Smart converters can help with the green transition

Tuesday 03 May 22
Artificial intelligence embedded in power converters can exploit the flexibility of the energy network to ensure reliable energy supply. Story in Danish Outlet 'Ingeniøren'.

The basis of our green transition is renewable energy from the wind and sun. But one of the main challenges of basing our energy supply solely on wind turbines and solar panels is that the wind doesn’t always blow, and the sun doesn’t always shine. And we need controllable energy generation in order to match our consumption. Using batteries and hydrogen electrolyzers to store renewable energy are most often suggested as a solutions for this challenge, but batteries and electrolyzers are expensive to produce, install and operate. 

Professor Tomislav Dragicevic from DTU has been awarded a Sapere Aude grant from Independent Research Fund Denmark, which is granted to particularly talented younger researchers who are ready to lead a research project at a high international level. He will use it to continue his work to develop a solution using smart converters to extract the flexibility of loads that anyways exist in the electrical systems. Examples are fans, pumps and compressors, which can to-gether with batteries and electrolyzers serve as cost-effective providers of the stable energy supply the green transition’s success depends on. 

“Smart converters can easily be installed in conjunction with a lot of electrical equipment and be used to extract flexibility that effectively acts as a virtual battery. Good examples are electric motors used in many places such as in fans, compressors, pumps, etc. My idea is to use new software and algorithms with these converters so that in the future, they will help us gain insight into and make use of the vast untapped flexibility that already exist in the energy net-work,” says Tomislav Dragicevic. 

Flexibility of energy network to be harnessed 
Tomislav Dragicevic has calculated that using just a couple of per cent of the network’s cost-free intrinsic flexibility could save us billions of Danish kroner. The flexibility comes from, for example, the pumps that are already installed in wastewater pumping stations. The pumps will still be fully operational, but as long as the tank is not at full capacity, wastewater pumping could be flexibly adjusted to counterbalance the variable green energy.

“Utilising this type of flexibility doesn’t cost almost anything—contrary to a battery or electrolyzer solution. All it takes is to process the available data and infer the needs of the energy network and about the flexibility of, for example, a wastewater pump. This  we can do relatively cheap by installing a proprietary IT equipment in conjunction with the converter on the site – and deploying that flexibility when the grid needs it the most,” says Tomislav Dragicevic.

“Our preliminary calculations show that access up to hundreds of small pumps and other motor loads may be needed to secure the tangible amount of flexibility that will be possible to sell as a service to Danish and European grid opera-tors. However, investment cost for such solution will still be orders of magnitude lower compared to batteries are electrolyzers of the same capacity.”

Tomislav Dragicevic has already worked with smart converters in several con-texts, including together with commercial partners such as Danfoss and Born-holms Spildevand. In the new Sapere Aude project, the focus is on obtaining data on the needs of the grid and the flexibility of the motors, so that the right algorithms can be developed for the smart converters. In addition, a cloud solution is developed, where data from the many different converters can be aggregated and exchanged in a computationally efficient way. 

“The idea is to test the solutions we find both in our Smart Converter Lab at DTU and at several wastewater plants on Bornholm. The latter is absolutely necessary, as things always behave differently outside of a lab, and we must be totally confident that the solutions work as expected before we try to scale them in up,” says Tomislav Dragicevic.

Company to sell the new idea
Tomislav Dragicevic is in no doubt that his solution will help solving one of the most important challenges we are currently facing in the green transition. He has therefore in 2021 launched a company PHLIT, which currently provides consultancy in the smart management and health monitoring of commercial energy assets from motor loads and stationary batteries, to fleets of commercial and private electric vehicles, charging stations, and electrolyzers. Down the road, the company’s ambition is to be behind the unlocking of low-cost flexibility from a variety of energy assets and aggregating large-numbers of them into reliable and cost-effective virtual power plants that will serve as highly competitive participants of the future energy markets.

Story published in Ingeniøren

Written by Anne Kirsten Frederiksen (anfred@adm.dtu.dk)

Contact Tomislav Dragicevic
email: tomdr@ dtu.dk
tel. +45 24989882
Department of Wind and Energy Systems