When an industrial developer or a warehouse operator hears that the transmission system operator has „freed capacity“ for connecting renewable sources, it sounds like an open door. The reality is the opposite. Slovakia’s transmission system operator, SEPS, published reserved capacity of which 577 MW is allotted to non-local solar and wind sources — and of that volume, according to SEPS data (compiled by ENERGOKLUB, 2025), only 3.6 MW was actually installed and connected. That is not an open door. It is a bottleneck that most companies discover only once the project is finished on paper and waiting for a connection agreement.

The gap between 577 MW and 3.6 MW is the single most important figure in this text. It says that the barrier to on-site renewables for industry in Slovakia today is not a lack of physical room in the grid, but the process, the cost and the regulatory uncertainty of connection itself. For a park developer and an energy manager this has a direct consequence: connection availability is as real a location factor as the price of land or transport access — it is just far harder to see in advance.

How connection capacity is measured in Slovakia

To make the 577 MW figure meaningful, two layers of the grid must be separated. The transmission system (high voltage, cross-border flows, system stability) is operated by SEPS. The distribution systems, to which the vast majority of rooftop and on-site solar connects, are run by three regional companies — Západoslovenská distribučná (ZSD), Stredoslovenská distribučná (SSD) and Východoslovenská distribučná (VSD). The pricing and licensing framework for all of them is set by the Regulatory Office for Network Industries (ÚRSO).

From a system-stability standpoint, SEPS determines how much variable output (solar, wind) the system can carry without threatening frequency and voltage. That limit has recently moved: according to SEPS data as reported by Energia.sk (2025), the installed-capacity limit from the point of view of system flexibility was raised from 747 MW to 917 MW, freeing an additional 170 MW for connecting new sources. On its own site SEPS also published reserved capacity of 1,837 MW, of which precisely 577 MW is set aside for non-local solar and wind sources (SEPS, compiled by ENERGOKLUB, 2025).

So the number exists, it is public, and it was even increased. That is exactly why the distance between it and the capacity actually connected is so telling.

The 577 MW versus 3.6 MW paradox

Of the 577 MW set aside for large non-local solar and wind projects, only 3.6 MW was actually installed and connected, according to SEPS data (compiled by ENERGOKLUB, 2025). That is roughly six tenths of one percent of the reserved volume. The capacity was released in prior years, yet its take-up lags by two orders of magnitude.

The common explanation is that the grid is out of room. The data says the opposite: the room was reserved and no one filled it. The real obstacle sits elsewhere — in what happens between the allocation of capacity and the energisation of the source. According to analyses by the Slovak Association of the Photovoltaic Industry and Energy Storage (SAPI), as reported by ENERGOKLUB (2025), the main barriers to large projects are high connection costs, regulatory uncertainty and specific charges within network tariffs. None of these three obstacles is about physical space in the line. All three are about economics and process.

For an industrial consumer this distinction is decisive. If the limit were physical space, the project could be moved to a site with a less congested grid. When the limit is the cost and process of connection, a move does not help — the company carries the problem with it wherever it goes.

Demand is rising, not falling

Low take-up of large reserved capacity could be explained by weak interest. Here too the data says the opposite. According to ÚRSO data as reported by ENERGIE-PORTAL.SK (2025), ZSD alone received more than 7,000 applications to connect small and local sources in the first half of 2025, a year-on-year increase of roughly 10%. Interest in self-generation on the consumer side not only exists — it is strengthening.

The overall solar build-out confirms it. According to SAPI data as reported by TECHBOX.sk (2025), Slovakia added around 243 MW of photovoltaic capacity and roughly 16,000 new sources during 2025; in the small-source category this was 15,062 installations totalling 124.16 MW. The contrast between that picture and the 3.6 MW connected out of the large reserved capacity shows where the system flows and where it stalls: small and local sources are being connected by the thousand, while large non-local projects sit in the bottleneck.

Put differently — Slovakia does not have a problem with interest in self-generation. It has a problem moving a large project through the connection process within a reasonable time and at a reasonable cost.

Where the real bottleneck lies

The gap between thousands of connected small sources and almost zero connected large projects is not an accident. It follows from how connection is structured.

The first factor is the connection cost. For a large project it can mean reinforcing a line, a new transformer or a connection at a higher voltage level — items that can overturn the economics of the whole scheme before the first megawatt-hour is produced. According to SAPI (compiled by ENERGOKLUB, 2025), high connection costs are the first of the three main barriers.

The second factor is regulatory uncertainty. If a developer does not know which rules and charges will apply at the moment of energisation, the project cannot be reliably priced or financed. A concrete example of shifting regulation is the change effective from 1 January 2026: under the ÚRSO price decree (as reported by ENERGIE-PORTAL.SK, 2025), exceeding the maximum reserved capacity for supply into the distribution system will begin to be billed according to the applicable price decree. For a self-generator planning to export surpluses to the grid, this is a new cost parameter that must be built into the payback calculation.

The third factor is specific charges within network tariffs that change the final economics of supplying the grid. The sum of these three elements explains why reserved megawatts did not turn into connected megawatts — and why connection is a legal and economic task more than a technical one.

What this means for on-site self-generation

From the standpoint of an industrial and logistics asset, one sober conclusion follows: the centre of gravity shifts from selling surpluses to the grid toward self-consumption on site. If connecting a large source in order to supply the grid is expensive and uncertain, the economically safest strategy is to produce the energy on the hall’s roof and consume it directly under the same roof.

The legislation has its own categories for this. The term „local source“ (lokálny zdroj) denotes a renewable generation facility that produces primarily to cover consumption at the point of consumption, with an installed capacity not exceeding the maximum reserved capacity of the offtake point (per the connection agreement; on average around 100 kWp). The term has been in Slovak law since 2018 (ENERGIE-PORTAL.SK, 2025; SAPI). A particularly simple regime applies to a „small source“ (malý zdroj) up to 10.8 kW: it needs no ÚRSO licence for electricity production, and the extensive obligations toward the short-term electricity market operator OKTE fall away (ENERGIE-PORTAL.SK, 2025). These two categories are precisely the segment being connected in Slovakia by the thousand — because it bypasses most of the barriers of a large project.

The economics of self-consumption confirm it. According to industry analysis (RETAIL magazín.sk, 2025), rooftop solar on a logistics hall reaches a payback of 5 to 7 years under conditions of a high share of own consumption (above 70%), an electricity price above 150 €/MWh and investment costs of around 800 to 1,000 €/kWp. The first condition — high self-consumption — is not incidental: it is the very path that minimises dependence on the expensive and uncertain connection for grid supply.

The price context only reinforces this logic. Industrial electricity is among the most expensive in the European Union in Slovakia: for the largest consumption band (above 150 GWh per year) it stood, in the second half of 2024 according to Eurostat, at 146 €/MWh excluding taxes and levies, or 183 €/MWh including taxes and levies (Eurostat, H2 2024). The more expensive the purchased electricity, the more valuable each kilowatt-hour produced and consumed on site — and the less it matters whether a surplus can be sold to the grid on favourable terms.

Conclusions for the developer and the energy manager

The situation around connection and self-generation in Slovakia can be reduced to a few sober points.

Capacity is not the same as connection. SEPS reserved 577 MW for non-local solar and wind sources, yet only 3.6 MW was connected (SEPS, compiled by ENERGOKLUB, 2025). A free figure on the system operator’s website is no guarantee that a project will actually connect on time.

The barrier is process and cost, not physical space. The main obstacles to large projects are high connection costs, regulatory uncertainty and specific charges within network tariffs (SAPI, compiled by ENERGOKLUB, 2025). That is why moving a project to another site usually does not solve it.

Demand is strong; the bottleneck is on the large-project side. ZSD alone received over 7,000 applications to connect small and local sources in the first half of 2025, up roughly 10% year on year (ÚRSO, compiled by ENERGIE-PORTAL.SK, 2025), and Slovakia added about 243 MW of solar during 2025 (SAPI, compiled by TECHBOX.sk, 2025). Small and local sources are moving; large non-local ones are stalled.

The safe strategy is self-consumption. The „local source“ (on average up to ~100 kWp) and „small source“ (up to 10.8 kW) categories bypass most of the barriers and, with a 5-to-7-year payback (RETAIL magazín.sk, 2025) and an industrial price of 146 to 183 €/MWh (Eurostat, H2 2024), make economic sense without depending on selling surpluses.

Regulation is moving — it has to be watched. From 1 January 2026, exceeding the maximum reserved capacity for supply into the distribution system is billed under the ÚRSO price decree (ENERGIE-PORTAL.SK, 2025). The payback of a project that exports to the grid must be calculated with this parameter in mind.

For a park developer and an energy manager there is one practical takeaway: check the availability and cost of connection with the relevant distribution company and with SEPS before deciding on the site and on the size of the source — not after. In Slovakia in 2026, grid connection is as real a location factor as the price of electricity.

Figures are valid as of the dates of the sources cited in the text (SEPS, ÚRSO, Eurostat, SAPI and industry compilations, 2024–2025). Reserved capacity and price decrees change over time; before any decision, verify the current status directly with SEPS, ÚRSO and the relevant distribution company.

This article is for general information only and does not constitute legal, tax or investment advice.