Going Solar

[ERD50]

I built out to 100% and I now kinda wish I had built it larger. Now that I can experience the benefits of solar, I'd like to replace my gas water heater with electric and perhaps even my gas heater and stove. ...

As an FYI, I have 5.05kwh solar and cost me $16,400 to have it installed turn-key. It is 16 panels of Solarworld 315w commercial panels with a SolarEdge inverter and power optimizers on each panel.

Here's a link to my solar information and graphs /charts;
Heitman House 5.040kW | Live Output

Fascinating chart. Can you get the production vs consumption numbers in a weekly or monthly format - I only saw daily?

So I see you do produce more solar power net than you use (at least in June). Since the solar is a sunk cost at this point, I guess it would make sense to go to electric heat (air and water), if the cost of gas is more than the equivalent heat from the 4 cents/kWh you receive for excess. Maybe with heat pumps, but here in N-IL, gas is far cheaper than resistive heaters for air/water @ ~ 11 cents/kWh, so @ your 4 cents it might just be close?

Looks like you are a fairly light kWh consumer ( ~ 500 kWh/month)? Why would you want to build out more, when you already produce more than you use?

What's the payback on your $16,400 investment? I don't know your kWh rates, but assuming ~ 30 cents in CA, and 500 kWh/month, that's (ignoring the 4 cents for excess for now) ...

500 ⋅ 0.3 ⋅ 12 = 1800 $1800 generated annually, so payback of around 9 years, not counting opportunity cost of the investment. But if we count opp cost at a conservative 3.5% WR, that pulls $575 out of the savings, so around 13 years?

That's why it's hard for the numbers to work in areas like IL, with lower kWh rates - payback takes near the life of the panels, which might outlive me!

-ERD50

 

[NW-Bound]

... As an FYI, I have 5.05kwh solar and cost me $16,400 to have it installed turn-key. It is 16 panels of Solarworld 315w commercial panels with a SolarEdge inverter and power optimizers on each panel.

Here's a link to my solar information and graphs /charts;
Heitman House 5.040kW | Live Output...

That's cool data.

I see that your peak production today is 4kW, out of a 5kW system. That's not too bad at 80% of rated output. The total daily production is 25kWh, which is more than what you use. But without the grid for banking the excess power, it would be very expensive to get enough batteries to store that excess power for overnight use.

Another thing I observe is that your power production peaks at noon, and starts to taper off past 2PM. Here in Phoenix where the AC load is horrendous, the temperature keeps on rising until sunset. Even at 11PM the temperature may still be at 100F or higher.

Hence, the power companies are right in saying that solar production does not help them downsizing their generator capacity, because they still have to meet the same power demand when the sun is already down.

 

[skipro33]

Fascinating chart. Can you get the production vs consumption numbers in a weekly or monthly format - I only saw daily?

Yes, you are viewing the 'live' chart. Click on the daily, weekly, monthly, yearly buttons for further out charts. Also, click on the day, a calendar pops up and you can look at any day of the year.

So I see you do produce more solar power net than you use (at least in June).

Yes, for June, but look at January. Almost no solar production. That is why 'true up' with the electric company is once a year. I make more power now, it's banked. I use more power in the winter, it's withdrawn.

Looks like you are a fairly light kWh consumer ( ~ 500 kWh/month)? Why would you want to build out more, when you already produce more than you use?

Weather is cool right now. Here's a link to June 4th where I ran my AC and the outdoor temps got above 100;
PVOutput

What's the payback on your $16,400 investment? I don't know your kWh rates, but assuming ~ 30 cents in CA, and 500 kWh/month, that's (ignoring the 4 cents for excess for now) ...

I figure I will recover my investment in 8 years unless electric rates increase over the next 8 years, then I'll recover my capital sooner. Right now, summer rates are 15 cents a Kwh from 9pm at night until 10am the next day. From 10am to 1pm it's 23 cents, from 1pm to 7pm it's 34 cents, 7pm to 9pm back to 23 cents and then it starts all over again. Weekends and holidays are a little different.
This is why it pays me to generate and bank during peak rate times and run my AC on the shoulder or off peak rate times. I can use twice the amount of electricity during off peak if I bank it during peak.

500 ⋅ 0.3 ⋅ 12 = 1800 $1800 generated annually, so payback of around 9 years, not counting opportunity cost of the investment. But if we count opp cost at a conservative 3.5% WR, that pulls $575 out of the savings, so around 13 years?

Only if electric rates NEVER raise during that time. Based on my last 10 years living here, electric rates have risen an average of 7% a year. Do the math now, based on the figures I gave you for time-of-use rates AND a 7% rate increase annually. I'll have my capital investment back relatively shortly.
Also, the solar equipment has a 25 year warranty and the labor is 15 years. No risk for me.

That's why it's hard for the numbers to work in areas like IL, with lower kWh rates - payback takes near the life of the panels, which might outlive me!

I have almost 300 days of sunshine a year here in California where I live. Annual rain fall is 36 inches over 66 days average.

California has a bill in the legislature that at least 50% of all energy must be from renewable resources by some future date to be determined. That is a lot of capital they'll have to expend and soon too. By 2020, in less than 4 years, California must be at least 33% renewable. That mandate is law.

Here's a news article about it;
California renewable energy mandate

Consider this;
If you had the opportunity to pay up front for electricity for a guaranteed 25 years, what would it be the dollar cost that would make it a decent long term investment. A lot of people get hung up on the 8 to 13 years of recovery of their capital investment plus earnings loss, but after that, it's all basically free electricity. I have now fixed my cost for electricity for the rest of my life, long as I remain in this house. The mortgage is paid, so no cost there. I have a well I put in a while back, (California drought? What's that?) it has it's own little battery/solar power source since that was cheaper than running power all the way to the pump house. It's a 12 volt system. If I can get off propane, or at least reduce it to a couple hundred dollars a year, I'll pretty much have no real monthly living expenses other than food and gasoline for my (paid off) cars. There's still property taxes (prop 13 has limited that to 2% increase max a year based on the market value of the house.) and insurance costs. My total monthly expenses are under $2,000 a month. My income is around $6,000 a month in retirement with a pension and 2% draw from my investments. I will start getting around $2500 a month (me and DW) in 2 years for Social Security. At that time, I won't need any draws from my investments.
My feeling is, I am not risk tolerant and now I don't have to be. Locking in electric rates for the next 25 years is one piece of the pie for achieving that goal, like the well was.

 

[Another Reader]

"I have now fixed my cost for electricity for the rest of my life, long as I remain in this house. The mortgage is paid, so no cost there. I have a well I put in a while back, (California drought? What's that?) it has it's own little battery/solar power source since that was cheaper than running power all the way to the pump house. It's a 12 volt system. If I can get off propane, or at least reduce it to a couple hundred dollars a year, I'll pretty much have no real monthly living expenses other than food and gasoline for my (paid off) cars. There's still property taxes (prop 13 has limited that to 2% increase max a year based on the market value of the house.) and insurance costs. My total monthly expenses are under $2,000 a month."

Now there's a true Californian way of thinking! My neighbor with the 10kw solar system wants a grid alternative and a well. The City water rates are skyrocketing and he had to let his huge (by Bay Area suburban standards) back lawn go because of watering restrictions and cost. Of course, no well, because we don't own the water rights, but self sufficiency in the face of increasing local and state government parasitism is increasingly popular.

 

[Zathras]

We have just completed the physical installation of our solar arrays on the house we are building.
The attached image is of the panels on the main house.
We also have panels on the garage roof.

Total array size is 17.8kWh and is calculated to provide 100% of the energy our house and both electric cars use on an annual basis.

We currently are waiting for the paperwork to be processed by the utility, and then we should be live

Payback is about 12 years if electricity doesn't get more expensive.
The house is all electric, no natural gas. We will be installing a battery backup system, however, the grid is pretty stable in our area.

For the curious, we have more information at my website.

 

[eytonxav]

We have just completed the physical installation of our solar arrays on the house we are building.
The attached image is of the panels on the main house.
We also have panels on the garage roof.

Total array size is 17.8kWh and is calculated to provide 100% of the energy our house and both electric cars use on an annual basis.

We currently are waiting for the paperwork to be processed by the utility, and then we should be live

Payback is about 12 years if electricity doesn't get more expensive.
The house is all electric, no natural gas. We will be installing a battery backup system, however, the grid is pretty stable in our area.

For the curious, we have more information at my website.

The house and your website are awesome, must be a lot of fun doing a build like this.

 

[ERD50]

Yes, you are viewing the 'live' chart. Click on the daily, weekly, monthly, yearly buttons for further out charts. Also, click on the day, a calendar pops up and you can look at any day of the year. ...

Just FYI to others, you need to register (simple to do) at that site to view some of the older data. Very interesting stuff.

California has a bill in the legislature that at least 50% of all energy must be from renewable resources by some future date to be determined. ...

As NW-Bound mentioned, it is a real challenge for solar when you get to these high levels. We can use your data as a proxy for this. I'm looking at June 16. Your generation is 50% of your usage. And we can see that from 7 AM to 5 PM, you produce more than you use, and your usage peaks ~ 8 PM, long after your panels have dropped to zero.

That means to do this on a large scale, CA would need massive amounts of storage. And it gets worse - we are looking at June with high solar output. To average 50%, June output will need to be even higher to compensate for lower output in January. OK, it looks like your AUG 015 output was over 4x your DEC 2015 output (and it looks like June 2016 is on track for 5x!). Some of that effect will be offset by A/C needs in summer, but I think it is clear that for large scale implementation, either storage is needed (at $$$ and lost efficiency), or some solar will just be wasted (bringing the average cost up). And you still need NG peakers for longer periods of limited sun.

For CA averages, some of this 50% would come from wind, softening this somewhat, but it makes the point.

IOW, the economics and realities of solar on a small scale looks a lot better than solar on a large scale. Things change when you start producing a net excess on the grid at any time of the day.

Also, I sure wish we would move away from these residential installations, and move to large commercial level installations. A large install just has so much more economy of scale, and is far safer (flat roof, one location to set up the job instead of 100's of residences, with steep, variable roofs). Let residents buy in to a 'share' of the industrial solar farm.

-ERD50

 

[Totoro]

Large scale installations incur distribution costs, which in some places already are >70% of total cost.

So there is an inherent advantage in (some) local generation.

 

[ERD50]

Large scale installations incur distribution costs, which in some places already are >70% of total cost.

So there is an inherent advantage in (some) local generation.

I'm not talking about an installation out in the desert somewhere, many miles from the users.

I'm talking about installing solar on big box stores, schools, warehouses, etc - any place with a large, flat roof. Those places are near the users, so distribution costs are low, losses are low.

Two schools near us installed 448.8 kWdc systems (each) on their flat roofs. That's two sites versus 178 rooftop installs like the one that skipro33 has. That kind of economy of scale makes sense to me. Flat roofs, far safer for installers and maintenance than 178 different sloped roofs that a crew needs to get out to, deal with trees, slopes, gutters, chimneys, fences, dogs, etc.

 

[GrayHare]

If you had the opportunity to pay up front for electricity for a guaranteed 25 years, what would it be the dollar cost that would make it a decent long term investment. A lot of people get hung up on the 8 to 13 years of recovery of their capital investment plus earnings loss, but after that, it's all basically free electricity.

With solar tech rapidly improving, after 8 to 13 years I'd probably be drooling over the new system with X% more output for Y% less cost than mine. Heck, by waiting just 1 year (solar OMY syndrome?) I can now get a better system for less cost.

 

[skipro33]

That means to do this on a large scale, CA would need massive amounts of storage. And it gets worse - we are looking at June with high solar output. To average 50%, June output will need to be even higher to compensate for lower output in January. OK, it looks like your AUG 015 output was over 4x your DEC 2015 output (and it looks like June 2016 is on track for 5x!). Some of that effect will be offset by A/C needs in summer, but I think it is clear that for large scale implementation, either storage is needed (at $$$ and lost efficiency), or some solar will just be wasted (bringing the average cost up). And you still need NG peakers for longer periods of limited sun.

For CA averages, some of this 50% would come from wind, softening this somewhat, but it makes the point.

IOW, the economics and realities of solar on a small scale looks a lot better than solar on a large scale. Things change when you start producing a net excess on the grid at any time of the day.

Also, I sure wish we would move away from these residential installations, and move to large commercial level installations. A large install just has so much more economy of scale, and is far safer (flat roof, one location to set up the job instead of 100's of residences, with steep, variable roofs). Let residents buy in to a 'share' of the industrial solar farm.

-ERD50

There a couple of points you bring up I'd like to reply and address;
Yes, solar is not an end-all solution. It's part of the equation though. In California, residential solar can only be 5% of the total grid production. No worries that the massive grid can't manage the residential solar as a resource in that volume.
Storing power has some 'interesting' solutions. The utility company I worked for had solar, wind, geothermal, nuclear (decommissioned now), gas fired and hydro generation. It also purchased generation from other utilities, some as far away as Texas and Utah. Those were oil and coal fired. (California has a cap-and-trade program on hydrocarbon so not really feasible to do oil and coal in-state.) Anyways, it's typical wind blows at night in our wind farm, when demand is low. What we do is use the wind generated power to pump water uphill from a lower elevation reservoir to a higher elevation reservoir during those times. Then when demand exceeds conventional generation, it's released. This process is repeated over and over. Viola! Stored electricity in the form of pumped storage. This too is only a percentage of the equation, but power on demand isn't an easy thing when there's all sorts of government regulatory hoops.

There are some advantages of residential over commercial solar for the utility company; no capital investment needed. That's all on the customer (and his federal tax credits) They instantly have a generation source to start drawing on. Also, that generation is distributed at the point of consumption. No long distances to deliver power. Of course that is already in place, but the capacity of the distribution system is not required to be carried solely on the backbone of a high voltage distribution system where there are numerous single points of failure.

California has some large scale solar. The utility company I worked for had a couple. They have since gotten out of solar and now contract with vendors for the generation. (This off shifts the liability of a failure to the vendor and is cheaper than the insurance costs to own a commercial solar generator) Solar is probably THE most dangerous source of power generation there is. You see, each solar panel has multiple solar cells. If there's a problem, electricity is still being generated despite what ever breakers, fuses, or other trips are in the system. If the sun is shining, there's electricity. We had several catastrophic fires on solar sites, sitting and watching it burn because there was no way to stop each cell from making electricity. Now days, some solar farms use motors to park their panels upside down, rotating them so the panel faces the ground and the sun can't shine on them. That is not financially viable though. Very expensive initially and to maintain. A system that can track the sun can pay for itself on a small, residential scale, because the design is small, not huge commercial size. The potential for fire from a solar array is addressed for residential but it's kind of spooky; the design must have a footprint that allows firemen to chop holes in the roof to vent in case of fire. Breakers accessible to firemen must be clearly labeled. Disconnects and reconnects to the grid are also carefully monitored and managed. But even so, potential solar buyers should carefully weigh the risks of sticking solar on their home's roof.

 

[ERD50]

With solar tech rapidly improving, after 8 to 13 years I'd probably be drooling over the new system with X% more output for Y% less cost than mine.

It does seem like costs are dropping faster than the payback of the past systems - so waiting could make economic sense?

But... that cost reduction has mostly come from lower panel costs. The cost of installation, labor, permitting, inverters, switches, etc is flat or rising and is now a large part of the total cost. I don't think we will see costs continue to drop as fast as they have in the past.

-ERD50

 

[skipro33]

It does seem like costs are dropping faster than the payback of the past systems - so waiting could make economic sense?

But... that cost reduction has mostly come from lower panel costs. The cost of installation, labor, permitting, inverters, switches, etc is flat or rising and is now a large part of the total cost. I don't think we will see costs continue to drop as fast as they have in the past.

-ERD50

There are diminishing returns by waiting. Sorta like investing. Sure, technology is constantly improving, but do you want to wait for the driverless car before you finally buy one? At some point, you jump in.

The real buttclincher is something I already mentioned; a 5% cap on residential solar attached to the grid. California will probably meet that before the end of next year. At that time, the utility company's restrictions on how to contract with new residential solar will be less favorable for the resident. While the installation material costs will be going down, the interface to the grid will be going up.
Also, federal tax credits are running out. I'm sure the feds will vote to pass some sort of credit, but the whole reason for the credit was of offset the costs of an installation to where it can be financially viable in order to encourage a fledgling source of power to get off the ground. That's being done, so the credits are probably going to be downsized over time.

With those two limitations on the horizon; restructuring of the rates between residents and utilities after a 5% grid saturation and the loss of solar credits, I suspect that, unless solar costs drop dramatically, it could kill off a lot of smaller solar installation companies.

 

[Another Reader]

The fire danger is not something of which I was aware. I don't recall reading about any solar panel failure-caused fires in residential arrays or in commercial for that matter. If they occurred, I would expect building codes to be altered to provide protection from the fire source. Could you elaborate on this?

 

[skipro33]

With solar tech rapidly improving, after 8 to 13 years I'd probably be drooling over the new system with X% more output for Y% less cost than mine. Heck, by waiting just 1 year (solar OMY syndrome?) I can now get a better system for less cost.

Solar is grossly over priced when purchasing a turn-key installation. There is a huge margin for profit and, for the customer, negotiation. My initial bids were about 50% higher than I actually paid. Most customers never even think to negotiate a solar project, let alone seek as large a reduction of the bid as I did.
I did my homework. I found sites on line that would sell me the materials I wanted and would deliver to my house for a cost that was around half what I finally paid to my contractor. I have the chops to have done my own installation. Everything these days in solar is Plug-n-Play. No skills need to wire stuff, it's all pretty much snap it together and it's a water proof connection good for a minimum of 25 years. There are NO moving parts even! The only reason I didn't do my own installation is because my wife hated the idea of me clamoring around on the roof and the risk of me falling off. (We had a good friend fall off his roof recently with tragic consequences).

As far as the technology, it's a byproduct of the space industry. Without getting too much into federal politics, I'll just say that right now, we don't even have a way to send a man into space any more. Solar technology isn't going to advance for long that way. Manufacturing probably will, but those changes will be absorbed by company profits for manufacturers mostly.
Some of the solar advances are pretty 'Star-Trek' like;
Solar generation involves photons from the sun striking the solar cell. This is what 'makes' the electricity. However, the photon easily can pass through the solar cell. Solar cells have a backing for strength, but if you didn't need that ridged strength, like in the vacuum of space, you could layer solar cells, one on top of the other, with the sun's photons passing through them all, making electricity along the way. The solar panel foot print would be greatly reduced. Maybe to the point that solar cars and planes could be feasible. If solar cells could be incorporated into road beds, and solar cars could draw on it as they rolled along, imagine where that could lead? These are the sorts of things NASA was doing experiments on that have been going away.

 

[skipro33]

The fire danger is not something of which I was aware. I don't recall reading about any solar panel failure-caused fires in residential arrays or in commercial for that matter. If they occurred, I would expect building codes to be altered to provide protection from the fire source. Could you elaborate on this?

Ask a fireman about fighting a house fire that has solar on it's roof. He can tell you the risks better than I, but here in my county, the code reads that no solar panel can be within 4' of and ridge or elevation change. This allows for firemen on a roof to cut holes and maneuver during a fire. Water and electricity don't mix. Solar makes electricity and firemen are spraying water around. Hacking into a hot solar cable is not something a fireman wants to do. The routing for the solar array wiring, the labeling of the conduits, etc are all highly regulated in the permit process. Can't have solar running in conduit with conventional wiring; what if there were a short? All the solar power could potentially be distributed to a deenergized house wiring and a fireman could be electrocuted.

Discounting the roof by 4' all around really cuts into a solar system sizing. I put my solar on a covered patio, not my actual roof over my living space, and wasn't subject to the 4' rule.

Here's a photo of my solar;

 

[ERD50]

There a couple of points you bring up I'd like to reply and address;
Yes, solar is not an end-all solution. It's part of the equation though.

... What we do is use the wind generated power to pump water uphill from a lower elevation reservoir to a higher elevation reservoir during those times. Then when demand exceeds conventional generation, it's released. This process is repeated over and over. Viola! Stored electricity in the form of pumped storage. This too is only a percentage of the equation, but power on demand isn't an easy thing when there's all sorts of government regulatory hoops.

There are some advantages of residential over commercial solar for the utility company; no capital investment needed. ...

Now days, some solar farms use motors to park their panels upside down, rotating them so the panel faces the ground and the sun can't shine on them. That is not financially viable though. Very expensive initially and to maintain. A system that can track the sun can pay for itself on a small, residential scale, because the design is small, not huge commercial size. ...

I agree with you, renewables will need to hit on many fronts (diversification is a good thing for many reasons), my analysis of your system at 50% solar was just to illustrate the issues. Diversification helps, but does not eliminate those problems.

Pumped storage can be a part of the solution, but from what I've read, it is very limited. Few sites can support the land requirements and also have nearby elevation deltas to make it work. The large planned installation in Sacramento was very $$$ and only offset a portion of power from daytime to evening (it allowed them to ramp down coal earlier) - no actual day-day storage at all. Oooops, it been cancelled:

https://www.smud.org/en/about-smud/news-media/news-releases/2016/2016-02-05-Iowa-Hill.htm

I don't follow the economic advantage of residential. It doesn't need to be the utility putting in the solar farm - 200 residents could form a co-op (or equivalent).

I don't see how a motor tracking system can be more viable on a small scale than a large scale. Things like that benefit from economy of scale.

Hope this isn't sounding too negative - I do think solar can make sense to a point. I just fear that many people extrapolate this out to larger levels, and that's where you hit different problems. Maybe they can be solved, but I don't see anything viable on the horizon.

-ERD50

 

[ERD50]

... you could layer solar cells, one on top of the other, with the sun's photons passing through them all, making electricity along the way. The solar panel foot print would be greatly reduced. Maybe to the point that solar cars and planes could be feasible. ...

Probably not. Solar cells now are ~ 15% efficiency. Theoretical eff% of a single layer cell is ~ 34%, but even if you go multiple layer cells and get something like 80% efficiency, that's about 5 times denser. I don't think that will move a real car very far (non-optimal angles, often in the shade, extra weight to carry).

... If solar cells could be incorporated into road beds, and solar cars could draw on it as they rolled along, imagine where that could lead? These are the sorts of things NASA was doing experiments on that have been going away.

You were making sense up until now. I don't have the time to inform you of all the problems (and zero benefits) to this, I think there's another thread on it.

And NASA bootstrapped the solar cell, I don't think they are really needed for further research, that seems to be happening on several levels.

-ERD50

 

[Another Reader]

So, it's not the solar that causes the fires, but having to deal with the solar array when a fire from another cause starts. I wonder if in a widespread wildfire, the firefighters might let the solar equipped houses burn when they are deciding which houses to save with a limited capacity to fight the fire.

Did you order the parts yourself or did you use the bid to get the turnkey bid reduced? Was your installer a large vendor or small local guy?

 

[skipro33]

I don't see how a motor tracking system can be more viable on a small scale than a large scale. Things like that benefit from economy of scale.

Hope this isn't sounding too negative - I do think solar can make sense to a point. I just fear that many people extrapolate this out to larger levels, and that's where you hit different problems. Maybe they can be solved, but I don't see anything viable on the horizon.

-ERD50

Not too negative at all! If more solar customers took the time to analyze solar like you are doing, and not just listen to a salesman, they'd be happier as an educated customer on expectations.
A tracking system for solar panels that weigh under 50 pounds is a lot cheaper than the commercial sized ones. I could build a tracking system for a 5kw solar array from my kid's battery operated jeep riding toy for example. There's a 12 volt motor, battery, switches, etc all in a package I could pick up at a thrift store for under $20. But seriously, what I'm saying is that the basic components to pan residential sized panels to track the sun by season are off the shelf. I don't think that's the case for commercial. I think a whole industry of engineers and designers are going to build a specialty product designed optimally for it's one specific task. That's expensive.

Co-op solar isn't a bad idea except for the solar footprint. Land isn't cheap. Rooftops are free, basically.

Speaking of co-op, I am surprised sub division contractors don't do that with electricity; have the utility drop a distribution transformer at the edge of the development, then privately do the distribution to the individual houses in the new neighborhood. The co-op pays for bulk power and manages it's own distribution metered to the individual homes and passes the savings onto the other co=op members. This is exactly how SMUD (you mentioned them earlier) or any municipal utility starts out; A co-op of rate payers who voted in a board to buy (or generate) bulk power and do it's own distribution.
Water same way. Someone puts in a big enough well to serve him and a couple neighbors, who pay him to offset his investment or to service the loan it took to put in the well.

 

[ERD50]

...

Co-op solar isn't a bad idea except for the solar footprint. Land isn't cheap. Rooftops are free, basically. ...

A co-op could make a deal with any local, large roof-top owner - the schools, big-box stores, warehouses, etc. that I mentioned earlier. Just because it might be called a solar 'farm' doesn't mean it needs to use up land

-ERD50

 

[jazz4cash]

Great thread. In 10 minutes I've learned things that I could not decipher in hours of web searching. The thing that surprised me the most is the fire risk because I was somewhat surprised that our homeowners insurance premium would not be affected by installing a $45k system on the roof. I don't think we have the 4ft limitation for placement of the panels in MD but that is a good example of how variation from state to state affects the industry. I think the goal for solar production share is 20% but I am not aware of any specific cap for residential.

I especially like how skip used his porch covering to comply with the 4' rule. This is an example to me how building designs need to evolve to specifically incorporate solar. When I looked into a system briefly, I quickly concluded that I would likely need to build a new home with solar integrated into the design but the builders in my area don't seem interested except at a very high end price point.

 

[jazz4cash]

I toured a local GM plant about 3 yrs ago and they had recently completed installation of a large rooftop system. They started the project before GM filed BK and the financing was pulled by the bank. After GM cleared BK they got new financing and completed the project. The system produces up to 80% of their needs and they mostly sell back to the grid on weekends. This improved their cost structure enabling them to bring work into the plant from Mexico and add 60 jobs. The work is production of hybrid transmission components so it's an all around good story of green-tech.

 

[Zathras]

The house and your website are awesome, must be a lot of fun doing a build like this.

Many thanks!
I am enjoying it quite a bit.

There are times though where I really don't want to see how the sausage is made

 

[ERD50]

I toured a local GM plant about 3 yrs ago and they had recently completed installation of a large rooftop system. They started the project before GM filed BK and the financing was pulled by the bank. After GM cleared BK they got new financing and completed the project. The system produces up to 80% of their needs and they mostly sell back to the grid on weekends. This improved their cost structure enabling them to bring work into the plant from Mexico and add 60 jobs. The work is production of hybrid transmission components so it's an all around good story of green-tech.

Sounds good, but that is hard to determine w/o knowing all the financial details. With payback so far in the future for many of these installations, and GM in a (hopefully) short term bind, can we really say this was a good financial move? Do their savings exceed the finance costs?

-ERD50