Decarbonizing the Greek electricity system under the energy storage context: Between ambition and reality

Decarbonization was set as an ultimate target of the European energy policy, and, under this frame, Greece has substantially reformed its electricity mix over the last two dec-ades. Yet, the rapid transition of the country's electricity production system towards a model that strongly relies on non-controllable renewables, without improving its energy storage means, has caused several adverse impacts that reasonably raise serious concerns on its sustainability. Further questions arise if accounting for projections and underlying assumptions reported in the National Energy and Climate Plan. In this vein, key policy, societal, technical, sustainability and science issues are discussed involving the chal-lenges, perspectives and potential drawbacks of long-term energy planning of Greece. To reveal the critical role of storage, a toy simulation-optimization model is applied at the national scale, to evaluate several scenarios of wind and solar P/V development under the premise of a theoretically fully decarbonized mix. This allows exploring tradeoffs of energy storage and power capacity needs against key performance metrics (frequency and quantity of deficits, percentage of rejected renewable energy). Prelimi-nary feasibility issues are also highlighted, considering alternative configurations of pumped hydropower storage units and associating their approximative investment costs with scale and geometry.