Solar Energy Storage: Page 4 of 14

Emerging Technologies, Markets and Applications

What are the major obstacles to the expansion of solar storage systems in the US?

Many new storage technologies are not yet ready for deployment. At the same time, many high-performing technologies have been tested and proven, and have recently achieved significant cost reductions and scale. Educating customers about what is available on the market and being able to show existing systems that have been operating in the field should go a long way toward accelerating deployment of energy storage. Costs must continue to come down, and customers must continue to demand access to DG in net metering scenarios without excessive tariffs on DG adoption. Regulations must continue to support storage and allow storage owners to be compensated for the benefits they provide.

To be attractive, energy storage must be cost effective and provide value. Understanding the various revenue streams available in particular applications, choosing the right technology to take advantage of them, and designing and operating the system properly are important. If the industry makes misleading performance claims or designs systems that do not operate as advertised, we risk alienating customers at an important point in market development.

Mark Hardin

Director of product marketing, Xtreme Power, xtremepower.com

What markets and applications provide an optimal value proposition for PV systems with integrated storage? How will this evolve over time?

To date, the majority of the market for PV systems integrated with an Xtreme Power Energy Storage System [ESS] has been island grids hoping to lower energy costs by displacing costly fossil-fueled energy with cleaner, less expensive renewable generation such as PV. These grids are usually smaller and less robust than mainland grids and cannot reliably absorb the rapid, uncontrollable fluctuations in power output associated with renewable generation. Therefore the island utilities require the renewable developers to include some method of reducing intermittency, or ramp control from the ESS, and provide grid-support functions such as frequency response and voltage support.

The value proposition is when the levelized cost of PV combined with an ESS is less than the cost of the fossil-fueled alternative generation and/or additional grid support services that may be required. Xtreme Power has seen this market grow from the Hawaiian Islands to include Alaska, Puerto Rico and various Caribbean locations. While this fractured market will continue to grow, new opportunities are taking shape in California and other mainland grids where forecasts indicate that the level of PV and renewable penetration will reach a tipping point that will require the unique operating attributes of energy storage systems. In addition, the increasing cost of demand charges and proliferation of behind-the-meter PV offer potentially lucrative savings for commercial and industrial customers interested in utilizing an ESS combined with PV to reduce metered demand and maximize the potential savings of PV generation.

What customer requirements do utility-interactive solar storage systems meet? What are the key market drivers?

Typical customer requirements are ramp control, or reducing the volatility of the intermittent output from PV generation, and various grid-support applications such as frequency response, frequency regulation, voltage support and responsive reserves. Customers are interested in these applications primarily to meet requirements outlined in a PPA to connect the solar project and deliver power. They are also interested in improving grid stability and reducing wear and tear on conventional generators, by using the energy storage systems’ ability to deliver power quickly and accurately, to help with frequency or voltage fluctuations that high levels of renewable penetration may be causing.

However, in larger, more rigid grids with lower levels of renewable penetration, the customer may not request some applications. Future customer requirements will evolve to solve the issue most adeptly illustrated by the CA-ISO “duck chart” graph. This graph shows the very steep and large load ramp-up period utilities will face when solar generation is declining and load is increasing in the early evening hours. Utilities are already looking to flatten their load curve by charging up solar storage systems during solar peak output in the midday period, and discharging during the early evening hours when solar generation is dropping and load is increasing. This time-shifting application is well suited for solar energy storage systems.

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