Solar PV with Storage vs. Wind: How to Choose the Right Technology for a Project in Romania
1. Production profile and capacity factor
Solar PV in Romania typically produces at a capacity factor of 13-16%, concentrated exclusively in daylight hours, with a strong seasonal peak in summer. Production is highly predictable based on meteorological modeling (PVsyst/RatedPower), with relatively low year-on-year variation.
Onshore wind produces at a capacity factor of 25-35% in Romania’s good sites (Dobrogea, Moldova), with a profile more evenly distributed throughout the day and stronger in winter complementary to solar, not competing with it. Year-on-year variability is higher than solar, however, and short-term production is much harder to forecast (24-48h forecast errors are significantly larger than for PV).
The technical conclusion: a mixed solar+wind portfolio reduces aggregate revenue volatility more effectively than doubling capacity in a single technology — an argument for diversification at the portfolio level, not just at the individual project level.
2. The role of storage (BESS) why it pairs with solar, not wind
Adding a storage installation (BESS) has different economic logic depending on the generation technology:
• With solar, BESS solves the cannibalization problem: production concentrated in low-price hours (midday, summer heat waves) can be shifted to higher-priced evening hours. The greater solar penetration grows in the market, the more pronounced the “duck curve” effect becomes, and the higher the marginal value of storage.
• With wind, the production profile is already more evenly distributed throughout the day, so the hourly arbitrage benefit of BESS is smaller. Here, storage delivers value more through ancillary services (secondary/tertiary balancing, frequency regulation) than through price arbitrage.
In practice, a solar+BESS project captures two revenue streams (energy + flexibility/arbitrage services), while a pure wind project remains fully exposed to wind’s natural hourly profile which is why most hybrid projects completed or under development in Romania pair storage with solar.
3. CAPEX, execution timeline, and technical complexity
Solar + BESS: Higher CAPEX per installed MW once storage is added, but a shorter and more predictable construction timeline standardized modules, a well-understood EPC learning curve, low technical risk. An RTB solar project can reach COD (commercial operation date) in 8-12 months from construction start, depending on size.
Wind: Comparable or higher CAPEX per MW (turbines, foundations, access roads, grid connection lines often longer due to siting in areas with good wind but less developed infrastructure). Longer execution timeline 12-18+ months due to logistical complexity (oversized component transport, foundations, stricter environmental permitting for flight corridors and bird migration routes).
For an investor seeking speed from acquisition to COD, solar remains the faster option with less exposure to execution risk.
4. Land footprint and site availability
A 50 MWac solar project typically occupies 60-90 ha, depending on panel configuration and row spacing. The land must be removed from agricultural use (if applicable) and requires an approved zoning plan (PUZ).
A wind project of similar capacity occupies a much smaller physical footprint per turbine (foundation + access roads), but requires a much larger dispersion area between turbines to avoid mutual shading (wake effect), plus minimum distances from residences and aeronautical/radar zoning restrictions. The availability of good wind sites in Romania is more geographically limited (concentrated in Dobrogea and parts of Moldova), while solar is viable across a much wider geographic area of the country.
5. Grid connection where the risks diverge the most
This is where the technical difference is most relevant for an investor who has already read our analyses on grid connection approvals (ATR) and network capacity:
• Solar projects are typically closer to existing transformer stations, with lower and more predictable connection costs.
• Wind projects are often sited in areas with less developed grid infrastructure, meaning longer connection lines, more frequent network reinforcement costs, and — as we’ve documented on other projects in our portfolio the risk of capped evacuation power until reinforcement works are completed.
6. Implications for CfD structuring
Romania’s first CfD auction allocated capacity separately for solar (500 MW) and onshore wind (1,000 MW) a distinction relevant for investors, because the strike price resulting from the auction and the dynamics of the reference price differ structurally between the two technologies, precisely because of the production profiles described above. A solar project competes on a reference price more exposed to cannibalization; a wind project competes on a reference price with higher variability, but less correlated with low-price peak hours.
7. Conclusion: not an “either-or” choice
From our perspective, as administrator and broker of projects in the Romanian market, the two technologies serve different portfolio objectives:
• Solar + BESS for investors seeking fast execution, high predictability, and the ability to capture hourly arbitrage value in a market with growing solar penetration.
• Wind for investors with a longer investment horizon, willing to manage greater execution complexity in exchange for a superior capacity factor and a production profile that complements solar.
A portfolio combining both technologies, correctly structured in terms of grid connection and chosen support scheme, remains the most robust option for an investor entering the Romanian market for the long term.
Solar PV in Romania typically produces at a capacity factor of 13-16%, concentrated exclusively in daylight hours, with a strong seasonal peak in summer. Production is highly predictable based on meteorological modeling (PVsyst/RatedPower), with relatively low year-on-year variation.
Onshore wind produces at a capacity factor of 25-35% in Romania’s good sites (Dobrogea, Moldova), with a profile more evenly distributed throughout the day and stronger in winter complementary to solar, not competing with it. Year-on-year variability is higher than solar, however, and short-term production is much harder to forecast (24-48h forecast errors are significantly larger than for PV).
The technical conclusion: a mixed solar+wind portfolio reduces aggregate revenue volatility more effectively than doubling capacity in a single technology — an argument for diversification at the portfolio level, not just at the individual project level.
2. The role of storage (BESS) why it pairs with solar, not wind
Adding a storage installation (BESS) has different economic logic depending on the generation technology:
• With solar, BESS solves the cannibalization problem: production concentrated in low-price hours (midday, summer heat waves) can be shifted to higher-priced evening hours. The greater solar penetration grows in the market, the more pronounced the “duck curve” effect becomes, and the higher the marginal value of storage.
• With wind, the production profile is already more evenly distributed throughout the day, so the hourly arbitrage benefit of BESS is smaller. Here, storage delivers value more through ancillary services (secondary/tertiary balancing, frequency regulation) than through price arbitrage.
In practice, a solar+BESS project captures two revenue streams (energy + flexibility/arbitrage services), while a pure wind project remains fully exposed to wind’s natural hourly profile which is why most hybrid projects completed or under development in Romania pair storage with solar.
3. CAPEX, execution timeline, and technical complexity
Solar + BESS: Higher CAPEX per installed MW once storage is added, but a shorter and more predictable construction timeline standardized modules, a well-understood EPC learning curve, low technical risk. An RTB solar project can reach COD (commercial operation date) in 8-12 months from construction start, depending on size.
Wind: Comparable or higher CAPEX per MW (turbines, foundations, access roads, grid connection lines often longer due to siting in areas with good wind but less developed infrastructure). Longer execution timeline 12-18+ months due to logistical complexity (oversized component transport, foundations, stricter environmental permitting for flight corridors and bird migration routes).
For an investor seeking speed from acquisition to COD, solar remains the faster option with less exposure to execution risk.
4. Land footprint and site availability
A 50 MWac solar project typically occupies 60-90 ha, depending on panel configuration and row spacing. The land must be removed from agricultural use (if applicable) and requires an approved zoning plan (PUZ).
A wind project of similar capacity occupies a much smaller physical footprint per turbine (foundation + access roads), but requires a much larger dispersion area between turbines to avoid mutual shading (wake effect), plus minimum distances from residences and aeronautical/radar zoning restrictions. The availability of good wind sites in Romania is more geographically limited (concentrated in Dobrogea and parts of Moldova), while solar is viable across a much wider geographic area of the country.
5. Grid connection where the risks diverge the most
This is where the technical difference is most relevant for an investor who has already read our analyses on grid connection approvals (ATR) and network capacity:
• Solar projects are typically closer to existing transformer stations, with lower and more predictable connection costs.
• Wind projects are often sited in areas with less developed grid infrastructure, meaning longer connection lines, more frequent network reinforcement costs, and — as we’ve documented on other projects in our portfolio the risk of capped evacuation power until reinforcement works are completed.
6. Implications for CfD structuring
Romania’s first CfD auction allocated capacity separately for solar (500 MW) and onshore wind (1,000 MW) a distinction relevant for investors, because the strike price resulting from the auction and the dynamics of the reference price differ structurally between the two technologies, precisely because of the production profiles described above. A solar project competes on a reference price more exposed to cannibalization; a wind project competes on a reference price with higher variability, but less correlated with low-price peak hours.
7. Conclusion: not an “either-or” choice
From our perspective, as administrator and broker of projects in the Romanian market, the two technologies serve different portfolio objectives:
• Solar + BESS for investors seeking fast execution, high predictability, and the ability to capture hourly arbitrage value in a market with growing solar penetration.
• Wind for investors with a longer investment horizon, willing to manage greater execution complexity in exchange for a superior capacity factor and a production profile that complements solar.
A portfolio combining both technologies, correctly structured in terms of grid connection and chosen support scheme, remains the most robust option for an investor entering the Romanian market for the long term.