Pictures of My Solar PV System

I finally climbed on my roof to take some photos of my solar PV system.

We have a low-pitched roof, we have trees in our front yard and our PV system sits on our second floor which makes our PV system only visible from one side of the street. Street View.

These days, panels are made to be nice and sleek. Roof View.

We only had enough space next to our Electrical Panel for the Shut Off Switch, so the Inverter had to be placed about 10 feet away on an empty wall space. The installers did a great job running conduit under our house to minimize any blemishes that my wife might complain about ;).

In one of my earlier posts, I mentioned the importance of having the installer do a physical site visit and evaluation. Here's a picture of some of the Roof Obstructions that would be difficult to identify from Google Maps or Bing.

Installer: Martifer Solar (Matt Rakocija)

4 Weeks Solar Production

Yippee!! We set a new daily production high of 9.6 KWH on Sunday.

We had a few days of rain these past couple weeks so our current daily average declined slightly to 7.3 KWH per day. But I'm very happy with this production level. February is supposed to be a low production month, yet we are very close to our average daily production target of 7.6 KWH to reach the CSI Estimated Annual Production of 2,781 KWH for our system. See Current Production Chart.

Total After 4 Weeks:
Production: 199.3 KWH
CO2 Saved: 338.8 lbs
Estimated Savings: $39.86

System Size DC (STC): 2.28KW
System Size AC: 1.93KW
System Size AC (California CSI rating): 1.63KW
Panels: 10 Sunpower Serengeti 228 Watt
Inverter: 1 Sunpower 3000M (SMA Sunny Boy 3000 rebranded under Sunpower)
Estimated Annual Production: 2,781 KWH

Direction: East facing

Installer: Martifer Solar (Matt Rakocija)

Part 3 of 3: A Home Buyer's Guide to Purchasing a Grid-Tied Solar PV System - Finalizing Your Decision

This is Part 3 of 3.  Please refer to earlier posts for Part 1 and 2.

I started researching solar over a year ago and got really excited about the opportunities. I started getting quotes from installers in May, put a deposit on a system in September and the installation was completed and we started producing electricity on January 26 , 2011. I hope this Guide will help you with your solar choices.

Steps in the process:

1. Get a general understanding and overview of solar PV systems for the home. (Detailed in Part 1 post)
2. Determine a rough estimate for your solar PV system. (Detailed in Part 1 post)
3. Find installers and request quotes. (Detailed in Part 1 post)
4. Standardize your quotes so you can compare and evaluate them on an apples-to-apples basis. (Detailed in Part 2 post)
5. Evaluate your quotes and your options. (Detailed in Part 2 post)
6. Evaluate your financials.
• I created a Solar Financial Model (that's what I do all day at work - build models) that you can use to evaluate your savings/returns. You'll need to use the estimates you calculated from Steps 4 and 5 and enter them into the GREEN cells in this model. Note - I changed the link because Google Docs tends to distort spreadsheets making it a little difficult to read. If you Save the file to your computer, you can see it in plain Excel.
• One of the key drivers of the financial returns is the energy price increase assumption. I received a quote that showed my returns based on a 7.6% annual price increase. I should find a study to get a validated figure (another thing on my list to do), but it's a safe bet that energy prices will rise at a faster rate than inflation. You can change this assumption in my model. Also at the bottom of the model are sensitivities for your returns based on different annual price increase assumptions.
• If you are buying the system with "cash", then you will want to look at the ROI section. If you are financing the purchase through your mortgage (refinance or home equity loan), then you will want to look at the ROE section. Even if you can not time your purchase with your mortgage, it still makes a lot of sense to buy your solar PV system now because of the rebates and tax credits currently available which will phase out over time (I purchased my system at a 43% discount). Then when you do eventually refinance your mortgage you can roll up the cost and you'll start seeing the better ROE returns.
• Note on the Annual Return calculation. If the Annual Return shows #NUM! or DIV/0! errors, it's OK. Actually, it's great because it likely means that your annual savings exceed your annual payments from the beginning so a return can not be calculated (i.e., you have an astronomical return on your investment). Interest rates were so good that I was able to maintain the same monthly payment even though I refinanced my new mortgage from a 30-year loan to a 15-year loan. The annual return for my solar system is 81%. If I assumed a 30-year mortgage with an interest rate of 6% in the model, I would get one of those errors because I would save more money than it cost me from Day 1 and have no net out of pocket costs at all.
• Solar Leasing. I did a cursory look into leasing (another item to add to my list that I will try to update in the future), but it didn't make sense in my situation because I was going to finance my purchase through my mortgage.
7. Select an installer.
• Your installer will be your primary resource, so you should choose one that you trust and feel comfortable working.
• Your installer will typically warranty their installation and repairs for 10 years, so you might also consider the longevity of your provider.
• I didn't find a good review site for installers - but, then again, I didn't search very hard for one. I think this is something that I will look into further and add some links.
• I mostly relied on contacting references provided to me by the installers. 1 Block Off the Grid, Cooler Planet and others have good questions and things to consider. Some of the questions I asked were the following:
• What is the size of your system and when did you have it installed?
• Has the performance of your system met your expectations? Have you noticed a drop off?
• Have you had any issues with the system (inverter failure, problems with the panels, monitoring, etc.)? How were they resolved?
• Have you had any roof leaks? How were they resolved? Was the Installer at fault?
• Does Installer provide any ongoing services to you?
• How satisfied are you with your PV system?
• How satisfied are you with Installer?
• What would you do differently if you had to do it all over again?
8. Other factors to consider.
• What is the condition of your roof? If it needs replacing, then it is better to have it replaced before or in coordination with the installation of the solar. Our roof had a few more years of life left, but we would need to replace it unless we moved so we had the roof redone in coordination with the solar installation (now it's good for another 40+ years). The solar installers installed the standoffs in the middle of the roofing process so that they would not need to make any penetrations in our newly shingled roof.
• What kind of shingles are on your roof? Installers have no problems with composite shingle roofs but they may have issues with wood shake and tile roofs. Many installers do not like installing solar on wood shake roofs since they have to replace all of the shingles that they crack and break during installation of the PV system. With tile roofs, installations are also more difficult. Some installers will not work on these roofs or will charge you more for the installation.
• What is your shading and tree situation like? We considered a South-facing configuration for our home, but our neighbors to the west of us have some big oak trees that would create significant shading in the late afternoons and in the winter months. While we get along with our neighbors, we did not want to inconvenience them to trim their trees every few years. Instead, we decided on an East-facing orientation because there would be no shade issues. To minimize the hassle and additional maintenance, we felt it was well worth sacrificing the 200 KWH per year of production (6.8% lower) of the South-facing configuration.
• Aesthetics. My wife only had one stipulation when I bought our PV system. She told me, "just make sure it doesn't look ugly." Fortunately, I was able to accommodate her on her request quite easily. However, if you have a high-pitched roof that faces the street, you may want specialized panels that are flush with your roof.
9. Go solar and enjoy the sunshine.
• At some point you have to take a leap of faith that your system will be reliable and produce the electricity you expect. I will be posting my solar production so you can have at least one live data point.
• Upsides. They say that solar adds $20 for every $1 you save in electricity per year to the value of your home.

Below is a summary of my home PV system:


System Size DC (STC): 2.28KW
System Size AC: 1.93KW
System Size AC (California CSI rating): 1.63KW
Panels: 10 Sunpower Serengeti 228 Watt
Inverter: 1 Sunpower 3000M (SMA Sunny Boy 3000 rebranded under Sunpower)
Estimated Annual Production: 2,781 KWH

Direction: East facing

Cost of System Before California Utility Rebate (Installed Cost): $13K
Cost of System After California Utility Rebate: $10.5K
Cost of System After Federal Tax Credit: $7.4K

Cost per DC (STC) Watt: $5.73
Cost per AC Watt: $6.77
Cost per AC CSI Watt: $8.01

Installer: Martifer Solar (Matt Rakocija)


                                        Mortgage                Electric Bill           Total Mo. Pmt
With Solar                         $1,050            +           $ 54             =         $1,104
Without Solar                  $1,000           +          $100             =         $1,100
Difference                                 $50                         $(46)           =           $       4
It costs me only $4 more per month to have clean energy.

3 Weeks Solar Production

We had problems getting our monitoring system up and running during the first week, so I had to run outside and check the system every day. Now that it's working, I can check it from the internet - so much better. See my daily production chart.

After 3 Weeks:
Production: 147.0 KWH
CO2 Saved: 249.9 lbs
Estimated Savings: $29.40

System Size DC (STC): 2.28KW
System Size AC: 1.93KW
System Size AC (California CSI rating): 1.63KW
Panels: 10 Sunpower Serengeti 228 Watt
Inverter: 1 Sunpower 3000M (SMA Sunny Boy 3000 rebranded under Sunpower)
Estimated Annual Production: 2,781 KWH

Direction: East facing

Installer: Martifer Solar (Matt Rakocija)

Part 2 of 3: A Home Buyer's Guide to Purchasing a Grid-Tied Solar PV System - Evaluating Your Quotes

This is Part 2 of 3.  Please refer to earlier post for Part 1.

I started researching solar over a year ago and got really excited about the opportunities. I started getting quotes from installers in May, put a deposit on a system in September and the installation was completed and we started producing electricity on January 26 , 2011. I hope this Guide will help you with your solar choices.

Steps in the process:

1. Get a general understanding and overview of solar PV systems for the home. (Detailed in Part 1 post)
2. Determine a rough estimate for your solar PV system. (Detailed in Part 1 post)
3. Find installers and request quotes. (Detailed in Part 1 post)
4. Standardize your quotes so you can compare and evaluate them on an apples-to-apples basis.
• Each installer will probably have slightly different configurations and panels made from different manufacturers. Therefore comparing one quote to another is very difficult since each quote really is it's own customized product. In addition, there are many different numbers and definitions that are difficult to understand and keep straight. 
• Personally, I got a multitude of quotes and configurations that ranged from 1.84KW to 2.58KW in size, different array directions (South, West and East facing), different shading assumptions, and of course different panels and inverters. There was no way for me to compare the quotes accurately based on what the installers gave me alone. So I found it essential to find a price/performance metric that I could use as a standard benchmark to evaluate my options.
• Before I get to the metric I found to be most useful, I want to define and describe a lot of the measurements upon which the installers will base their quotes and with which you will need to derive a standard metric.
• DC Rating STC. This is the name plate rating of your system based on Standard Test Conditions (STC) and this is the size of your system that your installer will quote you. When somebody asks you how big your PV system is, this is what you will give them. I think this has flaws as a benchmark because the performance in real world conditions can vary among different panels.
• DC Rating PTC. This is the DC size of our system based on PVUSA Test Condition (Photovoltaics for Utility Systems Applications) which is closer to real world performance than STC. Many refer to PTC as "Performance Test Conditions". I think this is better than DC STC.
• Inverter Efficiency. Solar PV panels produce electricity on a Direct Current (DC) basis but need to get converted to Alternating Current (AC) through your inverter so they can feed back into the grid (your house runs on AC power). This is how well your inverter converts DC to AC. The more efficient, the less electricity loss you have in the conversion.
• AC Rating (based on PTC). This is the the DC PTC Rating multiplied by the Inverter Efficiency. This is your real standard system size before design factor adjustments. The AC Rating is the base metric you will want to use. Further down, I will describe a variation of this base metric that I prefer to use (based on CSI rating).
• Shading Derate Factors. The performance of your system will be affected by the shading the panels will receive over the course of the year. When your installer does a site visit, he should do a shade test and provide you with a detailed shading report with his quote. The shading derate factors will be needed to accurately assess your design factor adjustments.
• Array Tilt. This is the angle that your solar panels are positioned relative to the ground. Your panels will most likely be the angle/slope of your roof. The ideal tilt depends on where you live. In my area in Los Angeles, the optimal tilt is 17 degrees.
• Array Azimuth. This is the direction that your solar PV system is facing. The array azimuth is shown in degrees with True North being zero degrees and South being 180 degrees. The ideal direction is South facing (180 degrees).
• As mentioned above, the AC Rating is the base metric you will want to use to compare all of your various quotes, but you will need to further standardize your quotes to compare them on the same basis.
• I found the CSI Calculator , a utility rebate calculator for the California Solar Initiative, to be the easiest tool to standardize my quotes. Even if you do not live in California, I would still recommend this calculator for you. In addition to ease of use, what I like about this calculator is that it is an official and industry standard calculation rather than an estimate produced by your installer (call me a cynic).
• The PVWatts Calculator is also another good calculator (can be used for any place in the world) developed by the National Renewable Energy Laboratory. Most calculators, including CSI, are based on the PVWatts calculations of solar radiation (how much annual sun). Again, like the CSI calculator, you can estimate your annual and monthly PV production and savings. If you live outside of California, you may want to use this to get your final estimated production. You will need to provide (or use their defaults) additional design factor adjustments, so it is a little more complicated than CSI. Also note that the dollar savings may be understated if you use their cost per KWH for your area because this is based on the total average and not at the higher tiers which your solar PV system would likely offset.
• Steps to standardize your quotes:
• I would suggest using your most preferred quote or the system setup that you think you are likely to purchase. Make sure you have an accurate shading report for this quote because that will be one of the critical assumptions you will use. Using the CSI Calculator, you will use the same assumptions for the following inputs/factors:
• Shading Derate Factors (monthly percentages from the shading report from your installer)
• Array Tilt (degrees)
• Array Azimuth (degrees)
• Also use the same basic information including Utility, Customer Type, Incentive Type and Mounting Method.
• The only variables that are not standard will be the make of the panels/modules, number of modules, make of inverter, number of inverters and quoted cost of the system.
• After inputting the assumptions into the CSI Calculator, you will have a report that will tell you your estimated Annual Production (Annual kwh), AC Rating (CEC-AC Rating) and CSI Rating. I like the CSI Rating because this is the performance rating (AC Rating multiplied by the Design Factor adjustment). You can save PDF versions for the reports you run for each of your standardized quotes. You will now have the performance for all of your quotes based on the same assumptions.
• Click this link for a step-by-step guide with screen shots for using the CSI Calculator.
5. Evaluate your quotes and your options.
• After you have standardized the quotes and created various scenarios through the CSI Calculator, you can now start to compare and evaluate the different quotes.
• The first step is to determine how the installers stack up against each other. Even though most installers will quote you based on Cost per DC Watt Installed (STC), I think the better metric is Cost Per AC Watt because this captures the conversion to AC and real world inefficiencies. Personally, I like using the Cost Per CSI AC Rating because that captures all of the design factors including direction of your array in case you are deciding between different roof placements. Using Cost Per AC Watt as your price/performance metric, you can now compare the installer costs for all of your quotes irrespective of system size, direction, etc. You can go back to your installer and question the system cost and see if they come back with a better price.
• The next step is to determine the best position of your PV system. The ideal position is South-facing, but the shading of your roof and other factors may make it less ideal. Using the CSI Calculator, you can run another scenario with your top quote choice by changing the direction and shading derate factors while keeping all other assumptions the same. This will calculate your estimated Annual KWH production with the new array direction that you can compare to your top quote choice.
• At this point, you will be able to determine which installer is offering you the best price and what direction/configuration will produce the most solar energy. Click link for Solar Quote Comparison Spreadsheet. Note - Google Docs tends to distort spreadsheets making it a little difficult to read. If you Save the file to your computer, you can see it in plain Excel.
6. Evaluate your financials. (Detailed in Part 3 post)
7. Select an installer. (Detailed in Part 3 post)
8. Other factors to consider. (Detailed in Part 3 post)
9. Go solar and enjoy the sunshine. (Detailed in Part 3 post)

Below is a summary of my home PV system:

System Size DC (STC): 2.28KW
System Size AC: 1.93KW
System Size AC (California CSI rating): 1.63KW
Panels: 10 Sunpower Serengeti 228 Watt
Inverter: 1 Sunpower 3000M (SMA Sunny Boy 3000 rebranded under Sunpower)
Estimated Annual Production: 2,781 KWH

Direction: East facing

Cost of System Before California Utility Rebate (Installed Cost): $13K
Cost of System After California Utility Rebate: $10.5K
Cost of System After Federal Tax Credit: $7.4K

Cost per DC (STC) Watt: $5.73
Cost per AC Watt: $6.77
Cost per AC CSI Watt: $8.01

Installer: Martifer Solar (Matt Rakocija)

                                        Mortgage                Electric Bill           Total Mo. Pmt
With Solar                         $1,050            +           $ 54             =         $1,104
Without Solar                  $1,000           +          $100             =         $1,100
Difference                                 $50                         $(46)           =           $       4
It costs me only $4 more per month to have clean energy.

2 Weeks Solar Production

Total production and savings after 2 weeks.

Production: 95.3 KWH
CO2 Saved: 162.0 lbs
Estimated Savings: $19.06

System Size DC (STC): 2.28KW
System Size AC: 1.93KW
System Size AC (California CSI rating): 1.63KW
Panels: 10 Sunpower Serengeti 228 Watt
Inverter: 1 Sunpower 3000M (SMA Sunny Boy 3000 rebranded under Sunpower)
Estimated Annual Production: 2,781 KWH

Direction: East facing

Installer: Martifer Solar (Matt Rakocija)

Part 1 of 3: A Home Buyer's Guide to Purchasing a Grid-Tied Solar PV System - Getting Started

I started researching solar over a year ago and got really excited about the opportunities. I started getting quotes from installers in May, put a deposit on a system in September and the installation was completed and we started producing electricity on January 26 , 2011. In a separate post, I described my reasons for going solar. In this post and following posts, I will focus on what I did, how I evaluated my solar options, what resources I found useful and other models/tools I put together to help me in buying my grid-tied solar PV system.

I've separated this Guide into multiple parts so I could provide more explanation in each step while limiting the size of each post. I hope this Guide will help you with your solar choices.

Steps in the process:

1. Get a general understanding and overview of solar PV systems for the home. 
• While I did most of my research online, I did find a useful book in the library titled Got Sun? Go Solar by Rex A. Ewing and Doug Pratt. The book was a great starting point and it provided me with a good practical overview and guide for understanding solar (and wind) for the home. Some of the items in the book that I found useful were the requirements and considerations in choosing a PV system (simple grid-tied or battery system) and the simple rules-of-thumb to help me easily understand and estimate energy production and other output. The authors also had lots of technical information (e.g., electrical calculations) and their opinions on some of the components and manufacturers that they used over their many years of installing PV systems (kinda like a Consumer Report for solar). All of this information was packed into less than 100 pages of text making it a quick read and nice reference guide.
• Cooler Planet provided good overview information. I used this site mainly to create my checklist of things to consider (Solar 101 tab) and to to get a rough estimate the size and cost of the system I wanted for my home before I started calling installers (easy to use calculator in the Solar Tools tab).
2. Determine a rough estimate for your solar PV system.
• Pull together the last 12 months of electric bills. This is your starting point for evaluating what size system will make sense for your energy usage. This is also the first thing an installer will ask you for so it's good to have it at your fingertips.
• In California, electric rates are based on a tiered system. There are five tiers with significant price increases as you move up from the lower tiers to the higher tiers. Tier 1 is also called "Baseline" and is very inexpensive, whereas Tier 5 can be very expensive (in my area it is 3X). In my area, the Baseline usage is 13.8 KWH (kilowatt hours) per day in the summer and 10.5 KWH per day in the winter and the rates are as follows:
• Tier 1 (Baseline) 11.8 cents per KWH
• Tier 2 (101-130% of Baseline) 13.8 cents per KWH
• Tier 3 (131-200% of Baseline) 23.0 cents per KWH
• Tier 4 (201-300% of Baseline) 26.5 cents per KWH
• Tier 5 (Over 300% of Baseline) 30.0 cents per KWH
• Optimally, you want to build a PV system that will cover your higher tier usage. If you are a heavy energy user, solar really makes a lot of sense because you are paying expensive rates.
• My electricity usage is in the Tier 3 range most months and I bought a PV system that should offset around 40% of my usage. Looking back, I think I would have gotten a bigger system since it really wouldn't have cost me much more per month. I think it's similar to the saying about buying a house - buy the biggest one you can afford - since it's a little more difficult to add on to your system later.
• Before I started calling installers, I used the Cooler Planet Calculator to get a rough estimate the size and cost of the system I wanted for my home (based on what percentage of energy I wanted to offset with solar).
3. Find installers and request quotes.
• As with most things, it's important to get multiple quotes. It's also very important to find an honest and reliable installer that you trust as your installer will guide you and be your primary resource for your new solar PV system. Of course, it's best to find some personal referrals. If not, there are sites that can provide recommendations for installers.
• Cooler Planet Mentioned above. I got referrals for some local installers here and I ended up purchasing my system from one of them.
• 1 Block Off the Grid evaluates and negotiates a group/volume discount rate with a designated installer for a particular area. The installer they recommended was very knowledgeable and the pricing was great. I think they are a great starting point. To me, they are like CarsDirect for solar - they'll provide you with a good installer at a good price. I would have been happy going with the installer 1BOG recommended.
• The installer will have an initial phone call with you. He will likely ask you to get onto Google Maps or Bing to look at your house configuration and have you provide your electrical usage over the last 12 months.
• The installer will then schedule a site visit so they can see your house and gather information to do a true assessment of your solar possibilities. Using a Solmetric SunEye, Solar Pathfinder or similar tool, the installer will be able to get an accurate reading of your sun and shading for every month of the year. Click this link for an example of one shade report I got for my house. With a site visit, the installer will take measurements of your roof and will be able to note any physical obstructions (eg, steam vents, dormers, DirecTV dish, etc.). It is very important to get a site visit in order to get an accurate assessment of your solar potential and where to put your system. Surprisingly, some installers do not do site visits before they give you a quote - I was told by one installer that they would do a site visit "if I was really serious".
• After the site visit, the installer should be able to give you a comprehensive quote(s) for your solar PV system based on the tilt angle and direction including hardware, cost, estimated electricity KWH production and $ savings, utility rebates (significant in California and other states) and other items.
• You may go through a few iterations of various configurations, size, placement, etc. of your system with the installer. Ask your installer a lot of questions since he will be your primary resource throughout the process.
• In my opinion, if you have gotten to this point, you have made the biggest step in going solar because you have actually started the process going instead of just "sitting around and thinking about it". And, most of the work up to this point is actually done by the installers who are preparing all of the quotes for you.
4. Standardize your quotes so you can compare and evaluate them on an apples-to-apples basis. (Detailed in post for Part 2)
5. Evaluate your quotes and your options. (Detailed in post for Part 2)
6. Evaluate your financials. (Detailed in post for Part 3)
7. Select an installer. (Detailed in post for Part 3)
8. Other factors to consider. (Detailed in post for Part 3)
9. Go solar and enjoy the sunshine. (Detailed in post for Part 3)

Below is a summary of my home PV system:

System Size DC (STC): 2.28KW
System Size AC: 1.93KW
System Size AC (California CSI rating): 1.63KW
Panels: 10 Sunpower Serengeti 228 Watt
Inverter: 1 Sunpower 3000M (SMA Sunny Boy 3000 rebranded under Sunpower)
Estimated Annual Production: 2,781 KWH

Direction: East facing

Cost of System Before California Utility Rebate (Installed Cost): $13K
Cost of System After California Utility Rebate: $10.5K
Cost of System After Federal Tax Credit: $7.4K

Cost per DC (STC) Watt: $5.73
Cost per AC Watt: $6.77
Cost per AC CSI Watt: $8.01

Installer: Martifer Solar (Matt Rakocija)

                                        Mortgage                Electric Bill           Total Mo. Pmt
With Solar                         $1,050            +           $ 54             =         $1,104
Without Solar                  $1,000           +          $100             =         $1,100
Difference                                 $50                         $(46)           =           $       4
It costs me only $4 more per month to have clean energy.

Week 1 Solar Production

It's so nice to see our meter spinning backwards. I can't wait to see my first electric bill.

Week 1 Production: 44.0 KWH
Week 1 CO2 Saved: 74.8 lbs
Week 1 Estimated Savings: $8.80

System Size DC (STC): 2.28KW
System Size AC: 1.93KW
System Size AC (California CSI rating): 1.63KW
Panels: 10 Sunpower Serengeti 228 Watt
Inverter: 1 Sunpower 3000M (SMA Sunny Boy 3000 rebranded under Sunpower)
Estimated Annual Production: 2,781 KWH

Direction: East facing

Installer: Martifer Solar (Matt Rakocija)