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Coal and oil are running out. Nuclear plants are being shut down.
We can't fully rely on sun and wind.
This green stuff might be one way of solving the energy problem.
It contains algae, like the kind you find in lakes.
These little plants can power a whole house.
Sarah Schultes found out how it works.
The algae in this bottle are microscopic,
but they will supply this house with heat and power.
How?
Biologist Dieter Hanelt studies algae at Hamburg University.
Algae are quite new to the field of electricity.
Professor Hanelt isn't surprised.
It's not that algae were underestimated.
No one knew about them. Humans live on land, not underwater.
Everything below the water's surface is out of sight and thus out of mind.
But studying microalgae makes sense.
Unlike trees, algae use all their cells for photosynthesis.
That means they can produce and store more energy.
Photobioreactors replicate the natural process
by exposing the algae to light.
Martin Kerner has big plans for algae and wants to make it profitable.
He has a pilot plant near Hamburg where he grows algae in panels.
He wants to use them to heat an entire house.
Sunlight hits the photobioreactors.
That heats up the water.
The water is transferred via a heat exchanger
to a cooling or heating system inside the house.
The heating system heats up the tap water or the radiators.
Martin Kerner and his team
have built special reactors for fixing algae to façades.
The glass structures are a storey high and look rather like solar panels.
Double glazing keeps the heat in.
The latest prototype is a big success.
It's because they're flowing so well. They're getting a good swirling around.
The sunlight situation is perfect. It's exactly what they need to flourish.
Not too much sun, not too little.
It's just right. They don't spend long in the dark.
And they're getting enough nutrients and CO2.
Kerner's algae will soon move to this building.
Once here, their job will be to provide the five storeys with heat.
All year round.
The façade will produce the most heat during the summer.
That means we'll have to store it for winter.
For that we use a downhole heat exchanger.
It stores heat in the ground during summer
and then in winter we take it back out
so we can use it to heat the building.
That's the theory.
But although Martin Braasch, head of Friends of the Earth in Hamburg,
thinks the algae experiment is a good idea,
he wonders if it's practical.
We've now got people working with glass façades,
which have to let in light so that the algae can grow properly.
The team will have to see how much time and effort is involved
in constantly making sure the façade is clean.
It's like a fish tank.
You get residue on the glass panels, on the substrate.
So we will need to wait and see if the panels work in the long term.
But the algae house, with its 15 flats, is already popular.
There have been 25 applications and it's not even finished.
Martin also wants to make energy from other things.
Apart from the algae, I hope to use organic waste.
So that's things like faeces and organic household waste.
We'd use hydrothermal conversion in the building or complex itself
to make hydrogen and methane.
You could then feed the methane into the grid and distribute it,
or you could keep it and use a fuel cell to convert it into electricity.
A self-sufficient building.
Perhaps algae and solar panels will soon be competing for roof space.