Improving the Power Outage Resilience of Buildings with Solar PV through the Use of Battery Systems and EV Energy Storage

Buildings with solar photovoltaic (PV) generation and a stationary battery energy storage system (BESS) may self-sustain an uninterrupted full-level electricity supply during power outages. The duration of off-grid operation is dependent on the time of the power fault and the capabilities of the home energy management system (HEMS). In this paper, building resilience is quantified by analyzing the self-sustainment duration for all possible power outages throughout an entire year. An evaluation method is proposed and exercised on a reference house in California climate zone 9 for which the detailed electricity usage is simulated using the EnergyPlus software. The influence of factors such as energy use behavioral patterns, energy storage capacity from the BESS, and an electric vehicle (EV) battery on the building resilience is evaluated. Varying combinations of energy storage and controllable loads are studied for optimally improved resilience based on user preferences. It is shown that for the target home and region with a solar PV system of 7.2 kW, a BESS with a capacity of 11 kWh, and an EV with a battery of 80 kWh permanently connected to the home, off-grid self-sustained full operation is guaranteed for at least 72 h

Future trajectories of renewable energy consumption in the European Union

Renewable energy sources (RESs) are able to reduce the European Union (EU)’s dependence on foreign energy imports, also meeting sustainable objectives to tackle climate change and to enhance economic opportunities. Energy management requires a quantitative analysis and the European Commission follows the performance of each Member State (MS) in order to define the corrective measures towards 2020 targets. Starting from historical data reported in the Eurostat database and through a mathematical model, this work proposes future trajectories towards 2020 of the share of energy from renewables (REs) in terms of gross final energy consumption (GFEC). Furthermore, a quantitative analysis based on two indices—(i) the share of REs in GFEC, and (ii) gross final renewable energy consumption (GFREC) per capita—permits a comparison among 28 MSs. The share of REs in GFEC in EU 28 varies from 19.4% to 21.8% in future trajectories towards 2020. Sweden and Finland occupy the top part of the ranking, while six MSs (Belgium, France, Ireland, Luxembourg, The Netherlands, and the United Kingdom) are not able to reach the 2020 targets

Developing vanadium redox flow technology on a 9-kW 26-kWh industrial scale test facility: Design review and early experiments

Redox Flow Batteries (RFBs) have a strong potential for future stationary storage, in view of the rapid expansion of renewable energy sources and smart grids. Their development and future success largely depend on the research on new materials, namely electrolytic solutions, membranes and electrodes, which is typically conduced on small single cells. A vast literature on these topics already exists. However, also the technological development plays a fundamental role in view of the successful application of RFBs in large plants. Despite that, very little research is reported in literature on the technology of large RFB systems. This paper presents the design, construction and early operation of a vanadium redox flow battery test facility of industrial size, dubbed IS-VRFB, where such technologies are developed and tested. In early experiments a peak power of 8.9 kW has been achieved with a stack specific power of 77Wkg−1. The maximum tested current density of 635 mA cm−2 has been reached with a cell voltage of 0.5 V, indicating that higher values can be obtained. The test facility is ready to be complemented with advanced diagnostic devices, including multichannel electrochemical impedance spectroscopy for studying aging and discrepancies in the cell behaviors

SEEV4-City Policy Recommendations

These policy recommendations were developed based on experiences and lessons from the Smart, clean Energy and Electric Vehicles (EVs) for the City (SEEV4-City) project. The SEEV4-City project, funded by the EU’s Interreg North Sea Region (NSR) Programme, aimed to demonstrate integrated electric mobility solutions with renewable energy in a local and central electricity grid decarbonisation context, and encourage their uptake at local, national and transnational levels. The policy recommendations were developed in consultation with relevant public and private stakeholders, including but not limited to those involved in the six Operational Pilots across four NSR countries implementing combinations of Smart Charging and V2X technology at different scales and levels. SEEV4-City identified the need for a policy framework that combines largely disconnected planning and policy domains, processes and tools across energy, climate change mitigation and transport/mobility. The SEEV4-City partners, include the Operational Pilot’s local and regional public authorities, universities and non-for-profit consultancy organisations as well as Europe-wide networks in electromobility and representative of cities and regions implementing innovative transport solutions. These partners worked through the current status of planning framework/guidance and plans to identify progress made already and still needed at different levels for the effective integration of the domains of mobility, energy and climate change mitigation. The SEEV4-City project has accordingly developed, and verified with stakeholders through a Webinar in June 2020, a set of policy recommendations at different levels (European/EU, national, local and regional) and for different actors identified in this document

Final report – Johan Cruijff ArenA Operational Pilot: Johan Cruijff ArenA Case Study

The Johan Cruijff ArenA (JC ArenA) is a big events location in Amsterdam, where national and international football matches, concerts and music festivals take place for up to 68,000 visitors. The JC ArenA is already one of the most sustainable, multi-functional stadia in the world and is realizing even more inspiring smart energy solutions for the venue, it’s visitors and neighbourhood. The JC ArenA presents a complex testbed for innovative energy services, with a consumption of electricity comparable to a district of 2700 households. Thanks to the 1 MWp solar installation on the roof of the venue, the JC ArenA already produces around 8% of the electricity it needs, the rest is by certified regional wind energy. Within the Seev4-City project the JC ArenA has invested in a 3 MW/2.8 MWh battery energy storage system, 14 EV charging stations and one V2G charging unit. The plan was to construct the 2.8 MWh battery with 148 2nd life electric car batteries, but at the moment of realisation there were not enough 2nd life EV batteries available, so 40% is 2nd life. The JC ArenA experienced compatibility issues installing a mix of new and second-life batteries. Balancing the second-life batteries with the new batteries proved far more difficult than expected because an older battery is acting different compared to new batteries. The EV-based battery energy storage system is unique in that it combines for the first time several applications and services in parallel. Main use is for grid services like Frequency Containment Reserve, along with peak shaving, back-up services, V2G support and optimization of PV integration. By integrating the solar panels, the energy storage system and the (bi-directional) EV chargers electric vehicles can power events and be charged with clean energy through the JC ArenA’s Energy Services. These and other experiences and results can serve as a development model for other stadiums worldwide and for use of 2nd life EV batteries. The results of the Seev4-City project are also given in three Key Performance Indicators (KPI): reduction of CO2-emission, increase of energy autonomy and reduction in peak demand. The results for the JC ArenA are summarised in the table below. The year 2017 is taken as reference, as most data is available for this year. The CO2 reductions are far above target thanks to the use of the battery energy storage system for FCR services, as this saves on the use of fossil energy by fossil power plants. Some smaller savings are by replacement of ICE by EV. Energy autonomy is increased by better spreading of the PV generated, over 6 instead of 4 of the 10 transformers of the JC ArenA, so less PV is going to the public grid. A peak reduction of 0.3 MW (10%) is possible by optimal use of the battery energy storage system during the main events with the highest electricity demand

Autonomous Operation of Stationary Battery Energy Storage Systems—Optimal Storage Design and Economic Potential

Global warming requires a changeover from fossil fuel based to renewable energy sources on the electrical supply side and electrification of the demand side. Due to the transient nature of renewables and fluctuating demand, buffer capacities are necessary to compensate for supply/demand imbalances. Battery energy storage systems are promising. However, the initial costs are high. Repurposing electric vehicle batteries can reduce initial costs. Further, storage design optimization could significantly improve costs. Therefore, a battery control algorithm was developed, and a simulation study was performed to identify the optimal storage design and its economic potential. The algorithm used is based on autonomous (on-site) optimization, which relies on an incentive determining the operation mode (charge, discharge, or idle). The incentive used was the historic day-ahead stock market price for electricity, and the resulting potential economic gains for different European countries were compared for the years 2015–2019. This showed that there is a correlation between economic gain, optimal storage design (capacity-to-power ratio), and the mean standard deviation, as well as the mean relative change of the different day-ahead prices. Low yearly mean standard deviations of about 0.5 Euro Cents per kWh battery capacity lead to yearly earnings of about 1 €/kWh, deviations of 1 Euro Cent to 10 €/kWh, and deviations of 2 Euro Cents to 20 €/kWh. Small yearly mean relative changes, lower than 5%, lead to capacity-to-power ratios greater than 3, relative changes around 10% to an optimal capacity-to-power between 1.5 and 3, and for relative changes greater than 10% to an optimal capacity-to-power ratios of 1. While in countries like the United Kingdom, high potential earnings are expected, the economic prospective in countries like Norway is low due to limited day-ahead price performance.publishedVersio

Balancing responsibilities:Effects of growth of variable renewable energy, storage, and undue grid interaction

Electrical energy storage is often proposed as a solution for the mismatch between supply patterns of variable renewable electricity sources and electricity demand patterns. However, effectiveness and usefulness of storage may vary under different circumstances. This study provides an abstract perspective on the merits of electrical energy storage integrated with decentralized supply systems consisting of solar PV and wind power in a mesolevel, residential sector context. We used a balancing model to couple demand and supply patterns based on Dutch weather data and assess the resultant loads given various scenarios. Our model results highlight differences in storage effectiveness for solar PV and wind power, and strong diminishing-returns effects. Small storage capacities can be functional in reducing surpluses in overdimensioned supply systems and shortages in under-dimensioned supply systems. However, full elimination of imbalance requires substantial storage capacities. The overall potential of storage to mitigate imbalance of variable renewable energy is limited. Integration of storage in local supply systems may have self-sufficiency and cost-effectiveness benefits for prosumers but may have additional peak load disadvantages for grid operators. Adequate policy measures beyond current curtailment strategies are required to ensure proper distribution of benefits and responsibilities associated with variable renewable energy and storage

A Real Multitechnology Microgrid in Venice: A Design Review

Electrical grids are evolving rapidly toward smart, self-regulating systems capable of managing distributed generation from intermittent renewable sources. Apart from hydroelectric, the large majority of them are photovoltaic (PV) systems grasping the fluctuating solar radiation and wind turbines (WT) capturing fickle wind energy, but other sources, which are at different stages of development, also generate energy with predictable or unpredictable intermittency. Several investigations have highlighted that, when power production from intermittent sources exceeds 20% of the total generation, the grid may face instabilities that can evolve into blackouts. Energy storage (ES) is a measure to balance source-load mismatches and to avoid such occurrence, but it can also provide a number of additional services which are part of the smart-grid paradigm. The operation of energy storage systems (ESSs) depends on the interface converters that manage the power flow and on the supervisors that control them according to the ESS, grid, and load features. Furthermore, the transmission system operator (TSO) may impose constraints on the ESS operation such as the obligation of contributing to primary regulation. Several numerical analyses have been developed to investigate the behavior of electrical grids provided with energy generation from renewable sources and energy storage, either islanded or connected to the national/transnational grid (macrogrid)