Salvation From the Sea?
Climate change is the biggest challenge of the 21st century, and the main culprit is the excessive CO2 output caused by the burning of fossil fuel. Scientists have found that Nature itself demonstrates one solution on a daily basis. Green plants filter greenhouse gas from the air through photosynthesis, as we know. Something similar happens in bio-reactors, in which quick-growing green algae transform CO2 into biomass. In 2009, Professor Hilmar Franke (University Duisburg-Essen) and his team came up with a fibre-optic ‘photo-bio-reactor’ based on the principle of photosynthesis.
This quite simple reactor can convert the emissions from heating systems into algae and oxygen. All it needs is a big tank with algae growing in it, some fibre optic cables and bright daylight. On a roof top for example, open to the sunshine, light is transmitted by the cable into the bio-reactor, where the algae ‘soup’ is constantly being infused with gas piped in from the emissions of an industrial plant. The light brought in by the fibre-optic cables stimulates the algae to absorb the CO2 and multiply. The constantly increasing biomass produced by the process is in itself valuable, as it can be used as fuel or in building materials.
A roof of 50 square metres would be sufficient to transform 1 ton of CO2 emissions per year, and an industrial roof of 1 hectare (10 000 square metres) could easily absorb 200 tons of greenhouse gas. This is more than a hectare of forest could do, and it provides 20 times more biomass than corn grown as a fuel – which is an important fact, since the production of bio-fuel in mono-cultures has become an environmental issue itself.
At the moment, these algae reactors can only be used with the concentrated emissions produced by industrial plants, but scientists hope to adapt them for use in private housing before too long. The city of Hamburg is building the first industrial algae reactor, intended to absorb emissions of one of the city’s heating reactors. For this project, a locally-growing algae will be used. The reactor is anticipated to be capable of absorbing 450 tons of CO2 per year, and at the same time will produce 150 tons of algae. Critics point out that the reactor’s efficiency will fluctuate between summer and winter because of the varying seasonal light levels, but the planning commission is ahead of them on that score. In winter, it proposes to use arctic algae, which are habituated to cold temperatures and work at greater intensity.
Does this mean some busy little green plants from the depths of the oceans can free us from our fears of global warming? Well, not quite yet. The scientists involved in the projects don’t nurse any illusions. They admit that to neutralise all the emissions of only one big heating reactor, they would have to cover the whole city of Hamburg with algae reactors. But algae-reactors certainly have a place as one of the jigsaw pieces needed to protect our climate.
