For 30-year-old Estonian entrepreneur Taavi Madiberk, 2019 was a good year. Skeleton Technologies, the ultracapacitor manufacturer he co-founded 10 years ago, signed over €150m ($161m) of new contracts in the automotive, transportation, grid, and industrial sectors and was listed in the Global Cleantech 100 for the sixth time in a row.
Skeleton Technologies also delivered 48V systems for a leading German OEM and, at the end of the year, another contract with one of the largest truck OEMs delivering ultracapacitors for reliable engine starting.
“2019 was a breakthrough year from us. First half of the year we got our manufacturing qualified with large automotive, grid, and industrial companies, which led to signing the first sizeable contracts,” Madiberk tells ZDNet.
“But this is only the start. We have perhaps achieved about 1% of our market potential.”
Ultracapacitor – sometimes also called supercapacitor – technology is an energy-storage technology that offers high power density, almost instant charging and discharging and long lifetimes.

Although ultracapacitor technology has been in development for decades, it has only recently reached a point where it is being implemented more broadly in a number of industries.
According to Madiberk, as the technology matures, it will replace the traditional lead-acid battery in various critical sectors already in the near future.
One of these sectors is public transportation where ultracapacitors, with their one million lifecycles, have several advantages over batteries with 2,000-3,000 cycles.
Because ultracapacitors charge faster, they can also take advantage of kinetic energy recovered while the vehicle brakes. Skeleton Technologies says its energy-storage systems for Škoda trams in Germany and Medcom trams for the Warsaw area save around 30% of energy, significantly improving the efficiency of public transportation.
Developing a more efficient technology that is also better for the environment in the context of fighting climate change is something that Madiberk views as a great business opportunity.
“When it comes to climate change, and cleantech technologies aiming to fight against climate change, Europe still has the opportunity to lead the transition to a carbon-neutral economy globally,” he says.
“Many people see cleantech and becoming carbon neutral as a cost, but it’s actually a huge opportunity. Climate change is the defining issue of our time and we are at a defining moment.”
This is also where Skeleton Technologies hopes to step in.
“Our ultracapacitors help save energy in all the major industries that are going to have to achieve energy transition. Industrialists and stakeholders understand that energy efficiency is crucial,” Madiberk says.
“The widespread adoption of energy-efficiency measures could reduce industrial energy use by over 25%. This potential is a significant reduction of 8% in global energy use and a 12.4% reduction in global CO2 emissions. It’s therefore good for the environment but it also saves a lot of money.”
He points out that ultracapacitors are going to be even more widely implemented as the share of renewable energy increases.
“The higher the market share of renewables from the energy mix, the more challenging it is to maintain sufficiently high-power quality. Coal, oil, natural gas, and nuclear are predictable and controllable energy sources and enable the increase or decrease of production based on demand,” explains Madiberk.
“The ability to control and forecast both production and demand enables a high degree of control over grid frequency and voltage, and stability in general. Renewables, such as wind or solar, are of course a much bigger challenge when it comes to forecasting production and being able to respond to changes in demand.”