Week 25 underlined a point that is often missed in renewable-energy finance: wind and solar are not the same asset class. Solar output rose in parts of SEE and helped lower prices in Greece and Bulgaria. Wind output, by contrast, weakened across the region, contributing to tighter evening conditions and greater reliance on thermal generation.
This distinction matters for investors, lenders and system planners. Wind and solar have different generation profiles, different correlation with market prices, different curtailment risks and different system values. Treating them as interchangeable renewable megawatts leads to poor modelling.
Solar produces during daylight hours and is increasingly exposed to midday price compression as installed capacity grows. Its strongest risk is capture-price cannibalisation. Wind has a different pattern. It can produce during evening and night hours, sometimes capturing higher prices than solar, but its volatility is more weather-dependent and can weaken across large areas at the same time.
Week 25 showed the system impact of weaker wind. Even with stronger solar, the market still needed more thermal generation because wind and hydro did not provide enough flexible or non-solar output. That pushed several markets higher despite falling gas prices.
For project finance, this means wind projects should be modelled with their own hourly price curves, production profiles and balancing assumptions. A wind farm in Serbia, Croatia or Romania cannot be assessed using the same revenue logic as a solar plant in Greece or Bulgaria. Wind may have stronger capture value in certain periods, but it can also face more volatile output and higher forecasting exposure.
Grid location is also critical. Wind projects are often located in areas with strong resources but weaker grid infrastructure. That raises connection, curtailment and commissioning risks. A project with excellent wind conditions but uncertain grid capacity may be less bankable than a lower-yield project with better grid access and a stronger PPA.
The policy implication is equally important. SEE needs both wind and solar, but it also needs flexibility, forecasting, storage and transmission investment. Solar-heavy growth without wind and storage increases midday compression and evening scarcity. Wind-heavy growth without grid reinforcement increases balancing and congestion risk.
Renewables should therefore be analysed as a portfolio, not as a single category. Solar, wind, hydro and storage each carry different commercial value. Week 25 made that distinction visible in market prices.
