The potentials of thermal energy storage using domestic electric water heater technology with PV systems in the EU countries
Authors: Zsiborács Henrik , Vincze András , Pintér Gábor , Baranyai Nóra Hegedűsné 
Published: December 2023

Abstract
Recently, there has been a considerable decrease in photovoltaic technology prices (i.e. modules and inverters), creating a suitable environment for the deployment of PV power in a novel economical way to heat water for residential use. Although the technology of TES can contribute to balancing energy supply and demand, only a few studies have investigated its potentials. These days, TES technology can play a significant role in mitigating the negative network effects resulting from higher proportions of electricity generated by PV systems. The presented research examined the possibility of applying a new technological direction in connection with PV utilization in the European Union (EU), with a view to promoting the spread of cost-effective energy storage and increase energy independence. The purpose of this study was to examine the deployment of combined TES and PV systems in the EU countries by the example of a special 3.5 kW inverter and a 200-l domestic electric water heating system. The innovative significance of the research is that it explores this practical solution, by determining the seasonal energy saving potentials of the application of this sensible heat storage method in the context of all the EU countries.

Graphical Abstract

Highlights

The recent extraordinary increase in installed photovoltaic (PV) capacity cannot be successful without integrating it with energy storage (ES) to store generated surplus power to be consumed later.

Technological developments and the trend of falling PV module and inverter prices makes it possible to apply economical solutions for hot water production for domestic hot water use and/or assisting space heating, based on the use of solar energy.

The combination of modern inverter technology, PV and domestic electric water heating systems provides a storage solution for PV energy with considerable cost saving potentials in the countries of the EU.

Many factors influence the ideal and economical size of such combined systems and their components, which need careful consideration and calculation.

For a better utilization of the potentials offered by this new solution more complex analyses and the investigation of the ways of linking thermal energy storage (TES) and PV systems and possibly other technologies is necessary.

Discussion

How can the efforts to decrease the household consumption of energy used for heating water and space heating connected to the issue of integrating variable renewable energy sources into energy systems?

How can currently commercially available technology be used for storing electrical energy generated by photovoltaic systems in the form of heat energy?

What determines the potential energy and costs savings achieved by a combined system of a small photovoltaic power plant and a home electric water heating system for the households in the various countries of the European Union?

What are the potentials of the suggested system in terms of energy and costs savings in the context of households in the EU countries?