Why a solar park needs storage in 2026
Hungary has over 7 GW of solar capacity and the midday price on HUPX regularly falls to a fraction of the evening price – on sunny weekends to zero or below. A PV park without storage sells exactly when the price is lowest, is curtailed when the grid is full, and earns nothing after sunset. Storage turns the same panels into a plant that sells when it chooses.
The numbers above come from the live HUPX data on our market price page and from our own project calculations; the uplift depends on the park's production profile and the grid-connection limit.
What a hybrid PV park consists of
Retrofitting storage to an existing PV park
Most Hungarian parks were built between 2019 and 2024 without storage, often under the KÁT or METÁR schemes and with a grid connection that is now the bottleneck. Adding storage behind the existing connection point does not need new grid capacity if the controller guarantees that the combined export stays below the limit – this is what makes a retrofit feasible in months rather than years.
- Sizing: storage power typically 30–50 % of the PV peak, capacity 1.5–2 hours – enough to shift the midday surplus into the evening peak
- Grid: notification or modification of the connection agreement with the DSO; the export limit stays, the controller enforces it
- Support scheme: KÁT/METÁR parks need the storage metered separately so the subsidised energy and the stored energy are accounted for correctly
- Grant: the Jedlik Ányos programme funds storage next to existing renewables – the 20 % sizing rule is easily met by a hybrid park
- Time: 4–6 months from decision to commissioning for a containerised system, depending on delivery and the DSO procedure
How the revenue stacks
| Revenue stream | How the hybrid park earns it | What the controller does |
|---|---|---|
| Price shifting | Midday production stored, sold in the 17:00–21:00 peak | Daily schedule from the HUPX day-ahead curve |
| Curtailment capture | Energy that the export limit would otherwise waste is charged instead | Export limit enforced at the connection point, surplus diverted to the battery |
| aFRR / FCR | Reserve capacity sold to MAVIR through an aggregator | Setpoints from the aggregator executed within seconds |
| Negative prices | Charging from the grid when the price is below zero | Price threshold in the schedule |
| Firm delivery | PPA with a flatter profile is worth more per MWh | Profile smoothing within the contracted band |
References
Kunfehértó: 13 solar parks (~8 MWp) with storage – construction and commissioning. Domaszék: hybridisation of an existing plant with storage and ComAp control. Szentmártonkáta: 2.44 MWh storage with BST Control Box. Details and photos on our references page.
Frequently asked questions
Can storage be added to a PV park without a new grid connection?
Yes, if the storage is AC-coupled behind the existing connection point and the plant controller guarantees that PV plus storage never exceeds the contracted export limit. The DSO has to be notified and the connection agreement may need an amendment, but no new capacity is required.
How big should the battery be for a PV park?
A common starting point is storage power of 30–50 % of the PV peak with 1.5–2 hours of capacity. The exact size comes from the park's 15-minute production data, the export limit and the price curve – we run this sizing in the feasibility check.
Does a KÁT or METÁR park lose its support if storage is added?
No, provided the stored energy is metered separately and the accounting rules of the scheme are followed. Grid-charged energy must not be sold as subsidised production; the metering concept settles this.
What is the payback of a hybrid PV park retrofit?
With current HUPX spreads and aFRR revenue, storage next to a PV park typically pays back in 4–6 years at market prices and 2–4 years with the 30–50 % grant – faster than a stand-alone system because the PV surplus charges it for free.
Can the park run in island mode during a grid outage?
With a grid-forming PCS and the right controller, yes – the storage sets voltage and frequency and the PV inverters follow. This matters for parks that also feed a site (industrial or agricultural) behind the same connection.
Have a solar park? Let's see what storage adds
Send us a year of 15-minute production data and the connection limit – we size the storage and calculate the uplift free of charge.
Request a feasibility check