System monitoring.
-
The sensor system consists of several different sensors that have the task of collecting data from the vehicle’s environment in real time. The data collected via the sensors are used for perception, route planning, obstacle distance calculation, or navigation. AVs have short, medium, and long-range sensors such as ultrasonic sensors, capacitive sensors, infrared sensors, lidar, radar, global positioning systems (GPSs), etc.
[30,31,32,33,34,35][28][29][30][31][32][33].
The development of AVs is a rapidly growing field that holds great promise for the future of transportation. However, navigating these vehicles in complex and unconventional scenarios is still a major challenge. The most difficult scenarios for AV algorithms, as well as human drivers, to react to were found to be harsh weather conditions, unsignalized intersections, traversing crosswalks, navigating roundabouts, and near-accident situations
[36][34].
The primary objective of autonomous cars is to mitigate accidents and human errors, thus enhancing road safety. However, several unresolved challenges persist in developing AVs. The software and system requirements are among the aspects that demand consideration in vehicle creation. While these aspects hold minimal significance in traditional vehicles, self-driving cars can potentially trigger damage, accidents, and diminished safety. Numerous challenges have arisen in this realm, primarily stemming from the intricacies of system design and the critical demands of data collection at the network level, which subsequently inform decision-making processes
[37][35].
Automotive manufacturers and policymakers seek new solutions in managing data and connectivity, ensuring robust infrastructure to support AVs, vehicle updates and maintenance, and post-production and post-deployment services. The concerns and growing challenges remain unabated, and global societal voices call for industry engagement and collaboration on new technologies and strategies, as well as understanding the impacts of the transformation to mobility-as-a-service (MaaS) and robotaxi services
[38][36].
2.5. Differences between EVs/AVs and Conventional Vehicles
EVs/AVs offer several advantages over conventional vehicles (CVs) that use petrol or diesel, especially when it comes to emissions, noise emissions, non-renewable energy consumption, and maintenance costs. Nevertheless, intelligent vehicles are equipped with advanced sensors, controllers, and actuators in combination with connecting communication technologies compared with CVs, for which the energy will definitely increase
[39][37]. On the contrary, EVs/AVs cause zero emissions during operation. Certainly, when it comes to the stopping phase, they also emit particles from tires and the friction elements of the braking system.
The production of EVs’/AVs’ batteries and their subsequent disposal after decommissioning pollute the environment, but this pollution is easier to control in relation to the emission of harmful substances from CVs. The complete supply chain of CVs with petrol or diesel pollutes the environment.
EVs’/AVs‘ and CVs’ powertrains are fundamentally different, and due to their external characteristics (i.e., depending on the torque and/or power of the output shaft on the number of revolutions), electric motors are more practical to use. This results in EVs/AVs‘ utilizing over 85% of the energy invested in their operation.
To start CVs, it is necessary to ensure the start of the internal combustion engine with a low speed and low torque on the engine’s flywheel. Unlike CVs, high torque can be transmitted to the motor shaft at start-up for EVs/AVs. Because of this, EVs/AVs do not need a mechanical power transmission to change gears.
EVs/AVs in the braking phase can accumulate (recover) energy. The recovery of energy is especially noticeable when moving on sections of the road that are falling and the brake is often used, and also in city driving, because the start-stop phases are often changed.
CVs are more convenient to use than EVs/AVs when it comes to the radius of movement. EVs/AVs still have a limited range and depend primarily on battery capacity. Due to the large presence of electronics within the vehicle, EVs/AVs have significantly higher energy consumption compared to CVs
[40][38]. With the level of vehicle autonomy, the carbon footprint increases
[39][37].
2.6. Carbon Footprint of the Additional Hardware of EVs and AVs
The comfort and safety elements of classic vehicles have a great impact on carbon footprints and, therefore, on the economy. To measure their implication, it must be considered that 100 watts typically corresponds to fuel consumption of 0.1 L every 100 km. For a journey time of 1 h, the power consumption is equivalent to 100 Wh, and the carbon footprint (carbon footprint vs. power consumption, available at
www.ceroco2.org/calculadoras/ (accessed on 7 November 2023)) is 0.03 kg of CO
2 emitted into the atmosphere. Taking as a reference the annual average price of CO
2 emission rights according to the European Trading Scheme (European CO
2 trading system, available at
www.sendeco2.com/es/ (accessed on 7 November 2023)) (ETS), this equates to a monetary cost of ~2.44€ (81.34€, according to the spot price calculated on 15 September 2023 using EU allocations). In this sense,
Table 1 shows the carbon footprint of some typical components aboard traditional vehicles.
Table 1.
Carbon footprints of some typical components aboard classic vehicles.
][39]. The latest cars equipped with cameras and radars typically generate ~12 GB of data every minute. Processing these images requires a lot of computing power, whose consumption can reach around 2500 watts in some prototypes, enough to power 40 incandescent light bulbs. From
Table 4, this results in 750 g of CO
2 emissions with a cost of 61.00€ every 100 km. As another example, the GM Cruise AV is equipped with 5 lidars, 16 cameras, and 21 radars. This results in ~7200 watts or 2.15 Kg of CO
2 emissions with a cost of 174.88€ every 100 km.
Table 3.
Carbon footprints of some typical components aboard modern vehicles.
Table 2 shows the battery packs used in current EVs and the impact of power consumption on autonomy and carbon footprints. Note that CO
2 emissions are measured in grams per every 100 km traveled, according to the EU Energy Label.
Table 2.
Carbon footprints of the current main EVs.
Modern EV/CVs are considered networks on wheels—in practice—as they are more connected to the internet, whose evolution of AVs will make them true data centers on the road
[39][37]. While PC gaming and smartphones currently increase RAM memory by up to 16 GB and 18 GB, respectively, the resource requirements of vehicles to meet Level 3 driving capabilities in 2022 were expected to reach 140 GB of RAM and 1 TB of internal storage. The consequence was that advanced driver assistance systems (ADAS) consume a considerable amount of energy and put a strain on batteries.
For further analysis,
Table 3 shows the carbon footprint of some typical components aboard modern vehicles
[41
Table 4.
Carbon footprints at different levels of intelligence.
According to a study
[41][39], it can be inferred that an average intelligence level dramatically increases the carbon footprint to 468 g of CO
2 every 100 km (i.e., 38.07€). Similarly, the carbon footprint of a basic intelligence car increases by 780 watts/100 km compared with classic vehicles, whilst the footprint of an advanced intelligence car increases by 1860 watts/100 km. In sum, the carbon footprint increases as the autonomous driving capability increases, with the automation function being the main cause and the connection function being the second one (
Table 4).
Hopefully, the future will be promising, and manufacturers such as, e.g., Nvidia, Intel, Qualcomm, and Tesla, are directing their efforts to decrease the size of in-vehicle electronics and reduce massive electrical consumption by developing low-power chips optimized for AVs. For example, Nvidia has designed a new processor called Xavier based on an octa-core CPU, a 512-core GPU, a deep learning accelerator, computer vision accelerators, and 8 K video processors with just 30 watts. Thus, fully autonomous driving could be a reality with only two processors and two dedicated GPUs—to ensure vehicle safety through the redundancy of the computing platform—with an acceptable power consumption of 500 watts and 150 g of CO
2 emissions every 100 km
[40][38].
Moreover, there is also a significant demand for solutions to move the intelligence aboard vehicles to remote intelligence in cloud computing systems. Remote intelligence will increase the management of AVs and their systems, increase computing capacity without requiring excessive hardware growth in cars, dramatically reduce the cost of on-board electronics and their carbon footprint, as well as allow greater synergy between the system control functions and online services. Addressing latency challenges is among the current priorities of both researchers and manufacturers. To this end, manufacturers are currently investigating distributed platforms for automotive services with real-time cloud access, thus making vehicles part of an intelligent transportation system (ITS)
[42][40]. This is the case of REMOTIS, a remote intelligence system for cars capable of connecting to a server and transferring all the information from their sensors to carry out critical driving functions remotely through a 5G infrastructure (
https://www.youtube.com/watch?v=uQk1kljyXZ4 (accessed on 7 November 2023)).
2.7. Implementation of Additive Manufacturing in EVs/AVs
A very important part of creating harmony between the accelerated technological development of EVs/AVs and the environment is the implementation of additive manufacturing (AM) and the usage of recyclable materials in 3D-printed automotive parts. AM, popularly called 3D printing, is the process of building a physical object using modeling data, and it represents one of the most revolutionary technologies of this era.
The first idea connected to creating this technology came from the last century and was based on the simultaneous photography of an object from different angles using 24 cameras while making a 3D model
[43][41]. This technology has facilitated the classical mass production of 3D-printed items and parts, a process that encompasses product design, involving iterative collaboration between production engineers and designers, optimization, production analysis, printing modules, post-production, and more
[44][42]. The benefit of additive manufacturing compared to classical manufacturing is that it applies a trial-and-error technique, which allows a designer to print a model and use it in practice without suffering any losses (other than filament losses). If a model does not operate as expected, the designer can make any necessary corrections until it performs all the desired functions.
The most important implementation of 3D printing has been in the areas of automotive manufacturing, medicine, architecture, art, design, and lately, even food
[45][43]. Moreover, due to advances in 3D printer technology, the market for 3D printing has recently experienced some of the manufacturing sector’s fastest growth. Especially after the outbreak of the COVID-19 pandemic, the 3D printing of protective equipment (e.g., face shields, masks, and bracelets) was essential for the whole world, and both freelancers and academics did their best to design such equipment
[46,47][44][45].
In 2009, the company MakerBot produced so-called “desktop” 3D printers, which were used for people to perform 3D modeling and printing at home
[48][46]. Today, MakerBot’s printer is sold as a kit that users assemble into a finished printer. The MakerBot company also created the first online library (i.e., Thingiverse) where files that can be 3D-printed and downloaded for EVs/AVs can also be found, and which is becoming the largest online community in the world concerning 3D printing
[49][47].
Today, there are several types of 3D printing machines or techniques, depending on the size, complexity, and scale of the product. The way an object is produced differs, depending on the type of printer used. There are many types of 3D printers, and their classification can be achieved according to several criteria: technology, materials, and purposes
[50][48]. To produce EVs/AVs, industrial 3D printers are mainly used and specifically designed for these applications. While price is an important factor, the real key differentiators are the specifications, performance, features, and functions offered by each industrial 3D printer, such as the following: the ability to work with materials of high performance and engineering quality; the possession of a large, actively heated chamber for building objects; a high printing speed, which equals high productivity; precision and the accuracy of dimensions; repeatability and reproducibility; operator safety, monitoring and productivity; and an open platform with certified materials.
According to a report from 2017 with the greatest emphasis on the analysis of countries in Europe and their users, the most commonly used materials for 3D printing are still polymer-based (plastic materials)—as much as 88%
[51][49]. Resin is the second-most-used material with characteristics of high resistance and strength. Of the metal materials that are in third place, both pure metal powders and alloys are used, most often stainless steel and alloys of aluminum, chromium, cobalt, nickel, etc. Apart from the mentioned materials, various types of ceramic powders based on zinc or aluminum can be used, then come powders based on gypsum, cellulose, various types of sand powders, biocompatible powders, etc. Precisely in the last few years has the increasing consumption of these materials has been observed
[52][50].
The automotive industry is the fastest-growing vertical using AM; therefore, the EV/AV market represents a great fit for AM as a production process. Many companies, instead of traditional plastic-injection-molding processes, choose cost-effective 3D printing processes, especially if they need fewer than 50,000 parts a year. Nowadays, manufacturers face low production volumes and highly uncertain demand. That is why automakers ranging from Ford and Volkswagen, along with startups such as Arash Motor Co. and Rivian, are investing highly in AM technology. The adoption of 3D printing in EV/AV manufacturing processes offers a multifaceted approach to environmental sustainability, including circular economy principles and energy optimization. For instance, 3D printing has potential in the circular economy of plastic components at the end of the lives of vehicles, offering opportunities for recycling and the decentralization of supply chains
[53][51]. Additionally, 3D printing has demonstrated substantial energy savings through selective laser sintering (SLS) in the automotive and aircraft industries
[54][52]. Other factors attributable to 3D printing in the broader industry (e.g., material efficiency, lightweighting, and customization or localized production) may also contribute to reducing the carbon footprint associated with the manufacturing processes of EVs/AVs, fostering environmental sustainability while enhancing economic viability.
On average, EVs/AVs could incorporate between 50 and 200 3D-printed parts (e.g., interior components, support parts, and prototype/tests, as well as custom components for sensor systems and autonomous technology). When the average values from
Table 5 are employed, the cumulative effect suggests an overall conservative reduction of approximately 60% in the carbon footprint. This assessment serves as a simplified estimation, and real-world impacts may significantly fluctuate, contingent upon the circumstances of each production process and vehicle model (i.e., more advanced and customized vehicles may have a greater number of 3D-printed parts, while more conventional models may have fewer). Furthermore, continued advancements in technology and materials hold the potential to further amplify these benefits over time.
Table 5.
Estimation of carbon footprint reduction through 3D printing in EVs/AVs.