Evaluating electricity self-consumption in different renewable energy supply conditions

Abstract

The aim of this article is to detect energy storage problems in dwelling buildings with PV panels and wind generator based electrical energy supply. The focus of the research is to maximise the yield of energy consumed on-site utilising two water heater boilers with equal volumes as energy storage devices and consumption in household devices as white goods, lighting, etc. Energy output from fluctuating sources like PV panels and wind generators is divided by a desired horizontal shaving level on the production curve, separating peaks and stable production. Energy peaks are fed to a pre-heating water boiler and the main part of energy below the shaving level is used in the main boiler and consumption of household devices, maintaining the equalised balance of produced and utilised energy. The observational period is one year with 5-minute averaged data points. Wind generator energy output is calculated according to three different wind conditions, evaluating self-consumption, while retaining PV panel yield on the same level. The produced solar and wind energy ratio is 30 %/70 %. The compared wind conditions result in a capacity factor of 0.055 in the worst case and up to 0.273 in better conditions, while the cover factor increased from 0.6 up to 0.68. If the energy demand is the same, the needed rated capacity of the wind generator can be 5 times smaller in the best conditions.