By Stephen Voller, CEO and Founder, ZapGo Ltd.
In the not-too-distant future, many of the world’s megacities – those metropolitan areas with a population of more than 10 million people – will be located in Asia, naturally including India. The viability of the country’s urban transport will be a major concern, and not only must residents be able to move around efficiently but air pollution in these densely populated areas must be minimized as well. It is well known that conventional diesel buses produce a great deal of emissions, and converting them to cleaner fuels such as natural gas does not eliminate the problem entirely. Therefore, the most desirable goal is zero emissions, entailing converting bus fleets to all-electric.
The prospect of all-electric bus fleets, however, presents a challenge. Envision hundreds, or thousands, of buses returning to a single depot at night. How can sufficient energy be supplied to recharge those vehicles simultaneously? With diesel buses, one can maintain diesel pumps and refuel one bus after another. But with an electric fleet, sufficient energy needs to be available to be able to plug multiple vehicles in at the same time. This presents a challenge in areas where the electric grid may not be particularly reliable.
A potential solution to this challenge involves a phenomenon known as ultra-fast charging, in which the prohibitively long charging times encountered with existing batteries for electric vehicles are drastically reduced. One technology that can make this potentially viable is Carbon-Ion™ (C-Ion®) cells, a fast-charging and safe alternative to lithium-ion batteries, the standard energy source for electric vehicles today.
C-Ion cells allow energy to be safely transferred to electric vehicles using extremely fast charging rates. Banks of C-Ion cells can be used to buffer the grid, and very-high-rate direct current chargers could then be connected to the C-Ion banks operating at 350kW, 450kW or even as high as 1,000kW. These DC chargers could be installed at bus depots without the need to install new grid infrastructure. ZapGo Ltd. is already working with utility companies on a grid storage product that would utilize large banks of its C-Ion batteries to provide high rates of charging at locations such as truck stops; bus depots easily could be another type of location where they are set up.
Ultra-fast charging could offer multiple benefits
Municipalities can make money from the Microgrid as a Service (MaaS) or Electrons as a Service (EaaS) model. This involves buying and storing energy at off-peak times, or at night, and selling the electricity during the day at peak times. Clearly this has major benefits when used in conjunction with variable renewal generation systems like wind or solar.
There are several potential benefits to the scenario in which large C-Ion batteries or storage containers are situated at bus depots. As in the MaaS model, these could be filled up at night or during periods where the grid is running reliably; when a bus pulls up, it is then charged from the stored energy on site rather than from the grid directly. This provides significant cost savings because off-peak electricity rates are comparatively lower than peak rates. It also avoids a nightmare scenario in which a multitude of buses require recharging in the middle of a night on which the electric supply is not available.
Separately, as an electric bus is proceeding on its regular route during the day, there will be multiple idling points, such as when the driver is taking a break. Recharging stations can be set up at these break points to minimize inconvenience to the driver and passengers alike. Alternatively, bus companies may opt to “take the charge to the bus.” This would entail placing a C-Ion storage container on the back of a flatbed truck. The container could be charged up at a sub-station with a high-rate grid connection, and subsequently driven to where the bus is – and plugged into it at that point. This would provide a rapid charge so the bus journey is not delayed on its route. Such a mobile energy storage system could provide a reliable and time-efficient method of ensuring the electric bus keeps to its schedule.
A further advantage of ultra-fast charging in general, and the use of C-Ion technology in this regard, relates to the sheer amount of energy required to keep a large fleet of electric buses adequately charged. It can require about one megawatt-hour (1MWh) of energy to charge a bus for a day of use around its various routes. This is the functional equivalent of 8,000 new homes being added to the electrical grid. If 100 buses are all charging simultaneously, it is clear to see just how much stress would be placed on a nation’s grid infrastructure. This challenge is compounded by the fact that the bus must be recharged in as little as five to 15 minutes – a great deal of energy to be transferred rapidly.
Beyond this, the use of ultra-fast charging with C-Ion cells can help avoid the challenges posed by weather extremes in temperate regions such as India; it can get extremely warm in the summer, and extremely cold in the winter, which can negatively impact the operation of certain types of conventional batteries. On top of this, conventional batteries require the use of raw materials such as lithium and cobalt, which are not sourced in India. This is in contrast to the situation with C-Ion; India has some of the most abundant graphite and carbon mines in the world, making sourcing for C-Ion batteries relatively easier.
For these reasons, the move toward all-electric bus fleets in India is not only a good idea; the goal can potentially be achieved with a significant amount of cost savings and efficiency through the use of ultra-fast charging – made possible with burgeoning technologies such as C-Ion. As the world moves toward a more energy-efficient, pollution-free future, it is a scenario well worth closer investigation.
Stephen Voller is CEO and Founder of ZapGo Ltd., the developer of Carbon-Ion™ (C-Ion®) cells, a fast-charging and safe alternative to lithium-ion batteries.