Augmentation of Self-Consumption of Electricity by Using Boilers and Batteries for Residential Buildings

The main problem of using renewable energy sources is their stochastic nature. To solve this problem, storage technologies are needed. In this study we explored a system that consists of renewable energy sources (wind and photovoltaic), non-shiftable loads (white goods, etc.) with a combination of two types of energy storage: boiler system and battery. Boilers as energy storage provide only one-way conversion of electrical energy into thermal energy. The boiler system consists of two vessels connected in series (the main boiler and the preheating boiler). The main boiler provides the necessary temperature level using energy from renewables or the grid. The preheating boiler stores energy that is not used on the non-shiftable load and feeding the main boiler. Excess energy from the main and preheating boilers is stored by the batteries. In the reverse scenario, in case of a lack of energy, energy is first taken from the batteries and then the grid. Our hypothesis is: using these two storage principles in tandem leads to a significant increase of supply cover factor. Our estimations show that a boiler system without a battery has a supply cover factor equal to 0.278. Whereas with joint usage of a boiler system and battery it is possible to achieve a supply cover factor of over 0.7.