800V Integrated BESS solution

New European standard for BESS

With 800 V voltage, you don’t need a transformer!

✅ Faster storage installation – immediate deployment!

✅ Efficient land use – inverter integrated within the BESS.

✅ Optimizing costs (CAPEX, OPEX) – no transformer needed

📈 The growing popularity of the 800 V AC standard in renewable energy installations and energy storage systems is driven by several practical technical reasons. In short: higher power – lower losses – cheaper infrastructure.

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We manufacture, invest, build, and maintain – with a 15-year warranty.

BESS you can rely on!

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Speficiations of 800V BESS containers and cabinets

Key features

As a Tier-1 manufacturer, according to the BloombergNEF Tier-1 ranking, we provide the highest levels of safety, reliability, and quality. Our BESS cabinet (261–418 kWh) and container (2 MWh, 4.18 MWh, and 5.016 MWh) systems are considered “bankable” for large-scale investments.

  • Liquid cooling system with temperature difference < 3 °C
  • Integrated fire suppression system
  • Multi-point BMS monitoring and alarms
  • Long lifecycle: > 8,000 cycles, designed lifespan of at least 15 years
  • Standards compliance: IEC 62619

RelyEZ VenturePro Fusion

261- 418 kWh
Liquid-cooled C&I cabinets

A comprehensive, integrated solution with built-in PCS offers batteries with a lifespan of over 10,000 cycles and an operational life exceeding 15 years. The system features advanced management of aluminum cells, enabling early detection of any abnormalities. It also incorporates liquid cooling technology and an AI-based intelligent fire protection system. The package is completed with an integrated EMS and cloud-based management.

Full 800V AC integration

Ideal for PV and wind farms, where most transformer stations operate at this standard.

The system is delivered with PCS installation, switchgear, BMS, fire protection system, and cooling system. Parameter compatibility minimizes losses and increases the flexibility of renewable energy installation configurations. Higher voltage improves charging and discharging efficiency during fast-response modes, which are critical for grid stabilization and ancillary services.

Optimized AC/DC efficiency

– by operating directly at 800 V, it reduces losses and the number of conversions.

In BESS systems integrated with renewables, this voltage allows more efficient coupling of the storage with photovoltaic or hybrid inverters, minimizing the need for additional conversion stages. Higher operating voltage also improves stability under variable PV generation profiles and enables more efficient energy transfer in high-power systems. As a result, the entire installation achieves higher efficiency and lower operating costs.

RelyEZ GridUltra (2- oraz 4-hour)

Variants: 2MWh, 4.18MWh, 5.016MWh
Containerized BESS

The modular design ensures flexibility, while high energy density delivers maximum performance. The system features simplified installation and maintenance, as well as an exceptionally long lifespan — over 8,000 cycles and up to 20 years of operation. An additional advantage is excellent temperature uniformity.

We know and understand your perspective as owning 10GWh BESS

Discover the variety of 800V applications

0,8 kV/MV solar farms

Comprehensive BESS solutions for PV farms with advanced energy management. Time-shifting allows excess production from midday hours to be shifted to the evening peak, increasing energy value by 20–40%. Peak shaving reduces load on GPZ infrastructure and optimizes connection costs. Dynamic Q(U) regulation ensures voltage stability in accordance with IRiESD requirements. AC/DC-coupled topologies are tailored to the specifics of each project.

Wind farms

Energy storage systems for wind farms smooth short-term power fluctuations, reducing the ramping rate in compliance with NC RfG. Reactive power compensation supplements generator capabilities, enabling STATCOM operation. Predictive management of grid constraints (curtailment) allows recovery of energy that would otherwise be wasted. Response time <100 ms, round-trip efficiency 85–92%.

Hybrid projects: PV + Wtg + BESS

Innovative solutions combining photovoltaics, wind power, and storage on a common 800 V DC bus. Eliminating redundant conversions increases efficiency by 3–5% and reduces CAPEX by 15–25%. The complementary operation of sources (PV during the day, wind at night) raises the utilization factor of the connection capacity to 40–60%. A single connection point = optimized infrastructure costs and simplified control.

Aggregation and capacity market

Advanced energy management systems (EMS), both offline and online, for revenue maximization. Participation in markets: FCR, aFRR, Balancing Market, Capacity Market (CM), and RDN/RSD. Collaboration with energy aggregators provides access to multi-market revenue stacking. Production forecasting, SOC optimization, and real-time dispatch. Communication via IEC 61850, telemetry <10 s, full compliance with PSE and TSO requirements.

We target best performance and reliability

Technical parameters

  • AC side: 800 V (±10%), 3-phase, 50 Hz
  • PCS/unit block power: from 250 kVA to >1 MVA (parallel configurations possible)
  • PCS efficiency: up to 98%+ (depending on operating point)
  • Power factor: fully adjustable (inductive ↔ capacitive), reactive power (Q) can be set to a desired value
  • THDi / power quality: compliant with grid power quality standards for operation at 800 V (details in datasheet)
  • Battery DC side: architectures compatible with typical ranges of 1000–1500 V DC (depending on modules/racks)
  • Communication/SCADA/EMS: Modbus TCP, integration with supervisory system, offline EMS mode (optional), aggregator API

Compliance and formal requirements met

  • Compliance with the requirements of operators incl. EU and Poland (IRiESD / guidelines of distribution and transmission operators) and recommendations of PTPiREE regarding the operation of generation/storage units.
  • Standards and safety: design compliant with relevant low- and medium-voltage standards, including protection against electric shock, grounding, and fire safety requirements for BESS.
  • Grid connection documentation: we provide all necessary data for connection conditions (power profiles, Q/U, LVRT/HVRT characteristics — if required).