Will requiring solar panels on new buildings reduce their overall cost?

[khanh dam]

Probably should be asking this in a general contractor forum. I have been reading with interest how California is now requiring solar panels on all new 2020 houses, and Massachusetts is considering a similar law.

It seems to me that anything that is mass installed should become cheaper. I would venture to say that because almost every GT install is Unique it drives up the cost by at least 30%. If a solar installer can have a dozen pre configured systems and all the wiring can be done before drywall, insulation is in the way, I think it should be much cheaper, plus the extra 10% of so that would be saved by buying the solar panels in bulk would be a bonus, Shipping fees easily add a few hundred to any installation as well.

I think the major obstacle for widespread solar is still it's inefficiency. A 2000 square foot house still requires about 20x28' feet of space for a 8kw solar array. If only efficiency could be improved by 50% or more it would be the best thing for solar!

[ButchDeal]

Probably should be asking this in a general contractor forum. I have been reading with interest how California is now requiring solar panels on all new 2020 houses, and Massachusetts is considering a similar law.

It seems to me that anything that is mass installed should become cheaper. I would venture to say that because almost every GT install is Unique it drives up the cost by at least 30%. If a solar installer can have a dozen pre configured systems and all the wiring can be done before drywall, insulation is in the way, I think it should be much cheaper, plus the extra 10% of so that would be saved by buying the solar panels in bulk would be a bonus, Shipping fees easily add a few hundred to any installation as well.

I think the major obstacle for widespread solar is still it's inefficiency. A 2000 square foot house still requires about 20x28' feet of space for a 8kw solar array. If only efficiency could be improved by 50% or more it would be the best thing for solar!

a few things.

Installers often buy in bulk anyway, this will not change the amount they buy. Construction as well as solar installers don't like to have a huge amount of inventory.
the equipment still has to be shipped
Not much wiring is done through the walls with most solar using outside conduit anyway
Where do you get that the uniqueness of installs drives up cost by 30%. Most home construction is unique in general. Most home electrical is unique. Solar is just the same as almost all other home construction stuff.
Tesla is trying to make packages but they are finding that this doesn't work so well on the construction side as a 4kW unit doesn't perform the same on every house even right next to each other with different azimuths, shadows, obstructions, even roofing types.

50% improvement in efficiency is not going to happen any time soon.
This is not going to get you the space savings you are thinking of as 50% improvement in efficiency would be from about 20% efficient to 30% efficient
It is far easier and what has been happening for the past decade to reduce the costs considerably not the area.

[khanh dam]

shipping 100 8kw systems to one new subdivision is going to be cheaper than shipping 100 systems to 100 different job sites.
If installers dont' like a huge amount of inventory then how can they buy in bulk like you claim, the two go hand in hand right, even if it is short term inventory for a few months. . no one likes inventory is basically true of every business. .
I get the 30% cost increase because that is about the amount of extra time designing every new system. Obviously unique designs take more time, whether that is 10% or 30% more time is up for debate, but the cost savings are real.

[ButchDeal]

shipping 100 8kw systems to one new subdivision is going to be cheaper than shipping 100 systems to 100 different job sites.

If there are building ALL 100 homes at the same time and they are all ready for the solar to be add at the same time. This would be an odd construction site. Generally only a few are under construction at a time and they are all staggered such that the different crews can move from building to building as they finish and that is only when they are building on spec. Usually they only build as the owner buy the land and choose the options.

If installers dont' like a huge amount of inventory then how can they buy in bulk like you claim, the two go hand in hand right, even if it is short term inventory for a few months. . no one likes inventory is basically true of every business. .

Installers like construction builders get things together so that they can order several projects at once. Often one or two weeks worth and schedule the deliveries most often to the site but some times to the installers location. months would be very odd for even large installers, one or two weeks would be a more typical order.

I get the 30% cost increase because that is about the amount of extra time designing every new system. Obviously unique designs take more time, whether that is 10% or 30% more time is up for debate, but the cost savings are real.

The solar design process is pretty automated at this point. If you have the building (roof really) in a cad system, you can input it and get the layout. The electrcal is pretty automated from there. All the surrounding shadow systems have to be added as well. The only savings at building construction is that you have the cad files need to input saving doing the actual 3D design of the building, but some of the systems like Aurorasolar can do much of that automated from LiDAR now.
Savings would be minimal in the design side, unless every house in the neighbor hood is exactly the same with same orientation and no shadows (a very odd neighborhood).

[emartin00]

I have seen studies on sub divisions where solar is mandated, and it can reduce the cost. This is because there are a limited number of house designs that can be chosen, and the solar installers work up a design for each one ahead of time. Once the initial engineering is done, there is no more design work to be done, and the initial building permit already includes the solar, so there is no separate permit costs.
The contractors can also work together and have the wiring ready to go, and the roofers can install the mounts as they go.

[khanh dam]

much of that automated from LiDAR now.

INTERESTING! so they use drones with lidar? Personally I am not a fan of these newer roofs with tons of valleys and intersecting lines, horrible for solar and doens't really look that great etiher.

[bcroe]

Hardly any of this applies to solar other places such as the mid west, we often
do not even put solar on the roof. I am used to seeing totally different house
designs, from different decades (or even different centuries) in any division.
Bruce Roe

[ButchDeal]

INTERESTING! so they use drones with lidar? Personally I am not a fan of these newer roofs with tons of valleys and intersecting lines, horrible for solar and doens't really look that great etiher.

There are LiDAR sets of whole sates flown by planes already that you can use without getting your own but YES there are some installers that have drones with LiDAR. We have done a few with them.

I tend to agree about the many facetted roofs that are common builder adders. It has little effect other than adding cost to the build, adding cost to every re-roofing that happens over the years, and making solar very difficult.

[ButchDeal]

I have seen studies on sub divisions where solar is mandated, and it can reduce the cost. This is because there are a limited number of house designs that can be chosen, and the solar installers work up a design for each one ahead of time. Once the initial engineering is done, there is no more design work to be done, and the initial building permit already includes the solar, so there is no separate permit costs.
The contractors can also work together and have the wiring ready to go, and the roofers can install the mounts as they go.

I call BS. Even if they only have one house the design would be different if it is on the north side of the road VS the south side, or east/west side.
And then there are options that homeowner choose.

What I have seen and we have seen people ask about on here a few times is yes the builder has a few options (but not designs). It is either a 3kW, 5kW, or 8kW, they then work it into the building design.
One builder only had options of 2,3, or 5kW. Talked to a homeowner how had all Electric home and two electric cars, who calculated we would need 11kW or more to offset but builder only would go as high as 5kW... and on top of that the difference in cost from the 2-5kW indicated a HIGH cost per watt.

The initial building permit does include all electrical so there should be saving there (~$200). Still need interconnect application though.

[azdave]

Will requiring solar panels on new buildings reduce their overall cost?

I doubt it. How often do you see a purchase mandated by law become cheaper for the customer than before when they had a choice?

[malba2366]

Yes, it will remove some a lot the soft costs related to sales. It will be something that regular electricians will start doing to serve the homebuilders, it will be.

[khanh dam]

Will requiring solar panels on new buildings reduce their overall cost?

I doubt it. How often do you see a purchase mandated by law become cheaper for the customer than before when they had a choice?

How often do you see the reverse? Something becoming more expensive over time? Governement higher insulation values, higher AC HVAC Seer values, hot water solar in HI, all save money in the long run for consumers.

[Markyrocks69]

How often do you see the reverse? Something becoming more expensive over time? Governement higher insulation values, higher AC HVAC Seer values, hot water solar in HI, all save money in the long run for consumers.

Lol everyday, it's called inflation.

[solarix]

Some of the most difficult, hassle-full systems I've installed are new-construction homes. Scheduling problems, working around other trades, General Contractor wanting to add their 10% to the cost of the solar system. The electrical contractor not knowing squat about solar, and worst of all - the architect wanting to cut the roof up into a bunch of expensive looking little patches. The owner's financing getting tapped out from everything being over budget so that the last installed item - the solar system, gets canceled.

[J.P.M.]

How often do you see the reverse? Something becoming more expensive over time? Governement higher insulation values, higher AC HVAC Seer values, hot water solar in HI, all save money in the long run for consumers.

Well, if solar energy utilization in CA is any measure, I'd say residential electric bills seem to be going up more than down just now. As for saving money, probably, but maybe not as much as you might think. More than a few folks I know who have added PV actually see lower electric bills as a carte blanche to use more electricity. The result is their bills are lower but not as low as pre PV usage would have you think.

Dirty little secret: Data is sketchy, but it may well be that residential electricity usage commonly increases after the addition of PV. It goes up about 10 % or so in the homes I monitor in my HOA after PV is added.

Conservation measures do reduce use no question. However, some to most of the benefit is often lost when the more draconian effects of the former high electric bills are removed by the better efficiency attained by conservation and by alternate energy generation. My guess is use then increases until the albatross of high bills again gets large enough to be a drag on reality.

In a way, energy conservation and alternate energy utilization can be thought of as ways to allow even more profligate energy use by reducing the size of the hammer swung by high electric bills that force use reduction by hitting consumers directly and seemingly continuously (it would seem) in the wallet.

Anyway, the idea of saving money long term by spending money upfront against future savings, while perfectly sensible and something I'm quite familiar with, is understood by few and practiced by fewer.

Alternate energy and conservation measures, when mandated by legislation, become overpriced when forced down people's throats by fiat and further adding more bureaucracy for admin./enforcement. There are better ways to get people to reduce the waste.