Enormous Floating Solar Farms Can Extract Carbon Dioxide from Seawater to Replace Fossil Fuels

Carbon dioxide is one of the most abundant and active gases causing the greenhouse effect, a process whereby the earth’s atmosphere traps radiation and heat from the sun, which results in global warming. CO₂ is a naturally occurring gas that can either be produced or increased by things such as animal respiration, volcanic eruptions, deforestation, and the burning of fossil fuels. Since the inception of industrialization, global CO₂ levels have increased by a third [1]. This is one of the reasons why global warming is happening at an alarming rate.

A group of scientists from Norway and Switzerland may have found a way to harness CO₂ for the production of fuel, a process that would, in theory, help to slow global warming [2]. Carbon dioxide is naturally stored in oceans and seas either as dissolved gasses or carbonate sediments. Infact, 70% of all the carbon dioxide on earth will eventually settle in the ocean [3]. The researchers believe that by using photovoltaic cells, more commonly known as  solar panels, they can extract carbon dioxide from seawater for conversion into methanol fuel. This renewable source of energy can be used to power industrial plants, vehicles, aircraft, and possibly, even spaceships.

 The paper was published in June 2019 in the Proceedings of the National Academy of Sciences Journal, PNAS [4]. The scientists proposed to “implement, on a large scale, marine-based artificial islands, on which solar or wind energy powers the production of hydrogen and the extraction of CO₂ from seawater and where these gases are catalytically reacted to yield liquid methanol fuel.”

The process

According to the paper, these solar islands would be located in areas with minimal waves and turbulent weather. Ideal areas would have low hurricane probability to prevent damage, and an water adequate water depth of less than 600 meters. Ideally, if the project plan pushes through, these facilities would first be built on the coasts of Southeastern Asia, northern Australia, and the Arabian Gulf. 

The solar islands would be built with the same concept used for floating fish farms, except that they’ll be equipped with solar panels to collect energy from the sun. Methanol is the simplest carbon-based fuel, formed from the fusion of hydrogen and carbon molecules. The solar cells would collect energy and work to power the hydrogen production and CO₂ extraction plants. These gases would be combined in a series of electrolytic processes to produce methanol. According to the paper, methanol can be used to power “existing gas turbines, modified diesel engines, and direct methanol fuel cells.”

Setbacks

Floating solar farms are not a new concept. The major problem holding back the deployment of this idea is a feasible means of large-scale production and extraction of carbon dioxide. Fossil fuels are non-renewable sources of energy being used up faster than they are being replenished. However, inventions have evolved over centuries to harness the energy they provide on a large-scale. 

“[The] biggest challenge is the development of a large scale device to extract CO2 from seawater,” one of the authors, Andreas Borgschulte told Newsweek [5]. “This process is the only one of the total system [that] has not yet been fully developed. All others exist already on an industrial scale.”

The team admits that the idea is a bit ambitious and is still undergoing a lot of prototyping. They estimate that about 70 solar islands would form a single plant. Populating the possible global locations with a maximum of 3.2 million farms would exceed the global CO₂ level from emissions from fossil fuels.  Speaking to NBC News, lead author of the paper, Bruce Patterson, estimates that one solar plant would produce more than “15,000 tons of methanol a year — enough to fuel a Boeing 737 airliner on more than 300 round-trip flights between New York City and Phoenix [6].”

“I don’t think the idea is totally bonkers, but I also don’t think it’s the world-saving concept its bid to be,” said Henry Snaith, Professor of Physics at Oxford University, to Forbes. “The other components needed for the idea, are extracting CO2 from seawater and then turning this into fuel. This part would be very energy-intensive and costly. Work on creating fuels from electricity – as opposed to directly from sunlight – is massively important. This will ultimately enable solar and wind to produce 100% of our power needs and should be encouraged.”

Effects on the climate crisis

The researchers believe that the project would massively reduce the extent of global warming and limit dependence on non-renewable sources of energy. However, some voices of authority are not fully convinced about the viability of this prospect. Mark Jacobson, a professor of civil and environmental engineering at Stanford University says that even though the plan may work for energy production, it won’t solve the ever-growing issue of global warming.

 “Some people think the only problem in the world is to reduce carbon dioxide, but that’s not the problem,” he said, describing the solar farms as a roundabout way of doing things. “The problem is air pollution, energy security, and carbon emissions. You have to solve all three of those problems together. This is a solution to a very narrow aspect of the problem, so to me, the idea is misplaced. “Floating solar is a good idea, but just for producing electricity. With this fuel conversion, it’s a fuel that we don’t really need. There are a lot more efficient uses for a solar panel.”

Well, even though it may not completely eradicate global warming, it could reduce it to a reasonable extent, which is far better than nothing. Harnessing solar energy to convert carbon dioxide into usable fuel sounds like a promising concept. Dubai has already declared an interest in this latest energy solution and is seeking to produce 75% of its energy from offshore solar plants by 2050 [7].