# Analysis of Instantaneous Energy Consumption and Recuperation Based on Measurements from SORT Runs
## 1 Introduction  
Electric buses have become an integral part of public transport systems in recent years [1, 2]. To ensure their optimal implementation by companies using buses in their fleet, appropriate tests are necessary to examine elements such as energy consumption [3], range, battery efficiency and durability in real conditions [4]. Conducting reliable tests is crucialfor fleet operators, manufacturers and decision-makers because they influence the decision-making process [5; 6; 7]. Reliable tests allow the verification of theoretical assumptions and, therefore, enable a reliable assessment of the performance of the given vehicles, as well as to illustrate the potential gains and losses in the operation of the tested vehicles [8; 9; 10]. Moreover, the value of standardised tests, such as the standardised on-road test (SORT), has been highlighted through their role in evaluating vehicle efficiency under real-world conditions. Recent studies have shown that these tests give important information about energy use and recovery. Battery health, driving habits, and road curves can all affect these processes. These studies show how important it is to use standard methods, such as the E-SORTs for electric cars, to obtain more accurate and reliable results [11]. One of the most common tests for vehicles is the standardised on-road test (SORT), which was created by the International Association of Public Transport (UITP). Since 2017, it has included the guidelines for testing electric buses [12]. The standardised on-road test (SORT) was designed to provide comparable results for commercial vehicles in conditions simulating real operations. It consists of three scenarios that differ in driving profile and frequency of stops, considering different types of routes: SORT 1: intensive urban traffic characteristics with a large number of stops; SORT 2: mixed driving conditions, with a moderate number of stops; SORT 3: suburban routes, with a minimum number of stops [13]. Each of these cycles reflects a variety of operating situations, allowing the assessment of the vehicle's energy efficiency in specific conditions [14]. Thanks to standardisation, the SORT also enables the verification of manufacturers' declarations and the comparison of different bus models. Standardisation allows the elimination of variables related to local traffic conditions. The analysis of the energy consumption and recuperation processes of electric buses, carried out using SORTs, is a very relevant topic when seeking to effectively manage resources and reduce operating costs. Scientific studies show that these processes depend on many factors, including route conditions, battery condition, vehicle specifications and infrastructure management strategies. A crucial aspect of advancing sustainable transportation systems involves identifying methods to reduce the noise generated by electric buses. It is essential to consider this when calculating energy consumption. A study in Gothenburg, Sweden, found that switching from diesel-hybrid buses to electric buses cut down on low-frequency noise levels in residential areas by a large amount. This reduction was evident in the third octave frequency bands, although it was not visible in the A-weighted parameter, which may underestimate the impact of metal facades on noise insulation. This means that, when using SORTs, it is necessary to take into account specific environmental parameters and measurement methodologies that can affect energy consumption and regeneration processes [15]. Implementing effective noise reducing strategies can also be an indicator of enhanced energy efficiency and optimal energy recovery in electric buses. Proper route planning is also a key factor in optimizing the energy consumption of electric buses. A study on an electric bus rapid transit system (EBRTS) showed that proper route planning can reduce the load on local power grids, ensure competitive ticket prices and provide an attractive return on investment.