Charged Magazine

Day: September 25, 2020

  • Electric Vehicles: Will EVs make our climate better?

    Electric Vehicles: Will EVs make our climate better?

    Electric vehicles have gained momentum in the recent years due to a considerable percentage of personal vehicle users as well as freight companies that converted from using internal combustion engine vehicles to some type of electric vehicles. Electric vehicles by definition, have at least some electric powerplant that powers the engine particularly or completely by one or more electric motors. This article forces on the environmental impacts of electric vehicles that entirely depend on batteries for storage and delivering  electric power for the motors.

    Plug-in hybrid electric vehicles (PHEVs) are being developed for a decade or so for mass production by the automotive industry by some major automakers. However, the rise of Tesla, the most valued automaker at the moment during the time of writing this article,  have pushed the limit of how an average car user can adopt completely to an all electric car and thereby save the environment from massive carbon footprint resulting from fossil fuels. PHEVs do not use any type of fuel other than battery packs that store and deliver energy. PHEVs have been touted for their potential to reduce the transportation system’s petroleum dependence and greenhouse gas emissions by using off-peak excess electric generation capacity and increasing the vehicle’s energy efficiency. As such, PHEVs are in a massive boom as several other companies have emerged with large financial backings that have pledged to produce EVs to save the environment and to ensure a zero emission transportation system in the future. The burning question is of course: do EVs actually have a significant impact in the improvement of environment?

    The U.S. Department of Energy’s has a Vehicle Technology Program that examines the precompetitive, high-risk research needed to develop the component and infrastructure technologies necessary to enable a full range of affordable cars and light trucks that are expected to reduce the U.S. dependence on imported oil and minimize harmful vehicle emissions, without sacrificing freedom of mobility and freedom of vehicle choice [1]. Although PHEVs are similar to the regular hybrid electric vehicles (HEVs), the battery can be charged using electricity from the grid by being recharged through a wall outlet. In terms of the overall environmental impact, PHEVs not only have direct impact as a result of not burning traditional fuels, but also the battery chemistry, the amount of grid electricity that can be stored in the battery, recycling ability of the raw materials, and the ability to give unused “power back to the grid” could significantly impact the environment. 

    Below is a schematic showing the life-cycle for a typical EV from production to termination of usage. An EV, by its nature of production type as well as type of usage, typically have less carbon footprint in each lifecycle phase compared to that of a fossil fuel burning vehicle.

    It is important to note that while PHEVs offer the potential for significant reduction in the usage of fossil fuel and resulting emissions of greenhouse gases, the actual benefit calculations need to take into account the upstream energy and emissions penalties that are associated with the electricity generation needed to power the charging systems and the load on the grid. Few studies have indeed taken all of these factors into account for certain vehicles that offer a choice of electric or internal combustion engine options for the same model. A study on the well known Volkswagen Golf model showed that, using the latest EU electricity mix, the current Golf TDI (Diesel) emits 140g CO2/km on average over its entire life cycle, while the e-Golf1 reaches 119g CO2/km. Based on the report, most of the emissions occur during the use phase of the internal combustion engine vehicle. Here the diesel reaches 111g CO2/km while a corresponding vehicle with electric drive emits only 62g CO2/km during the same phase [2].

    Key findings about EV and carbon emission

    1. Several european countries where EVs are prevalent have significantly more carbon-intensive power generation – due to reliance on coal plants – EVs still perform better there on a lifecycle basis, which includes the emissions in manufacturing the battery and vehicle. Based on the Polish average, an EV emits 25% less CO2 over its lifetime. In Sweden, which has one of the cleanest energy mixes in the EU, an EV emits 85% less than a diesel car [3]. The figure below shows a summary of the study [3,4].

          EV Climate impact for different Energy Mixes (reproduced from Transport and Environment) 
    2. Replacing a traditional ride-hailing car with an electric vehicle would deliver three times the environmental benefits and emission reductions, according to a new study. The finding comes as a new cost analysis shows that e-vehicles are cheaper to run for Uber drivers in many European cities, and Uber in Portugal says it will only take on new drivers if they have an EV.
    3. Both Uber and Lyft have made recent statements expressing their intention to move towards a totally electric fleet. But now, for the first time, a study has looked at what the environmental impact might be. The study by University of California’s transportation institute, looked at 400,000 journeys made in a battery EV by 1,000 ride-hailing drivers, and compared the impact with 118,668 journeys made in a petrol or diesel car, as well as over 15,000 in a plug-in hybrid EV [5].
    4. The biggest finding is that the potential environmental and emission reduction benefits of replacing a ride-hailing traditional car with an EV are ‘approximately three times higher compared with those of regular vehicle usage in California’, and on emissions alone this was ‘the most pessimistic scenario’. This is because vehicles owned by Uber, Lyft and other ride-hailing drivers are driven more than if they were only used for private use (about 305km on average per day compared to 48km) [5].
    5. Below is a chart based on data from EPA in the US for greenhouse gas emissions by different sectors [9] . Based on the data, it can be seen that transportation sector contributes to a large amount of green house emission. It will be interesting to see the insights about how EVs and PHEVs come into play.
    Share of Greenhouse Gas Emission by Sector

    How to calculate carbon footprint:

    Carbon offsetting funds solutions to reducing carbon emissions now. Frequently carbon offsetting reduces emissions much faster than you can as an individual/single company. Carbon offsetting projects help to combat global climate change as well as caring for local communities. In many instances providing much needed employment, health improvement, biodiversity,  reforestation and broad social benefits to impoverished communities.

    Calculator:

    This free to use online carbon calculator tool is independently audited on an annual basis as part of the Quality Assurance Standard (QAS) for Carbon Offsetting. 

    https://www.carbonfootprint.com/calculator.aspx

    Reference:

      1. Elgowainy, A., Burnham, A., Wang, M., Molburg, J., & Rousseau, A. (2009). Well-to-wheels energy use and greenhouse gas emissions of plug-in hybrid electric vehicles. SAE International Journal of Fuels and Lubricants, 2(1), 627-644.
      2. https://www.lowcvp.org.uk/news,vw-study-shows-co2-benefits-of-evs-over-whole-lifecycle_3946.htm (accessed October 2020)
      3. https://www.transportenvironment.org/press/electric-cars-emit-less-co2-over-their-lifetime-diesels-even-when-powered-dirtiest-electricity (Accessed September 2020)
      4. Messagie, M. (2014). Life cycle analysis of the climate impact of electric vehicles. Journal of Life Cycle Assessment, 2014, 14.
      5. Jenn, A. (2020). Emissions benefits of electric vehicles in Uber and Lyft ride-hailing services. Nature Energy, 5(7), 520-525.
      6. Noori, M., Gardner, S., & Tatari, O. (2015). Electric vehicle cost, emissions, and water footprint in the United States: development of a regional optimization model. Energy, 89, 610-625.
      7. Data from US Dept of energy: https://afdc.energy.gov/data/10347  (annual energy usage impact) (Accessed September 2020)
      8. https://afdc.energy.gov/data/10301  (US HEV sales by model) (Accessed September 2020)
      9. https://afdc.energy.gov/data/10802  (Green house gas emission by economic sector) (Accessed September 2020)
  • The von Neumann Architecture

    The von Neumann Architecture

    The von Neumann Architecture

    Introduction

    Have you ever wondered how your computer works? Who decided that we should use keyboards to tell our devices what to do? And who else later decided that touch screens were cooler much of the time. Much of how we think about computing we currently owe to John von Neumann, who developed the current way of thinking about computers.

    The Von Neumann architecture is a model that was developed in the 1940s by John von Neumann, a physicist and mathematician, who was an early computer researcher. During World War 2, cracking secret codes and the development of nuclear weapons led to an increase in public funding for computer research, as machines could do lots of arithmetic quickly and accurately. Von Neumann would go on to outline a model for building any sort of computer in his The First Draft Report on the EDVAC (the EDVAC being a computer he was working on at the time) that has been the standard for all computing devices since.

    In his model, von Neumann illustrates that a computer should have several main components:

    • Arithmetic Unit
    • Control Unit
    • Memory
    • Input
    • Output

    Flexibility of the Model

    This model is relatively flexible – in his paper, von Neumann mentions that different machines could very well have different capabilities while still being built with all of these components in mind. Computers that use the von Neumann architecture range from very simple (such as the one in your microwave) to the massive supercomputers that have dedicated buildings. The wide scope of computers that fall under the von Neumann model are proof that von Neumann achieved his goal when it came to creating a model that was versatile.

    Components and What They Do

    The control unit, as described by von Neumann, is the part of the computer that keeps track of what is supposed to run when. When you turned on your computer, your PC’s control device (most probably inside of a CPU) queued up the correct start up operations. The purpose of the control unit is to allow a computer to run many different kinds of programs, and switch between them when necessary. While this seems trivial now, the first computers were manually operated. If you wanted a computer to do something different than what it was previously doing, you had to go in and change all of the wires yourself. The conception of a control unit allowed the computer to modify its own hardware and software, allowing a great deal of abstraction for users. Computers being able to modify themselves (and other computers) essentially enables modern computing as we know it, the good (high level programming languages, not swapping about the wires in your desktop) and the bad (it would be impossible to hack a pre-von Neumann computer without performing an elaborate heist operation to change around the wiring yourself).

    The arithmetic unit of a computer does the logical processing. Computers were originally designed for doing lots and lots of math, so von Neumann designated an entire component of his model to do that. Despite being called the arithmetic unit, this unit is also responsible for doing logical operations as well. Arithmetic units allow computers to distinguish if two sequences of binary are completely the same (an AND operation), if some of the numbers are the same, or allowing sign flippage.

    The memory component of this model is probably simplest to understand. If we want computers to do work in a useful capacity, they need to be able to remember what we’ve done. Most modern computers have two types of memory. They’ve got long term, slower memory, which is usually kept in the hard drive. Computers also have faster, short term memory. This is typically stored in RAM. Traditionally, RAM memory has been volatile. This means that it is erased when you turn the power off. This is also why you used to lose everything you did on older video games without saving – if you didn’t tell the computer to move your data out of RAM and onto the hard drive, it was just lost.

    The last components of a computer are its input and output components. Input is just how the user puts instructions into a computer. These days, inputs are most often keyboards and/or touch screens, although speakers are becoming more common. Output is how a computer communicates what it’s doing to the user. Most computers have a visual (a screen) and an audio (speakers and/or headphones) component to the output.

    Conclusion

    The von Neumann model for computing has lasted for nearly a century. Pretty much any device that you use will have been built and designed with the von Neumann architecture in mind. That being said, scientists are looking beyond this model for the future. Quantum computing and other innovations may mean we say good bye to the von Neumann architecture.

    References

    Brandl, M. F. (2017). A Quantum von Neumann Architecture for Large-Scale Quantum Computing. (https://arxiv.org/abs/1702.02583)

    Freiberger, P., & Swaine, M. (2016, November 14). Von Neumann machine. Retrieved September 15, 2020, from https://www.britannica.com/technology/von-Neumann-machine

    von Neumann, J. (1945). First draft of a report on the EDVAC. doi:10.5479/sil.538961.39088011475779