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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 PostgreSQL database with a table named charging_sessions with the following columns:

charging_sessions

ColumnDefinitionData type
garage_idIdentifier for the garage/buildingVARCHAR
user_idIdentifier for the individual userVARCHAR
user_typeIndicating whether the station is Shared or PrivateVARCHAR
start_pluginThe date and time the session startedDATETIME
start_plugin_hourThe hour (in military time) that the session startedNUMERIC
end_plugoutThe date and time the session endedDATETIME
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 startedVARCHAR
weekdays_pluginThe day of the week that the session startedVARCHAR

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
gen_view
variable
SELECT * FROM public.charging_sessions;
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DataFrameas
unique_users_per_garage
variable
-- unique_users_per_garage
-- Please paste code into first cell
SELECT
	DISTINCT public.charging_sessions.garage_id AS garage_id,
	COUNT(DISTINCT public.charging_sessions.user_id) AS num_unique_users
FROM public.charging_sessions
WHERE public.charging_sessions.user_type = 'Shared'
GROUP BY public.charging_sessions.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
	public.charging_sessions.weekdays_plugin,
	public.charging_sessions.start_plugin_hour,
	COUNT(*) AS num_charging_sessions
FROM public.charging_sessions
WHERE public.charging_sessions.user_type = 'Shared'
GROUP BY public.charging_sessions.weekdays_plugin, public.charging_sessions.start_plugin_hour
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, avg_charging_duration
FROM
(
SELECT 
	public.charging_sessions.user_id AS user_id,
	AVG(public.charging_sessions.duration_hours) AS avg_charging_duration
FROM public.charging_sessions
WHERE public.charging_sessions.user_type = 'Shared'
GROUP BY public.charging_sessions.user_id
) AS subquery
WHERE avg_charging_duration > 10 
ORDER BY avg_charging_duration DESC;