The stop-start market is experiencing rapid growth in Europe due to tightening emissions reductions requirements for vehicles with diesel engines. Ultracapacitors have been tested in pilot projects in electric buses and fuel cell vehicles, but they are not being used in great numbers commercially in other transportation market segments. Early-stage applications for ultracapacitors also include grid-scale energy storage and wind turbines.
Ultracapacitors’ greatest advantages over their primary competition (lithium ion batteries) are superior cycle life and power density. However, ultracapacitors are viewed as too expensive for most energy storage applications and the technology is commonly viewed as not sufficiently mature for transportation applications.
Advances in technology and cost reductions in the cost of ultracapacitors have not kept pace with lithium ion batteries primarily because of much smaller investments in research and development and manufacturing. Researchers are developing hybrid ultracapacitors that include components from batteries in efforts to greatly enhance the devices’ energy density.
This Pike Research report provides a comprehensive assessment of ultracapacitors in key application areas including stop-start vehicles, hybrid and fuel cell electric vehicles, and utility grid applications including ancillary services for energy storage. The study includes an examination of technology and market issues, profiles of key industry players in the emerging ultracapacitor market, and market forecasts through 2020.
A Breakthrough in Ultracapacitor Technology
Over the last few days, I’ve come across a number of items documenting the exciting technological breakthroughs occurring within the battery industry. While batteries have continued to evolve at a remarkable pace, the cost associated with these new technologies remains the predominant barrier preventing the widespread commercialisation of battery- and fuel cell-powered vehicles.
According to recent reports, newly engineered ultracapacitors present a real opportunity to significantly reduce these costs. MIT’s Technology Review reports that graphene electrodes developed by researchers at Nanotek Instruments in Dayton, Ohio, may inspire ultracapacitors with more than five times the energy density of current commercial devices.
Ultracapacitors store charge electrostatically with ions from an electrolyte clinging to the electrodes within the capacitor. Through the utilization of grapheme (described as atom thick sheets of carbon) Nanotek is able to significantly increase the surface area of the electrodes found within the ultracapacitors. Graphene is able to store a much large charge as ions are able to layer across the carbon sheet enabling easier attachment and subsequent detachment. This allows for large-scale increases in storage capacity.
Nanotek’s tests show that the grapheme electrodes could store 85.6 watts of energy per kilogram. Compare that to current ultracapacitors with an energy density of around five to ten watt-hours per kilogram.
When paired with batteries, ultracapacitors are expected to allow for significant improvements in storage capacity and performance as well as substantial reductions in battery size.
These advantages suggest dramatics reductions in the costs associated with in battery- and hybrid-powered vehicles are very much on the horizon. Researchers at Argonne National Laboratory in Argonne, Illinois estimate that ultra-capacitors could lower the costs of these vehicles by hundreds of thousands of dollars.
Up to this point, public acceptability of these vehicles has been largely determined by the costs associated with the technologies. With the exciting developments taking place within ultracapacitor tech space, mass commercialisation of the battery and fuel-cell powered vehicle markets is taking yet another gradual step forward.