Solar Energy Storage: Page 13 of 14

Emerging Technologies, Markets and Applications

Phil Undercuffler

Director of strategic platforms, OutBack Power,

What products does OutBack Power offer for utility-interactive solar storage systems?

OutBack Power manufactures the Radian inverter series for grid-interactive battery-backup applications and off-grid systems, as well as several models of our grid-interactive FX Series inverter/chargers. Two specific Radian models, the soon-to-be-released GS8048A (8 kW) and GS4048A (4 kW) utility-interactive multimode inverter/chargers, include an advanced GridZero AC input mode for self-generation and self-consumption programs. In 2013, we introduced an AC-Coupling Center that provides stable electromechanical coupling of grid-direct string and microinverters with OutBack’s Radian battery-based inverters. OutBack also offers two VRLA battery lines and integrated battery racks with code-compliant string disconnecting means.

What markets and applications currently provide an optimal value proposition for PV systems with integrated storage?

PV integrated with energy storage has existed since the very beginning of solar, providing power beyond the reach of the grid. Although during the last decade the grid-connected PV market eclipsed this market in size, it remains strong and healthy, with solid growth driven by the true cost of energy rather than by easily disrupted incentives, financial structures and regulatory barriers. As an example, with the expanding need for data, Internet connectivity and cellular service, we’ve seen strong growth in the industrial off-grid market, since the costs of PV energy are a fraction of that of diesel-fueled generation.

When it comes to the grid-connected market, most designers have considered grid-tied with battery backup [GTBB] to be the only option for a system consisting of PV, grid and batteries. Certainly, with increasing numbers of extreme weather events, more homeowners are requesting solar with backup to achieve both power stability and reliability. As more designers learn about the easy-to-install options available for GTBB, we’ve seen increasing growth into the grid-connected market. However, OutBack Power believes the greatest opportunity is in the growth of systems that provide benefits every day for both the grid and the system owner, rather than only in the event of a utility outage or future disaster.

The grid-connected solar market traditionally has focused on energy production and lowering the overall LCOE. However, what the grid and therefore we as a society face today is a variability or intermittency issue—intermittency of both production and load. The value of PV-generated kWh has become commoditized and is decreasing in value, while cost impacts of variability are rapidly increasing. For instance, the value of a kWh is measured in pennies, where the impact of demand charges is measured in dollars. Energy storage can provide designers the ability to reduce the impact of demand charges due to load surges or solar variability, in addition to being able to sell traditional kWh. That increases the value of a traditional PV system, providing developers a robust mechanism to improve the economics of PV.

How will California’s Assembly Bill 2514 impact the deployment of solar storage systems in the state?

This is a great opportunity. California has a clear mandate to reduce greenhouse gas [GHG], and solar is a key component in meeting that goal. However, we need to address many issues to achieve this goal, one of which is solar variability. The traditional way for utilities to meet variability in load is to add more spinning reserve to the grid. We cannot generate our way out of solar variability. Aside from the additional GHG emissions that would result, there is a point of diminishing returns that cannot be avoided. A 250 kW energy storage device can provide the same performance benefit to the grid as a MW turbine because it can operate as both a generator and a load, and it can operate at full-rated capacity in either direction.

How are recent challenges to state net metering laws impacting the growth trajectory of solar storage?

It’s no secret that the electric utilities view solar as a disruptive challenge, and many have been active both politically in framing existing net metering programs as “cross-subsidies” that shift the burden onto ratepayers without solar, as well as logistically in terms of creating new barriers to PV interconnection. This is unfortunate, as energy storage can provide a substantial benefit to the utilities by optimizing operations of their network and reducing variability caused by solar and loads, a point some utilities have admitted themselves. Many regions are approaching the point of grid parity. Some areas like Hawaii have surpassed grid parity, with the LCOE of PV power well below the cost of utility power. The more utilities create barriers to solar, the more likely customers are to look for other options. Thirty years ago, a regulated monopoly provided phone service, and the only options available were wall mount and desktop. Today, customers have multiple options for telecommunication, and many customers no longer choose to have a landline phone service. Will energy follow a similar path?

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