RED WoLF: Combining a battery and thermal energy reservoirs as a hybrid storage system

Abstract

Energy consumption of households is not evenly distributed. To satisfy peak demand, additional CO 2 intensive generators are turned on when demand peaks. To avoid peak demand from dwellings, the RED WoLF (Rethink Electricity Distribution Without Load Following) hybrid storage system is proposed, consisting of batteries, storage heaters and a water cylinder. This aims at avoiding the use of these peak generators and integrating a higher share of renewables on the Power Grid. This system is planned to be tested in 100 houses distributed in 6 pilot sites in Great Britain, Ireland and France, which are currently undergoing construction or refurbishment. This study presents the theoretical model of the controlling algorithm, which enables the uptake of Grid electricity only when CO 2 intensity is below a dynamically computed threshold. The algorithm is tested in computer simulations over the four seasons with varying size of batteries and photovoltaic arrays. Results show how RED WoLF algorithm satisfies households demands while, at the same time, successfully avoiding domestic peak demand, with a significant drop of CO 2 emissions. This is achieved by both increasing photovoltaic self-consumption and uptake of low carbon Grid energy. For example, with a 7 kWh battery and a 4 kW photovoltaic array, CO 2 emissions drop by 30% to almost 100%, depending on the season, relative to the same house without the RED WoLF system. The system has the potential to shift residential demand from peak power/peak times to low value electricity at a time of low demand.

RED WoLF hybrid storage system: Adaptation of algorithm and analysis of performance in residential dwellings

“…However, as such system has not being tried to be implemented before, these results could provide sufficiently good estimates of systems performance and guarantees safety before it could be tested in pilot sites that would be occupied with residents. Similarly to [31], we assume that power flow in each minute is different to the one predicted by adding white noise to historical one. Such a process allows to present the system stability.…”

“…The basic RED WoLF system [31] is an important step towards a more sustainable future. Achieving carbon emission reduction secures a more lively environment, and changes the direction our society is heading in.…”

“…In this manuscript we expand the idea of progressive threshold approach described in [31] and employed for systems equipped with battery only in [35].…”

“…In order to simulate the performance of the system we take PV power generation and appliance consumption from [36] and [37], respectively. These data was previously used in [38] and [31]. We should note that [37] data were detrended from seasonal effects, which may contribute to heating and normalised to 5 MWh annual consumption for electric appliance in the UK and France in accordance to [39].…”

“…Depending on their storage meth-ods the systems can be divided into 4 groups with mechanic, electrochemical, electromagnetic and phase change energy storage modes [27,28,29,30]. One such system is the RED WoLF Hybrid Storage System (HSS) first mentioned in [31]. The system consists of smart coupling of the SHs, a DHW Cylinder, a battery and a PV array.…”