How to calculate a superyacht’s carbon footprint
The pinnacle of conspicuous wealth, superyachts might also be the pinnacle of oversized personal carbon footprints. I’ll show you that they have an immense impact and also how you can calculate the carbon footprint of fuel yourself. All the data and tools described are publicly available and there is a surprising amount of online detective work we can do in 2019 if there is something you want to investigate.
There are an estimated 200 plus private pleasure craft with a length over 70 m in the world. These are superyachts. At up to US$100 million and more each, that could be US$20 billion of luxury powering around the beautiful beaches of the world. All largely powered by diesel. We’ll take the Venus as an example vessel and calculate its footprint for one year. It’s a 78.2 m long superyacht designed by the famous French designer Philippe Starck and owned by the late Steve Jobs’ wife, Laurene Powell Jobs. In 2018-19, my calculations show it travelled 51,796 km. That’s a hell of a long way, the same as driving from Melbourne to Darwin and back seven times. But the real shock, apart from the yacht’s reported US$120 million price tag, is its fuel bill and carbon emissions.
We’ll look at the carbon footprint of the fuel only, but that will make up the bulk of the overall footprint by a long margin. Basically, the footprint of fuel is calculated by multiplying the amount of fuel by an emissions factor. That’s easy if you know exactly how much fuel is consumed, but we’ll need to do some detective work to figure that out. I’ll show you where to get the proper emissions factors and I’ll also highlight the quality of data to show that we can sometimes only find rough figures. Hopefully by taking you through the footprint calculation process step-by-step you can feel empowered to investigate your own interests in carbon emissions.
Unfortunately, ocean travel dynamics like drag and wave conditions are completely different to car road travel dynamics, so the distance travelled alone doesn’t let us calculate the fuel used for ships like it would with cars. Fuel use for yachts is given per hour so we’ll need to find a bit more information to first calculate the total fuel amount used in a year. The calculations below can be viewed here.
Step 1: Find the vessel’s fuel consumption. Searching the web finds one website that lists it as 800-1000 litres of diesel per hour We’ll use 900. Data quality: unverifiable.
Step 2: Find how far the ship travels in a year. Signing up for a free trial at a ship tracking website (like the websites that track all the airplanes in the sky, but this shows the ships in the ocean) allows us to find the ship’s travel history. Unfortunately, there is no convenient total distance travelled. But we can export the travel history in the form of a breadcrumb trail of latitude and longitude coordinates. Luckily, we can use an Excel formula to calculate the distance between each coordinate. We can sum all these distances to find the total distance the yacht travelled. The space between data points is quite large so we don’t have the most detailed path history – the ship could be doing a lot of zigzagging that this data doesn’t show. Data quality: low.
Step 3: Determine the average travelling speed. If we assume that when the yacht is travelling it’s doing so at one cruising speed, we can find the total travel time as we know the distance travelled. Using average travel speed rather than average speed should account for the time stopped at anchor in our calculations. Keep in mind, this is very rough. Looking at the ship tracking data, which gives an amazing level of detail such as the speed of the ship over the course of the day, we can see that it cruises at about 16 knots. We’ll take its average speed as a little lower than this to account for the times it’s travelling but travelling at slower than cruising speed. Data quality: low.
Step 4: Divide the average speed over the distance travelled to get the total time travelled. Data quality: low.
Step 5: Multiply the time travelled by the fuel consumption rate. This gives our diesel fuel consumption as 1,679,884 litres. Data quality: low.
Step 6: Look up the Australian Greenhouse Accounts Factors to find the emissions factor for diesel. Rearranging the emissions factor given on the Department of Environment and Energy’s website (they are given per gigajoule of fuel, not per litre) we can use a diesel emissions factor of 2.72 kg CO2-e/litre. Data quality: high.
Step 7: Multiply the emissions factor by the amount of fuel. Multiplying the fuel from from step 5 and the emissions factor from step 6 gives the total emissions as 4,571 tonnes of CO2-e. Data quality: high.
In this calculation we used a lot of low-quality data, so our result is low quality too. But it’s the best estimate we can arrive at without investing significant resources and without the cooperation of the yacht’s owners and operators. We could say our figures are a pretty reasonable ballpark.
The Venus emitted 4,571 tonnes of CO2-e in the last year. So how does that compare to other footprints? Well, it sounds like a massive number and it is. The average Australian’s annual footprint is 16.4 t CO2-e. That 4,571 t is just for boat trips, not the owner’s full annual carbon footprint, and is 279 times an average person’s footprint here in Australia or 594 times the average Chinese footprint. If the other 199 superyachts above 70 m in the world all emitted like the Venus, that would be 914,294 t CO2-e emitted globally each year. Again, this is ballparking the figures as we are basing this off only one data point. Yet that figure, nearly 1 million t CO2-e, is staggering.
This highlights the inequality of climate change. The world’s poor will feel its effects the most, yet they are the least responsible for it. They aren’t emitting thousands of tonnes of CO2-e just on a holiday. When climate change begins to bite us hard, the poor will suffer because they won’t have the resources to manage and adapt to the crisis. The ultrawealthy can just sail away. If every family had a yacht like the Venus, the world’s emissions would be 185 times what they are now, and we’d be baking in an unimaginable climate, that is, if life were still possible. Is it right for one person or one family to emit so much carbon dioxide just for pleasure when it contributes so much to climate change for everyone?
You can view my calculations here. I hope you calculate some things for yourself after reading this. Leave a comment here if you would like some help in doing so!