Ultracapacitors in the Grid
Maxwell Ultracapacitors are a proven solution for key application challenges in the grid market, with a total installed power of >30 GW as of June 30, 2012…and still growing! Maxwell ultracapacitors are becoming the solution of choice for numerous grid applications across a multitude of industries.
Renewables ride-through and firming, Hybrid Energy Storage Systems component
As renewable energy sources grow in use and the percentage of grid power met by renewables increases (due to Renewable Portfolio Standards – RPS), grid stability becomes an increasingly important issue. The variability in wind and solar output creates instability on the grid. This variability also results in poor utilization of these resources by 30-50%.
The Challenges and Solutions
VARs support - Electromechanical machines such as wind turbines output low power factor. A reactive power source is needed for high quality power output to the grid. While electronics systems can provide sub-cycle to single digit cycle reactive power, ultracapacitors provide a few seconds of reactive power in a cost effective and smaller package size.
Renewable firming - Wind output has sudden drops and spikes in output due to wind variation while solar has variations due to clouds and other shadow effects. In both cases, the vast majority of events are less than 5 minutes and the majority of these are less than one minute. The long life, high power and charge/discharge cycling of ultracapacitors make them the ideal energy storage for firming the output of renewable installations. System designs can result in lifetimes over a million charge/discharge cycles.
Firming, Ancillary Services - Multiple value streams can also be captured when combined in a hybrid energy storage with a battery. With the excellent volume cost of batteries, but relatively short cycle life, a hybrid energy storage system can be cost effective for short term requirements as well as 15 minute clearing for frequency regulation.