A passenger car emits between 1-4 tons of CO2 per year depending on vehicle specific consumption and mileage. A small 1MW marine crane working in the North Sea can emit 453 tons of CO2 a year doing just one thing: compensating for wave movements to stabilize the load, be it a servicing crew for windmills, a cable attached underwater autonomous vehicle or a drilling rig.
A typical wave heave compensation system operates 4 hours a day, seeing a wave every 6 seconds per wave, more than 800 000 waves per year. Every year more than 1 GW worth of Active Wave Heave Compensation Systems are installed emitting nearly half a million tons of CO2. That is, unless the energy used to lift the crane is recuperated with the opposite side of the wave - when the ship is lifted and crane can drop. Theoretically such a system could recuperate all energy if the waves were identical, but for the inefficiencies of electric motors or losses in energy storage.
The current project deals with the storage side of the equation. An ultracapacitor is an energy storage device capable of storing the energy at 98% efficiency, for 15 years of continuous operation and costing no more than 60 000 € per system, capable of servicing a 1MW system as described. At the simulated 98% efficiency, using ultracapacitor-based energy storage would save ~440 tons of CO2 and ~220 000 l of diesel fuel per year.
The current state-of-the art energy storage solutions use batteries. Managing wave energy recuperation with battery storage is feasible if there are more than 500 kWh of battery storage already available for each MW of wave heave compensation for ship-wide energy storage backup. With a typical NMC battery (e.g. Tesla) this would allow the system to run at approx. 75%efficiency. Even in this case, using ultracapacitors to augment the power reserve of the batteries, would save an additional 100 tons of CO2 per year with an additional 50 000 € in cost savings. The system would reach break-even in less than 18 months with additional benefit of battery life extension.
Up to date, there are a handful of experimental ultracapacitor-based wave heave compensation systems launched. While these “pilots” have proven successful, two issues remain:
The project addresses these issues by developing, certifying, and launching a marine-industry specific ultracapacitor module based on ultracapacitors with more than double the power density of the ultracapacitors used in the existing pilots.
Doubling the power density allows to reduce system size by 50% or lengthen the system lifetime by a factor of four, or any combination of the two.
The project is funded by Norway Grants and Enterprise Estonia to facilitate cooperation to reduce economic and social disparities in Europe.
Project “Development of marine-certified ultracapacitor modules” has been supported by Norway Grants "Green ICT" programme with € 727 000. Project is carried out from August 2020 to January 2022. The aim of the project is to develop marine-certified ultracapacitor modules with first use in active wave heave compensation systems.
Project Manager: Egert Valmra, Programme Director
Email: egert.valmra (at) skeletontech.com
Project Manager: John Breiland
Email: john.breiland (at) nxtech.no
The Norway Grants and the EEA Grants represent Norway’s contribution towards a
green, competitive and inclusive Europe.
Through the Norway Grants and the EEA Grants, Norway contributes to reducing
social and economic disparities and to strengthening bilateral relations with beneficiary
countries in Central and Southern Europe and the Baltics. Norway cooperates closely
with the EU through the Agreement on the European Economic Area (EEA). Together
with the other donors, Norway has provided €3.3 billion through consecutive grant
schemes between 1994 and 2014.
Norway Grants are financed solely by Norway and are available in the countries that
joined the EU after 2003. For the period 2014-2021, the Norway Grants amount to €1.25
billion. The priorities for this period are: