Material Insights · Understanding the Material World

Capacitors and supercapacitors: Impact and additionality

Fast stability services that let more renewables connect

What this tab covers The impact and additionality lens: what it displaces on the grid, who gains and who bears the burden along the supply chain, and what happens at end of life.

Supercapacitors do not shift solar into the evening; their climate value is indirect, supplying the fast stability services that fossil turbines used to provide so more inverter-based renewables can connect.

Grid decarbonisation versus fossil displacement

Mixed

With discharges of seconds, supercapacitors displace almost no fossil energy directly. Their contribution is replacing the inertia and fast reserve that spinning coal and gas units supply, reducing the need to keep those units online. In hybrid plants such as Jiayuguan the 25 MW supercapacitor section handles inertia and frequency while 475 MW / 1,000 MWh of LFP batteries do the energy shifting, so the supercapacitor is 5% of rated power (calculated).5

Supercapacitor share of Jiayuguan power rating 5% (calculated, 25 of 500 MW)5

Just transition and local community impact

Favourable

DOE's 2023 assessment says all supercapacitor manufacturing and most active companies are in Asia, with activated carbon made mostly from coconut shells in Japan and South-East Asia. That is now dated: Skeleton opened a EUR 220 million factory at Markranstädt near Leipzig, Germany, in 2025, rated at up to 12 million cells a year, and says it is building a curved graphene material plant at Bitterfeld-Wolfen. India has a domestic maker, SPEL, which sells lithium-ion capacitors. Coconut-shell carbon links the chain to agricultural regions, including India, but no source quantifies jobs or labour conditions. Mining exposure is low compared with batteries.23411

Share of manufacturing in Asia (DOE, 2023) all3 Skeleton Markranstädt factory EUR 220 million; up to 12 million cells a year11 Skeleton employees (company figure) about 3602

Circular economy and end of life

Mixed

A long life (about a million cycles and 16 years) means few replacements over a project. Cells are mostly aluminium, carbon and electrolyte. That avoids the high-value metals that make battery recycling pay, but it also leaves recyclers little to earn from. We found no published recycling rate and no dedicated industrial recycling route. Research shows electrodes can be reused: a 2024 study took apart a 500 F commercial cell and reused its carbon to remove salt from water, holding 5.8 to 7.9 mg of salt per gram. The flammable, toxic acetonitrile has to be captured safely during dismantling.3910

Cycle life about 1,000,0003 Calendar life 16 years3 Desalination capacity of reused electrodes (lab) 5.8 to 7.9 mg/g10

Sources

  1. Skeleton Technologies company introduction 2026 (company presentation, hosted by Energy Saxony) Skeleton Technologies, 2026
  2. Technology Strategy Assessment: Supercapacitors (Energy Storage Grand Challenge, #10) US Department of Energy, Office of Electricity, 2023
  3. Hybrid supercapacitors: solution to the power-energy trade-off (trade press; manufacturer figures as reported) Best Magazine, 2026
  4. China switches on world's first GWh-scale supercapacitor-energy storage project (trade press, based on ESS News) pv magazine, 2026
  5. CAMEO Chemicals datasheet: Acetonitrile US National Oceanic and Atmospheric Administration (NOAA), 2024
  6. Life after death: re-purposing end-of-life supercapacitors for electrochemical water desalination (Ren et al.) Batteries and Supercaps, vol. 7, e202400506 (Leibniz Institute for New Materials), 2024
  7. Skeleton Technologies opens new SuperFactory in Germany European Institute of Innovation and Technology (EIT), 2025