Residential Solar In San Francisco - 2010   

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As you already know solar has many benefits. Being more green for the environment and reducing energy cost are key reasons. But ultimately for me , it is the cost of electricity. My energy usage for 2009 is listed in fig 1 (kW hour). My energy usage in december alone was 1200kW hour. I'm at tier 5 and I am paying a heavy price. Screw PGE, I'm doing something about it!
Fig 1
1 1104
2 1037
3 1175
4 867
5 989
6 1008
7 956
8 952
9 999
10 972
11 966
12 1238


Despite the cost, fortunetely there are a wide array of solar options to fit everyones budget. But before we even dive into the solar options there are many things to consider. Is the roof strong enough? How many layers are currently in the roof? Do building department allow you to add panels on a roof with multiple layers? Do you require removing your old roof first? What type of roofing do you need? Are your rafters 2x4 or 2x6 or 2x8? How far apart are the rafters? Any dry rot to worry about? Shading problems? Do you have problems facing south if you live in northern california? Lets tackle some of these major issues one at a time.

ROOFING FIRST!

The first things anyone should considers before adding a solar system would be the foundation for which the solar system would depend on. Can you electrical panel support the addition circuits required to hook it up? Do you have breakers or old school fuses? Do you even have an electrical panel? In my situation, what worried me was the tar and gravel on my roof. The roof was roughly 15 years, had 2 layers, and was due for replacement. Obviously you do not want to install a solar system on top of an old roof or a cheap roof. Imagine how much work you'd have to do to remove the panels later. So I started my research on different roofing materials besides tar and gravel. In my research I've discovered that there are many criteria for roofing. Especially on a flat roof like mine the choices are fewer but problems increase. I have to worry about ponding water adding weight to the structure and leaking in. Also seems can crack, UV damages a lot of different materials. There were not a lot of choices either. Tar and gravel is a good cheap choice and can usually be installed in San Francisco for around $5k or less. The problem with this type of roofing tho is that it is nearly impossible to find leaks once its started because the gravel really hides the source of the problem. These type of roofs don't generally last very long and the debrea from the gravel can potentially damage or scratch the panels on a windy day. I wanted a roof where it would last my entire lifetime and easy to maintain so this was out of the question. A couple of my friend has Modified Bitumen roof with an aluminum paint to coat it for protection against UV. So I did some research and discovered that this method of roofing requires a torch to melt the asphault sheets together to form a tight seal. This type of roofing is petroluem based and offers a cheap alternative to tar and gravel. Unfortunetly petroluem based roofing material are susceptible to UV damage. Most roofing failures of Bitumen roofing are due to UV damage on the edges, corners, or around flashing surrending pipes or chimneys. You will see the damage in the form of cracking in the sheets on the surface. This type of roofing also requires that you regularly go on the roof to slap on a coat of paint to avoid UV damage to the asphault material. Once UV breaks down the asphault you can feel it loosing its adhesion to the roof and it will feel bubbly as you walk over it. So this is a faily high maintanence roof and not for me. But the pro's is, its still fairly cheap and much better then tar and gravel.

At this point I started looking into PVC membrane type roof or more specifically IB Roof systems. I learned that this type of roofing system is basically PVC sheets hot air welded together. The seams are melted together and is very strong, often stronger then the material itself. The flashings and everything is made of PVC so there is nothing to rust on the roof. The PVC or IB membrane are secured to the roof physically with clads. All corners and edges are also PVC. No painting required, no maintenance required, and extremely durable. It is almost like having a giant tuper wear sitting on top of your house. This system has a residential life time warranty against materials failure and a 15 year warranty from the installer. So low maintanence, high strength, and lifetime warranty. This system is also gauranteed against ponding water, is fire resistant, and is easy to repair in the future. IB systems are only sold the certified installers and the only way to become certified is if you took the training corses. Sounds good to me.

I didn't really look at EPDM roofs but basically from my basic understanding, its a rubber membrane roof. The membranes are glued together and are chemically bonded. There also isn't any certifications or license required to install EPDM roofs. Anyone can buy it and do it so its hard to judge who had the knowledge to do it and do it correctly. EPDM roofs are UV stable and does not break down from UV. But I don't know if you can say the same regarding the flashing around the pipes, edges, or any weird corners that may require a lot of glue. I think the glue would be the weakness for EPDM. Heat and UV would be the villains here. The lack of certification for installation of EPDM also bugs me but not a deal breaker if you know you found professionals. Not sure what the price is. Seems like a fairly low maintanence roof but I am gonna pass on this.

Finally there are Foam roofs. I don't know much about it except it adds some insulation to your roof by its own nature. It sprays down on the roof so preperation is very key to its success. It also requires a layer of paint on top of the foam for physical protection of the foam itself. I belive some companies call for a resurfacing after the first 5 years, then every 10 years after that. Failure to follow maintence program basically voids all warranty. Also the though of dropping a sharp object and piercing through the foam and causing a leak scared the crap out of me. I am of the belief that if your gonna buy something, buy something that can handle the punishments of a man. You need a MAN roof and a foam roof isn't it.


I decided to go with IB systems and started contacting contractors who were certified by IB Roofing. I called IB roofings sales rep for local dealers around the San Francisco Area.

SOLAR Design

As with Anything else there are many options with Solar. Most cells are produced in china and now more and more people are manufacturing the panels locally to save on shipping. Suntech is a major chinese company that started producing their panels in the United States vs importing it (manufactured in Arizona.) For me a solar panel should maximize your roofs square footage by being as efficient as possible and also as high of a capacity as possible. Solar panels are made from silicon which is the same stuff in your computer chips (Polycrystaline). Monocrystalline panels are cut from a single piece of silicon and have no grain boundaries. So these tend to be more efficient and expensive but it seems like polycrystaline has really improved as of late.

Thin film solar panels are the least efficient of all solar panels. They are made of silicon layered onto various materials and require more surface area for the same power output. I'd avoid thin film if possible. With so many different types of panels you need to be careful as a buyer what people are trying to sell you and how things are rated. A few KEY questions you need to ask is, what is the minimum warranted power, what is the efficiency of the panel, what is the PTC rating of the panel. PTC is very important because its a standard rating at specific conditions all panels are measured at and is defined by the government. STC rating is what the manufacturers can theoretically pull out of the panel in ideal conditions and could be different from manufacturer to manufacturer. YOUR ONLY way of comparing panels is via PTC rating. You also need to ask what the power production warranty is. Generally its about 90 percent over 10 years and 80 over 15 or 20.

Solar irradition directly affects solar power output. Thats why we buy solar panels. More sun , more energy. Summer months have more day light so more energy is producted during the summer. But did you know that solar power output is also affected by Temperature ? Temperature has a direct impact on its output and the higher the temperature the lower the output. Being in San Francisco has the effect of keeping panels cool and producing more energy then in a desert environment.

Pointing your solar panels correctly to gain the most sunlight average in a day is vital to maximizing your light collection. In San Francisco if you pointed your solar panels directly south, you essentially get that. Now its not exactly south but very close. Fortunetly my roof has a clear unobstructed view of the south with no shading.

Solar panels must also be installed at an angle. Don't let installers tell you they can be installed flat or they must be installed flat for your situation. Most of the time instalation at an angle can give you more sunlight but more importantly there are no chance of ponding water on the panels if installed at an angle. Ponding water or debris on flat panels can cause shading problems. This would amplify in problem if left unmaintained. Now that last thing any of us want to do with a solar system is to maintain in daily or weekly by climbing onto our roof to spray down our panels with water to clean it. You also run the risk of damaging the panels with water because of shock cooling (if the panels are heated by the sun all day long and you go up there spraying cold water on it). Do yourself a favor, put the panels up in an angle that gives you the most sunlight and least headachs. I was given the option to add 30 panels flat or 28 panels at an angle. I choose 28 panels. The reason for that is you need to ensure the panels don't shade each other also so I just didn't have the room for 30 panels at an angle.

The next biggest problem you will hear regarding solar panels is shading. The reason why its such a big problem is because imagine your $40k solar system was like christmas lights. If one of the bulbs suddenly stopped working due to defect (or shading in solar terms) then you've basically broken the circuit and it will stop working. Shading is such a serious problem in solar systems that the standard for installation is to stay 2x the radius of the hight away from the shade. Inverters require a certain voltage to operate. If a single circuit composed of 5 solar panels had one of its panels shaded then you just lost the entire circuit because the inverter requires 5 panels worth of voltage to operate. The current flowing through the series is also affected by the least efficient one. If its shaded it will offer high resistence. Most large solar installations consist of a few circuits, maybe 3 to avoid shading problems. But even if a single solar panel is shaded, you can theoretically loose 1/3 of your capacity.
Now if you dive deeper and look at a single solar panel, you will also notice that it consist of several solar cells connected in series to produce a higher voltage. Again as you can see shading can affect a panels output in terms of voltage and current. Inverters depend on detecting proper voltage to operate.

Now that we understand solar panels we must understand why inverters are so important to the design of solar panels. Inverters are simple devices that convert DC to AC current. Our household uses AC current (120V, 60hz). I won't go into detail of what that is. Most people will probably install a grid-tied system. Solar systems require a load to operate (or batteries). I won't get into the details of batteries because I am installing a grid-tied system but trust me, unless you live in the woods, you don't want to maintain batteries. Grid tied systems means you are selling your power back to the utility. I've already discussed how inverters can affect circuit design of the overall system. There are two major types of inverters. A single Central inverter or a new technology called microinverter.

Central inverters work by connecting several panels in series and running DC current at high voltage back to the inverter. Usually you'll have atleast 2 circuits. You will have to know the capacity of your system and future growth before you buy this type of inverter because its specific to the setup. You also have to make sure all your panels are identical. These type of inverters offer the ability to monitor it over the internet. Thats really nice since you can watch your solar system produce power and you can chart its progress over time. Central inverters tend to be economically priced, they are easy to replace since its a single component, but its also a single point of failure. Central inverters is also the only way you can possibly add batteries if you decided to go off grid. Although these type of inverters can save you a few thousand vs micro inverters there are draw backs. All the conversion from high voltage DC is done in one location. Components tend to wear out faster due to the heat and resource demand on the circuit. Again if the inverter goes down your electrical production is down also until its repaired. DC current can also kill a person vs AC. In a Solar array we are talking very high DC voltages too (very bad combination).

Microinverters are inverters that are installed at each solar panel. If you have 28 panels you'll have 28 inverters. All inverters are wired in parallel so no single point of failures. It also resolves shading problems because of parallel design. And because of this parallel design it makes it easy to determine which panel is broken because every microinverter has a monitoring chip on it. We could go to the management webserver that is an additional component of the microinverters to chart the performance of the solar array and also chart the performance of individual panels. This is something central inverters can't do. Microinverters also send back 120V AC to your home so NO DC current to worry about. In fact its fairly safe to service these inverters yourself and you could probably troubleshoot and fix the problem without hiring anybody. Now all these features come at a price. Microinverters are roughly 2x more expensive in an equivalent system.

So now that we talked about Roofing, Structural support, Panel and circuit design, and Inverter setup. Then you basically have an idea on what you want and how much you want to spend. For me microinverters must be installed on a roof I can trust and panels made in the US that are efficient but economical. I decided to go with Siliken 225W panels with Enphase Microinverters M190.

DEALER SELECTION

Solar installation is a major investment. Your paying these people a lot of money to handle your expensive equipment you just ordered. Also remember there is a limited supply of panels and they are generally sold in pallets. Would you trust your $60k Mercedes to a high school graduate who received training and certification from a 2 year or less degree from a NON Accredited University?

Some of these people may also have a criminal background. Although they are trying to turn their life around by taking advantage of job training programs allowing them to install Solar and being certified to handle solar installations, I have heard stories of the very same people coming back to the home a year later to rob it because they remember what kind of valuables are in the house (the theives were cought via finger prints left behind the scene on a recently replaced exterior window).

San Francisco has a program called go solar SF that gives you credit for hiring local workers from San Francisco. After meeting several companies and seeing their corporate office you have to think twice. Looking at the dealer list on sf.solarmap.org you can see from google map that some of these companies are located in a persons home, a store front that looks like a liquore store, or companies that have so little invested in themselves that if they decide to run with your money you would have very little assets to go after. Some dealers are so large on this list that they don't even bother returning your call. Would you go with someone that don't want to talk to you before they take your money? Can you imagine what would happen after they have your money?

Don't let your dealer drop ship the panels to your property. The last thing you want to do is have a blame game on who damaged the panels. Some companies don't have the facilities for a shipping and receiving department and run the operation out of their home. Shoot again I refer you to sf.solarmap.org. The minute a shipment of panels arrives to your house, YOU are responsible. And these things are delicate. You paid the installer, let them deal with it.

One major problem with certain dealers is that they don't have your best interest in mind. Racks and accessories can be a high margin area. You should be sure your not getting some home made install racks or cheap ones. Unirac makes a very good racking system and they even have a heavy duty rack if you have a questionable roof structure.

Week 1 - Researching Roofing companies Jan 6, 2010

I started out trying to find a roofing company to work with. The company had to be IB Roofing Systems certified and easy to work with. With the advice of IB Roofing sales rep (he had nothing but good things to say about MR Roofing in South San Francisco) and Yelp.com, I gave them a call. Ricardo from Mr Roofing came out the next day for a site visit. He was happy I had already done my homework so he didn't spend much time explaining the pro's and cons of most roofing systems. We jumped right into the details of my situation. It was a fairly straight forward install and armed with google map he had already done some homework. He took measurements of my roof, asked questions, brought samples, and over all I had a really good impression of him. Very professional. They use only full time employees and he does not sub contract any work. Some roofers may use day laborers (again think about what I said regarding home roberies). He returned in person 2 days later with a proposal and we went over it in detail. He understood I wanted to put solar panels in and he offered to give me more accurate pricing once I nailed down what he needed from me regarding installing the stand off's for the panels themselves so that it would be integrated into the roofing structure and the IB system itself. In the end the proposal I received was 10,500 for the IB, another $900 to upgrade to 0.080mil material, 2,500 for insulation, 2500 for getting the standoffs sealed , and 900 for the tear off of the old roof. This proposal does not include fixing dry rot but he will fix it at a fixed cost of $7 per linear foot. It was also an additional $440 for copper drainage pipes.

Week 2 - Researching Solar Companies Jan 14, 2010

With any major projects you should always get multiple proposals. I've found that different companies work differently and it all boils down to what you are looking for. A company I initially delt with, lets call the Company A, sent a single person to evaluate the site. Company A did not care about what I wanted but instead they were focused on maximizing return on investment and they really wanted to sell my a prepackaged solar system based on my prior years solar usage pattern. What they offered me was either 4kw system or a 5kw system with a Fronius Central Inverter using Canadian Solar 230W panels (I had mentioned I wanted to atleast try expand the system at a future date so I didn't want to use up all the space on my roof.) By their calculations they think I could sqeeze 31 panels on the roof with room for a few more panels in the future. The one thing this vendor kept mentioning was that he was not sure if my roof would support the weight of my panels. He also mentioned something about possible panel work (he took pictures), and we discussed micro Inverters. Since I didn't have access to the craw space he couldn't confirm I met building code so he left the property with his measurements and informed me that he would have to look into it. The very next day I decided to cut a hole in my closet and I measured the rafter size. Turns out I had 2x6 running width wise with 25ft spans. They were 32" on center and were supported by a load bearing wall at the center. I mailed this to Company A and a few days later he tells me my roof did NOT meet building code and that I had to do some structural work to increase its strength. I realized this company didn't really talk to me, didn't really get my requirements, and overall did not work with me. I decided to get a second opinion.

At this point in time I decided to contact some roofers regarding possible re-roofing and its at this time I decided to see if they had recommendations on a solar company. I was referred to Company B and they kindly made the drive out to San Francisco in the rain to inspect the roof and bring me a proposal. This company sent 2 representatives and were failry professional. I can tell these two guys were not very technical and did not favor the micro-inverters due to it being a new technology. Thats cool, they wanted to sell something they were comfortable with. They brought over a bid for a standard system with 175W panels using a Central inverter. The bid came in very competitive but it did not include what I had decided at this point in time which would be atleast 225W panels with micro inverters from Enphase. Whats nice about Company B was that they did their homework, took satellite pictures, and did some engineering to determine maximum panels I can add on the roof without too much shading problems with the panels and the chimney. They had determined that the maximum number of panels I can add is 30, and 28 being ideal since this would be away from the chimney. I was a little confused since Company A had recommended 31 panels with possibilty for more. This told me Company A did not put much effort into their proposal , did not take into account the little things like panel upgrades, nor did they do any homework regarding shading. Company B was nice to work with because they really understood my needs, was priced nicely (not as cheap as company A), but the one thing that I did not like was the fact that they did not include the cost of the panel upgrade on my service panel. They didn't have a electrician available. Not sure they even bothered to get one. Often times these are considered extra charges and I would be stuck with the charge at a later time. These are ways a company tries to lower their proposal price to compete with other companies. With this potentially costing thousands I decided to get another bid just to have something to compare with.

My final bid came from Company C. This company had sent out 3 people. An engineer, a project manager, and a electrician. Of the 3 companies this one is the most professional. They took notes and measurements on my requirements and roof size. They made measurements of my rafters to ensure I meet buildig code. They spent the time to talk to me about all my options. To be fair I found this company when I decided to buy my solar system online and I was going to install it myself. I worked with an online company who then referred me to a local installer they like to use for my area. So I had 2 companies to deal with. I worked with the internet parts supplier first to narrow down the specification of the panels and inverters I want, and I worked with the installer regarding installation. From the very first visit with these 3 gentlement, I learned that my panel required upgrading which would run roughly 2k.. The electrician went into technical detail on my panel.. Informed me that I had good wiring from PGE and knew exactly what I needed to make this project work. The engineer who was this site visit brought a shade meter and took detailed profile of my roof and had a detailed engineering drawing of what was the most ideal placement of the panel and also the angle to the sun. The project manager brought it all together and made everything very clear. Overall very professional. I was very impressed. I was also affraid that all this professionalist would equal high cost. These guys kept in touch with me every day or 2. The engineer had contacted the city of San francisco building department and had confirmed that I would pass building code for my roofing structure. Remember company A said I had failed the code!!!!!! COMPANY A did not even check! At this point Company C sent me a proposal highlighting everything I need including the panel, installation, engineering drawing for the structure and also electrical diagram. Their proposal met all of california's legal code for proposal including the start time, end time, my right to cancel the contract within 3 days (required by California CODE), and we went over the proposal in detail. I appreciated the entire proposal.

With 3 proposal in hand I started to compare price and I did my best to try to get these 3 companies to compete against each other. Company A was out because I had a real hard time communicating with them. Seems like they did not want my money. I figured if I had this much trouble with them before I gave them money, imagine how much trouble I would have after I gave them money. So I talked to Company B and Company C. I was really leaning toward Company C because of professionalism and no hidden cost of the service panels. I was able to talk to the engineers, electrician, and they truly wanted to build me a system I wanted. I decided to give Company C a call and asked them to re-work their price to be more competitive with Company B. They were only off by maybe $2k. I managed to close the gap by $1k with company C so I decided to sign with Company C on Jan 26, 2010.

The system I decided to buy was a 6.44kW system using Siliken 225 Panels and the Enphase M190 Microinverters with Unirac heave duty rail system. Actualy Company C found the rails for me because they were concerned about the 32" spacing on my rafters. Better safe then sorry. The price I ended up paying is roughly $40,500 for the entire system with labor. The parts alone from the online site was rougly $26,000. You can do the math on how much the installation company will get.


Week 3 - Selecting a Roofing Company

I decided to get an alternative bid for a roofing company and was referred to one by my solar guys. Overall I wasn't really impressed. The roofing company did not communicate well with me or at all. I talked to him a total of maybe 2 times, the first being the initial call I made and the 2nd was maybe a week later when he had a proposal for me. He had offered to come out to measure my roof for me and inspect while I was not there.. To this day I still have no idea when he came out. He apparently had been in communications with my solar guys but was not sure if I had decided to go solar yet (I didn't sign any deals with solar company C yet) so he didn't bother calling me back. Kind of weird. They were priced OK and I used that to leverage a slightly lower price from MR Roofing (roughly $400) so in the end it worked out for me. I decided to sign with Mr Roofing on Jan 26, 2009 to redo my roof with IB Roof 80mm material, add 32 standoffs for the solar, and blow insulation into my house since i had none. They would also tear off my 2 layers of tar and gravel. I negotiated the price for all this work to $16,000. I plan on having them invoice me seperately for the insulation and for the solar stand offs so I can take advantage of the rebates.

Total out of pocket cost so far: $56,500 not including rebates.

Week 3 - Work starts! Feb 15, 2010

Roofing Work started today. Pictures speak a thousand words.

At 8 am

At 10 am

At 11 am

by 12:30 pm

by 2:30 pm, end of day relaxing, cleanup till 3pm


Week 3 - 2nd day of roofing! Feb 16, 2010

The second day of roofing. Today its IB Roofing system day! First segment of the install. Most times were spent on gutter and drainage work and corners.

8:05am

12:35pm

2:35pm


3nd day of roofing! Feb 16, 2010

All done. The next step is solar !!!!!
2:05pm


4th day of roofing! Feb 17, 2010

Final day of roofing and the beginning of solar installation. Today we finally installed the IB systems attic ventilation system and also all 28 standoffs. We even installed an IB Systems gray walk way to protect the 80mm white IB membrane.

5th day of solar project! Feb 22, 2010

With the roofing done its time to prepare the solar panels electrical connection. Because the old panel was not up to code and didn't have enough slots for solar, I had to upgrade the panel to a larger size. By using a 125A breaker I am able to use a 225 A box which should allow for future growth without exceeding my service.
Here is a copy of the engineering diagram. 755-triple-line-diagram.pdf



6th day of solar project! Mar 04, 2010

The day has come for the actual solar installation. We were hoping to finish today but one panel came in cracked and we were missing some cables due to a mistake by the supplier. No big deal we got half the system up and running and I am already starting to produce electricity the next day.


I've already integrated the Envoy Management unit to cacti so you can see what the production output looks like on a stormy San Francisco day. At this point in time only 1/2 of the 6kw system is actually hooked up due to missing parts as described above. From what you can see I'm peaking at 2.65kW and the patchy clouds are really dropping the output of the system. It is also worth noting that during the Winter season the solar system doesn't really kick into high gear until about 10 or 11am and last until 4pm roughly before dropping off. That is roughly 5 hours of solar hours for production.



A picture perfect day on 3/10/2010

7th day of solar project! Mar 19, 2010

Wrapped up the final bits and pieces today. Installed conduits on the roof, closed up and finalized wiring. We finally turned on the last branch circuit so all 28 panels are now online. Today was inspection day and we failed the final inspection. Basically the inspector wanted a sticker on the panel that says this system has a PV and he wanted a #8 wire for ground from the roof to the panel instead of a #10. We still have one damage panel to replace but he didn't see it. Anyway here are the results. I should get final approval next week. I am still awaiting PGE for a new meter and my rebate from the state.



8th day of solar project! April 9, 2010

Final inspection completed today and all systems a go. Inspector wanted to swap the ground cable from number 10 to number 8. He also wanted a few stickers on the panel and we are done.