversupply.

 

That means, unless some magic comes along, diesel, petrol, gas, electric, wind, solar, etc of the same difficulty/supply demand will cost and perform similar. With the exception of really expensive systems (nuclear etc), or really "free" (hydro electric in the main), the pricing will stabilize.

 

Which means you can only play the strengths of the system. Petrol for easy storage and delivery. High density and performance. Solar/electric for less logistics (no longer need to drive to a petrol station ), or "off grid" systems. Low maintenance (vs generators) or tax/price guarantees (unlike petrol prices that fluctuate, the sun outpt is rather steady state).

 

Early adopters can get in before others, use that benefit to gain a foothold in the market, or take early gains on price/supply. But generally things balance out. For example, over the life of the car, a diesel or petrol can work out the same costs, even though the fuels have different prices/performance on MPG. It depends how long you use each, how large the vehicle. It's not as simple as "A is cheaper than B". It is only "A is cheaper than B when C applies".

I get what you're aiming at though I don't believe it will simply balance out to the extent you're talking. Sometimes a is simply cheaper than b due to cheaper materials, cheaper process, etc

[TechyBen]

Oh, but Solar generally is not. The cost of producing good panels + batteries + charge/controllers makes it break even over the 10 years for consumers. Though industries can get it at bulk and better returns.

 

Where as a generator tend to be more expensive than buying off the grid. Buying off the grid is generally cheaper in the short run compared to solar. It's not just "B is cheaper" (see my example of diesel vs petrol cars).

 

Basically anything a consumer can do, the electric company can do in bulk and thus cheaper, and you could just buy it off them at that rate. Their prices are what purely sets if solar is worth it or not economically. Your needs (off grid etc), is what sets if it is worth it to you personally.

[dalekphalm]

2 hours ago, VegetableStu said:

hmm interesting. wondering from the standpoint of a houseowner though. Paul recently converted his roof to a locally-stored solar roof recently o_o

Paul went with a more expensive solution - he went with SolarCity (Tesla's sister company) + a Tesla Power Wall. SolarCity itself seems to be fairly cost competitive with any premium solar installer, so no problems there. But the Power Wall is very expensive. You could buy or build a much cheaper battery array, but it'll be dumb as nails.

 

So he bought the more expensive "turnkey" solution, because it was literally "drop in place and go". Which is awesome - you just have to pay a premium for it.

 

He also has the benefit of living in SoCal, so his location is fairly ideal for sun efficiency, not many rainy or cloudy days, no snow, etc.

 

Solar for a residential home is still a good investment if you can afford the upfront costs, especially if you can afford to pop a battery in, so you can utilize your solar power during the night.

 

I plan to eventually install Solar after I buy a home, though I haven't worked out any specifics yet.

[Commodore Sim]

4 hours ago, TechyBen said:

Supply and demand. If you supply solar at cheap rates, everyone wants it, so demand goes up, so pricing goes up because of shortages of stock.

If you up the price, demand goes down, so you tend to get forced to reduce price to meet sales, or keep a high price and no one buys it.

 

If Solar panels cost 50c/p each, and made $/£100 electricity a day, then the price of panels would skyrocket to meet the demand, or the price of electricity would plummet because of oversupply.

 

That means, unless some magic comes along, diesel, petrol, gas, electric, wind, solar, etc of the same difficulty/supply demand will cost and perform similar. With the exception of really expensive systems (nuclear etc), or really "free" (hydro electric in the main), the pricing will stabilize.

 

Which means you can only play the strengths of the system. Petrol for easy storage and delivery. High density and performance. Solar/electric for less logistics (no longer need to drive to a petrol station ), or "off grid" systems. Low maintenance (vs generators) or tax/price guarantees (unlike petrol prices that fluctuate, the sun outpt is rather steady state).

 

Early adopters can get in before others, use that benefit to gain a foothold in the market, or take early gains on price/supply. But generally things balance out. For example, over the life of the car, a diesel or petrol can work out the same costs, even though the fuels have different prices/performance on MPG. It depends how long you use each, how large the vehicle. It's not as simple as "A is cheaper than B". It is only "A is cheaper than B when C applies".

So market prices are a ring and do matter, however every product has a base price, meaning a minimum sustainable price.  This includes production costs, shipping cost, sales cost, install cost, and done profit so those people can provide enough of a living to incentivize keeping their company in business.

 

I have much trouble following your writings, but it doesn't seem like your philosophy has accounted for this minimum.

[TechyBen]

Yeah, sorry. Was rather rushed in posting.

 

Minimum price seems redundant to me, unless you are a producer. For example, iPhones cost around £100 to produce. But you could not buy one for that!

 

Solar is not cheap, it's minimum is not low. Gas/petrol/grid power is not either, but has a larger existing base to cover some startup costs.

 

As an example where solar does work, is there not India? IIRC it's the cheapest "cost" per watt: https://economictimes.indiatimes.com/industry/energy/power/india-solar-goal-has-a-secret-weapon-rooftops-of-small-business/articleshow/63180449.cms

 

But even they are hitting supply/demand limits.

 

(As an example, I did a small solar installation cost to check the value to me a few years ago. It turned out, at a low usage, it only really swaps convenience, as a generator+fuel would have cost around the same. However, at other scales, it totally makes sense!  )

[Commodore Sim]

4 hours ago, TechyBen said:

Yeah, sorry. Was rather rushed in posting.

 

Minimum price seems redundant to me, unless you are a producer. For example, iPhones cost around £100 to produce. But you could not buy one for that!

 

Solar is not cheap, it's minimum is not low. Gas/petrol/grid power is not either, but has a larger existing base to cover some startup costs.

 

As an example where solar does work, is there not India? IIRC it's the cheapest "cost" per watt: https://economictimes.indiatimes.com/industry/energy/power/india-solar-goal-has-a-secret-weapon-rooftops-of-small-business/articleshow/63180449.cms

 

But even they are hitting supply/demand limits.

 

(As an example, I did a small solar installation cost to check the value to me a few years ago. It turned out, at a low usage, it only really swaps convenience, as a generator+fuel would have cost around the same. However, at other scales, it totally makes sense!  )

Solar PV is an interesting technology.  As far as installation goes it scales linearly.  Though I will admit that buying in bulk is always cheaper.  

 

But this is to say that adding panels gives you a 1:1 increase in output.  No other system is like this except wind turbines. Most systems have exponential effect when you change the scale. Or recieve other limitations.  

 

The only part of solar that does scale exponentially is the quality of the inverter you can provide.  Though you need an epicly huge array before this triggers.  Though this is really more of a comment on grid integration.

 

I feel that solar is a great technology to charge batteries and I'm mostly looking at vehicles when I say this.  I think it's a terrible technology for mission critical applications.

 

I also like it for 'some electricity is better than none' think rural locations in the developing world.  Any amount of labor saving machines to liberate women, or powering Internet access for education.

 

But if a grid exists I prefer concentrated generation, particularly nuclear.

 

That being said I do like the idea of renewable DC micro grids.  Small towns or suburbs that share solar but aren't inputting to the main grid. Though this is very bourgeois.