Tassos Vlassopoulos is the CEO of HelleniQ Upstream (HelleniQ’s Upstream Business Unit including CCUS).

Prior to this role, before 2020, he has held senior international management positions at GE and has an overall 35 years of global experience, acquired in oil & gas, energy, strategy consulting (BCG), M&A and product management. Furthermore, he has also held a non-Exec Board position with PPC.

In an effort to reduce the costs of production of hydrocarbons, following the downturn in the previous decade, he published an influential SPE paper on “Standardisation – Learnings from Industrial Sectors” and led discussions with Majors and several North Sea industry stakeholders.

At the beginning of his career, he worked as a Research Officer at the London Business School, where he co-authored a book and academic articles on industrial and business strategy.

He holds a MSc in Operational Research from the London School of Economics and Political Science and a 1st class BSc (Hons) in Economics from the University of Piraeus.

Tassos Vlassopoulos Q&A

Tassos, could you elaborate on your role as CEO at HELLENiQ UPSTREAM?

As CEO of HELLENiQ UPSTREAM, I have the privilege of leading the upstream exploration activities of HELLENiQ ENERGY in Greece. Our business unit is responsible for managing a portfolio of nine exploration assets from early-stage evaluation to more advanced exploration activities, i.e. drilling in Block 2.

The role is both challenging and rewarding as it requires balancing strategic decision-making, with operational excellence while ensuring that all activities are carried out safely, efficiently, and in full compliance with environmental and regulatory standards. It is equally important to foster strong collaboration across multidisciplinary teams (e.g. technical, commercial, procurement and legal), with our partners and the authorities.

Ultimately, our objective is to unlock the hydrocarbon potential in our licenses, adding value to the HELLENiQ ENERGY Group.

What qualities and values do you think make a great leader?

I believe great leadership starts with integrity, accountability, and the ability to inspire trust with co-workers, partners, and stakeholders.
 
In Upstream, where decisions are often complex and long-term, a leader must combine strategic thinking with technical understanding, while always placing safety, people, and environmental responsibility at the forefront.

It is equally important to empower teams, encouraging collaboration, and foster a culture of continuous learning and innovation (in processes and products). Success is never the result of individual effort. 

What career challenges have you faced, and how did you overcome them?

Throughout my career in Energy, which includes roles in energy, oil and gas, and management consulting, I have faced a range of challenges that are typical in complex multinational and capital-intensive businesses.  

The most consistent challenges have to do with dealing with market volatility, regulatory change, and the technical complexity of large-scale industrial projects. Another has been leading diverse, cross-functional teams across different time zones and organizational cultures, often under tight timelines and demanding performance expectations. For 12 years, my manager was on a different continent than me, while only less than 10% of my team were in the same location, London.

I addressed these challenges by hiring the best people available to me, focusing on clear and regular communication and disciplined execution. I have also found that maintaining a structured decision-making approach, grounded on data, is essential. Ultimately, these experiences have reinforced the importance of resilience, continuous learning, and teamwork in delivering sustainable results in the energy industry.

Can you share the biggest and proudest undertaking in your career to date?

One of the most significant and rewarding undertakings in my career has been leading large-scale transformation across commercial and product management for a large OEM across the Oil & Gas value chain.

Across different roles and organizations, I had the opportunity to contribute to complex projects that require building alignment across diverse stakeholders (HQ and Regional), improving operational performance, and driving execution across the globe. These experiences often involved taking organizations through periods of change—whether through restructuring, integration of new technologies, or improving efficiency.

What I am most proud of is not a single project, but rather the consistent ability to add value. Seeing teams grow stronger and more capable through these journeys has been particularly fulfilling.

Looking back on nearly forty years, I would choose the following projects:

• Most recently, revitalizing & refocusing HELLENiQ’s E&P portfolio through a new key partnership with Chevron, while satisfying all license obligations in existing assets  
• Rationalizing the product portfolio across five Oil & Gas product lines, through robust capital allocation tools 
• Transforming Commercial & Product Management teams and redesigning a new org
• Driving entry to offshore wind through a pilot acquisition in Scandinavia 
• Being responsible for $800 million re-financing in the North Sea
• Leading successfully four (4) E&P M&A efforts in Europe and Eurasia
• Building a “war game” to simulate the gas market in Europe 
• Fronting an SPE published article about learnings from other industries (e.g. aerospace) to reduce costs in Oil & Gas, influencing initiatives in the UKCS
• Publishing an academic article on market leaders at a reputable journal

How well do you think oil and gas companies are adjusting to the challenges of the energy transition?

Oil and gas companies are actively adapting to the challenges of energy transition, but the pace of change naturally varies across organizations and geographies. 

The sector is undergoing a significant transformation, while there is a clear strategic commitment to decarbonization. The transition is complex and takes time to materialize. Many companies are investing in lower-carbon solutions, improving operational efficiency, and integrating new technologies to reduce their environmental footprint. 

At the same time, they must continue to ensure we have energy security, meeting ongoing demand, which requires a pragmatic approach. The recent conflict has further highlighted the importance of secure affordable energy supplies prompting companies to reassess their strategies in parallel with the energy transition.

Looking longer term, what’s your vision for HELLENiQ UPSTREAM?

My long-term vision for HELLENiQ UPSTREAM is to build a value-driven exploration and production business for the HELLENiQ ENERGY Group.

Key priority is the continued maturation and expansion of our exploration portfolio, including the systematic evaluation and advancement of our licensed blocks. This involves robust subsurface work, even where we are not operators, high-quality geological and geophysical analysis, and careful progression of selected opportunities towards drilling.

Equally important is strengthening our partnerships and strategic alliances. The complexity and scale of modern upstream projects require collaboration with experienced international partners, enabling knowledge sharing, risk balance, and access to best-in-class capabilities and technologies.  

What advice would you offer to individuals looking to join the energy industry?

My key advice to anyone entering the energy industry is to remain curious, adaptable, and committed to learning. This is a sector that is evolving rapidly, is highly technological and challenged by energy transition dynamics, global market forces and geopolitics.

Building a strong technical foundation is important, but equally valuable are soft skills such as communication, teamwork, and the ability to work effectively in diverse and cross-functional environments. 

I would also encourage young professionals to embrace challenges early in their careers, as they provide the best opportunities for growth. Exposure to complex projects, international environments, and operational realities builds resilience and a deeper understanding of the industry.

What’s a fun or unexpected fact about yourself?

An unexpected aspect of my life is how closely my personal interests connect with my professional world. 

I particularly enjoy helping my daughter with mathematics and science, as needed. It is a simple but meaningful way to spend time together, while also revisiting the foundations of problem-solving that are so central to our daily lives and, of course, the energy industry.

These moments are a reminder that behind the complexity of our work, there is always curiosity and learning. It reinforces my belief in inspiring the next generation to engage with STEM.

About HELLENiQ UPSTREAM

HELLENiQ ENERGY Holdings S.A. is one of the most prominent integrated energy companies in Southeast Europe, combining a long-established presence in oil and gas with an increasingly ambitious expansion into renewable energy. Headquartered in Greece, the company operates across multiple segments of the energy value chain, including refining, petrochemicals, fuels marketing, power generation, and renewable energy development. Its evolution reflects broader structural changes within the global energy sector, where traditional hydrocarbon-based companies are under pressure to decarbonise while maintaining profitability. HELLENiQ ENERGY’s strategy is therefore defined by a dual focus: sustaining strong cash flows from oil and gas operations while progressively building a diversified and lower-carbon energy portfolio.

HELLENiQ ENERGY's wholly owned subsidiary, HELLENiQ UPSTREAM was established in 2015. The company’s vision is to develop activities and execute projects that involve every phase of the industry of hydrocarbon exploration and exploitation (upstream), as well as to provide consulting services in related matters. HELLENiQ UPSTREAM personnel consists of highly skilled, qualified scientists with international experience in the oil and gas industry.

HELLENiQ ENERGY have developed a promising portfolio of selected areas in Greece, aiming to explore their hydrocarbon potential.

In September 2025, HELLENiQ UPSTREAM participated in the latest international tender of the Ministry of Energy & Environment, in joint venture with Chevron in four new areas: A2, South of Peloponnese, South of Crete 1 and South of Crete 2.

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