Solar Southwest Florida

In my previous post about plug-and-play solar panels, I discussed the realities of this technology in terms of current product offerings. The US Department of Energy just released a request for information from parties interested in developing plug-an-play technology.

The US government is about to spend up to $30M of taxpayer money to partially fund development to make this technology viable under the “SunShot Initiative.” The idea is to make solar electricity economically viable without incentives and make installation as easy as plugging in a TV. In other words, they want to put solar electric contractors out of business.

That last comment was a bit facetious, but it would have that effect. Fortunately, or unfortunately depending on what side of the fence you are standing, I don’t see it happening. Solar electricity is no less dangerous than electricity from the utility company. In fact, it’s more dangerous to handle in some ways. The concept of an appliance that simply plugs in is very nice in theory, but in practice is much more complicated.

When household generator backup became more popular in Florida over the last few decades, there were many fires and deaths attributed to people trying to connect the generator output to their home using an electrical outlet. Similarly, connecting a generator to your circuit breaker panel is extremely dangerous without a proper transfer switch to protect both the household wiring and utility line workers that are repairing systems during an outage. The difficulties with the plug-and-play solar panel concept are similar in many ways, with the added complexity of physical mounting of panels on a roof or ground rack.

In any case, a licensed electrical contractor is going to be required to make a home ready for any future plug-and-play technology that is developed. The physics involved with a standard electrical outlet will not allow safe operation of parallel sources of power on existing wiring systems. It’s like trying to fit four lanes of traffic on a two lane highway. It’s not going to work – at least not safely!

The SunShot Initiative seeks to remove some of these barriers through new product design, standardized connectors, utility and building department cooperation, and building/electric code changes. Regardless of what innovations come out of this project, don’t expect solar panels to be available at your local retailer that you can take home and plug in without some sort of major upgrade to your existing electrical distribution system.

Hopefully there will be significant cost reducing technologies that come out of this initiative. We very well may be able to reach solar cost parity with the utility in the next decade, with or without this project, and without turning every homeowner into a solar installer.

The full text of the RFI can be found here:

DE-FOA-0000634: Plug and Play Technologies and Systems Request for Information (RFI)

You may have seen the promise of plug-and-play solar panels coming to a store near you. I’ll try to make sense of these “new” products and tell you what they will and won’t do for you. There are two kinds of “plug-and-play solar panel” promises floating around out there. There is the solar panel that you can plug into your house and use or sell back to the utility, and there is the solar panel system into which you plug devices directly.

The first “plug-and-play solar panel” product promises that you can plug your solar panels into an existing outlet and feed power back into your home. This is completely unsafe and will not meet any building code in existence. This would require that the system have a male plug that you insert into the outlet. Guess what – that plug with exposed metal conductors could have live power on it (unless the inverter is listed to UL 1741 – let’s not get too technical here!) Even if the proper inverter were used, there are numerous National Electric Code sections that would not allow its use in this manner. No utility company would allow this power to be sent back to the grid. This is not an approved interconnection method, and it is completely unsafe.

Consider that you have a 15 amp circuit breaker feeding a string of outlets in your home. The wire and outlets on that circuit are capable of safely supplying 15 amps of power. If you plug a solar panel’s output into an electrical outlet, you have increased the amount of power available to that wire and all receptacles on the circuit. Furthermore, there is no way to restrict the number of solar panels that a homeowner would plug into a circuit. The homeowner could theoretically install dozens of solar panels into power strips on a single circuit. Hopefully the closest fire station is close by…

The second kind of “plug-and-play solar panel” is really nothing more than a complete mobile off-grid solar electric system. The components include a solar panel, an inverter, and possibly a battery. With this system you can plug devices directly into the inverter output using a standard AC receptacle. There is nothing wrong with this concept, except that it has serious limitations in usefulness, efficiency, and value.

A new product of this kind from Onyx Service and Solutions Inc promises to revolutionize plug-and-play solar. There is really nothing new with this product except that it is larger and higher powered than most other portable solar power devices. I use the word “portable” loosely here because it’s hardly something you can pop in the trunk for an afternoon outing. The included 330 watt solar panel is at least five feet long by three feet wide. The premise of this product is to include a solar panel, a battery, and an inverter in a single box with a standard AC outlet. That’s great, but the amount of power generated and stored isn’t even enough to run a laptop computer for 24 hours.

This system cannot be attached to your home’s electrical system and it cannot sell electricity back to the grid. Don’t be misled!

This type of product is fantastic for small power needs, like charging phones, tablets, or other small devices, or using some higher powered devices for shorter periods of time. They key is to make it portable enough. There is a nice consumer product line from Goal Zero that is perfect for modest power needs, and it does exactly what the Onyx system does, albeit on a much less powerful scale, but it is truly portable.

The promise of “plug-and-play solar panels” is a long way away. There is hope. The best opportunity for a plug-and-play type system may be using a transfer switch similar to the generator input to a home. One thing is certain – you will need to upgrade your home wiring or provide a proper receptacle that in some way makes this type of installation safe, and it will need to be done under the current or future requirements of the National Electric Code.

The best bet in solar electric today is still the basic grid-interactive solar electric system. Don’t be misled by promises of new revolutionary products that can’t deliver. If you want a portable consumer grade solar energy system, educate yourself on the limitations, and if it meets your needs, by all means, proceed!

Early morning dew covers PV panels at Naples Botanical Gardens

Fafco Solar has completed the FGCU Naples Botanical Garden photovoltaic system installation. I am particularly proud of this system and the expert installers that did the heavy lifting. The system includes 164 SolarWorld 245 watt solar photovoltaic modules, 164 Enphase M215 microinverters, a Unirac SolarMount mounting system, and S-5! Clamp attachments.

Because of the existing electrical system at the facility, the photovoltaic system is divided into two sub-arrays backfeeding power into two 208V 3-Phase electrical distribution panels. Commercial 3-Phase installations are always interesting from a design standpoint because typically we are dealing with various existing transformers and often generator backup systems.

Workers Install PV Module

It was truly a pleasure working with the Naples Botanical Garden staff and Manhattan Kraft Construction on this project. The weather cooperated for the most part. The job went very smoothly, finishing about a week ahead of my expectations.

This job is a model for future PV construction projects. We look forward to the next big PV job as we move on to a large multi-tenant solar water heating job in Fort Myers.