Why Do We Use Kilowatts as the Standard for Electricity Measurement? What is a Kilowatt?

Kilowatt-hours (kWh) provide a consistent way to understand and compare energy usage across various devices and appliances, including your Tesla or other EV. Understanding kW/h helps you understand EV cost better, as it relates to all forms of charging.

A Universal Practice

A kilowatt-hour (kWh) is a unit of electrical energy, measuring the amount of electricity consumed over one hour at a constant rate of one kilowatt (1 kW). This practice of measuring electricity in kilowatt-hours is widely accepted and used in many countries on Earth. Specific terms and pricing structures for electricity do vary, and the fundamental unit of measurement, the kilowatt-hour (kWh), remains a universal standard for understanding and managing electrical energy consumption.

Why Measured Per Hour?

KWh is measured per hour to quantify the total energy used over that time frame, similar to how you measure how quickly water flows from a faucet or how fast your car consumes gasoline. This standardized approach ensures consistency and uniformity in assessing electricity usage.

Comparison to Water

To help myself understand it better, I compared it to my water bill. My water meter measures how many gallons of water I use, and I pay based on the volume I consume. Kilowatt-hours (kWh) are similar but for electricity. They measure how much electrical “energy” is used, and my bill is based on the amount of energy consumed. Just as you pay for the water that flows through your pipes, you pay for the electricity that flows through your wires. Whether it’s water or electricity, the more you use, the higher your bill. And, like water, the cost per kilowatt-hour (kWh) can vary depending on where you live or where you charge your EV. Having solar and power walls to charge your EV is like having a natural spring nearby. Your water well, pump, and filters that you invest in save you money from having your water delivered by a water-tank truck.

My Thoughts

I pay attention to how electricity prices change, always looking for the best rates per kWh to charge my Tesla Model Y via the Tesla App. Understanding kilowatt-hours (kWh) allows me to plan my charging more efficiently. During road trips, I also consider the cost per kWh at each Tesla Supercharger I encounter because these prices can vary due to multiple factors. On my recent road trip to San Antonio, where I visited Six Flags, I managed entire drive without needing to charge while on the road. The night before the journey, I charged my vehicle to 100%, providing a range of over 300 miles, which was more than enough for a round trip from near Leander to Six Flags Fiesta. To conserve energy, I disabled both Sentry Mode and Cabin Overheat Protection. When I returned home, I still had 20% of the battery charged. It’s all about making informed energy choices and optimizing efficiency.