2020-04-02_Science_Illustrated

scienceillustrated.com.au | 19

Solar and wind power can be stored

locally by using the energy

to build a tower of

concrete blocks.

Energy storage

uses gravity

Cranes powered by electricity can

store energy by building a tower of

concrete blocks. When the energy is

to be consumed, the blocks are

lowered to the ground again.

CHARGING

of the energy store takes place as

the electric cranes lift a concrete

block to a higher level, supplying

it with more potential energy.

DISCHARGING

takes place when the block is

lowered again. The steel cable

powers a generator that converts

the stored energy into power.

Concrete block is

lifted and lowered.

Radiation against a cancer
tumour can be more accurate
if the patient holds her breath.

ENERGY Wind turbines and solar cells

have been made far more efficient in recent

years, but scientists are still struggling to find

efficient methods to store the clean energy so

we can consume it when we need it, and not

only when it is sunny or windy.

Engineers from the Swiss Energy Vault

company have an idea that is simple yet

ingenious. It is based on the same principles

used to store clean energy in dammed lakes.

There it happens by water being pumped up

into the lake behind the dam, which gives the

water potential energy. When we want to

harvest it, the water is directed through an

ordinary hydroelectric power station. The

advantage of Energy Vault’s new concept is

that it doesn’t require the use of lakes and

rivers. Instead of water, the energy is stored in

35-tonne concrete blocks, which are lifted up

by 120m-high electric cranes. When there is a

surplus of power, the cranes build a high

tower by stacking the blocks on top of each

other, and when the energy is to be harvested,

the cranes lower the blocks onto the ground

again one at a time. The steel wires that are

fastened to the blocks power a generator which

converts the kinetic energy back into power.

The company plans plants that can store

up to 80MWh of energy, meaning that a

plant would be able to supply 8MW for

16 straight hours, sufficient to provide

1250 average households with power.

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SHUTTERSTOCK
MEDICINE According to
British scientists, breathing
exercises could lead to improved
results from radiation therapy
against cancer. The better the
patient is at lying still, the more
accurate the treatment becomes.
Radiation therapy typically
involves the patient lying in an
accelerator which focuses the
radiation very accurately at the
cancer tumour inside the body.
By aiming from several angles,
doctors hit the cancer cells with
the maximum radiation, while
surrounding healthy cells get as
little as possible. The patient
clearly needs to lie still, and if
the tumour is in the breast or
stomach region, it is a further
advantage if patients hold their
breath throughout the procedure.
Scientists from the UK’s
University of Birmingham studied
how quickly we can be trained to
hold our breath for a long time,
having 30 male and female
volunteers undergo breathing
exercises, subsequently
breathing oxygen-rich air for a
few minutes. Finally, they were
asked to hyperventilate, making
as much carbon dioxide as
possible leave the blood. After
only one day of practice, the
participants could hold their
breath for about six minutes, and
after a few days could do so
several times interrupted by brief
breaks, up to a total of 41
minutes per hour. This could
improve radiation therapy so
much that it is worthwhile
testing in clinical trials.
Cancer patients
hold their breath
Concrete block tower
stores clean energy
Swiss engineers have developed energy storage that involves
building of a tower of concrete blocks, only to tear it down again.