Dear readers, at this point your co-author would like to speak up quite explicitly. Although I actually really enjoy writing, I really can’t be bothered with this chapter. That’s not because the topic isn’t important to me. I worked in environmental protection for ten years, and when we moved from a flat in Berlin with double-glazed windows dating from 1930 and an ancient oil-fired boiler in the cellar to our house in Erfurt, I was delighted to be drastically reducing my carbon footprint.
Incidentally, every German emits more than 10 tonnes of CO₂e per year. The small ‘e’ stands for ‘equivalent’ and means that emissions of other harmful greenhouse gases are also included in the calculation. For example, 1 kilogram of methane is equivalent to almost 30 kilograms of CO₂, because methane is more harmful to the climate.
Thanks to the renovation, our house is so well insulated that a heat pump with a power output of just 2 kilowatts – the same as a hairdryer – is enough for us. So it’s almost as if we were heating our house with a hairdryer.
The great hope: life on a boat as a climate benefit
I’d expected moving onto our boat to have a much greater impact on our carbon footprint; after all, I’d also be able to drastically reduce my travel: no more commuting to work, to school or going on holiday.
But my dream and reality were to drift apart, and so the issue of sustainability became a real test. Highly motivated as I was, a remark from Katrin brought me back down to earth: our boat is made of plastic, steel and aluminium – all materials whose production is particularly energy-intensive. And so the question arose: is sailing really as environmentally friendly as people think?
Just how environmentally friendly is a boat really?
So I decided to take a closer look at the materials from an environmental perspective: The resins that hold the fibreglass in our boat together account for up to 7 kilograms of CO₂e per kilogram of resin; polyester accounts for up to 14; and aluminium can even exceed 20 kilograms of CO₂e per kilogram. To be honest, I’m not an expert in this field and didn’t know how to put these figures into perspective, so I did some research to compare them with how many kilograms of CO₂e are produced when making 1 kilogram of beef. It’s 112 kilograms, and I was quite shocked. Definitely a point in the boat’s favour – the materials aren’t actually that bad. Yes, I know what you’re thinking now: a 10-tonne boat can hardly be compared to a steak on a plate.
All right, let’s look into this further: a boat of our size produces a whopping 100 tonnes of CO₂e by the time it’s finished, which is as much as a German person emits in ten years – that’s a real whopper. But a 120-square-metre solid-built house produces just as much, so never mind – you’ve got to live somewhere. Not quite – a house, if it’s well built, will last a few hundred years; the oldest GRP boats I know of date from the 1960s.
The Inconvenient Truth
Let’s keep it simple: so far, we’ve sailed from Greece to Panama and used 4,000 litres of diesel – that’s 4 cubic metres of fossil fuel. To me, that feels like an insane amount – after all, one cubic metre of it weighs heavily on my own shoulders. If you factor in extraction, transport and refining, one litre of diesel produces around 3.2 kilograms of CO₂e. So my personal burden weighs 3.2 tonnes.
To cheer myself up, I work out a person’s carbon footprint for a flight from Greece to Panama. It’s only 2.2 tonnes. That’s not what I’d expected. Of course, we did take a few lovely detours on our trip, but I’m still shocked.
So I’m looking at how the CO₂e emissions of an average German are broken down, and where we might consume less – or perhaps more – on our boat. If we take the 10 tonnes per year mentioned above as a basis, the breakdown looks like this:
- 28% consumption = 2.8 t CO₂e
- 22% housing = 2.2 t CO₂e
- 19% transport = 1.9 t CO₂e
- 15% food = 1.5 t CO₂e
- 11% public infrastructure = 1.1 t CO₂e
- 5% electricity = 0.5 t CO₂e
The on-board balance sheet: Where life on the move cuts CO₂ emissions
I can’t change much about our consumption – it’s much the same on the boat as it is on land, perhaps a bit less because we simply go shopping less often – so I’ll round it down to 2.5 tonnes. When it comes to housing, we’re doing brilliantly, because we produce everything we use ourselves, so that’s 0 tonnes.
Although we did use the generator in an emergency, its diesel is part of our travel arrangements. As I’ve already worked out above, my personal carbon footprint for our sailing trip comes to 3.2 tonnes – more than if I’d flown. Spread over a four-year journey, that works out at 0.8 tonnes per year. Phew, I think to myself, I’ve got lucky, because in Germany I would have produced 1.9 tonnes.
Now, on to the topic of diet: as a vegetarian, I generate around 40 per cent less CO₂e from my food and can deduct 0.6 tonnes. That leaves 0.9 tonnes for food.
The ‘Public Infrastructure’ category is difficult to estimate. When we’re at anchor or sailing from A to B, we don’t need it. Sometimes, however, we moor outside a large harbour, hire a car and go for a stroll around town. So let’s say 0.5 tonnes instead of 1.1 tonnes.
We generated our own electricity using solar power, and the generator’s diesel consumption is already factored into the mobility section. So 0 tonnes here as well. In total, 2.5 + 0.8 + 0.9 + 0.5 equals 4.7 tonnes. That’s only half of what I would have produced in Germany!
When sustainability becomes an expensive and frustrating project
I lean back contentedly, but a little devil whispers smugly in my ear: ‘You know that’s a lie!’ Gritting my teeth, I carry on with my calculations, because I’m getting to the real reason why I’m not enjoying writing this chapter at all. The fact is, I feel cheated. Cheated out of 10,000 euros’ worth of solar investments, cheated out of 10,000 euros’ worth of investments in electric motors, and cheated out of at least three months of my life spent on repair work and frustrating email exchanges.
Solar panels on the roof: For electricity generation, we opted for flexible solar panels costing 7,500 euros. The panels were marketed as suitable for marine use and seemed ideal for the gentle curves of our roof. To prevent overheating, I built a supporting structure. The materials and adhesive cost a further 2,000 euros. Thanks to the under-roof ventilation, the temperature could be kept below 50 degrees Celsius even in strong sunshine – this increases efficiency and slows down the ageing of the panels.
The modules had a total output of 7 kilowatts, which is enough energy to power our boat through the water. For every kilowatt of solar power, the production of our modules results in emissions of around 45 kilograms of CO₂e – so for us, that’s just over 300 kilograms of CO₂e. If you add another 200 kilograms for the supporting structure, that brings the total to 500 kilograms of CO₂e. Unfortunately, however, the very first delivery was of such poor quality that it had to be replaced. That makes it two batches of 500 kilograms each – a whole tonne – which doesn’t bode well for our sustainable round-the-world voyage.
The second delivery also turned out to be electronic waste. In the end, we decided to install standard solar panels in the Canary Islands, the sort you see on house roofs. These aren’t flexible, are six times as heavy and, with an output of 3 kilowatt-peak, added 1,500 kilograms of CO₂e to our carbon footprint. That brought the total to 2.5 tonnes.
From rising star to total write-off
Electric propulsion for our catamaran and dinghy: after a great deal of research, I was won over by a particularly promising and powerful model with an output of over 10 kilowatts. This is roughly equivalent to a 20-PS outboard motor – ideal for our dinghy. I’d long dreamt of powering the engines of my future catamaran using solar energy. So, initially, I even considered ordering five electric motors: one for the dinghy and four for our catamaran – two for each hull. I wanted to try this setup for a few years, and then the old, smelly diesel engines would have been thrown overboard.
Fortunately, Katrin put her foot down, and we reached what I thought was a half-hearted compromise: we would order just two motors – one for the dinghy and one as a wind-shift motor for our catamaran. For me, that was a slap in the face, as it meant our dream of powering our boat electrically was over. One motor would be enough to propel our catamaran at 3 or 4 knots on a mirror-smooth sea when there was no wind, but that’s simply not enough power for manoeuvring, let alone dropping the anchor. Today I’m infinitely grateful to Katrin for her caution, because what I’d absolutely never thought possible actually happened: the engines were nothing but junk. Our first two each lasted about four weeks, then they started to rust from the inside and the rust ate through the waterproof insulation.
Engine number three also lasted four weeks and looked just as rusty as its predecessors afterwards. The last two replacement engines were delivered to us in the Caribbean, where they lasted a little longer, but soon stopped working as well due to other design flaws. Frustrated, and against my better judgement, we bought a 25 PS two-stroke petrol engine. Two-stroke engines are an environmental disaster, but they’re very simply built, and you can easily repair them yourself.
The environmental impact of the engine fiasco
The manufacture of an electric motor generates around 200 kilograms of CO₂e – which is, after all, less than a petrol engine that is almost twice as heavy, which accounts for 300 kilograms of CO₂e.
However, we must also factor in the transport of around 50 kilograms of air freight, which generates approximately 400 kilograms of CO₂e. We therefore estimate 600 kilograms per motor, which, with five motors, amounts to 3 tonnes of CO₂e for our electronic waste. Together with the one tonne for the non-functional solar panels, that makes 4 tonnes of waste alone.
In the end, I have to admit that I felt as though the world had played a trick on me. The dinghy seized by customs, the two deliveries of faulty solar panels and the five broken electric motors caused me nothing but trouble for months on end.
In the end, it’s a positive result – but it doesn’t feel right
Let’s summarise our carbon footprint roughly at the end: on average, every German produces 10 tonnes of CO₂e per year. Statistically speaking, our small family would have produced 160 tonnes of CO₂e over the four years of our journey. Despite our misguided investments, we were probably around half that figure and saved 80 tonnes. However, if we factor in our flights (Germany–Greece, Portugal–Germany, Germany–Portugal and Panama–Germany), that adds another 40 tonnes. All in all, we’re very likely still well in the black … But I’d imagined it would be different.
About the book “A Change of Course into the Blue”
In *Kurswechsel ins Blaue*, Katrin Linke and Karsten Brensing recount their two-and-a-half-year journey with their children, travelling by catamaran from the Mediterranean to the Caribbean (Malik, 22 euros).
