LESSONS LEARNED

To date, SCE has learned valuable lessons in the key areas pertaining to efficient project execution: building structure, permitting, and PV panel racking and wind loading issues.

Building selection is a critical issue that can derail an installation plan. For example, SCE found that buildings can appear to be excellent candidates and comply with previous building codes, but are not amenable to the utility's rooftop PV arrays. This type of problem was discovered when SCE and First Solar were in the panel-layout stage for another site in the pilot project.

The building chosen was slightly older than the target age of five years or younger. It met the construction regulations for the time it was built, but construction regulations had changed since then. The building did not include as large of a roof-weight safety factor as more current codes require. By the time it was discovered the roof could not hold the weight of the PV array, in addition to withstanding wind and earthquake loading, much time had been spent negotiating lease terms and developing the system design. In response, SCE now has a pre-screening process in place to filter out buildings that look like good candidates but are not strong enough for a PV facility.

Permitting on the Fontana site, initiated by ProLogis, had gone smoothly until the end of construction. The local fire department was concerned about first-responder safety in the event of an emergency at the site. At the time, there were no comprehensive standards for labeling conduit, combiner boxes and inverters. The California State Fire Marshall's office published a draft PV installation guideline on the Internet.

SCE found that the guideline provided some suggestions for residential and small commercial PV installations; however, very large facilities, such as the Fontana site, were not fully addressed. SCE came to an agreement with the local fire department regarding the signage the department wanted to have on the PV hardware. Once the type and number of signs needed were negotiated, SCE had the signs made and installed. After that, SCE and ProLogis were able to get the sign-off on the construction permit and commission the unit.

From this experience, SCE learned to identify the localities that encourage green power construction and the importance of working with them early on in the permitting process.

Transforming the PV Market

SCE's objective in requesting approval from the CPUC for this program is to transform the PV market by initiating a program that is large enough to lower the costs of PV component parts and installation. SCE also plans to develop a larger-trained PV installation workforce in Southern California. Both of these objectives will benefit not only SCE customers but also the people of California. SCE will have more green-collar jobs for people who will install PV generators of fossil-fuel-free renewable power.

SCE sees these very large warehouses with little on-site load as an under-utilized resource for PV installations. The California Solar Initiative, also known as the Million Solar Roofs program, provides rebates to customers who install less than 1-MW PV arrays on the roofs of their homes or businesses. The generation from these residential or small commercial PV facilities serves the electrical load of the host building, with any extra generation going to the utility grid.

SPVP proposes to build primarily 1-MW to 2-MW PV generating units on rooftops of huge warehouses that do not use enough electricity to justify installing a PV array. The warehouse owner will lease the rooftop space to SCE, gaining a revenue source previously unavailable.

SCE has identified large commercial warehouses in Southern California's Inland Empire with maximum rated wind speeds in the range of 80 mph to 105 mph (129 kmph to 169 kmph). SCE's first installation used First Solar's nonpenetrating racking system. No penetrations were made in the roof; instead, ballast (brick pavers) was used to weigh the system down, thereby reducing the potential for any roof leaks. SCE is evaluating both penetrating and nonpenetrating systems for future installations. As SCE considers buildings in the higher wind zones, penetrations may be needed to make sure the PV array does not overload the roof. When needed, these penetrations need to be designed to be reliable, leak-proof and accessible for inspection.

Next Steps to a Greener Grid

SCE's SPVP will contribute 0.5% to its RPS goals by 2014, if and when all 250 MW have been built. PV is currently and projected to be a relatively small contributor to RPS goals nationwide because of the high capital cost. In order for PV to make a more significant impact on RPS goals, the PV industry needs to become more cost competitive with other types of renewable generation. SCE's SPVP will help drive PV costs down, thereby helping to accelerate the commercial viability of PV and enable many more individuals and business to install their own PV generating units.

SCE is currently the only California Independent System Operator (CAISO) participant scheduling rooftop solar PV resources into the CAISO electric grid. SCE is very aware of the challenge solar-generated electricity creates. Solar PV resources of more than 1 MW must schedule power with the CAISO and will likely participate in the CAISO's Participating Intermittent Resource Program (PIRP).