It's very encouraging to see someone trying to build this paradoxical problem. Because it's high time.
This is my attempt to articulate charging needs if I were to buy an EV. Being an engineer, I love to put numbers on my thoughts. So here it goes.
The same thought pattern will apply to EV. But a couple of issues make it a bit trickier. Charging infrastructure is not as widespread. And the range can change with the use of A/C and stop-n-go traffic. So there is some added concern, a.k.a. range anxiety.
Let's walk in EV shoes. If I am driving an EV with a range of 100 km, then until 65 km or so, I don't worry about charging. I will be in 'comfort zone'. At about 65 km I will start thinking about charging. Considering the range anxiety I have, I will start keeping an eye on charging options at this point. So it's within that 65 to 85 km span that I need to find my charger but I am not overly worried. Let's call this span 'comfort charging zone'.
At 85 km or so, I will stop where I am going and make finding charger my first priority. The span from 85km to 95 km is 'anxious charging zone'. I am trying to find charger.
From 95 km to my car is dead, it's 'Panic charging zone'. I am not even sure whether I can drive to nearest charger even if you tell me turn by turn directions. Because I am stressed and might make mistakes. It might be risky if it's night. I will never plan to be in this zone. If I am in this zone, it's because something has happened that has screwed up my plans big time.
I have different needs in different zones and I want my charging infra to fulfill all the needs. In case I end up in 'anxious charging zone', or 'panic charging zone', I want the charging infra to get me back to 'comfort charging zones' as quickly and painlessly as possible. This is the 'objective' of this system design problem.
What I need in 'comfort zone'? -
I am happy driving my EV in comfort zone. All I need to know is there are chargers available around the time I will reach my 'comfort charging zone'. An EV app showing charging options, highlighting the options close to my comfort charging zone, is enough.
What do I need in 'comfort charging zone'? -
'Comfort charging zone' is when I know that when 35 km to 15 km range is left on my car, there are fast chargers available and working. Within that 20 km span, the frequency of charger equipment should be enough to address all the possible problems faced even after finding a charger location. E.g. what if the charger is not working? What if all the charging stations are occupied? A typical system design engineer will advise redundancy. Shall we say, 'One level of redundancy for every risk factor with high probability'?. So if we have two risk factors, we need two redundant chargers, So total three chargers within 20 km span, or 3 chargers spaced 10 km apart each, will make me feel comfortable. These must be fast chargers because they will be used most often.
What do I need in 'anxious charging zone'? -
do not have enough range to reach one of the fast chargers. I need to get back to 'comfort charging zone', i.e. ability to reach 3 fast chargers and still have some range left. In that case, it would help if I can see community charging stations or friendly private charging stations in a cell phone app. These need not be fast chargers. Because they will be used less often and they will be only used to get enough charge to go to the nearest fast charger. My need here is to get back from 'anxious charging zone' to 'comfort charging zone'. Best if there is a human guiding me on phone, but it's not a must.
What I need in 'panic charging zone'? -
I need an emergency vehicle to drive to me and provide me with enough charging boost so that I can get to nearest fast charger. I need a human voice on the phone to guide me through it. If I am in this zone, I am panicked and stressed and cannot be relied upon to act rationally and coherantly. Best solution for me is to pull over and wait for help. A trained human who can reassure me, keeps me calm, see my location on their system and have a speed charging van or motorcycle dispatch to help me is blessing from heaven.
The bullet list of what I need is as follows
- I must be able to charge within my charging comfort zone range (from 65% to 80 % of the range) most of the times.
- I must be able to find a working charger without major detour on my way.
- I must be able to find a working charger without significant wait.
- I must be able to charge the car in reasonable amount of time. If I am on road, 30 minutes is reasonable. 1 hour is pushing the limit.
- I am willing to pay extra cost to charge when I am on driving out of town and long distances. Because the amount I save when I am driving daily and charging at home creates more than enough savings for me.
- It would be great if there is an emergency vehicle, van or motorcycle that travels to me and gives me 'jump start' like charge enough to get to the nearest charger. Having ability to call such a vehicle will go a long way to increase my comfort level. Again, I am willing to pay extra for this facility.
- An app that tells me the location of nearest chargers - commercial or community, tells me if I can make there or not, tells me how busy the charger is and allows me to call the 'electric jump start vehicle' will be very handy. Icing on the cake is to be connected to human. Because in highly anxious state of mind I am very prone to mistakes and a trained human assistance can go a long way in making me comfortable and reaching my destination quickly. It's psychological factor, but a big one.
- I am willing to pay extra for such app and service.
So such a service, if provided will have five main components.
1. Fast chargers
2. Community or friendly chargers
3. An app that has location and availability data of these chargers
4. A human assistance
5. A vehicle that can provide emergency charge assist.
The charger locations must fit driving patterns. So in a city like Mumbai, if I am out, I could be driving anywhere to anywhere. If mumbai is not my home, then I have no access to charging other than commercial charging locations. So for every 15 km driving throughout the city, there must be three fast chargers. (This number must be adjusted as the number of electric car increases, but later about that.) These must be fast chargers, because these will be used most frequently.
On highways that connect big cities, the driving patterns are more linear. So the chargers must be located in clusters within the 'charging comfort zone' from both the cities.
I am have made many assumptions and tried to put number on my gut feeling. But there is ample of scope to define this as a problem and solve with 'Discrete Event Simulation', with a software like Arena. Google the terms to know more. Discrete event simulation is used by many companies and agencies in the world to simulate and solve many complex supply chain problems. The problem of building a charging infrastructure is essentially a supply chain problem. If someone were to make such a simulation, it will have following variables.
- number of cars
- car driving range
- probability of someone taking long drive in a given time span
- charging time
- charger up time probability
- traffic patterns
- and more as we get in depth of this.
Charging infrastructure is critical piece of EV puzzle. This problem will be best solved by companies coming together, or at least not going against each other. This is something I have often observed in USA but not that much in India. Even the companies that are fiercely competing in one area will co-operate in another areas. Companies typically like to co-operate in the area that is not your competitive strength (a point based on which you can outsell your competitors). Since it's a very lofty goal for an Indian EV builder to build enough chargers to make chargers a competitive strength, it makes perfect sense to co-operate in this area.
Not to be overlooked is another last piece, the government support. Any new venture, when blessed by the government, will have much better chance to succeed. Add to this the support of enthusiastic and vibrant EV community in India and what looked like distant dream yesterday can be quite closer to reality tomorrow.