Solar Plus Storage Microgrids Show Strong Promise

May 12, 2017
Dynapower’s Chip Palombini describes what’s driving growth in solar plus storage microgrids in the U.S. and how to derive maximum production from the systems.

Dynapower’s Chip Palombini describes what’s driving growth in solar plus storage microgrids in the U.S. and how to derive maximum production from the systems.

The promise of energy storage enabled microgrids, particularly solar plus storage microgrids, is just emerging. We at Dynapower see a bright future for these projects with recent installation numbers supporting that optimism, and legislative initiatives on the state level making microgrids an important part of the US’ energy evolution.

Chip Palombini, sales manager, Dynapower Energy Storage Group

A recent Navigant Research report shows that energy storage enabled microgrid capacity grew 238 MW in 2016. Navigant also reported California boasts more than 120 existing, developing or proposed microgrid projects, adding up to 650 MW of peak capacity, with many using solar PV as their power source. Well over 25 percent of the 15 GW of microgrid capacity worldwide now use energy storage systems in some capacity, and solar PV capacity in microgrids is five times greater than CHP capacity growth.

Legislative pushes across the country on a state-by-state basis are pushing energy storage to new heights — and energy storage enabled solar plus storage microgrids we believe will be a part of this growth.

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The updated California Self-Generation Incentive Program (SGIP) program will now give priority to solar plus storage installations making it more economically attractive than just solar alone. New York is putting up tens of millions of dollars to spur microgrid growth for grid resiliency in wake of Hurricane Sandy. Connecticut is seeking microgrid growth as well through state programs. Massachusetts is pursuing a similar mandate to California to scale energy storage and diversify its distributed energy portfolio. Boston treats microgrid development as a climate strategy. And some 50 countries, 69 cities and 62 regions/state now have stated goals to be run on 100 percent renewable energy. We believe energy storage enabled microgrids will play a central role in the evolving distributed energy transition.

The complexity behind solar plus storage microgrids

Having been a part of the development of numerous solar plus storage microgrids from the Pacific islands to the Caribbean to projects in both United States and Canada, we at Dynapower recognize the complexity of selecting the right storage solution to power a microgrid.  The power electronics — whether it be an AC-coupled, DC-coupled or hybrid solar plus storage solution — must be carefully weighed to match the end goals of any energy storage enabled microgrid, be it a standalone microgrid or one connected to the grid. And with combined heat and power, solar PV, and lithium ion energy storage being touted as the ideal mix of technologies, particularly in the United States, attention must be paid to selecting the right inverter — one that is capable of balancing the needs of all power generation sources.

And with the right energy storage solution selected, microgrid power production can be increased particularly in the instance of PV power generation.

Energy storage coupled to a solar powered microgrid can increase energy production from the PV arrays. For example, with common inverter loading ratios of 1.25:1 up to 1.5:1 on utility-scale PV (PVDC rating : PVAC rating), there is opportunity for the recapture of clipped energy through the addition of energy storage. In other words, energy that normally might go unused can now be stored and used for later use.

And with the right energy storage solution selected, microgrid power production can be increased particularly in the instance of PV power generation.

Using a simplified system for illustrative purposes, consider a 14MWDC PV array behind a total inverter capacity of 10MWAC. Depending on your location and type of racking, the total clipped energy can be over 1,000,000 kWh per year. With storage attached to the array, the batteries can be charged with excess PV output when the PV inverter hits its peak rating and would otherwise begin clipping. This stored energy can then be fed into the microgrid from the battery at the appropriate time for use. Without energy storage, all of this energy would be lost.

Increasing production, capturing lost energy

Additionally, the use of energy storage in solar enabled microgrids can increase hours of solar production..

This phenomenon also takes place when there is cloud coverage. In both cases this lost energy could
be captured by a DC-coupled energy storage system and utilized in the solar plus storage microgrid.

For grid-tied solar plus storage mIcrogrids, systems that can operate in islanded or grid-tied mode, there is opportunity to sell excess energy by turning energy generated into a dispatchable asset when energy storage is coupled to the microgrid. System owners can participate in supporting frequency regulation, energy arbitrage and demand response to drive revenues and lower the total cost of the grid-tied solar plus storage mIcrogrid.

The use cases and benefits of adding energy storage to a microgrid whether grid-tied or not, particularly when solar is involved as the power generation source, is particularly compelling. We invite you to download our white paper on solar plus storage system options to learn more, or drop us a line to discuss the benefits of adding energy storage to your microgrid.

Chip Palombini is the sales manager for the Dynapower Energy Storage Group.

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