Zimbabwean

Wind Energy
Spins at Redhill
Glynn Morris 2000 Glynn Morris

F
eather Energy has erected a small
wind turbine as part of a hybrid
wind/PV/genset electricity supply
system for a home and office at the
Redhill Mountain Reserve, a private
addition to the newly established Cape
Peninsula National Park, above Simons
Town, South Africa. The African Windpower bird above the telecomms array.

The property has a passive solar home and office, with PC, laser printer, deskjet printer, scanner, network hub,
a PV-powered water pump and microwave telephone fax machine, PABX, and an answering machine. The
exchange, and a wind energy system for house and domestic loads include a washing machine, TV and
office loads. The system includes a 1 KW wind VCR, small kitchen appliances, and power tools.
generator, a 1 KWp PV array, and a 5 KVA petrol
The system is a joint initiative between Feather Energy,
genset supplying a 1,000 AH 24 V battery and a 2 KVA
owner and operator of the site; African Windpower
sine wave inverter.
(AWP), the wind turbine manufacturer; Siemens Solar,
The energy demand is roughly 3.5 KWH per day during who supplied the PVs and batteries; Photovoltaic
the weekfor the office and domestic needsand 800 Design and Installation (PDI), controller manufacturer
WH per day on weekends. In addition to lights, the and system designer; and MLT Power, who supplied
office equipment includes two desktop PCs, a notebook the inverter and battery charger.
Wind Generator
The passive solar home and offices at Redhill Mountain Reserve.
The wind generator is manufactured
by African Windpower in Harare,
Zimbabwe. It is specifically designed
for lower wind speed regimes which
are typical of the inland areas of
southern Africa. But it can also
perform well in high winds found in
coastal areas.
The AWP36 is keeping the Redhill
systems battery bank fully charged,
with the ammeter often showing up
to 35 amps at 29 voltsover 1,000
watts. It often supplies between 20
and 30 amps in furled mode due to
the high wind speeds encountered
at Redhill. The machine looks and
feels substantial, and yet it is very
elegant, with good aesthetics.

52 Home Power #76 April / May 2000

 Systems

Heavy Metal
The machines rotor diameter (3.6 m; 12 feet) is large
compared to its maximum power output (1 KW). This
gives it the torque to deliver good power in lower
windspeeds, when other machines are unable to catch
as much wind. AWP believes it is more important to
have a steady, day to day supply of amp-hours into the
battery than to have a high peak-power rating. This is a
heavy metal wind turbine, built for low speed and long
life.
The turbine uses a direct-drive permanent magnet
alternator, but with skewed windings to eliminate
cogging. The alternator is heavy because it has many
magnets and coils in it. Lighter alternators generally run
at higher speeds. These lighter, high-speed wind
turbines are noisier and wear themselves out sooner.
Power comes from a 3.6 m diameter rotor with three
GRP blades (glass reinforced plasticfibreglass). The
wind turbine is protected against high winds by a AWPs large diameter, low rpm wind turbine.
simple, passive system which has been tested in winds
exceeding 160 kph (100 mph), without incident. As the turbine capable of producing the equivalent power of an
wind grows stronger, and maximum power is reached, array of six 85 Wp PV modules in mean windspeeds of
the turbine yaws sideways from the wind. This 3 meters per second (6.7 mph). The principal attraction
prevents the blades from overspeeding. There are a was that almost all the value added in the production of
minimum of moving parts involvedno springs, and no the machine would be in local currency, hence
highly stressed components. protecting against the foreign exchange variations that
affect imported PV modules.
Wind Power for Africa
The machine is the direct result of a development The turbine has operated to specification at the Redhill
project initiated through the Zimbabwe Energy site. It is also useful in many different locations due to
Research Organisation (ZERO) in Harare. It has been its ability to operate effectively in low-wind regimes. Its
designed by world leaders in small turbine and machine robust construction is highly suited to low-maintenance
design. These include Geoff Watson (Manx Wind sites. The machine was installed on a guyed 7.5 m (25
Energy), Hugh Piggott (Scoraig Wind Electric), and foot) steel tower on the open, treeless Redhill site. It
Oloff Smyth and Duncan Kerridge of African was erected over three days by Duncan Kerridge and
Windpower, among others. two inexperienced helpers. Its encouraging to see this
quality product come out of a developing country.
The initial objective was to investigate the feasibility of a
locally-manufactured, simple battery charging wind The wind turbine installation required an environmental
impact assessment (EIA) to comply with the
AWP36 Power Curves environmental management requirements of the Cape
1,400
Peninsula National Park. The EIA concluded that the
turbine was by far the most cost-effective and
Output Power (watts)

1,200 environmentally acceptable electricity option for the

1,000 park.
800
Access
600 Author: Glynn Morris, Feather Energy, PO Box 576,
400 Simons Town, 7995, South Africa +27 21 780 9024
200 Fax: +27 21 780 9019 glynn@feather.co.za
0 Oloff Smyth, African Windpower, Box 4533, Harare,
3 5 7 9 11 13 15 17 Zimbabwe 2634-771581/4 Fax: 2634-771580
(7) (11) (16) (20) (25) (29) (34) (38) power@harare.iafrica.com
Wind Speed in meters per second (mph) http://homepages.enterprise.net/hugh0piggott/african36
12 volt 24 volt 36 volt 48 volt 220 volt

Home Power #76 April / May 2000 53

 Systems

Duncan Kerridge, 135 Airport Rd,

Hatfield, Harare, Zimbabwe
+263 4 570804
dragon@mango.zw (text only)
Jon Adams, Siemens Solar, Private
Bag X71, Halfway House, 1685,
South Africa +27 11 652 3655
Fax: +27 11 652 2959
jona@siemens.co.za
Noel Smith, Photovoltaic Design
and Installations (PDI), PO Box
2086, Parklands, 2121, South Africa
+27 11 880 2283
Fax: +27 11 880 9646
pdi@pv.co.za
Michel Malengret, MLT Power, 11
Harris Dr., Sunset Park, Cape Town,
South Africa +27 21 704 2710
Fax: +27 21 73 9278
mltdrive@global.co.za
Hugh Piggott, Scoraig Wind Electric,
Scoraig, Dundonnell, Ross shire,
IV23 2RE, UK
+44 1854 633 286
Fax: +44 1854 633 233
hugh.piggott@enterprise.net
http://homepages.enterprise.net/hug
h0piggott
Dr. Geoff Watson, Manx Wind
Energy Services Ltd,
1 Church Rd., Port Erin, Isle of Man,
IM9 6AH British Isles +441624
832021 Fax: +441624 832 176
geoffw@manxwind.com
www.enterprise.net/manxwind

54 Home Power #76 April / May 2000