Ultra Capacitors
Here are some key points about using ultracapacitors for large-scale energy storage:
- Ultracapacitors can store and discharge electricity very quickly, making them well-suited for short duration load leveling and frequency regulation applications.
- They have high power density (up to 10 kW/kg) but relatively low energy density (around 5-10 Wh/kg), so large banks would be needed for bulk energy storage.
- Ultracapacitors have high cycle life (>1 million cycles) and high round-trip efficiency (95%+) which is attractive.
- Cost is still relatively high compared to Li-ion batteries at around $200-300/kWh for the ultracapacitor system. Rapidly improving though.
- Large ultracapacitor banks connected to the grid often use a hybrid system configuration with batteries or other storage to optimize performance and costs.
- Ultracapacitors provide excellent complement to batteries by handling high power transients and smoothing fluctuations.
- Safety advantages over batteries with no fire/explosion risks. More environmentally friendly.
- Could potentially reduce the required size of substation equipment like transformers and switches.
- Challenges include developing pilots to demonstrate benefits, reducing costs further, integrating into grid infrastructure and energy markets.
So in summary, ultracapacitors have promising characteristics for large scale energy storage but may be better suited to specific high power applications rather than bulk energy storage due to cost and energy density limitations currently. Their role alongside batteries warrants further exploration.