I am not familiar with the specific Greek energy market.

However from a supply-and-demand perspective,

• Intermittent energy sources do not meet the Quality of Service requirement which is essential for energy.
• As long as the source can be turned into electricity, all energy sources are near perfect substitutes. Hence, one cannot isolate the price of a selection of sources vs the rest.
• When demand is inelastic and grows, as it is the case for energy demand, it's the supply that has to grow.