by D.A. Barber
When installing a PV system becomes as simple as plugging an appliance into an outlet, the residential PV market will grow at a faster rate, both due to the simplicity of installation and the associated reduction in cost of the overall system. This is the reasoning behind why many solar energy companies now offer residential PV panel “kits” that include all the wiring, inverters, charge controllers and mounting hardware need to quickly and easily install the system. With the advent of micro-inverters, these “Plug-and-Play” systems have taken off in the past year and a half with everything from portable PV units to easily installed systems for use in remote developing areas. And these plug and play PV systems have quickly made their way into the consumer mass market giving homeowners the option of purchasing a complete, pre-packaged solar PV system. In September 2011, Westinghouse Solar introduced an “all-in-one” solar home PV system, and companies like Colorado’s Onyx Service and Solutions, as well as Seattle-based Clarian Technologies have been offering plug-and-playPV kits for over a year.
With the plug and play concept filtering over to other practical uses, the United States Department of Energy is now investigating the development and economics of such plug-and-playtechnologies and is expect to offer developmental funding later this year.
“Plug and Play” in Developing Countries
Typically, it takes some knowledge and skill to set up an electricity generating system. Whether they are solar, hydropower or wind, these systems require a variety of different hardware that is not always available in developing countries. If any of this hardware is improperly installed, or if wires are not the proper size, the efficiency of the entire system will suffer. In fact, when these systems are installed in developing countries, the required higher-grade wires may not be used because simply because they are too expensive or not available. But if the systems are supplied as plug-and-play units that can be installed relatively easily and quickly already containing high quality and correctly sized wiring and components, the communities will be able to get as much energy as possible from the unit, sacrificing nothing to poor wiring.
SolarNexus, a pre-wired solar power generation system that can be installed relatively easily and quickly, is one of the forms of plug-and-playdevices introduced by U.S.-based Solar Nexus International (SNI). The company currently works with NGOs, aid organizations and humanitarian groups to bring the benefits of solar energy to communities worldwide. As a quick solution to getting self-contained solar power generation up and running quickly, SNI created SolarNexus to help power developing areas, such as in rural Africa where over 92 percent of people do not have access to electricity. SolarNexus links all the wires, transformers, converters, inverters and batteries required in an off-grid electricity system. SNI custom-designs these systems for each client, and then ships out a container that includes all the materials needed for a U.S. code-compliant system. Once the shipment is received, the provided instructions allow local workers to quickly install the system.
In Nigeria, SPACE Nigeria is a new company offering an entire plug-and-playsolar-powered dwelling. SPACE (Self Powered Adaptive Container for Everyone) is a secure portable building fabricated from recycled, shipping containers equipped with PV panels capable of generating up to 3.5kW of power. The energy is stored in the built-in backup battery array that can last for up to five days if used conservatively, according to the company.
SPACE units come with a painted and insulated interior, stained plywood floors, interior lighting and electrical outlets. The entire modular unit with foldable PV racking system can be transported easily from place to place and due to the nature of the recycled shipping container, the SPACE units can resist harsh climatic conditions.
DOE Gets Involved
The U.S. Department of Energy is investigating the development and economics of these transformational plug-and-play technologies and systems to reduce the soft costs of the Balance of System components. From the DOE’s perspective, this includes permitting, inspection, and grid interconnection.
DOE has asked industry respondents to comment on the value of plug-and-play PV systems, as well as how their organization or company anticipates participating in any future funding opportunities. The topic areas of interest to DOE include PV module technology, power electronics design, grid integration approaches, racking hardware design, and system installation process. Late last year,DOE held a plug-and-play solar workshop in Washington, D.C., that focused on the development of plug-and-play solar technologies in order to identify the current barriers and possible solutions for these technologies. From that workshop DOE determined that successful plug-and-play solar applications should meet a few basic specifications:
- Simple installation: The PV system must be simple enough to install in only a few hours by people with no special expertise or training. This most likely requires the use of an AC module and no conventional racking materials.
- No permitting or commissioning required: Traditional PV systems may need both electrical and structural permits depending on the government authority having jurisdiction. Permits are generally required to ensure that installing the equipment does not create a public hazard. Removing the need for a structural permit may require the development of lightweight/flexible AC modules that are easy to install and will cause no hazard even if they do fall from the roof.
- Smart grid capability: Upon interconnection with the utility, the PV system will communicate to the utility all the pertinent information required to ensure that it does not interfere with the normal operation of the grid. The inverter may also need other capabilities (reactive power, voltage regulation, etc.) to ensure normal grid operation as well. This assumes that the utility is set up to receive information from the PV system, has the ability to make appropriate decisions based on the information it provides, and may require command and control to maintain grid reliability.
Based on feedback from the information, DOE says it may issue a Funding Opportunity Announcement (FOA) which will be open to all potential applicants.
The potential funding opportunity will “address the process-related issues and barriers by taking a fresh look at the grid and distributed PV systems as a whole and explore new technology pathways to reduce total system costs and ease installation.” While DOE is not expecting any one company to provide a complete plug-and-play system, they are hoping for a collaboration of many companies who provide the various individual components of a plug-and-play system with standardized interfaces.
“Plug and Play” Market
Since the “Plug n’ Play” concept eliminates the need for relatively costly wiring and installation by a professional electrician, it can significantly reduce the balance of systems costs of purchasing and installing residential and small business PV systems.
Moreover, the greatest advantage of some plug-and-play systems is the ability to start drawing renewable energy from the PV panels by simply plugging in an extension cord, the applications - and the markets - for these self-contained systems are expanding.
Clarian SmartBox Solar Module
The initial target market is homeowners and small-business owners. But a new market that is unattainable for conventional roof top systems are renters. According to Clarian, their system works by plugging into any outlet in a home and that power can then be used anywhere in a home and will flow where needed. The system basically supplements the power already coming into a home. Similar to cable TV equipment “boxes” in terms of installation, if you are a renter you bring it in, set it up and plug it in. And if you move you can take it with you. This is a powerful point for the residential market as well: not only do homeowners have to pay $20,000 to 30,000 for a conventional and permanent roof-mounted system with a payback time frame of as much as 15 years, there's not a lot of homeowners who can guarantee they're going to be in their home for that period of time to recoup their investment. The plug-and-play system can target this market segment that could not be reached by the renters and homeowners unable to invest in or commit to the conventional roof-mounted systems.
