Green Energy Brief No 04 · June 2026

01Headline Number

SEEPEX day-ahead, lowest hourly clearing

−€45.50

per MWh · delivery 7 June 2026

The Southeast European Power Exchange enabled negative prices on 5 May 2026. Exactly one month later, the day-ahead market printed nine consecutive negative hours, the lowest at −€45.50/MWh - and Bulgaria's grid was charging.

Source: SEEPEX day-ahead market, Balkan Green Energy News, June 2026

02Market Snapshot

Eight markets, eight stories

Material developments since the last issue, country by country.

🇧🇬 Bulgaria

The 840 MWh of BESS commissioned by Enery (Nova Zagora) and Rezolv (St. George) is now operating into a market that didn't price negative power until five weeks ago. Charging on cheap midday electrons; discharging into evening peaks.

See §03 for operational signals

🇷🇴 Romania

CfD Round 2 cleared. Solar weighted average €40.35/MWh - well below the €73 cap and below 2025's day-ahead average of €110/MWh. Solar awarded 1.49 GW (49% above quota); wind only 1.26 GW of 2 GW (~37% unallocated). Transelectrica's new grid-allocation rules in force.

See §04 and §05

🇬🇷 Greece

876.5 GWh of renewables curtailed Jan–Apr 2026 - up 49% year-on-year. CfD solar parks lost up to 60% of theoretical April revenue. Government granted zero-price remuneration as a tactical patch.

See §05 for policy details

🇷🇸 Serbia

SEEPEX enabled negative day-ahead prices on 5 May - the record −€45.50/MWh print came one month later. Separately, large-project grid connections officially deferred to 2029; Linglong and HBIS filed Serbia's first active-consumer self-supply applications.

See §01 and §05

🇭🇷 Croatia

A US-backed €50 bn hyperscale data-centre will be supplied entirely by behind-the-meter PV plus BESS, bypassing the grid queue. HERA's draft connection-fee methodology arrives after a three-year delay, with ~3 GW of stalled pipeline waiting.

See §04 and §05

🇲🇰 N. Macedonia

EVN Macedonia commissioned a 10 MW / 20 MWh BESS at its Probištip PV plant on 13 May - the first storage at an EVN-owned site, and the second-largest operational BESS in the country after Mey Energy's 30 MW/60 MWh. Strategic energy MoU with Croatia signed 27 May.

Active pipeline: Renalfa 50 MW / 200 MWh under construction at Oslomej

🇸🇮 Slovenia

Two regulatory unlocks in two weeks: nationwide electricity-sharing framework registration opened 1 June, live from 1 July; and Borzen published the BESS rebate scheme on 8 June - €10M budget, up to 45% of eligible CAPEX, cap €225/kWh. Applications open 4 August. Cumulative PV 1.65 GW.

Strongest SI policy month in two years

🇧🇦 BiH

Quiet month at the policy level. Visible pipeline carries: 132 MW Poklečani wind (EPHZHB, EIB-financed 2025) and 125 MW Stolac PV (Aurora Solar, under construction) advance toward 2027 commissioning. Installed PV ~280 MW; total renewable pipeline ~900 MW.

Watching for FBiH energy strategy revision in H2

03BESS Tracker

First-month operational signals

A direct follow-up to Brief No 02. What does the data say now that the systems are live?

🇧🇬 Nova Zagora · Live

601.8 MWh standalone - 3 months commercial

Enery's 150 MW / 601.8 MWh facility in Sliven Province started commercial operations in March 2026 (officially inaugurated 7 May). The asset operates under a VPPA with Vitol - a hybrid offtake structure pairing a financial PPA floor with merchant arbitrage upside. The model SEE banks now use as the bankability template for the next standalone wave.

Reference: the offtake structure, not the size, is the replicable insight here.

🇧🇬 St. George · Live

225 MWp + 90 MW / 240 MWh co-located

Rezolv Energy's first operational asset. The BESS component received a NextGenerationEU grant, materially de-risking the storage CAPEX line. Solar offtake via a 12-year VPPA with AGP-Europe (110 GWh/year). Brief No 02 framed this as a co-located benchmark; we'd add: the EU-grant + corporate VPPA combination is the cleanest bankability stack we have seen in SEE.

EPC: Solarpro + CMC Europe. HV works: Green Solar Energy.

🇧🇬 Maglizh · New

Hybrid PV + 72 MWh BESS commissioned 25 May

A smaller addition to the Bulgarian fleet, but notable: a hybrid configuration where the storage component was sized against the existing PV nameplate, rather than as a separate standalone project. This is the model the EU's BESS-co-location grants were designed to incentivise.

🇷🇴 Premier Energy · Financed

200 MW / 400 MWh - €100M from ČSOB

Czech ČSOB closed €100M project financing for a 200 MW / 400 MWh BESS in Romania, online late 2026 / early 2027. The capital structure is increasingly conventional: a regional bank, a single-purpose vehicle, and a project-finance facility - without recourse to the parent. Storage is becoming a bankable asset class in Romania on the same terms as utility PV was two years ago.

04Deal Flow

Money, M&A, project closings

Net-new deals not covered elsewhere in this issue.

🇭🇷 Croatia · Hyperscale

Pantheon AI: €50 bn campus + 500 MW PV + 2 GW / 8 GWh BESS

Announced 28 April at the Three Seas Summit in Dubrovnik. US-led Pantheon Atlas (€12 bn initial, €50 bn total with tenants) will host hyperscale AI compute at Topusko, fully supplied behind-the-meter by a 500 MW solar plant + 2 GW / 8 GWh BESS built by KKR-owned Greenvolt. Construction 2027, operations Q1 2029. Largest single private investment in Croatian history.

The signal isn't the data centre - it's the off-grid energy architecture that comes with it.

🇷🇴 Romania · CfD II

2.75 GW awarded: 1.49 GW solar + 1.26 GW wind

49 winners across 2,751 MW - solar overshot the 1 GW quota by ~50%, wind missed the 2 GW target by ~37%. Wind weighted average €73.89/MWh; solar €40.35/MWh (range €35.77–45.20). Modernisation Fund underwrites the 15-year contracts. Largest single solar award: West Power Investments, 520 MW (Dama Solar). Round 3 in preparation.

🇽🇰 Kosovo · Wind

Çalik Renewables + Eurokos: 72 MW wind, online July

One of the few utility-scale renewables additions in the Western Balkans this year outside of Serbia and North Macedonia. Turkey-based Çalik and domestic Eurokos are in final commissioning works.

🇹🇷 Turkey · Hybrid

Energo-Pro 40 MW PV at the 280 MW Alpaslan 2 hydro plant

A solar array integrated with an existing hydroelectric station in eastern Turkey. Hydro + PV hybridisation is a configuration to watch - Bulgaria's NEK has published studies on similar deployments at Belmeken and Chaira.

05Policy Watch

Rules of the game

Including the implementation timeline for the EU inverter restrictions covered in Brief No 03.

🇪🇺 EU · Continued from Brief No 03

Chinese inverter restrictions - implementation calendar

The Commission has set a phased schedule: 1 July 2026 - all EU services review ongoing activities and propose integration of the restrictions; 15 July - assessment of whether alternative suppliers can meet demand; 1 November - existing-project assessments under the previous framework with possible additional cybersecurity measures; April 2027 - full enforcement on new contracts. Limited derogations on security or political grounds.

For SEE EPCs: BoQ specifications and procurement contracts dated after 1 July should anticipate the November supplier review.

🇬🇷 Greece

Zero-price remuneration for CfD solar plants

The Greek government accepted a request from CfD-holding producers to receive zero-price remuneration during negative-price hours, rather than pay back the difference under the strike-price mechanism. It relieves stressed asset owners, but shifts cost to the budget and signals the conventional CfD model is buckling under SEE solar penetration.

🇷🇸 Serbia

Large applications deferred to 2029

For utility-scale wind and solar applications already submitted, processing is now officially deferred to 2029. EMS' Jelena Matejić states the grid can technically connect 12 GW over six years - but the queue, not the wires, is the binding constraint.

🇭🇷 Croatia · 🇷🇴 Romania · 🇸🇮 Slovenia

Three grid-connection & storage reforms in three weeks

HERA published Croatia's draft connection-fee methodology after a three-year delay (~3 GW of stalled pipeline waiting). Transelectrica's revised allocation rules in Romania set fixed timeframes for auction rounds for projects ≥5 MW. Borzen published Slovenia's BESS rebate scheme on 8 June (€10M budget; 45% / €225/kWh cap; applications open 4 August). Three regulators, same logic: predictability and storage incentives are the bottleneck, not policy ambition.

06Elevat Angle

Three months of live data - and a UK precedent that travels

Synthesis. Not a recap of the issue.

The most useful frame for the next 24 months of SEE storage is not a forecast. It is the UK BESS revenue stack between 2022 and 2024.

In 2022, frequency response was 80% of typical UK BESS revenue. By 2024, it was 20%. The opportunity didn't disappear - it migrated. Market saturation compressed ancillary prices; arbitrage and capacity markets absorbed the difference. The operators who built early captured the peak of the stack. Those who came later built into a structurally different return profile, on the same CAPEX.

Southeast Europe is running the same play, faster. Bulgaria has allocated 14+ GWh of standalone storage under RESTORE - a volume that will saturate the BG ancillary market well inside 24 months. Romania's ancillary prices today (~€9/MW/hr aFRR, ~€70/MW/hr FCR) look generous because the market is shallow. Each new 100 MW of operational BESS compresses them.

The data from this month is the inflection. SEEPEX enabled negative prices on 5 May. Within a month, the day-ahead printed nine consecutive negative hours. Nova Zagora and St. George - commissioned a few months earlier - were charging into that negative-priced window. The arbitrage thesis is no longer projection; it is this quarter's revenue.

Three implications follow.

One - the timing premium is the single largest IRR contributor available to SEE BESS in 2026. Projects reaching commercial operation before mid-2027 will operate at the top of the revenue stack. Projects commissioning in 2028 will operate in an arbitrage-dominant, compressed market. Same equipment, same CAPEX, materially different returns. The window is open and visible.

Two - the conventional bankability framework needs revision. Lenders modelling Romanian or Bulgarian BESS on today's ancillary headlines are pricing yesterday's market. A 2027 base case should assume UK-2024 composition: roughly 60–70% arbitrage, 20% ancillary, 10–20% capacity. The Nova Zagora / St. George structure - financial PPA floor with merchant arbitrage tail - is already the template the next financings should follow.

Three - Romania CfD II at €40.35/MWh is a structural warning, not a celebration. Greek CfD solar lost 60% of April revenue against negative prices and curtailment. Romanian developers who bid the cap without an in-built storage strategy will discover the same arithmetic by 2028. The Greek government's zero-price ruling is a fiscal patch; it does not change the underlying physics. Every new SEE PV megawatt without a credible storage line is a future stranded cash flow.

What we are watching next month: the first ENTSO-E balancing data from the Nova Zagora and St. George BESS, Romania's Q3 CfD Round 3 framework, and whether Croatia's draft HERA fees actually clear the regulatory backlog or stall again.

Elevat Solar Consulting · Independent technical advisory · Sofia · 11 June 2026