Seaweed to cow feed: Why is Sweden building the world’s largest algae factory?

The seaweed factory
The seaweed factory Copyright Volta Greentech
Copyright Volta Greentech
By Nichola Daunton
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Sweden is investing in seaweed to cut methane emissions in cows.


A Swedish start-up is building the world’s largest algae factory to create emission-reducing seaweed feed for cattle.

But how do you reduce greenhouse gases from the world’s most polluting animal? 4 per cent of the world’s methane emissions currently come from cattle, which is two times higher than the whole aviation industry put together.

While cutting down on cow farts may not be the sexiest science, reducing the problem would make a huge dent in the world’s greenhouse gas emissions, and help dairy and beef farming become much more sustainable.

“There are more than one billion cows on the planet, and the emissions from these continue to increase. Despite that, there are no widespread solutions to decrease the emissions, and research in the field is progressing far too slow,” says Fredrik Åkerman, co-founder and CEO.

But how do you stop a cow passing gas? Volta Greentech believes it has the answer.

Run by an international group of scientists and climate innovators, the team has created ‘Volta Seafeed’, a supplement made from the red seaweed Asparagopsis taxiformis.

When fed to cows at a daily dose of just 100 grams, the feed reduces their enteric methane (gas fermented in the intestines of cows, sheep and goats) emissions by up to 80 per cent.

How does seaweed-derived cow feed reduce methane?

The production of methane by a natural fermentation process, takes place in the rumen (the largest of a cow’s four stomachs). As they digest their food hydrogen and carbon dioxide are released, and a natural enzyme then combines the two gases, creating methane in the process.

Feeding a cow 100 grams of the seaweed feed, however, naturally suppresses this enzyme and methane emissions are reduced as a consequence.

The feed has been through several rounds of international testing over the past six years, and Volta Greentech is now working in collaboration with Sweden’s biggest feed company Lantmännen.

Volta Greentech
This is the seaweed feed they give to the cows.Volta Greentech

“The methane-reducing effect has very largely been proven, and we now want to investigate how this affects other parameters. We want to find out if the cows eat the feed to the same extent, if the milk production is affected when it comes to yield and composition,” says Cecilia Lindahl, a product developer at Lantmännen.

“So far, the results look promising.”

Scaling up production

With over one billion cows in the world, scaling up production of its seaweed feed is a top priority for the Swedish company. Several rounds of investment mean it has been able to open its first factory ‘Volta Factory 1’ in Lysekil, which is due to be followed in 2022 by ‘Volta Factory 2’, billed as the world’s biggest seaweed factory.

The company is aiming to tackle Sweden’s cattle first, with the hope that it can expand internationally in the future.

Focusing on sustainable production methods for the seaweed, which is grown in vertical bioreactors to maximise production, is also a top priority.

Volta Greentech
Making the feed in a lab.Volta Greentech

How to produce sustainable seaweed

“By constructing a closed system, we make sure that we retain constant production and quality over time, regardless of environmental factors such as water quality or weather,” says

Åkerman about the factory’s production methods. “The approach also enables drastically improved efficiency and productivity over time by continuous iterations of the cultivation recipe in our laboratory.”

The factory is also powered sustainably, with waste energy from local industries used in production.


This, along with the automation of the processes, ensures that there is stable seaweed growth 365 days a year, with a daily growth rate of 10 per cent.

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