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Abstract The European Union has set specific targets for reducing energy consumption, shifting the main focus of European energy policy towards a firm commitment to enhancing energy efficiency. In light of the limited progress reported in Greece's energy efficiency action plan, the objective of this paper is to help redesign the near-term national policy framework. In this respect, a risk-oriented optimisation model is developed to support the optimal budget allocation to energy efficiency measures, with a view to achieving the 2020 national targets. The transdisciplinary methodological framework initially builds on the Energy Efficiency Action Plans for Greece and involves stakeholder engagement, multiple-criteria decision making and portfolio analysis. The evaluation of the policy instruments is based on two criteria, namely energy savings and implementation risk, under a set of technical and financial constraints. Finally, the robustness of both the optimal policy portfolios and the individual policies composing these portfolios is assessed. The results indicate that, given the financial and technical constraints, the 2020 target cannot be achieved. By stochastically analysing the impact of external uncertainty, three policies emerge as the most robust, while portfolios achieving savings of more than 1000 kTOE until 2020 are found highly vulnerable to underlying uncertainties. Highlights • Greece strives to achieve its national energy efficiency targets in the near-term. • We propose a risk-oriented framework to support the redesign of the national policy. • Given the financial and technical constraints, the 2020 target cannot be achieved. • Three policies appear to be robust and contribute the most in the optimal portfolios. • Policy portfolios achieving more than 1000 kTOE are highly vulnerable to uncertainty. [ABSTRACT FROM AUTHOR]

Abstract: The intraday nonparametric estimation of the variance–covariance matrix adds to the literature in portfolio analysis of the Greek equity market. This paper examines the economic value of various realized volatility and covariance estimators under the strategy of volatility timing. I use three types of portfolios: Global Minimum Variance, Capital Market Line and Capital Market Line with only positive weights. The estimators of volatilities and covariances use 5-min high-frequency intraday data. The dataset concerns the FTSE/ATHEX Large Cap index, FTSE/ATHEX Mid Cap index, and the FTSE/ATHEX Small Cap index of the Greek equity market (Athens Stock Exchange). As far as I know, this is the first work of its kind for the Greek equity market. Results concern not only the comparison of various estimators but also the comparison of different types of portfolios, in the strategy of volatility timing. The economic value of the contemporary non-parametric realized volatility estimators is more significant than this when the covariance is estimated by the daily squared returns. Moreover, the economic value (in b.p.s) of each estimator changes with the volatility timing. [Copyright &y& Elsevier]