1. Introduction
2. Highlights
3. Data Analysis and Rationale
4. Top 10 Cities - Watts per Capita
5. Top 10 Cities - Watts installed
6. Top 10 Cities - Number of systems installed
7. Counties - Number of systems installed
8. Counties - Watts installed
9. Counties - Watts per Capita
10. September 2007 Update

Read about the 

Download Spreadsheets:

1. City Solar data
2. County Solar data
3. All Data for Bay Area Solar Installations Report
4. All California incentive data as of May 2007

Download Report Information

1. Formatted report for printing
2. Press Release

Find Solar installations in your SF neighborhood from the SF Solar Map

 

Courtesy images provided by ProehlStudios.com

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Introduction

Californians have purchased more than $2.8 billion in solar electric technology (PV), representing 31,380 PV systems and 336 megawatts (MW) of solar power.[1] California has offered financial incentives for grid-tied solar electric systems (PV) since 1998, and in January 2007 the state implemented a new incentive program called the California Solar Initiative (CSI). The CSI is a ten-year $3.2 billion incentive program with the goal of installing 3,000 MW of solar power on the equivalent of one million rooftops. The CSI was a much heralded program due to its size, length, and cutting-edge policy goal of establishing a sustainable solar industry.

This report by NorCal Solar Energy Association (norcalsolar.org) uses publicly available solar incentive data to describe the number and amount of grid-tied solar photovoltaic (PV) installations as of 12/31/2006 in ten Bay Area counties and 165 communities. The data is provided in an file and is useful to consumers, the solar industry, and decision makers to consider the following:

• Tracking local prices and cost trends
• Measuring installation progress against CSI goals
• Setting specific city level goals for PV installation and tracking current status
• Uncovering trends in equipment, system sizes, number of installers, and new types of installation business models

Highlights from Bay Area data:

• Average aggregate cost of systems under 15kW $9.49, about the same as May 2006
• Average cost of systems 15-50kW $8.69 per watt
• Average cost of systems >50kW $8.58 per watt
• Average size and cost of residential sized systems (under 5kW) is 3.6kW (up from 3.5 in 2006)
• Total sales of systems (prior to incentives and tax credits) is $787 million

Interesting trends in solar include the increasing use of third party financing for large commercial systems, the increase in average system sizes for residential systems, and an increase in the average cost per watt for smaller systems.

NorCal Solar Energy Association plans to update this data annually. In the report website we have provided the raw data used for these summary tables in a pivot table which allows for easy sorting, comparisons, and selection of individual cities data. We have also provided an Excel sheet with the entire statewide data set for all incentives since 1998 through May 2007. Readers can use this worksheet to sort and search for specific regional data.

Data Analysis and Rationale

NorCal Solar Energy Association focused on ten Bay Area counties because this region leads the growing wave of solar adoption across the state. Apparent reasons for strong solar adoption in the Bay Area include solar-friendly utility rates, net metering, ample sun exposure, supportive local governments, a strong environmental ethic, and the attention brought to PV technology through the Vote Solar initiative in 2000.

NorCal Solar Energy Association limited the records to those indicating installed systems as of the end of 2006 so we can do a comparable annual analysis, and so the data was easily compared between the old and new rebate programs (Emerging Renewables Program and Self-Generation Incentive Program versus the California Solar Initiative). In order to compare communities equitably we defined cities based on population:

• small - 10,000 or less
• medium -50,000 and less
• large – more than 50,000

The raw data for this report includes incentive records from the California Energy Commission (CEC), data from PG&E for the Self-Generation Incentive Program (SGIP), records from Silicon Valley Power (SVP) which serves the City of Santa Clara, and the City of Palo Alto Utilities (CPAU).

To produce the final Top Ten lists, we first established a list of all the zip codes and place names included in all ten Bay Area counties [2]. The second step was to sort through and correct city and place spellings in the central data file (merged from two ERP files and one SGIP file). Finally, we copied the essential data (date installed, size system, system cost, utility, county) into a new workbook and generated a pivot table [3]. After adding population and county data, we checked our summary data against the original raw data to ensure the error rate was reasonable given the corrections to city spellings and missing city or zip code data [4]. It is estimated that the Top Ten lists are accurate within 5% of the raw data sets used.

There are numerous odd records included in the dataset, such as three systems in San Francisco showing a $7,000+ dollars per watt cost. We excluded these outliers for the cost per watt summary data, but we did not exclude other records that also seemed out of bounds such as $43 per watt for a small system in Marin. These records either demonstrate that some solar projects have unique and high expenses, or that some records had data entry errors. Excluding all projects with costs above $20 per watt did not significantly affect the averages so these are included.

Disclaimer: all attempts were made to present the actual incentive data within the specified parameters. Please report any missing incentive data to This e-mail address is being protected from spam bots, you need JavaScript enabled to view it .

[1] Raw data from May 7, 2007. ERP included 30,339 records and totaled 140.12 MW. SGIP included 1,036 records and totaled 195.8 MW. There is a fairly high drop out rate but demand trends indicate all drop-outs will be replaced by new reservations at current incentive levels. 

[2] Brainy Zip used for zipcodes. Census data from 2000

[3] This report is an expansion of a report published in August 2006 that was drafted by Bill LaCommare and Liz Merry. The pivot tables used to generate the statistics and many of the report parameters and strategies were authored by Bill LaCommare.

[4 ]Note: the protocol for records that included city names with incorrect or incomplete zip codes was to maintain the city name and delete the zip code. Approximately 3-5% of the original records included zip code errors.

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*September 2007 Update
The data from the May 2007 SGIP file (used to create this study) was compared against the SGIP data from July 17, 2007. The vast majority of SGIP systems in the Bay Area Installs Report are listed as "Completed" in the July data. However, there are several systems listed in the July data that were not listed, or not listed in the same way (e.g. with same city or zipcode), in the May data. Also, there are 3 systems in the May data in the City of Newark, which in the July data are missing or withdrawn. Without these systems the City of Newark is outside the Top Ten list for medium cities # of watts installed.