The Shed – September-October 2019

mounted and you can clamp the runner

straight to the half-inch shaft, with no

alignment problems.

Soldiering on

Our little set-up churns away 24/7, year

in, year out. In the early days, I’d take

my morning coffee down and watch

it, grinning contentedly. Nowadays, I

only go there if a visitor shows interest.

It’s on its second Gentle Annie motor

because second-hand motors are cheaper

than replacement bearings. And I’ve got

50 more in the shed; probably enough

to see me out.

The intrusion has made it no harder

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up and down the waterway. It breaks no

new technological ground and claims no

records, although I like that it was built

from recycled materials. A lot of similar

systems are dotted around New Zealand,

many a legacy of the old hippie days, but

there must be thousands of such sites

going begging.

Windmill pumping

Pumped hydro is slightly different. With

micro-hydro, the sun lifted the water for

us as rain. With pumped systems, we

are supplying that lifting, my favourite

method being pumps directly driven by

old-school windmills. Overseas, pumping

is used to store off-peak nuclear energy,

often lifting seawater up to headlands

at night and dropping it back during

peak demand.

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reasonably big to be of any use; indeed

there was a study done into pairing

the Manorburn dam and Lake Onslow

as such a system. In energy terms it is

a net loss, of course; you never get out

what you put in and the culprit is the

usual one: friction losses manifesting

themselves as irretrievable, low grade

heat. There are ecological and safety

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volumes in such places too, but the

ability to store intermittent generation

from wind and solar is undeniable. The

two concepts combine naturally, of

course. I’ve often contemplated a wind-

fed header tank for our own system to

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a second Pelton nozzle for a temporary

power boost. One thing I am sure of —

we are going to see a lot more of both

technologies in the future.

A techie friend

steered us away from

SmartDrive washing-

machine motors and

towards Gentle Annies

Below: The Gentle Annie motor comes with
its own bearings, eliminating alignment
problems

Our little set-up churns away 24/7, year in,

year out. The 32mm intake feed is on the

left; the cowling (below) directs spent water

to avoid bank erosion

Resources

earth.waikato.ac.nz/staff/bardsley/

download/EEA_conference_pumped_

storage.pdf

power-calculation.com/

hydroelectricity-energy-calculator.php