Panel session: Towards 100% RES Energy Systems, the Next Steps

Session chair
Prof. Neven Duić, University of Zagreb, Croatia

Panellists

Željko Tomšić (University of Zagreb, Croatia)
RES and NE: are they competitors or supplements in carbon free electricity market?
Brian Vad Mathiesen (Aalborg University, Denmark)
Storage options in smart energy systems and the steps towards 100% renewable energy
Goran Krajačić (University of Zagreb, Croatia)
Use of pumped hydro storage in further integration of RES in the EU and neighbouring countries

Abstract

The goal to switch energy systems to renewable energy sources is becoming more attractive with decrease of the investment costs of renewables and continually volatile prices at the high of fossil fuels. The resources are bountiful, especially wind and solar, while biomass, hydro and geothermal are limited and not found everywhere. Meanwhile, integrating them into current energy systems is proving to be a challenge. The limit of cheap and easy integration for wind is 20% of yearly electricity generation, while a combined wind and solar may reach 30%. Going any further asks for implementation of really free energy markets (involving day ahead, intraday and various reserve and ancillary services markets, but not capacity market), and it involves integration between electricity, heat and transport systems.
The cheapest and simplest way of increasing further the penetration of renewables is integrating power and heat systems through use of district heating (which may be centrally controlled and may have significant heat storage capacity). In countries with low heat demand water supply system may be used to increase the penetration of renewables, by using water at higher potential energy as storage media, or in dry climates desalination and stored water may be used for those purposes, and reversible hydro may be used as balancing technology. Electrification of personal car transport allows not only for huge increase of energy efficiency, but also, electric cars due to low daily use may have excellent demand side management and even storage potential. That will allow reaching 80% renewable in energy system, but the remaining 20% may be more uphill battle.
Long haul freight road transport, aviation and ship transport, as well as high temperature industrial processes, cannot be easily electrified. Biomass, if not used for producing electricity and heat, may cover half of those needs, but the rest will have to come from some other technology. Currently, synthetic fuels are at the most researched option, but other option may yet prove to be winning for the last 20%. Some of the high temperature industrial processes may still be electrified, like electric arc furnaces, or roads may become energy generating and a source of electricity for trucks. The panel will discuss overview all of these and some more issue on the way to 100% renewable energy systems.