An integrated PV system analysis tool for households incorporating battery storage, energy-efficiency measures and electric car charging

Panel: 2. What's next in energy policy?

This is a peer-reviewed paper.

Authors:
Sebastian Albert-Seifried, Büro Ö-quadrat GmbH, Germany
Vicky Albert-Seifried, Büro Ö-quadrat GmbH, Germany
Dieter Seifried, Büro Ö-quadrat GmbH, Germany

Abstract

Residential sector has been a key driver for photovoltaics (PV) applications in Germany. Over 80% of new PV systems installed in 2017 were smaller than 10 kWp and every second newly installed residential PV system was combined with a battery. The investment decision on PV installations is largely based on analysis of solar potential and collector area.

The role of energy efficiency measures and its effects on the costs and CO2 emissions are rarely considered. Additionally, battery electric vehicles (BEVs) that exhibit significant growth in recent years are expected to have a profound influence on the energy system in the future. However, their impact on the CO2 footprint of households is not fully understood. In view of these shortfalls, an integrated energy analysis tool has been developed to enable calculations of the economic performance and carbon balance of PV installation with battery storage, energy-saving measures and BEV charging. The Excel-based tool was developed in collaboration with the Öko-Institut and a local utility. It is publicly available and intended for energy consultants and interested households.

Using a typical 3-person household in Germany as an example, an analysis over 15 years shows that the implementation of energy-saving measures at the time of PV installation can reduce the overall costs and increase the internal rate of return. The application of PV-battery systems is not profitable with the current system price of about 1500€/kWh. Nevertheless, considering the current rate of decline in battery costs, it is anticipated that solar battery systems will become cost-effective in the coming years. In contrast to the common belief, the use of BEVs leads to an increase in CO2 emissions compared to conventional gas-powered cars. BEVs can reduce the carbon footprint only if they are coupled with a PV system. The full paper will present the energy analysis tool and results of various scenarios that will shed light on future energy policies.