Plug-and-Play Solar Systems: Automating the Permitting, Inspection and Interconnection Processes

Can you imagine installing a photovoltaic (PV) solar system on the roof as easily as installing a television system in your living room? There would be no special tools, better yet, no electrical or structural permit applications and driving down and wait at your city’s planning department.

That time may be getting closer. Both the public and private sectors have been working together to make PV systems installation faster, easier, and less expensive — like a household appliance. 

Plugged-in Solar PV System Kits

Currently a few grid-tie, plug-and-play solar systems are available in the U.S. market. Ensupra Solar LLC (Huston, Texas) has developed and markets do-it-yourself (DIY) PluggedSolar system kits, which can be installed in one day. Sunil Sinha, CEO of Ensupra Solar, said that the key is the standardization. Standard design and installation processes reduce the cost of installed solar system by almost 40 percent compared with traditional systems, which are highly customized.

The company offers 1.2- and 1.5-kW grid-tie solar systems that can be directly connected to the 120-volt household outlet and does not require a licensed electrician to make the connection.  The kit comes with pre-configured and pre-wired UL certified components (PV modules, grid-tie inverter, converter, and wires) with racking for either ground or roof mounting. 

1.2-kW Plugged Solar System by Ensupra Solar

The PluggedSolar systems have been installed in 35 states in the U.S. The company created larger systems, 3- and 5-kW with a 240-volt plug-in, because a few states didn’t allow the 120-volt plug-in. “Some of the utilities that didn’t allow 120-volt plug-in originally are allowing it now.  I think it is a learning curve for utilities,” said Sinha.

The company offers the less costly and easier to install solar systems, but homeowners still have to go through the bureaucratic side of the process like installing traditional solar systems.

Over the phone or via email, the company’s support center helps homeowners fill out necessary paperwork such as permit applications and interconnection requests and also provides electrical line diagrams. A homeowner must submit the necessary applications to local agencies (such as the city planning department) and the local utility.

Once the system is installed, it still requires a physical inspection by the local enforcing agency and the local utility’s approval to connect to the electricity grid before it can officially be “plugged in” to the wall outlet.

Reducing the “Soft Cost” of Residential Solar PV Systems

Simplifying the solar system design can reduce the installation cost, but this is only half the story.  The great future success and commercialization of plug-and-play PV systems will come not only from simplifying hardware and installation process, but also streamlining or reducing permit/inspection and utility interconnection requirements.

While recent technological advances have drastically reduced the cost of solar hardware, soft costs — non-hardware balance-of-system (BOS) costs, including permitting, inspections, and interconnection — continue to account for an increasing portion of average installed residential PV system prices. In fact, soft costs accounted for approximately 64 percent ($3.19/W) of system costs in 2012, according to a report published by the National Renewable Energy Laboratory (NREL) in October 2013.

In the U.S., regulatory requirements and the permit process are often arduous and costly. With more than 18,000 jurisdictions and 5,000 utilities, many installers face frustration with layers of paperwork and the lack of standardization in permit and interconnection requirements and the various fees. Completing and submitting a permit application, waiting for the permit to be processed, and getting the inspection; each of these processes add significantly to the soft costs.

For the project, the Institute for Energy and the Environment at Vermont Law School (IEE) compiled a comprehensive list of the codes and standards applicable to residential rooftop solar systems in jurisdictions across seven states. It also identified various regulatory barriers to the plug-and-play concept. 

The team is taking a variety of measures to make the plug and play PV system compliant with existing codes and standards wherever possible. The team will propose modifications to current codes and standards to develop a voluntary plug-and-play system standard.

The DOE believes that plug-and-play systems will make the process of buying, installing, and connecting solar energy systems faster, easier, and less expensive, potentially unlocking major reductions in the soft costs — with a specific goal of $0.65/W by 2020.

The SunShot Plug-and-Play Vision by the DOE 

In December 2012, the Fraunhofer Center for Sustainable Energy Systems (CSE) was awarded US $11.7 million over a three-year period to develop plug-and-play solar systems through the DOE SunShot initiative. The Center has partnered with a multidisciplinary team of equipment manufacturers, utilities, local governments, universities, and research institutions to develop standards for plug-and-play residential rooftop solar systems, which are “as easy as buying and installing a washer/dryer combo,” said Christian Hoepfner, Director at the Fraunhofer Center and Principal Investigator for the Plug and Play PV project.

A streamlined and simplified permit and inspection process is very important for further deployment for residential PV systems. But how the process is created and implemented is up to jurisdictions and utilities. “What we can do is to make [installing a PV system] as easy as possible for them by eliminating their safety concern” said Hoepfner.

Designing PV System and Architecture with a Focus on Safety and Code Compliance

The Center is also working with Lumeta, a BIPV module maker based in Irvine, Calif., to develop “peel & stick” modules with advanced adhesives.  The PV system with a flush mounting will be lightweight, have no roof penetration, and require few tools for installation, which will greatly reduce installation time and costs.

The modules weigh two pounds per square foot, which is equivalent to the weight of a layer of asphalt shingles. This means that adhering lightweight modules is comparable to adding a second layer of shingles, which is already permitted in most jurisdictions without a structural review. 

Sticking modules to the roof without metal frames or racking has another advantage. Grounding the solar system is very important for safety to avoid fire and electrocution. Adhering modules to the roof eliminates exposed metal on the rooftop, and therefore there is no need for equipment grounding, according to Hoepfner. 

The Center is also working with Infinite Invention to develop a standardized PV-ready meter collar that is mounted between the meter socket and the utility meter.  The collar functionality includes the necessary communication with the jurisdiction and utility to automate system permitting and inspection.  The appropriate meter will need to be installed by the utility prior to system installation.

The plug-and-play project objectives include automation or elimination of electrical permitting and inspection processes, reduction or elimination of structural review and permitting, and remove utility reporting and grid interconnection.

PV systems are not exactly home-appliance-material in nature — they are very big and heavy, they become part of the outside building structure, and they can inject power back to the grid. These factors bring safety concerns, and therefore a solar system must comply with electrical, building, and fire safety requirements enforced by state or local agencies and utilities.

If the industry can standardize codes and regulations across various jurisdictions and create solar systems that comply with those codes and ensure fire and health safety, a homeowner may be able to install and “commission” the solar system within one day, virtually without significant permitting, inspection and interconnection processes, as the DOE envisions.

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Junko Movellan is a Solar Industry expert who writes and analyzes the US and Japan PV downstream markets. She has more than 15 years of experience in the PV industry, analyzing industry trends and developing business strategies for global companies. She previously worked as a Senior Analyst at Solarbuzz and as a Market Development Analyst at Kyocera. She is based in California, USA.

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