Deep below the surface of the ocean, on the bottom of the Pacific, they abound: substances that are needed for electric cars are in abundance here – about halfway between Hawaii and Mexico.
In the Clarion-Clipperton Zone (CCZ), an estimated 21 billion tons of "polymetallic tubers" are waiting 5000 meters below the water surface to be collected by mining robots.
In total, the ore lumps known as manganese nodules contain an estimated six billion tons of manganese, 270 million tons of nickel, 230 million tons of copper and 50 million tons of cobalt. They are used in the manufacture of electric car batteries, electrical cables and technical solutions that are crucial for the transition from a world with fossil fuels to a world with clean technologies.
"Measured by their dry matter, the tubers typically consist of approximately 31 percent manganese, 7 percent iron, 1.4 percent nickel, 1.2 percent copper and 0.17 percent cobalt," explains Carsten Rühlemann, head of the marine geology and deep sea mining department at Federal Institute for Geosciences and Natural Resources (BGR).
"Coincidentally, the composition of these tubers is pretty much what electric vehicle manufacturers need," said Gerard Barron, CEO of Deep Green Metals (DGM) from Vancouver, Canada, to DW. "Car manufacturers will need a lot more of these metals to build battery cathodes and electrical connections for an electric vehicle fleet of about a billion cars and trucks by the middle of the century. Today there are just five million electric vehicles."
Manganese tubers are as small as pebbles or as big as potatoes or melons. They arise in millions of years
According to Barrons, Deep Green Metals' mission is not just limited to harvesting the tubers: "First, we have to mine enough of these metals to deliver the enormously increased amount that we need for the renewable energy-powered e-mobility of the future then we have to. "
Mining on land or harvesting on the ocean floor?
Barron and Rühlemann both say that there are good reasons to believe that mining the tubers on the seabed will pollute the environment far less than mining on land – especially when it comes to greenhouse gas emissions, solid waste and the release of toxins.
large areas need to be cleared, a lot of overburden moved and huge amounts of rock crushed, Barron emphasizes. Ores mined on land are also dirtier because they contain more toxic heavy metals. And while the CCZ tubers on the seabed contain four metals that are important for the electric car industry in the handy packaging of manganese tubers, three mines on land would be required to extract these four metals.
A comparative life cycle assessment (LCA) commissioned by Barron's company Deep Green Metals entitled "Where should the metals for the green turn come from?" was released in April 2020. The result of the life cycle assessment is a clear victory for the manganese nodules from the sea floor.
While 37 billion tons of CO2 are emitted into the earth's atmosphere every year when fossil fuels are burned, on-site metal production generates over 350 billion tons of partially toxic waste.
Metal mining is the cause of "the biggest waste problem on the planet", the report states: "If we produce metals for the green transition as we have done so far, we are actually shifting the ecological and social burdens of fossil fuels Metals ".
In contrast to the land-based mining of the same metals, there are essentially no solid residues, no waste ores and no toxic waste when the tubers are collected and melted. There is no need to clear forests, about 70 percent less greenhouse gas emissions and 90 percent less sulfur and nitrous oxide emissions. In addition, 90 percent less water is used.
The mining of manganese nodules in the deep sea is more environmentally friendly than conventional mining on land
Before you start dismantling
But two hurdles have to be overcome before the mining of manganese nodules on the sea floor can begin. One is technology: up to now there are no commercial machines capable of harvesting manganese bulbs at the high pressure 5000 meters below the surface of the sea. But engineers are already working on their development, say Rühlemann and Barron.
The other hurdle is regulatory: the preliminary assessment of the impact on biodiversity and the ecosystem is still pending. But this is necessary before the International Seabed Authority (ISA) completes its mining code and allows mining. That will likely happen in the next two to three years. Because the Clarion-Clipperton Zone is in international waters, the area is managed by the ISA, which was established in 1994 under the United Nations Convention on the Law of the Sea (UNCLOS).
The only impact that seabed mining will have, which onshore mining does not have, is disrupting deep sea ecosystems. The surface of the seabed has to be "skimmed" to harvest tubers, which are then pumped up to the surface by mining vessels. All of this whirls up the mud on the seabed and disrupts the organisms living in it – most of them are seaworms. In addition, extensive mud plumes are created, which remain in the water for a long time and can affect the life of the fish.
In the cold, dark depths of the ocean, everything takes time. According to Carsten Rühlemann of the BGR, available research results indicate that the so-called microbial communities of microbes, bacteria and other microorganisms that serve as a food base on the seabed can take up to 50 years to recover from mining. A Deep Green Metals spokesman relies on other research that says the microbial communities could recover within three decades. For comparison: Some studies indicate that soil microbes have not yet fully recovered four decades after being mined on land.
It is not yet known whether some species on the seabed only occur in the Clarion-Clipperton zone. To minimize the risk that harvesting the manganese nodules leads to a loss of biodiversity, the ISA has designated nine large areas within the CCZ as protected areas known as Areas of Particular Environmental Interest (APEI). Two or three additional 160,000 square kilometers of APEI protection zones are likely to be added soon.
Mining operators are expected to identify between ten and 30 percent of their mining areas as "no-take zones" that provide additional protection for the habitat.
A special boat can harvest around three million tons of "wet" tubers per year with its equipment on around 200 square kilometers of seabed. This corresponds to a dry matter of two million tons
The Clarion-Clipperton Zone is approximately 4.5 million square kilometers, slightly larger than the total land area of the 27 member states of the European Union. The area that the International Seabed Authority (ISA) has previously licensed to research manganese nodule mining is only 1.2 million square kilometers – that's just a small fraction (0.7 percent) of the 165 million square kilometers of ocean floor in the Pacific.
According to Rühlemann, around 80 percent of the licensed areas will remain untouched by mining because probably only the most economically profitable 20 percent will be harvested.
"So far, ISA has granted 16 license areas, each covering around 75,000 square kilometers, to companies or agencies that they knew had the technical resources to carry out work to explore the area. One of them was my employer BGR," explains Rühlemann.
To obtain a license, an applicant must first explore an area of 150,000 square kilometers. Upon completion of the preliminary investigation, the ISA divided each of these areas into two 75,000 square kilometer units of approximately the same size. The ISA, which can allocate these "reserved areas" to developing countries, retains the exploration rights for half of them. The other half remains with the exploration company.
Since 2006, Rühlemann and his BGR research team have sailed the Pacific for about 40 days every summer from the American research ship Kilo Moana, which was chartered by the University of Hawaii, or from the German research ship Sonne, and have taken samples in the German license area.
"About 20 percent of the area has a particularly high commercial value due to the high tuber density and the flat seabed topography. We have intensively examined 4000 square kilometers of these economically valuable areas."
Referring to a report from MIT's Materials Systems Laboratory to ISA for 2019, Rühlemann estimates that the initial investment costs for a CCZ tuber removal vessel and smelter will be between 1.5 and 2 billion euros within a single license area . The annual operating costs are likely to be in the order of 200 to 400 million euros per year. About two thirds of this is for the costs of smelting the tubers on land, the rest for the mining operations in the sea.
The total production of the manganese nodule fields in the CCZ would be in the order of 32 million dry tons of tuber ore if all 16 current license holders were to operate a mining ship at the same time. Of course, with more ships per license area, things could be accelerated.
The number of harvesting operations that will be optimal depends on global market demand and ore prices. Rühlemann estimates that probably only three to five mining ships will be in the Clarion-Clipperton zone at the same time.