The Australian - Carbon laws to hit carmakers with $2bn bill

In the latest attempt to curb CO2, this time from the transport sector, unintended consequences threaten to make things worse.

Best intentions aren't enough.

The policy in question: limiting average vehicle CO2 emissions to 105gCO2 per km.

The article by Ben Packham in The Australian highlights the potential cost of implementing the policy - a cool $2 billion.

But there is another angle to this issue.

Consider the alternative: electric vehicles.

Energy Minister Josh Frydenberg predicts a 'revolution' for EVs, with 1 million of them to be travelling our roads by 2030, up from 4,000 today.

The potential cost is significant. Electric vehicles cost more than traditional vehicles. And don't be fooled by EV subsidies; like solar subsidies, someone always pays, and it's not the government.

This story has two key numbers: 105gCO2/km and 1 million EVs by 2030.

What does 105g/CO2/km mean? Simply, 18 of the top 20 selling cars in Australia exceed this value.

Need a ute for work? Sorry, you're out of luck.

Live in a rural or regional area and need to transport loads frequently over long distances? Sorry, you'll need to plan in charging stops of several hours to 'refill'.

However, those practical absurdities aside, the real issue is the underlying aim of reducing CO2 and what it will take to achieve that outcome.

Let's start with a look at EV emissions.

EVs have no direct CO2 emissions. But they do charge their batteries from the grid.

This means we can calculate the current gCO2/km based on the grid's CO2 emissions per kWh.

The Clean Energy Regulator publishes generation and emissions data here.

Their most recent data is for 2016-17, which shows grid-wide emissions of around 774g CO2 per kWh.

The most efficient EV on the market appears to be the Tesla Model 3. It achieves 6.7km/kWh. We calculate this from the claimed range of 500km and battery capacity of 75kWh; 500/75 = 6.7.

For reference, the Nissan Leaf achieves around 5.7km/kWh.

The Tesla Model 3 is relatively affordable, so let's use that as the basis for calculating the CO2 footprint of an EV in Australia:

• The grid emits 774g of CO2 per kWh
• Battery charging efficiency for the Tesla is about 80%
• It takes 94kWh to charge the 75 kWh battery, which gives you a 500km range
• Emissions = 94kWh x 774g = 72,756g / 500 = 145.5gCO2/km.

EVs, charged from the grid, don't meet the proposed 105gCO2/km standard based on the current mix of electricity generation sources.

This brings us to the next challenge: scale.

Fast forward to 2030, when we have 1 million EVs on the road.

Let's make a couple of reasonable assumptions:

• The EV fleet achieves the same average efficiency as the Tesla Model 3
• EVs travel an average of 15,000 km a year
• We decided that charging EVs must be via wind or solar, so they don't have a CO2 charging footprint
• Wind generator capacity factor of 30%

To provide enough renewable electricity to charge 1 million EVs, we would need:

• 22% more wind capacity, or;
• 30% more solar capacity.

Given that most cars charge overnight, solar is likely less efficient than wind.

So, wind it is. And don't forget, this is in addition to the residential, commercial and industrial electricity requirement.

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