February 23, 2024

How to lower your electric vehicle’s environmental impact

How to lower your electric vehicle’s environmental impact

There are many studies and opinions about how much carbon emissions you’re saving by swapping from a petrol car to a battery electric vehicle (BEV). In reality, it depends on many different factors, especially when manufacturing emissions from EV battery production are taken into account.  

That said, total emissions from an EV’s manufacturing process may not influence which model you buy, but there are other factors you’ll have greater control over after purchasing such as how and when you charge your EV. These will have a much bigger impact on your EV’s total life cycle emissions.

Today we’re talking about EV charging with renewable energy sources and sharing helpful tips and tools you can use to reduce your CO2 emissions when charging your EV.

Tesla Model 3 driving in New Zealand

Can you run an electric car without emissions?  

It’s possible, but also difficult to eliminate all carbon emissions when charging an EV. You’ve probably seen references online to EVs as 0% emission vehicles. This is only true in part. While there aren’t tailpipe emissions produced when driving an EV, the energy sources used to charge it may still be reliant in part on carbon intensive fossil fuels like coal or gas to generate the electricity.

Unfortunately, electricity generation is one of the highest contributors to global CO2 emissions. New Zealand and Australia both burn fossil fuels to varying degrees to produce electricity to meet demand, and by charging your EV from the local electricity grid, this will contribute to your overall carbon impact.

How clean or dirty your electricity is depends on the types of electricity generation sources feeding the grid at a given time. This is known as an energy mix or generation mix.

The renewable percentage of your electricity grid’s generation mix will depend on where you live (available renewable electricity generation sources), electricity demand (time of use), and amount of renewable energy available on a particular day (weather).  

For example, New Zealand’s renewable energy percentage is around 80% and made up largely of hydro, geothermal, and wind with some support from coal and gas.

Ultimately your emission contribution from EV charging will come down to how renewable your local grid’s generation mix is when you start charging and how much power you draw. But do you really have any control over these things?

The good news is there are some strategies (besides controlling the weather) that you can use to actively reduce you daily environmental impact from EV charging.

1) Harness your own renewable electricity.

The best way to guarantee your EV is being charged with renewable energy is to generate it yourself at home. Consider installing a home solar system and use Solar Export Diversion to charge your car for free while the sun is up, or utilising a home battery system for storing and charging later after the sun goes down.

Check out our guide on solar EV charging for suggestions for how big your solar system should be to charge your EV at home.

2) Charge at times of high renewable energy % on the grid

If it’s not practical for you to charge your EV using solar, you can still lower emissions by charging at times of high renewable energy generation from your local grid.

While renewable energy sources are great for environmental benefits, they are a poor form of energy demand response. You can’t just make the wind blow stronger, or increase the water flow to hydro dams. So, when electricity demand peaks, additional electricity generation is used to meet demand. Carbon-intensive energy sources like fossil-fuelled power plants offer much more flexibility to handle an increase and decrease in electricity production as demand fluctuates.

So how do you know when the cleanest time to charge is? Well, for your area it could be starting after midnight, or even midday when the sun is up. It really depends on your location and can change depending on the season or even day to day.

Thankfully, there is a smart feature that can help called carbon monitoring.  

What is carbon monitoring?  

Carbon monitoring is a smart EV charging tool that allows drivers several advantages when it comes to charging their EV as cleanly as possible, while at home.  

It offers visibility of your local grid’s electricity generation, the % of renewable energy currently being generated, as well as what generation sources are powering the grid.  

This can be displayed as a live figure and show historical grid data (like the below 24-hour summary from the Evnex charging app) to better understand what the cleanest time to charge has been recently.

X Axis - Time of day| Y Axis -Grams of CO2 emitted per Kwh of electricity

How does carbon monitoring help power emission reduction?

These tools help you stay better informed throughout the year about the cleanest times to charge your EV as energy demands shift and your electricity grid’s generation sources change.

Looking at a live grid view can help inform you if it’s a good time to charge your EV now, or delay your charging session until later when there is more renewable electricity being generated.  

Example 1: It’s not a clean time to charge right now

Let’s say you arrive home around 7:00pm after work and check your charging app before plugging in. Looking at the past 24 hours, you can see there was a spike in carbon emissions around this time last night when electricity demand was high (likely from other people arriving back from work and turning on their heating, cooktop, and other appliances). Several hours later, around 12:30am, was the least carbon-intensive time of the day.  

Instead of charging right away, consider scheduling a charging session around midnight, when carbon intensity has recently been at its lowest, around 1/3 less than if you charged then rather at peak time.

Example 2: It’s a clean time to charge now:  

In this scenario you arrive home early, around 2:00pm, and check if it’s a clean time to charge. You can quickly see there is a 72% renewable generation mix at the moment, which is the highest it’s been over the past 24 hours, so go for it and make the most of that clean grid solar production!    

Can I track how much carbon my charging session created?

Although there is no way to track a specific electron from the electricity generation source to your EV, we’ve developed these features to help you track your progress of reducing your charging-related emissions. This is shown as estimated grams of CO2 emissions, based on how renewable the grid generation was at the time you charged and the amount of electricity that was used.  

This appears in several places on the Evnex app, both on your individual charging session history, as well as your charging summary. It gives you a single figure you can track week-to-week, month-to-month, or year-to-year to see how your clean charging habits are aligning to reduce your environmental impact.

This calculation also considers the use of any home solar which will be calculated at 0 grams of carbon dioxide emitted / kWh of electricity used.

Where is carbon monitoring available?  

Evnex’s carbon monitoring features are available to use for free with any Evnex smart charger in New Zealand and Australia. We use local charging data from Electricity Maps for accurate calculations of each Australian state, and em6 API (one of the commercial arms of Transpower) for our New Zealand grid information.

What’s next for carbon monitoring?

While it’s helpful to understand and see how your local grid’s energy mix will affect your charging emissions, it still requires you to actively decide when to charge your EV. The Evnex team are exploring automating this feature in future to allow EV drivers to set specific charging preferences based on their tolerance for of dirty vs clean energy generation. This will one day help you achieve a cleaner form of EV charging without you having to even think about it.  You can learn more about the current carbon monitoring features available the Evnex app.  

Did you find this article helpful? Or have topic ideas you’d like us to cover? Send us a message below. Learn more or buy an Evnex E2 for your home charging setup.

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February 23, 2024