Energy Storage Technologies for Off-grid Houses

Abstract

Off-grid houses have the potential to become an important asset for tomorrow’s electricity grid. Access to electricity inside homes is an important ingredient for creating quality of life. On the one hand, off-grid houses may enable such an access in regions without a proper grid infrastructure such as Sub-Saharan regions in Africa. On the other hand, due to the predicted consequences of a world-wide climate change, the vast majority of countries are making plans towards a massive integration of renewable energy; especially solar photovoltaics (PV) and wind turbines. The introduction of this huge amount of renewable energy leads to a lot of challenges. Off-grid houses may become an important asset which can support the integration of renewable energy as they tend to keep the generated energy locally. In this thesis we research off-grid houses, in particular (semi)off-grid or standalone houses that are capable of being electrically self-sustained for a certain period of time. These houses should depend electrically primarily on renewable sources (e.g. solar PV), used storage units (e.g. batteries) and backup power (e.g. fuel cells or the grid if it is present). We consider a setup for an off-grid house based on research on new storage technologies done by University of Twente and the company Dr Ten in the Netherlands. The setup focusses on electrical devices in a house and in particular a wastewater treatment unit, which are powered mainly by Solar PV combined with a Sea-Salt battery and a Glycerol Fuel Cell as backup power. In the first part of this thesis, the Sea-Salt battery and the Glycerol Fuel Cell are studied separately with regard to their electrochemical behaviour. In the second part, we study the sizing of Solar PV, the Sea-Salt battery and the Glycerol Fuel Cell for use in two cases: a standalone wastewater unit and for a house in the US and in NL.