The energy footprint of automotive electronic sensors

Abstract

Information and communication technologies (ICT) have emerged as one of the leading technologies to reduce global emissions, particularly in the mobility sector. Automotive electronics, such as sensors/actuators and microcontrollers (commonly known as electronic control units (ECU) which control one or more of the electrical systems or subsystems in a vehicle), play a key role in ICT. Sensors/actuators are key in electronic ICT devices, starting with the data collection and data communication with the internet. The latest two big trends of electrification and automation in vehicles, are projected to increase the use of worldwide automotive sensors from 7.5 billion units in 2017 to 11.0 billion units by the year 2024. A representative state-of-the art automotive sensor system, (i.e., an ultrasonic backup system), including the ECUs controlling the vehicle electrical systems/subsystems, has been considered to estimate the energy footprint in terms of manufacturing and operational energy of global automotive sensors use. A widely used life cycle energy assessment method (i.e., cumulative energy demand) was used as both direct and indirect (including the extraction, manufacturing, and disposal of the raw and auxiliary materials) energy use can be considered for the energy footprint estimation. The embodied manufacturing energy impacts of the system was estimated to be 559 MJ/system, compared to the 417 MJ/system for lifetime system power and additional gasoline use. The share of purchased energy to the embodied energy where the upstream energy isn't included in the former case, is less than 10% and ~ 85% for the component manufacturing and vehicle operation energy uses, respectively. As the purpose of this ultrasonic backup system is to prevent rear crashes, an estimated 1.0 MJ/system is avoided from reduced lifetime vehicular repairs (from an estimated 11% chance of requiring a rear bumper replacement). While all of this is small compared to the overall automotive manufacturing and use energy, the 11 billion automotive sensors expected to be produced in 2024 could require 1540 PJ for manufacturing and those sensors would require an additional 780–1150 PJ for lifetime energy use.

Introduction

Information and Communication Technology (ICT) development has spurred a growth in a sector-wide connected economy, with the creation of a tremendous value through the technology-enabled links between people, machines, and organizations. There are more than 31 billion global connected devices in 2018, of which 928 million devices are in automotive and transportation, with an anticipated growth of 21.4% Compound Annual Growth Rate (CAGR) during the 2013–2030 period [1]. It is projected that ICT can enable a 20% reduction of global CO₂e emissions by 2030, holding emissions at 2015 levels through improved efficiencies, lower use of resources, and behavior changes [2]. Sensors/actuators are the key ICT electronic components for the initial stage of data collection and data exchange to the internet through other major electronic components of an Internet-of-Things (IoT) electronic device such as input/output module and controller in a connected economy [3]. Worldwide trends toward a more connected economy (such as connected or automated vehicles) are projected to increase energy consumption from the manufacturing and operation of connected IoT devices. Conversely, the growing availability of established and new services on single platforms or devices in addition to the availability of more efficient electronic devices may dampen this increasing energy consumption trend. A 2016 Swedish study on the energy and carbon footprint for the ICT sector (defined as all but ICT electronic devices used in the entertainment & media sector) indicates both footprints had peaked around 2010 and then started to decrease, despite growing number of usage (data traffic) [4].

A sensor is an electronic device that converts a physical or chemical stimulus into an electrical signal. That electrical signal is processed by an integrated circuit or microprocessor, transforming it into usable information for another system, such as an electronic control unit (ECU) and from there, an actuator, which can act and perform a function (e.g., turn on an alarm or open a window). The total global sensor market was $102 billion USD in 2015, and is expected to almost double in 6 years [4]. By end-use, consumer electronics is the top market, followed by the automotive industry. The automotive sensor market represents about one-quarter of the global sensor market [4] [5]. Within this, engine and drivetrain sensors dominates the market but safety and security related sensors have the highest growth [6]. Bosch and Denso were the main actors in the 2013 market with more than 25% market share [6]. Growth in 2015 was led by the IoT, though industry automation will be the top driver by 2022 [7].

Based on market projections, the global automotive sensors market is expected to register a CAGR close to 8% during the forecast period, 2018 to 2023, with total unit sales reaching 11.7 billion by 2023 [8]. The increasing demand for safety and security in the automobiles is the main factor that is playing a vital role for the growth of this market. The two big current trends for vehicles are electrification and automation; there is rapid integration of high value sensing modules like radio detection and ranging (RADAR), imaging, and light detection and ranging (LiDAR) in automotive systems. The adoption of electric vehicles will greatly change the amount and the sensor types, with increased emphasis on position, speed, temperature and pressure within the car, in the long term. Increasing demands for more vehicle infotainment (entertainment and informative features such as video players and GPS) and safety features (e.g., backup cameras and sensors) have also resulted in an increase in vehicle electronics (both sensors and ECUs). These new components account for about 30%–35% of the total cost of a vehicle, and are expected to reach 50% by 2030 [9,10]. The manufacturing of the microcontrollers (ECUs) for these new electronics will increase the total energy of vehicle manufacturing; however, electronics are more than just the microcontrollers. Electronics wiring has added 45–65 pounds to vehicles [11], which likely have significant manufacturing and use phase energy contribution. Overall, the number of sensors in vehicles is increasing each year, with more in higher class vehicles (a premium vehicle has more sensors than an economy class vehicle) [12]. Fig. 1 shows the increase in both sensors and ECUs in vehicles over time and over vehicle class: Economy (E); Premium or Luxury (P); and Standard (S). This paper focuses on automotive sensors, but the analysis also includes the energy impact of the ECUs and wiring required for a full sensor system.