Hi Giobria, let's crunch some numbers for the fun of it, as I'm sure we all we'll learn something from this exercise.
If we want to charge 250 vehicles a day, and typical battery size is 60kWh and typical charge is 20-100%, (is the battery size of the EVs travelling across the Sympson desert the average or above?? very likely much bigger) then all your business will be based on the 250x60x0.8 = 12,000kWh charged per day. Your revenue will be according to what you charge per this service.
What do you need to provide 12,000kWh (12Mwh) into EVs a day?
We have to add the charger efficiency 95% , BESS/PV inverter efficiency 98% and you need to produce actually 13MWh to sell 12MWh.
The energy is to be produced by a solar farm ; let's assume that we have an avg capacity ratio of 25% , which means that we would need a solar farm with an AC capacity of 2.2MW. Then we assume we use solar tracker and bifacial panels for maximum energy harvesting, and we'll need around 20-25% higher power installed on the solar field that at the inverter, even more if the panels are exposed to high temperatures for most of the period (we are in the desert). A solar field with 3MWp would do the trick.
When operating at full power the solarfield can deliver the energy directly to the chargers, although we can not rely 100% on the solar field if you need to deliver charge overnight, or make allowance for some cloudy days, etc...
You should study the traffic distribution to see how the load ( charging ) matches with the resource (sun) , and fill the gaps with storage.
If you assume that most of the people will drive during sun hours i.e. 12 hours , and that 60% of the traffic will be concentrated in 40% of the time ( peak time around lunch ie) , you have to charge 150 cars in 5 hours; that's around 30 cars per hour.
1 hour chargers ( 50kW x 1 hour ; 60kwh*80% =48kWh) would require to have 30 chargers 15 minutes charger (200kW) would require 8 chargers.
All up around 1.6-1.8MW AC required in chargers; this needs to be matched by the BESS or at least by a combination of BESS+Solar.
If we assume that 30-40 cars will come during night time you'll need at least 2MWh stored in a BESS , that could give you a guide for the minimum size, and will help to match load with solar output filling the gaps and storing the excess. I would store minimum 14 MWh , this is just a 4 of 20feet containers with LFP batteries. If you want a smaller battery you need to increase the solar field size.
That would bring a system with 1.6MW charging capacity, 3MWp solar field with 2.5MW inverter and a 14MWh BESS with 2.5MW to match the inverter. All up 0.5M the chargers, 3MAUD the PV, 5MAUD the BESS... all up 8.5M AUD.
To pay it in a year , you would need to sell the 4,380MWh you sell per year almost at 2000$/MWh....or 95$ per EV charge.... or almost 2$/kWh while Tesla superchargers charge around 40-60c/kWh.... I would say it would pay off in 4-5 years.. (the energy facility) not bad.
What's clear is that the simultaneity factors used for sizing the electrical network are going to change a lot, and that the solution is not grid augmentation but storing the energy close to where it's going to be consumed...when possible.
Have a nice week.
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