30.06.2026
In his personal blog, Serhiy Yermilov – Minister of Fuel and Energy of Ukraine in 2000–2001 and 2002–2004, former Head of the National Agency of Ukraine for Ensuring the Efficient Use of Energy Resources, Honored Power Engineer of Ukraine – continues a series of publications on the future architecture of the Ukrainian energy system. The author consistently builds the concept of a transformational transition from the Soviet centralized model to the modern decentralized and digitally managed energy of the 21st century.
In the third part of his blog, Serhiy Yermilov focuses on a fundamentally new challenge for the United Energy System of Ukraine – not so much a generation deficit, but a deficit of controllability against the backdrop of the rapid growth of distributed energy resources (DER), microgrids, storage devices, and electromobility. The Honored Energy Engineer of Ukraine explains how the change in the structure of the power system from “a few large producers” to millions of active market participants makes classic centralized management impossible and requires a multi-level coordination architecture, where TSOs, DSOs, aggregators and microgrids perform different but interconnected functions.
The biggest challenge for Ukraine’s UPS in the next decade may not be a generation deficit, but a deficit in manageability in the face of rapid DER growth
Ukraine is facing a strategic fork. The reconstruction and reconstruction of the energy system should not be a return to 2021 – it should be a leap into 2031.
I am convinced that we have a chance to use the post-war reconstruction not to restore the old energy sector, but to create the first large-scale sustainable decentralized energy system in Europe, which will become a powerful infrastructure capable of supporting the new economy of the state.
Let’s briefly summarize what the USSR left us as a legacy.
Soviet architecture:
Changes in recent years (2015-2026):
Now let’s try to gradually and logically consider what architecture we can get.
In the 2021 model, the dispatcher saw a relatively small number of large facilities: nuclear power plants, thermal power plants, hydroelectric power plants, several large wind power plants, several large solar power plants.
The system was complex, but manageable through a limited number of nodes.
In fact, it was an architecture: few producers → millions of consumers.
It was for this model that the following were created: forecast balances; transmission system code; operating modes; dispatching procedures.
Now let’s imagine Ukraine in 2031.
Conditionally:
In such a system, the dispatcher physically cannot manage each resource separately, because this is a different class of system.
And the problem is not that centralized control is no longer needed. The problem is that centralized control is no longer enough. These are fundamentally different statements.
The Ukrainian UPS will still need:
That is, the TSO does not disappear. But what it manages changes.
You can draw an analogy with the Internet.
The telephone network of the 20th century was similar to classical energy:
Now the Internet works differently:
No one controls every packet from a single center. But the network remains unified.
It is to this type of architecture that the energy sector is gradually moving.
That’s why in O. Svetelyk’s quote: “We created an aggregator that should unite everything and provide access to our main dispatcher,” what confuses me the most is not even the word “aggregator,” but the phrase “unite everything.”
Because modern architecture does not involve uniting everything into one control point. It involves multi-level coordination.
To simplify, the 2031 model looks more like this:
TSO (TSO)
↓ coordination of system parameters
DSO / TSO + ADMS
↓ local network management
DERMS / Aggregators
↓ coordination of distributed resources
Microgrids / Energy Hubs
↓ local optimization
Prosumers / EV / Storage / DER
After 2022, another criterion appeared for Ukraine, which was practically absent in energy planning before the war.
This is the system’s resilience.
In the Soviet and post-Soviet logic, the main indicator was reliability. In the new reality, an additional question arises: what happens after the loss of part of the system? This is where:
are not fashionable words, but elements of the defense capability of critical infrastructure.
Therefore, the architecture of the future UPS of Ukraine should remain a single synchronous system coordinated by the TSO, but the management within it should become multi-level, distributed and digital. Decisions should be made as close to the point of occurrence as possible, and the central level should coordinate the system, rather than trying to directly manage each resource.
In my opinion, this is the key difference between “rebuilding what was” and “building the next generation energy system”.
Returning to the beginning of the conversation, we can finally get the result that was worth such a long discussion and allows us to avoid the common mistake when the discussion is artificially reduced to a choice between two extremes:
– a rigidly centralized systemma Soviet-style;
– a set of autonomous islands without a single management.
In fact, modern architecture is between these extremes.
What actually changes?
In the classical model, the TSO performed almost all the balancing through a relatively small number of large power plants. Schematically:
TSO⇒ NPP / TPP / HPP⇒ DSO⇒ Consumer
Several new management levels emerge in the new architecture:
TSO+SCADA⇒ DSO + ADMS⇒ DERMS / Aggregator⇒ Microgrid EMS⇒ DER / Storage / EV / Prosumer
And each level gets its own area of responsibility.
The new role of the Distribution System Operator
In my opinion, this is where the most profound transformation lies.
Historically, Ukrainian DSOs were mainly owners and operators of network assets: lines, transformers, substations. In fact, they managed the infrastructure. But with a large number of distributed energy resources (DER), this is no longer enough. The DSO gradually becomes:
That is, there is an evolution from a “cable and transformer farm” to an “active system operator.”
What is transferred to the microgrid level
400;”>A microgrid does not have to coordinate with the TSO or DSO dispatcher every second of its battery or inverter operation. It independently decides:
For the external system, the result is important. For example:
At the connection point, I guarantee not to exceed a certain import or export of power. And the internal logic remains local. This is what distributed intelligence is.
Why did my colleague’s phrase “no clusters” bother me? Because technically, a modern system already consists of clusters. Not necessarily in a geographical sense, but in a functional sense — like this:
All of them are actually locally managed subsystems. And this does not contradict the existence of a single Unified Energy System.
At this stage of the discussion, we can get another interim conclusion:
The future Unified Energy System of Ukraine should not turn into a set of isolated microgrids, but it cannot remain a system where all decisions are made exclusively by the central dispatcher. It should evolve to a multi-level architecture where the TSO provides system coordination, the DSOs manage active distribution networks, and microgrids and DER platforms carry out local balancing and resource management in real time.
Sergiy Yermilov – Minister of Fuel and Energy of Ukraine in 2000–2001 and 2002–2004, former Head of the National Agency of Ukraine for Ensuring the Efficient Use of Energy Resources, Honored Power Engineer of Ukraine
