California’s Solar Demands Reshape Grid’s Energy Load

Renewables are beginning to make real changes to the energy grid, especially in California where solar power – in particular – has become more widely adopted. The state currently leads the US in solar energy production, and in 2012, 983 MW of grid connected PV capacity were added in the state. Growth in renewables, especially from solar, is predicted to continue affecting the use of traditional energy sources.


In the past, California has enacted several programs designed to increase the use of renewables, particularly solar (e.g. the California Solar Initiative, which expired in 2013). More recently the state passed a relatively flexible energy storage mandate, which requires utilities to acquire 1325 MW of energy storage devices by 2020.

Why include storage in renewable energy mandates? The idea of utilities using energy storage during the day (when prices from traditional energy options are higher) is relatively new and only makes sense in a renewable energy context. Thanks to solar, it’s anticipated that demand for energy from traditional sources has started to decrease during mid-afternoon when solar power is peaking. But sunset brings with it a new ramp up in power requirements just as solar generation is ramping down. This creates a spike that has been, to date, mainly responded to by bringing more generator turbine capacity online. The new model, that includes battery storage, will allow the turbines to run all day and store the excess energy created in batteries. These batteries in turn, will discharge their stored power in the early evening hours to smooth the surge in power requirements as consumers return from work and turn on air conditioners, lights, televisions, etc. This is the reverse of the way batteries have been used in the past, especially in states like California where the power demand from consumers has been steadily increasing. Southern California’s major population center around Los Angeles comprises a huge draw on power around sunset, as does the Bay Area, California’s second-largest population center. Utilities that incorporate renewables will require energy storage in order to continue to run their turbines during the day and store energy for use at sunset to smooth spikes. These ‘spikes’ are created by an increase in power usage at the intersection of a decrease in renewable power supply..

There’s also the matter of frequency regulation. Increased demand on the grid (such as at sundown in California) can destabilize the frequency of the grid. Energy providers are required, under federal and state regulations, to manage the power frequency on the grid and respond immediately to fluctuations. Energy storage provides a ‘fast reacting’ method of correcting frequency variation. The Federal Energy Regulatory Commission, as outlined in their Order 755, recognizes the benefits of fast reacting storage systems.

As mentioned in a recent New York Times article by author Matthew L. Wald, oversupply can be just as dangerous as undersupply from a grid stability standpoint. The generation of excess solar power can create frequency instability and overwhelm the grid. Energy storage, consistent with what the Axion PowerCube™ provides, will manage frequency regulation and power smoothing at either end of the spectrum. As the grid becomes increasingly shaped and changed by renewable energy, incorporating energy storage technology is critical to ensuring continuous power delivery and instantaneous response (the PowerCube responds in 55 milliseconds). In California, the increased use of energy storage has been mandated. Can the rest of the US be far behind?

Article contributed on behalf of Axiom Power International, Inc. and re-posted in agreement with EarthTechling.

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