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I'm going to be the grumpy utility economist here and remind everyone of a few inconvenient truths:
- Unless you're truly off-grid, you're not generating the power that your car uses. You are offsetting the power you use with power from your panels. Depending on where you live, this may not fully offset your carbon footprint (or it may more than offset your carbon footprint).
- Only about half of your electricity rate is to cover the cost of the electricity generation (both capital and operating costs). The other ~half covers the cost of the distribution and transmission system. So, until PV costs are equal to or below the generation component of your electricity tariff, it is still uneconomic (from a societal POV).
- The fact that uneconomic power is economic from the consumer's POV points to a serious problem that cannot continue. Allowing customers to avoid paying for their share of the transmission and distribution costs, just because they generate electricity on-site, is ultimately unsustainable. If you're off-grid, this doesn't apply to you. If you generate surplus power during the day, and buy needed power at night, you are indeed benefiting from the utility's wires; so, it's inequitable that you should not help cover their costs or, even more bizarrely, be paid at a rate (=the full retail tariff) that implies that you built and maintain the grid.
MitchL
S#945
Robert,
I fully agree with all your points, but for comfort, you could also look at it this way:
* Fully true about being fully off-grid and not generating the power the car uses (night shift people aside, that is). I view the utility as a sort of battery -(energy to money to energy). During the day is peak energy usage in an industrial area, so home PV systems are definitely helping the utilities. I think it's easy to posit the we do offset our carbon footprint by reducing the need to bring extra capacity online during daylight, when demand is highest.
* With customers installing their own PV or other generation equipment, they are essentially reducing the capex of the local utility (we home PV systems are providing capital for their use). With enough PV, the utility may not need to install additional generation capacity of its own, or can run existing facilities at reduced capacity (and hopefully reduced cost, even when fuel is factored out). Even not building a single small facility could mean huge savings for the utility.
* I understand that with since deregulation, generation is mostly separate from distribution, but you still find the same companies both building generation facilities and maintaining the lines. (it's all money at some point).
* If a real, significant percentage of all power generated by a utility was from home PV systems, you can bet the PV owners would get (rightfully) hit with a "grid tie fee" in the form of T&D costs.
Until we reach the "significant percentage" tipping point, the least that the utilities can do for us as "home power exporters" is to help cover the T&D. It's in their best interest, isn't it?
That said, on or off grid, I'm still pretty stoked to be installing PV on the house, and in my mind I'll imagine that it's being used to charge the car
.
/Mitch.
I fully agree with all your points, but for comfort, you could also look at it this way:
* Fully true about being fully off-grid and not generating the power the car uses (night shift people aside, that is). I view the utility as a sort of battery -(energy to money to energy). During the day is peak energy usage in an industrial area, so home PV systems are definitely helping the utilities. I think it's easy to posit the we do offset our carbon footprint by reducing the need to bring extra capacity online during daylight, when demand is highest.
* With customers installing their own PV or other generation equipment, they are essentially reducing the capex of the local utility (we home PV systems are providing capital for their use). With enough PV, the utility may not need to install additional generation capacity of its own, or can run existing facilities at reduced capacity (and hopefully reduced cost, even when fuel is factored out). Even not building a single small facility could mean huge savings for the utility.
* I understand that with since deregulation, generation is mostly separate from distribution, but you still find the same companies both building generation facilities and maintaining the lines. (it's all money at some point).
* If a real, significant percentage of all power generated by a utility was from home PV systems, you can bet the PV owners would get (rightfully) hit with a "grid tie fee" in the form of T&D costs.
Until we reach the "significant percentage" tipping point, the least that the utilities can do for us as "home power exporters" is to help cover the T&D. It's in their best interest, isn't it?
That said, on or off grid, I'm still pretty stoked to be installing PV on the house, and in my mind I'll imagine that it's being used to charge the car
./Mitch.
I have Sunmodule SW 255 panels
http://www.solarworld-usa.com/system-designers/~/media/Global/PDFs/datasheets/sunmodule-solar-panel-255-mono-ds.pdf
I have inside information which indicates that the cost per watt of solar is likely to drop below 20% of what it is now within the next 10-20 years, and the cost per watt of energy storage will almost certainly drop to less than 10% of what it is now, so I suspect that's going to swamp most other effects; it will make it much easier to go "off the grid". At some point the grid maintenance costs will have to be reduced to match the new battery costs, or the grid will just be dismantled. Grid balancing will become a more and more serious issue, though the same people who've made the battery and solar panel breakthrough think they have a solution for that problem too.
I have to say I'm putting off solar panel installation until these new technologies are commercialized; I decided to focus on insulation and energy use reduction instead. I wasn't willing to put off getting an electric car, though (partly because it may well be 10 years before the technology gets into electric cars).
At the moment, I really think of the current solar panel subsidies as a system for creating a vibrant network of competent solar panel *installers*, which we're going to need. (Installation & mounting is half the cost of your average home solar panel implementation, and the most fraught with trouble -- poking holes in roofs, etc.)
Warning: possibly an amazingly stupid rookie question below:
So I want to get solar panels for my house. I will also need to do major roof replacement in the next 3 years or so. Is there any point in getting panels before I get a new roof? How hard is it to get those on and off (i.e. will the cost to remove them for roof repair be covered by a couple of years' worth of sunlight)?
So I want to get solar panels for my house. I will also need to do major roof replacement in the next 3 years or so. Is there any point in getting panels before I get a new roof? How hard is it to get those on and off (i.e. will the cost to remove them for roof repair be covered by a couple of years' worth of sunlight)?
I don't think so. You may be better off just redoing your roof now if you want to get the solar system done soon.
Found this:
Frequently Asked Questions (FAQs) about Home Solar Power
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Google "PV roof tile". Lots of unified roofing/power-generation solutions that would work well in California.
bonnie
I play a nice person on twitter.
I have inside information which indicates that the cost per watt of solar is likely to drop below 20% of what it is now within the next 10-20 years, and the cost per watt of energy storage will almost certainly drop to less than 10% of what it is now, so I suspect that's going to swamp most other effects; it will make it much easier to go "off the grid". At some point the grid maintenance costs will have to be reduced to match the new battery costs, or the grid will just be dismantled. Grid balancing will become a more and more serious issue, though the same people who've made the battery and solar panel breakthrough think they have a solution for that problem too.
I have to say I'm putting off solar panel installation until these new technologies are commercialized; I decided to focus on insulation and energy use reduction instead. I wasn't willing to put off getting an electric car, though (partly because it may well be 10 years before the technology gets into electric cars).
At the moment, I really think of the current solar panel subsidies as a system for creating a vibrant network of competent solar panel *installers*, which we're going to need. (Installation & mounting is half the cost of your average home solar panel implementation, and the most fraught with trouble -- poking holes in roofs, etc.)
Even though the cost will invariably drop substantially (inside information or no) in the next 10-20 years, my system will pay for itself in six years. So why wait til the cost drops with such an immediate ROI?
That's strange. The site must be down for some reason. I clicked on the link after I posted it and it was working. Basically it said to consider replacing your roof prior to installing a solar system as they can last 20 years. The installers wouldn't cover the cost of taking the system down and putting it back up but they would work with you and the roofers (something like that).
Here's the same text it looks like from here
Questions About Photovoltaic Power | Bonterra Solar
It sounds like it's a judgement call but if you were thinking about replacing the roof in only 3 years anyway, it would probably be easier to coordinate the job between the roofers and installers and get it done once instead of having installers come back in 3 years.
MitchL
S#945
If you do them both at the same time, you'll have better looking results. We've got a spanish/mediterranean style roof, but with our upcoming remodel we'll be able to inset the panels into the roof - it'll look clean and neat. (the roof remains one plane, no panels hovering over tiles). Our contractors tell us that they'll basically install a composition roof first, then the panels, then backfill the areas around the panels with the tiles. I think it'll look nice. Our solar contractors sent me a photo way back when, I'll try to post it if I can find it.
One other factor I keep forgetting in my sizing calculations is that the amount of A/C you need in the house goes down - with the sun's energy going into the panels, not the attic as heat, upstairs rooms will be cooler even without running the A/C. It's a double win, but I'm not sure how to quantify it.
/Mitch.
Question: what problem do those solve? Are they just to keep the attic (which we never go into) cool, or does it help keep the whole house cool by venting more hot air? Since there's a payback, I assume there is some functional purpose.
The attic gets so hot that some of that heat gets into the living spaces requiring use of your air conditioning. It basically puts less load on your air conditioning allowing you to use less energy.
Solar Attic Fans
I couldn't find a independent link talking about it but that's how I understand they work at least.
MitchL
S#945
For a number of reasons, it's important to have good airflow in the attic. It keeps room temps lower, prevents mold buildup, and helps in climates with snow (keeps attic cold, reduces ice damming). Typically one has soffit vents at the bottom of the roof and eave or ridge vents at the top, in many cases convection is enough to get good airflow. The solar fans provide some assistance if you don't have ridge vents that run along the entire roof.
I'm going from one super noisy electric attic fan (drives me nuts!) to four solar fans. Can't wait for that noisy fan to be gone!
/Mitch.
Thanks, that's what I assumed, just never realized that contributed to AC costs.
Thanks also. I hope our builders consider this (though I guess they would). Is it common these days?
