Alexandre Millet: Analysis of the integration and impact of GRIDSOL technology, Masters's Thesis, DTU, 2017.


The European Union has set ambitious targets to reduce the CO2 emissions in the power sector by 2050. Renewable sources such as wind power or Photovoltaics (PV) are reaching competitiveness against traditional fossil fuel based thermal power plants. However, most of the renewable sources have a variable power production which requires back up or storage technologies to ensure grid stability. This master thesis is investigating how Gridsol, a smart renewable hub composed of a Concentrated Solar Power (CSP) with thermal energy storage, a gas turbine and PV can provide a firm power and be integrated in an island energy system, applying both a technical and an economical perspective.

For several reasons, Crete has been chosen to assess Gridsol: the Greek island has a great potential for renewables (wind and solar power), electricity prices are high and the grid is rather weak and not interconnected with the mainland system.

The modelling tool Balmorel is applied, starting with a calibration of Crete energy system in 2015. Projections are made until 2050 for key assumptions including electricity demand, technology costs, CO2 and fuel price. A reference scenario is built and the investment module of Balmorel decides the optimal energy mix with milestones in 2020, 2030, 2040 and 2050. In a second scenario, the smart renewable hub Gridsol is modelled in Balmorel and implemented in Crete. The Gridsol scenario is then compared to the benchmark and the impact on Crete energy system is measured in terms of avoided CO2 emissions and renewable penetration. Eventually, a feasibility analysis from a socio-economic perspective is performed with an optimal configuration of Gridsol.

Gridsol can provide a continuous and flexible power production based on renewables in summer with a large thermal energy storage configuration. The CO2 emissions in Gridsol scenario are lower than in the reference scenario. In 2050, 90% of the production is ensured by renewable energy sources (including biomass), compared to 19% in 2015. The result of the various scenarios shows that Gridsol could be implemented in Crete by the horizon 2040, participating actively in the grid stability while increasing the share of renewables. The combination solar and batteries is the major competitor of Gridsol technology, thus the competitiveness of Gridsol technology will rely on the cost development of the battery technologies.