Worldwide PV sales surpassed $10bn annually and total installed PV capacity projected to exceed 25 GW by 2011

DUBLIN, IRELAND: Research and Markets has announced the addition of the "Disruptive Technologies Affecting the PV Industry, Microinverters and DC-DC Solutions: Economic Factors, Application Drivers, Architecture/Packaging Trends, Technology and Regulatory Developments - First Edition" report to its offering.

The emergence of disruptive power architectures including microinverters and dc-dc converters will be one of the most important trends in the photovoltaic (PV) market in the near-term. The shortcomings inherent in today's central inverter architecture are expected to provide a host of opportunities for several new technologies.

In fact, there are a growing number of companies developing products and technology specifically designed to generate more power from the PV panels already on the market. A distributed inverter architecture using either of two specific disruptive technologies, microinverters or dc-dc solutions, are expected to present a significant challenge to the conventional central inverter architecture over the coming years.

Among the areas covered in our latest analysis are the technology, architecture and packaging trends affecting the industry, as well as a thorough discussion of new and emerging technologies and materials, applications, potential threats and the latest regulatory developments and standards.

Executive summary
The emergence of disruptive power architectures including microinverters and dc-dc converters will be one of the most important trends in the photovoltaic (PV) market in the near-term. The accelerating worldwide growth in grid-tied PV will be driven by a number of factors including: improved technology, cost reductions, strong deployment incentives, growing consumer interests, renewable portfolio standards, climate change concerns, and a host of other policy mandates.

The number of relatively large PV projects feeding power directly to the grid will increase, but most systems will be deployed in behind-the-meter applications, where the technology competes with the retail rate of delivered electricity rather than the wholesale cost of energy supplied by central-station generating plants. In fact, worldwide PV sales have surpassed $10 billion annually and total installed PV capacity is projected to exceed 25 GW by 2011.

As a result of the growing demand for PV, the outlook for inverters used in PV systems is expected to remain strong. There are a large number of PV system configurations available and a wide range of inverters on the market. Some models use transformers and some are transformerless, and many come with sophisticated communications and monitoring systems.

Regardless of the type of inverter used, the system is usually configured in traditional central inverter architecture. Since the PV industry is constantly evolving, inverter manufacturers must continually design new products.

Despite the ubiquitous nature of the central inverter system, it has a number of limitations. It relies on one device (the inverter) that when faulty, brings down the entire system, and its inherent design means the weakest panel in each string eliminates the benefits of the better performing PV panels. (The "weakest link" module determines the string current and has a disproportionate impact on overall PV system performance.)

This latter point is especially important because PV systems are constantly exposed to the elements and that means one or more panels over the lifetime of the system will be covered by debris, dust or another form of shading. In fact, some panels may fail or weaken as a result of age or simply lose power due to panel mismatch.

The shortcomings inherent in the central inverter architecture are expected to provide a host of opportunities for several new technologies. In fact, there are a growing number of companies developing products and technology specifically designed to generate more power from the PV panels already on the market.

A distributed inverter architecture using either of two specific disruptive technologies, microinverters or dc-dc solutions, are expected to present a significant challenge to the conventional central inverter architecture over the coming years.

A significant advantage both of these disruptive technologies have over traditional central inverter technology is the ability to perform maximum power point tracking (MPPT) at the panel level. The goal of the MPPT algorithm is to extract the greatest power available from the solar array. (The better the MPPT algorithm, the greater the power output.) Due to variation in shading, dirt, and aging of solar panels, individual panel voltages will vary, causing the output voltages of strings of panels to vary.

In addition to improvements in efficiency, the ability to reconfigure PV arrays without additional complex string calculations and improved operational flexibility, another opportunity for both microinverter and dc-dc solutions is the further development and availability of communications systems for both commercial and residential PV systems.

Manufacturers of disruptive technologies such as microinverters and DC-DC solutions have picked up on this trend and are incorporating them into their respective systems.

Challenges and opportunities relating to distributed PV integration will be strongly influenced by the current and future attributes of PV and balance-of-system technologies. Among the more promising is the development of the building-integrated PV (BIPV) systems.

A building-integrated PV system involves integrating photovoltaic modules into the building envelope material and power generators. Evidence of this opportunity can be seen in the number of successful BIPV projects worldwide, ranging from individual residential units to large commercial developments.

The demand for technology to address the problem of PV shading is another area of opportunity for both microinverters and DC-DC solutions. Due to the nature of solar array configuration, small amounts of shade (for example, shading of less than 10 percent of the surface area of a PV system) can lead to disproportionate power losses of more than 50 percent.

One completely shaded cell can reduce a solar panel's output by as much as 75 percent, and three shaded cells can decrease 93% of the panel's output. Common causes of shade include structural objects such as trees, chimneys and dormers, and intermittent debris including falling leaves, bird droppings, dust and clouds passing overhead, which is an unavoidable challenge that cannot be engineered out of an installation.

In an effort to promote the use of disruptive technologies such s microinverters and dc-dc solutions, a number of microinverter and dc-dc solutions manufacturers have adopted a strategy of partnerships and alliances within the industry. In fact, a number of solar suppliers and utilities have made either alliances or acquisitions of distributed electronics vendors in what is clearly a validation of the potential for both of these new disruptive technologies.

The authors expect that the trend towards business partnerships and alliances between manufacturers of disruptive technology and established PV distributors, manufacturers and distributors will continue to grow as the technology becomes more established.

An inverter is the most critical electronic component in any PV photovoltaic system. Among the challenges facing inverter manufacturers are maintenance issues, since in a PV system, the inverter is the component with moving parts.

In order to compete with the traditional inverter architecture, end users of both microinverters and dc-dc solutions must be assured that the products they use will come with warranties comparable to traditional solutions. Manufacturers of products considered to be disruptive technology, such as microinverters and DC-DC solutions, realize this and offer a range of warranty options.

The market forces affecting the traditional PV inverter industry also apply to the disruptive technologies presented in this report. Especially important are interconnection and regulatory standards.

Despite the efforts of a number of government and regulatory bodies worldwide, the goal of achieving agreement in both is still a work in progress. However, there are a number of groups working on electrical interconnection standards with the objective of reducing or removing barriers between distributed generation technology and the utility grid.

A survey done found that most projects, including PV, meet some sort of resistance from the utility companies when they try to interconnect with the grid. The expensive and sometimes difficult interconnection requirements currently in place worldwide comprise a key barrier to the increased use of alternative systems.

One of the more interesting technologies being developed to drive interconnection is the development of a "smart grid." However, removing current interconnection requirements is not as simple as changing policies, and a method of resolving these barriers is ongoing.

Among the areas covered in our latest analysis are the technology, architecture and packaging trends affecting the industry, as well as a thorough discussion of new and emerging technologies and materials, applications, potential threats and the latest regulatory developments and standards.