Innovation in energy doesn’t happen overnight – but sometimes, it happens in one concentrated week. In June 2025, Tallinn became the global capital of direct current technology, bringing together researchers, companies, and policymakers to explore how direct current (DC) systems can accelerate energy transition.

A week that sparked awareness

From June 2 to 5, Tallinn became the unofficial global capital of direct current technology. In just five days, Estonia demonstrated that it is possible to move from lab research to real-world implementation of direct current energy systems. More than 200 participants from over 30 countries and over 100 local participants engaged in Tallinn DC Week – a series of events exploring how DC systems can power the next generation of climate-neutral buildings, transportation, industry, and urban infrastructure. Visitors included not only engineers and scientists but also city officials, energy policy experts, renewable energy enthusiasts, and Tallinn citizens – all curious to understand what a fully DC-powered building looks like, feels like, and requires in terms of infrastructure.

For many, the most surprising part was how natural it all seemed. Plugging in LED lamps or charging a laptop on DC didn’t feel exotic – it felt intuitive. It underscored a powerful idea: the technology is ready, and with the right ecosystem, it can scale. The event also served as a networking hotspot, fostering spontaneous dialogue between researchers, companies, and decision-makers.

The week kicked off with the TalTech DC Experience Day 2025, where guests toured one of Europe’s most advanced DC experience centers: the TalTech Residential DC Innovation Hub. This event became a centerpiece of increasing awareness about DC among the public. Here, appliances, lighting systems, and office electronics all ran on direct current, powered by rooftop and façade solar panels, as well as battery energy storage – eliminating the need for alternating current (AC). Despite global interest in DC, it remains unfamiliar to most energy professionals. Few have ever seen a fully functioning DC microgrid in real life. That’s why the TalTech DC Experience Day made such an impact: it transformed a complex concept into a tangible reality.

“DC Experience Day was a breakthrough moment, not just for TalTech, but for how we communicate innovation. Visitors could touch, test, and truly understand what a real-life residential DC microgrid looks like. That’s how you turn curiosity into conviction. Therefore, we plan to organize this event every year in the foreseeable future.” said Dmitri Vinnikov, Head of TalTech Power Electronics Group and the main driving force behind the Tallinn DC Week.

After its official opening in May 2024, the TalTech Residential DC Innovation Hub has became focal point for many campus visitors form all over the world, with number of yearly visitors exceeding 500. Moreover, the DC Hub got strong support from many European industrial companies. In recognition of the innovation level, it received the TalTech Green Action 2025 award. Nowadays, it is under constant development in cooperation with Estonian and European enterprises. For example, this May a solar carport produced by Estonian company Solarstone was added. Also, DC street lighting infrastructure was realized to increase number of practical DC applications showcased on campus.

“Partnering with TalTech’s DC Hub lets us show how solar energy and DC can work hand-in-hand – not just in theory, but in action,” said Henri Lass, Head of Products of Solarstone OÜ, which provided a solar-powered carport to support the hub’s expansion. “We are  proud to jon the TalTech’s initiative that connects research, business, and infrastructure in advancing DC technologies,” he added.

Much of what visitors saw during Tallinn DC Week was made possible by long-term research efforts at TalTech supported by the Estonian Research Council (ETAg). The PRG1086 project laid the foundation for the Residential DC Innovation Hub by enabling a breakthrough in applied design of power electronic systems for DC microgrids, advancing topologies, control, optimization, reliability, and lifetime extension methods.

The ongoing PRG2055 project is taking power electronics to the next level, building ultra-efficient, compact converters with smart diagnostics and even cybersecurity features. Meanwhile, the Centre of Excellence in Energy Efficiency (ENER) is embedding DC into Estonia’s broader vision of sustainable buildings. Together, these projects have turned the TalTech Residential DC Innovation Hub from a research concept into a living laboratory where Estonia’s energy future can be seen, touched, and tested. Combining expertise from electrical and construction engineering, social sciences, and digital modeling, the TalTech’s DC Hub team is helping rethink how DC systems can support healthier, zero-emission buildings across the country.

Training the next generation of DC experts

While technology is advancing, one critical ingredient is still in short supply: people who understand DC systems. From design and installation to safety and control, DC requires a specific skill set, and today’s engineering graduates aren’t always prepared.

That’s why TalTech is integrating DC education into multiple levels of its academic programs. This educational integration isn’t just about transferring knowledge, it’s about shaping mindsets. During Tallinn DC Week, this commitment was on full display. DC technologies challenge conventional design assumptions, pushing students to think critically about energy efficiency, control strategies, and system-level optimization.

On June 3, TalTech hosted a DC seminar for students, where PhDs, postdoctoral researchers, and seasoned experts introduced key topics such as grid architecture, appliance safety, renewable energy integration, and electric vehicle charging. This event bridged the traditional divide between academia and industry. It allowed students to understand the practical context of their work. At the same time, companies gained insights into emerging talent and fresh ideas. Instead of lectures, the format emphasized discussion and hands-on learning, with students actively engaging in Q&A and exchanging ideas.

“There’s a growing demand for people who understand DC – and we’re working hard to fill that gap,” explained Andrei Blinov, the seminar organizer. He emphasized that “bachelor students are already building fully functional DC prototypes for their graduation theses, including DC-microgrid-powered kettles, USB hubs, etc. Their work feeds directly into ongoing research, bridging the gap between theory and practice.”

In TalTech Power Electronics Group, PhD students are developing cutting-edge DC technologies, following a project-based learning approach cultivated for over a decade. One of the newest research directions is DC-compatible heating, ventilation, and air conditioning (HVAC) systems, which will be developed in close collaboration with Daikin Europe as well as Airobot Technologies, an Estonian company renowned for its innovative heat recovery ventilation.

“At Airobot, we believe the future of indoor climate control lies in decentralised, efficient systems. Collaborating with TalTech allows us to push the boundaries of ventilation technology even further — building DC-powered solutions that are not only intelligent, but purposefully designed for a world that demands more from less.”  said Gert Valdek, CTO at Airobot Technologies.

These partnerships ensure that Estonia isn’t just teaching DC – it’s training professionals who will shape its future and drive local innovations.

IEEE ICDCM 2025 Conference – Estonia at the Heart of Global DC Innovation

One of the most impactful highlights of Tallinn DC Week was ICDCM 2025 – the IEEE 7th International Conference on DC Microgrids, making its first appearance in Estonia. Held from June 4–6 at the Original Sokos Hotel Viru, just steps from Tallinn’s medieval Old Town, the conference brought global attention to the fast-growing DC ecosystem.

ICDCM 2025 welcomed participants from around 30 countries, with delegates traveling from New Zealand, Japan, the United States, and across Europe, Asia, Africa, and South America. This global turnout underscored how relevant DC microgrids have become to urban infrastructure, industry, and climate goals, no matter the geography.

The diversity of the audience, from young PhD students to senior industry executives, helped create a multi-perspective dialogue that went far beyond technical details. Many participants highlighted the warm and well-organized atmosphere of Tallinn, which not only hosted cutting-edge content but also provided a cultural and social setting that fostered long-term collaboration and networking.

The choice of Tallinn as the host city also sent a broader signal: the DC transition is no longer limited to big countries with massive energy budgets. Smaller, agile nations like Estonia can be testbeds for global innovation – and this, perhaps, was one of the strongest messages of the entire conference.

The conference program included over 100 oral and poster presentations, establishing a unique setting for exchanging ideas and sparking innovation in DC technologies. Estonia’s own researchers were well-represented, with several talks by TalTech experts showcasing advances in converters, digital control architectures, and resilient residential DC microgrids.

“Hosting ICDCM in Tallinn proves that Estonia isn’t just following global trends – we’re shaping them,” said Andrii Chub, one of the event’s local organizers. “The event was more than a milestone – it was a catalyst, opening doors to new European partnerships, elevating Estonia’s international visibility, and reinforcing its leadership in sustainable power innovation,” he emphasized.

Setting DC Standards: Current/OS Assembly in Tallinn

Tallinn DC Week also featured the plenary assembly of the Current/OS Foundation, a global alliance working to create open-source standards for DC microgrids. Held on June 5 at TalTech, the meeting brought together a broad coalition of companies, alongside select academic partners, united by a shared goal: making DC systems more scalable, safe, and interoperable than the AC grids we’ve relied on for over a century.

It wasn’t just a technical meeting, it was a strategic alignment session for the future of open DC grids. Members reviewed recent pilot deployments, addressed key interoperability challenges, and outlined a roadmap for broader rollout across multiple sectors — with particular attention to emerging opportunities in data centers.

Estonia was chosen for its unique combination of agility, ambition, and depth in applied research. The event offered hands-on exposure to innovative hardware and energy management solutions at TalTech Residential DC Innovation Hub, anchoring discussions in practical, demonstrable systems.

“We need real testing grounds for open DC systems, and TalTech’s DC Innovation Hub is one of the best in Europe,” said Yannick Neyret, President of the Current/OS Foundation. “Estonia brings both the mindset and the infrastructure.”

The event welcomed representatives from companies, including industry giants such as ABB, Eaton, Schneider Electric, Siemens, Tridonic, Daikin, and Nexans. The plenary was opened by Tanel Järvet, CEO of Estonian company CAFA Tech, with a powerful example of how DC can help save lives.

“Unmanned vehicles (UxVs) are becoming increasingly important in disaster relief. All UxVs operate on DC power. Therefore, in emergency situations, more and more DC energy is needed, which is easy to deploy, efficient, and available – and DC systems deliver exactly that,” Tanel explained, referring to robotic disaster-relief systems. “From emergency response to building energy retrofits, the case for DC is growing stronger, and Estonia is right at the center of that momentum.”

Estonia’s Direct Path Forward

Tallinn DC Week 2025 was more than a series of events, it was a turning point. It showed that when research, education, and industry align, real innovation happens. Ideas move from whiteboards to working prototypes. Partnerships turn into standards, and technologies become part of everyday life.

Estonia is proving that innovation doesn’t require scale, it requires focus. With strong university-industry collaboration, a supportive policy landscape, and living labs that invite participation, the country is creating not only greener energy systems but also smarter, more human-centered ones.

“Tallinn DC Week was a milestone, not a conclusion,”said Dmitri Vinnikov. “We are already preparing for the 6^th Estonian DC Innovation Workshop which will take place in mid-November, continuing our mission to position Estonia as a true DC ambassador in Europe — not only advancing the technology, but also sharing knowledge across borders”.

* Read more about the projects with the help of Estonian Research Council :
PRG1086 https://www.etis.ee/portal/projects/display/9c9cda20-2179-4a46-902c-93510b213888
PRG2055 https://www.etis.ee/portal/projects/display/db8275c1-c87e-4d18-a3de-b77b8d3ffd0e

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