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Project Sunroof

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Re: Project Sunroof

#91

Post by thrownaway2424 »

_delirium wrote: post #88
thrownaway2424 wrote: post #83

Earlier quoted context omitted.

The 3-4c wholesale rate is for base power (giant infrastructure generators, hydroelectric dams and such things), but solar knocks the top off the mid-day demand curve, at which time PG&E is paying much more for "peaker" power generation. But they don't have to pay you the peaker rate, they pay you the baseline rate. Anyway, to my mind, any system in which current comes out of your PV installation at 3 cents and flows…

Even peaker plants run ~15 cents these days, since the price of gas has fallen so low. edit: I'm more familiar with the Texas grid, but beyond the cheapish price of modern peaker plants, in that case the most expensive input sources (small peaker plants, and esp. spot-market purchases) are rarely used at all. Demand prediction and management is good enough to avoid the more expensive inputs, through a mixture of loca…

Yeah, but that makes PG&E's "smartrate" summer afternoon price of 75c per kWh even less justifiable.

This data may not be publicly available, but I'd love to see graphs of current flowing out of PG&E substations vs. time of day. At some point the PV generation capacity is going to make them have weird upside-down diurnal cycles.

Re: Project Sunroof

#92

Post by VLM »

thrownaway2424 wrote: post #83
bostonpete wrote: post #81

Earlier quoted context omitted.

> It's basically a scam. Why is it a scam that PG&E won't pay you more for power than they can buy it wholesale?

The 3-4c wholesale rate is for base power (giant infrastructure generators, hydroelectric dams and such things), but solar knocks the top off the mid-day demand curve, at which time PG&E is paying much more for "peaker" power generation. But they don't have to pay you the peaker rate, they pay you the baseline rate. Anyway, to my mind, any system in which current comes out of your PV installation at 3 cents and flows…

Something I worry about with solar is once power is psychologically "free" I'll be tempted to set the thermostat down to 65F or whatever, and end up paying full rate when clouds blow by. I think it would be difficult not to increase power use once its free. I'm not talking about explicitly leaving stuff on for fun, but more like "well, power is free, so I guess I can afford a tropical reef tank instead of a plain fish tank" and there goes 1 KW of lighting continuously plus a chiller whereas right now my fish and I are very happy with ten watts of LEDs. This kind of thing needs to be taken into the financial analysis.

Also in the winter if I have "free" electricity and have to pay for natgas to heat, I'll simply buy a raid array of plug in electrical heaters to eliminate that "free" electricity and eliminate paying for some natgas. Or maybe I'll just install a bigger raid array. Either way, I like free heat in the winter and typical analysis usually doesn't consider heating. If you pay me 3 cents per KWh in the winter, and charge me 15 cents equivalent in natgas energy, I'm not going to sell you a single KWh until my house is above 75F in January.

Re: Project Sunroof

#93

Post by TeMPOraL »

thrownaway2424 wrote: post #83
bostonpete wrote: post #81

Earlier quoted context omitted.

> It's basically a scam. Why is it a scam that PG&E won't pay you more for power than they can buy it wholesale?

The 3-4c wholesale rate is for base power (giant infrastructure generators, hydroelectric dams and such things), but solar knocks the top off the mid-day demand curve, at which time PG&E is paying much more for "peaker" power generation. But they don't have to pay you the peaker rate, they pay you the baseline rate. Anyway, to my mind, any system in which current comes out of your PV installation at 3 cents and flows…

I suppose that part of the price difference is that you're an unreliable source of unreliable electricity, whereas your neighbor pays for stable, reliable service.

Re: Project Sunroof

#94

Post by dreamcompiler »

uptown wrote: post #65

Are firefighters any less likely to enter a house fire where the roof is covered in heavy solar panels? I've heard stories, but never dug into whether it was anti-solar FUD.

Three layers of asphalt shingles (which many houses have) is a lot heavier than solar panels. Firefighters assume residential roofs to be generally pretty crappy in a fire. Their decision to enter will be based more on the extent of the fire and whether they believe anybody's in the house who can be saved.

Re: Project Sunroof

#95

Post by dkhenry »

andyl wrote: post #21

Fusion of maps, 3d modeling, electricity & lease rates, solar intensity, installers. Easy to use. This feels like something new and powerful. For society: I wonder if it is safe for so much power to be concentrated in one organization. As a technical accomplishment: I'm impressed.

Its not really new, and its not really powerful. From what I can see all this does is give you an estimate based on the square footage of your rooftop. There is a lot more that goes into a real estimate then how big your roof is, namely how can you arrange the panels to cover the roof. That is a neat trick and this company does that http://www.modsolar.net/

I worked with their stack for a bit and from my understanding their tool has been doing what this site does and then some extra stuff to actually get the panels installed.

Re: Project Sunroof

#96

Post by dreamcompiler »

VLM wrote: post #86
uptown wrote: post #65

Are firefighters any less likely to enter a house fire where the roof is covered in heavy solar panels? I've heard stories, but never dug into whether it was anti-solar FUD.

It smells of the anti-hybrid astroturfing from a decade or so ago where numerous Ford and GM employees would be glad to tell you on social media that if you get into a car accident in a hybrid, emergency services will leave you to bleed out and die because its a hybrid so you should have bought a SUV or truck like a RealAmerican(tm). My father in law did the volunteer fire dept thing in his rural area and its very de…

Everything above is correct. (I'm a volunteer firefighter.) Firefighters nowadays are trained to deal with the high-voltage DC that's present in hybrid and electric cars. It may take a little longer to extricate a victim, but it won't stop us. As for houses, we won't bother entering a burning residence at all unless we're likely to find a person still alive, or the nature of the fire is such that the danger to us -- with our PPE and training -- is minimal.

Re: Project Sunroof

#97

Post by devy »

justplay wrote: post #61

404 when accessed with Indian IP

same 404 when posting to facebook (where its spiders automatically extracts a title, blobs and images) where their server IPs are probably not all U.S. based. Weird.

Re: Project Sunroof

#98

Post by _delirium »

jsprogrammer wrote: post #78
thrownaway2424 wrote: post #73

Earlier quoted context omitted.

Solar power systems don't necessarily come with batteries but a decent installation company should be able to propose and implement an integrated system. The Tesla battery pack is an example of some recent innovation in that area. You can sell power into the grid but PG&E only has to pay you wholesale rates, 3-4 cents per kwh, not what they are charging you to take the same amount of energy out, which is 34 cents per…

Is there no real solar power market then? If your local utility is a monopoly then you basically have to accept whatever the utility wants to pay you (even far below 'market' rate). You have no power to negotiate, only capitulate or try to get the local regulator to enforce fair trade.

I suspect you'd fare pretty badly in a market, even if a better one existed. In Texas's deregulated electric marketplace, the market price for large-scale solar installations selling into the grid has fallen to around $0.05/kWh. Power from a single small-scale residential installation with less reliable delivery is probably worth less than that.

Re: Project Sunroof

#99

Post by dreamcompiler »

uptown wrote: post #89
VLM wrote: post #86

Earlier quoted context omitted.

It smells of the anti-hybrid astroturfing from a decade or so ago where numerous Ford and GM employees would be glad to tell you on social media that if you get into a car accident in a hybrid, emergency services will leave you to bleed out and die because its a hybrid so you should have bought a SUV or truck like a RealAmerican(tm). My father in law did the volunteer fire dept thing in his rural area and its very de…

Seems like it's likely mostly anti-solar propaganda, but I guess there is some concern regarding the electrified nature of solar panels rather than their weight. http://solarenergy.net/News/tackling-risks-solar-panels-pose... I care little about the house in a fire. I do care about its occupants, and also the safety of the firefighters attempting to extract anyone still inside.

I've not encountered discussions of solar panels in firefighter training, but my intuition suggests it's probably not a big deal. For nighttime fires, the panels won't be generating any electricity anyway. For daytime fires, smoke and water will likely occlude the panels and decrease their voltage. Firefighters ventilating the roof would need to be trained to avoid HVDC wires connecting a series-connected panel array to the inverter. We might also just lob foam onto the panels and turn them off that way.

Re: Project Sunroof

#100

Post by birken »

TTPrograms wrote: post #84
birken wrote: post #60

I live in San Francisco and just had a solar system installed last week, so I have a few comments about this. 1) It vastly overestimated how big a solar system that could fit on my roof (by about 5x). It didn't care about chimneys or skylights (which are easily visible through Google maps), nor SF fire code which states that you need a 3-foot empty pathway on both sides of the crest of your roof [1]. So for almost ev…

Is the cost primarily proportional to the size, or do inverters present a major fixed cost? For the former it doesn't really matter how much you can cover, as it's simply an investment with a certain rate of return that has the amount you can invest limited by roof area.

I think all of the hardware will be very proportional to the size. In my case I had micro-inverters on each panel, so it was directly proportional, but this was actually more expensive than having a single large inverter (though more performant).

However, the marginal cost of things like engineering, installation and inspection will certainly go down with the size of the system. How much of that passes to the consumer I don't know, but some of it certainly does. You can imagine the cost of putting 1 solar panel on your roof is not going to be 10x less than putting 10 of them up there.

It is hard to get exact numbers from solar sites as they are very sales-oriented, but it seems like the hardware cost is estimated at anywhere from 20-50% of the total cost of the solar system. The rest of it is engineering, installation, inspection, customer acquisition, profit, etc.

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