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As electronic vehicles (EVs) become more popular, there is an increasing need for access to charging stations, also known as ports. To that end, many modern apartment buildings have begun retrofitting their parking garages to include shared charging stations. A charging station is shared if it is accessible by anyone in the building.

But with increasing demand comes competition for these ports — nothing is more frustrating than coming home to find no charging stations available! In this project, you will use a dataset to help apartment building managers better understand their tenants’ EV charging habits.

The data has been loaded into a Google BigQuery database, containing a schema called VEHICLES and a single table named CHARGING_SESSIONS with the following columns:

VEHICLES.CHARGING_SESSIONS

ColumnDefinitionData type
garage_idIdentifier for the garage/buildingSTRING
user_idIdentifier for the individual userSTRING
user_typeIndicating whether the station is Shared or PrivateSTRING
start_pluginThe date and time the session startedTIMESTAMP
start_plugin_hourThe hour (in military time) that the session startedNUMERIC
end_plugoutThe date and time the session endedTIMESTAMP
end_plugout_hourThe hour (in military time) that the session endedNUMERIC
duration_hoursThe length of the session, in hoursNUMERIC
el_kwhAmount of electricity used (in Kilowatt hours)NUMERIC
month_pluginThe month that the session startedSTRING
weekdays_pluginThe day of the week that the session startedSTRING

Let’s get started!

Sources
  • Data: CC BY 4.0, via Kaggle,
  • Image: Julian Herzog, CC BY 4.0, via Wikimedia Commons
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DataFrameas
unique_users_per_garage
variable
-- unique_users_per_garage
SELECT 
	garage_id, 
	COUNT(DISTINCT user_id) AS num_unique_users 
FROM `VEHICLES.CHARGING_SESSIONS`
WHERE user_type = 'Shared'
GROUP BY garage_id 
ORDER BY num_unique_users DESC;
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DataFrameas
most_popular_shared_start_times
variable
-- most_popular_shared_start_times
SELECT 
	start_plugin_hour,
	weekdays_plugin, 
	COUNT(*) AS num_charging_sessions 
FROM VEHICLES.CHARGING_SESSIONS  
WHERE user_type='Shared' 
GROUP BY 
	start_plugin_hour, 
	weekdays_plugin 
ORDER BY num_charging_sessions DESC
LIMIT 10;
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DataFrameas
long_duration_shared_users
variable
-- long_duration_shared_users
SELECT 
	user_id, 
	ROUND(AVG(duration_hours), 2) AS avg_charging_duration 
FROM VEHICLES.CHARGING_SESSIONS 
WHERE user_type='Shared' 
GROUP BY user_id
ORDER BY avg_charging_duration DESC;