How to Build a Profitable Commercial Battery Storage Project in Romania

Choose the Right Business Model

A commercial BESS in Romania can create value through peak shaving, solar self-consumption, energy arbitrage and revenue stacking. The appropriate strategy depends on the site's load profile, PV generation, electricity tariff, grid connection and access to electricity markets.

Romania's electricity market provides opportunities for battery flexibility. According to OPCOM market data for 2025, the country's average daily day-ahead price spread was around €156/MWh, with solar generation contributing to lower daytime prices while prices can increase later in the day as solar production falls.

Peak Shaving

Peak shaving uses the battery to discharge when a facility's electricity demand reaches its highest or most expensive periods.

For example, a factory with a 2 MW peak could use a 500 kW battery to reduce its grid demand by up to 500 kW during the relevant period. The battery needs sufficient power (kW) to reduce the target peak and enough usable energy (kWh) to maintain that reduction for the required duration.

Peak shaving can be particularly suitable for factories, warehouses, cold storage facilities and commercial buildings with predictable demand peaks.

For Romanian sites, the actual savings should be calculated from the electricity contract, tariff structure and hourly meter data rather than assuming a standard demand-charge model.

Solar Self-Consumption

A BESS can store excess electricity from onsite PV when solar production exceeds site demand and discharge it later when the facility needs electricity.

This can be attractive when solar generation occurs during lower-value daytime periods while the site has significant afternoon or evening demand.

The important question is not simply how much PV the site generates, but how much surplus solar can be stored and subsequently consumed when its value is higher.

A large PV system does not automatically justify a large battery. The battery should be sized according to the actual hourly mismatch between PV generation and site consumption.

Energy Arbitrage

Energy arbitrage charges the battery during lower-price periods and discharges it when electricity prices are higher.

Romania's relatively wide electricity price spreads create an opportunity for arbitrage. However, the €156/MWh average daily day-ahead price spread observed in 2025 (OPCOM) should not be treated as €156/MWh of direct battery revenue.

Round-trip losses, trading and market-access costs, battery degradation and the percentage of the price spread that the system can actually capture all reduce the realized value.

Financial models should therefore use a conservative captured price spread rather than the theoretical maximum market spread.

Revenue Stacking

Revenue stacking combines multiple uses of the same BESS, such as solar self-consumption, peak shaving, arbitrage and flexibility services.

Using several revenue streams can improve asset utilization, but it does not automatically make a project more profitable. Each application must be compatible with the battery's operating limits, grid connection and market-access arrangements.

Romania's flexibility market is also developing. For larger market-connected BESS projects, flexibility services may provide an additional source of value when the project meets the applicable technical and commercial requirements.

Which Business Model Is Best in Romania?

There is no single business model for every Romanian C&I site. For facilities with rooftop PV and significant afternoon or evening demand, solar self-consumption combined with peak shaving is often a practical starting point because the value can be linked directly to site consumption.

Larger market-connected systems may also benefit from energy arbitrage and flexibility services, provided market access, grid connection and EMS capabilities are available.

The revenue strategy should be defined before finalizing battery size because a BESS designed for peak shaving can require very different power and energy capacity from one designed for market arbitrage.

How to Size Your Commercial BESS

There is no universal BESS size for a commercial site in Romania. The appropriate system depends on the site's load profile, PV generation, electricity prices and selected revenue strategy.

The basic sizing relationship is:

Power (kW) × Discharge Duration (h) = Energy (kWh)

For example, assume a Romanian factory has a 2 MW peak load and wants to reduce that peak by 500 kW for two hours:

500 kW × 2 h = 1 MWh

The preliminary requirement would therefore be a:

500 kW / 1 MWh BESS

This is only a starting point. A real Romanian C&I project should be sized using hourly electricity consumption, PV generation and electricity-price data.

For peak shaving, the key variables are the size and duration of demand peaks. For solar self-consumption, the battery should match surplus PV with later site demand. For arbitrage, additional capacity is only worthwhile when the expected price spread and profitable cycling can justify the additional CAPEX and battery degradation.

The financial model should also use usable energy rather than nameplate capacity, taking into account operating SOC limits, round-trip efficiency, degradation and auxiliary consumption.

For the financial example in this guide, we use a 1 MW / 2 MWh C&I BESS as the reference system. This is an illustrative project case, not a recommended standard for Romanian commercial sites.

Estimate Your Commercial BESS Investment

For the financial example, assume an illustrative 1 MW / 2 MWh C&I BESS with an all-in CAPEX of €1 million.

This is a project-modeling assumption rather than a fixed Romanian EPC price. Actual costs vary according to the battery supplier, PCS configuration, grid connection, MV equipment, civil works, fire protection, permitting and project scale.

At this assumed cost:

€1,000,000 ÷ 2,000 kWh = €500/kWh

The resulting €500/kWh should not be interpreted as the standard price of a 1 MW / 2 MWh BESS in Romania.

For C&I projects, the battery system is only part of the total investment. MV equipment, grid connection, installation and site-specific engineering can materially increase the cost per kWh, particularly for smaller projects.

Grid connection should therefore be assessed at an early stage. A project that looks attractive based on battery pricing can become uneconomic if transformer requirements, protection equipment, connection works or grid upgrades significantly increase CAPEX.

Account for OPEX

The €1 million figure represents CAPEX, not the total cost of operating the BESS over its lifetime.

Annual OPEX can include:

• Maintenance
• Insurance
• EMS and software
• Monitoring
• Asset management
• Site-related operating costs

Battery augmentation may also be required later depending on the degradation profile and warranty conditions. For the payback calculation below, these ongoing costs are represented by an annual OPEX assumption.

Calculate Annual Savings and Payback

The key investment question is:

How much annual value can the 1 MW / 2 MWh BESS actually generate?

For the illustrative project, assume three value streams:

These figures are illustrative assumptions for financial modeling, not guaranteed Romanian market returns. A real project should calculate each value stream from hourly load, PV generation, electricity tariffs and applicable market prices.

Simple Payback

The basic formula is:

Payback = CAPEX ÷ Net Annual Benefit

Using the illustrative figures:

€1,000,000 ÷ €130,000 ≈ 7.7 years

The project therefore has an illustrative simple payback of approximately 7.7 years before subsidies or financing effects.

However, the result depends heavily on how much annual value the battery actually captures.

This sensitivity analysis shows why a BESS should not be evaluated using a single optimistic revenue forecast. A project that appears attractive with €170,000 of annual benefit becomes much less attractive if the actual benefit falls toward €90,000.

For a real investment decision, the financial model should also include IRR, NPV, financing costs, taxes, battery degradation and augmentation requirements.

What About Romania's 2026 Storage Funding?

Romania's 2026 Modernisation Fund provides a potential source of support for new stand-alone battery storage projects.

The current scheme allows competitive support of up to €69,000/MWh of installed storage, with a maximum of €15 million per company. Eligible projects must meet requirements including at least 1 MW of installed power and a minimum 2:1 MWh/MW ratio.

For the illustrative 1 MW / 2 MWh project:

2 MWh × €69,000/MWh = €138,000

However, €138,000 represents the maximum theoretical support, not a guaranteed grant amount. The scheme uses a competitive allocation process, so the actual approved support may be lower.

If the project received the full theoretical €138,000, the effective investment would become:

€1,000,000 − €138,000 = €862,000

At the illustrative €130,000 annual net benefit:

€862,000 ÷ €130,000 ≈ 6.6 years

The financial model should therefore treat the subsidy as a scenario rather than guaranteed funding and use the actual approved aid amount and eligible costs once available.

What Can Make Your BESS Project Unprofitable?

A strong BESS investment model should also test what happens when the original assumptions do not hold.

1. Oversizing

A battery larger than the site's actual requirements increases CAPEX without necessarily increasing annual value proportionally.

For example, increasing capacity from 2 MWh to 4 MWh does not automatically double peak-shaving value if the site's load profile only requires 2 MWh of usable energy.

Mitigation: Size the system using actual hourly load, PV and revenue data rather than a standard MW/MWh ratio.

2. Low Utilization

A battery that spends much of its time idle may not generate enough value to justify its capital cost.

However, maximizing cycle count is not necessarily the right strategy because excessive cycling can accelerate battery degradation.

The objective should be profitable utilization rather than maximum cycling.

3. Lower Electricity Price Spreads

Romania's strong electricity price spreads in 2025 should not be treated as guaranteed future arbitrage revenue.

If the difference between charging and discharging prices narrows, the value of energy arbitrage can fall significantly.

Mitigation: Test conservative, base and upside electricity-price scenarios and determine whether the project remains viable under lower price spreads.

4. High Grid Connection Costs

Transformer requirements, protection equipment, connection works and grid upgrades can significantly increase CAPEX or delay commissioning.

Mitigation: Confirm grid capacity, connection requirements and estimated costs before final investment approval.

5. Battery Degradation

Battery capacity and efficiency decline over time, reducing the energy available for future revenue generation.

Mitigation: Model the supplier's degradation guarantee, end-of-life capacity, expected cycling and augmentation requirements.

Overall, lower revenue, higher CAPEX and faster battery degradation can significantly extend the project's payback period.

If a project only works under optimistic electricity spreads, low grid costs and high battery utilization, it is not yet a robust investment case.

Is Commercial Battery Storage Profitable in Romania?

Commercial battery storage can be profitable in Romania, but the return is highly project-specific.

A profitable Romanian C&I BESS needs a revenue strategy that matches the site's electricity consumption, PV generation and tariff structure. The battery also needs to be sized according to actual operating data rather than a generic MW/MWh ratio.

Grid connection costs, electricity price spreads and battery degradation can have a major impact on the final payback period. Developers should therefore test the project under conservative revenue and cost assumptions instead of relying only on historical electricity prices or maximum subsidy levels.

The best starting point for evaluating a commercial battery storage project in Romania is the site's meter data, PV plan, tariff structure and grid-connection conditions.

Ultimati Energie supports commercial operators across Europe with solar and battery storage solutions designed around site-specific load profiles and energy strategies.