|For clients with a
potential water supply, at Carbon Concepts we believe that a water
turbine offers much more potential than a wind turbine for the
- stable power supply
- self regulating (as rivers go into
spate, the head at weirs generally reduces, thereby dropping the
- lower machine cost
- generally lower installation costs
- no complex control electronics
- no over-speed protection
- "invisible" installation
- much lower mechanical risk
- payback over 2 - 3 years rather
than 20 - 30 for wind
We are looking at three types of
turbine, covering applications for most hydro situations, initially
up to 5 KW
For a client requiring 2 KW to offset
the electrical energy use in a house or office, the water turbine
will provide that power continuously, unless there is extreme spate
To provide this average power, how large a
wind turbine do we need? Well, based on the B&Q publicity
for their Windsave wind turbine, the average wind speed is typically
4 m/s. Most wind turbines are rated at 12 m/s, and the power
is proportional to the cube of wind speed, so to provide an average
of 5KW, the wind turbine has to be rated at
(12 / 4)3 x 2
= 54 KW !
This would be a VERY expensive piece
of equipment to install.
CAN I HAVE WATER POWER?
To get useful power out of a water source we need;
- in most cases, a sufficient volume of flow so that
the turbine installation does not affect the river flow and upset
The technology is infinitely scaleable. The Hoover
dam shown here is a little extreme, but does show that, given a
sufficient head and flow, powers of 10s of megawatts are possible.
The graphs shown below indicate the potential power
and required flow for a given head.
CARBON CONCEPTS TURBINES
The illustration on the left shows our first water
turbine. It has a 110mm diameter turbine and is rated at 500
watts with a 1.5 metre supply head.
Although we intend to develop this into a
production machine, we have intentionally started with a small
turbine so that it can easily be transported for
demonstration. It uses the 200
watt generator shown in our site.
We hope to move rapidly to a 220mm turbine, which
will produce 2 kw at 1.5m head, and 4 kw at 2.5m head.
The graphs presented below illustrate how the
power and water flow vary with diameter and head.
For applications where there is a low head (in
this case less than 1metre), but where there is plenty of flow, we
have designed the unit shown on the right. To draw this power
from such a small head we have a 300mm diameter turbine which
requires a flow of 240 litres per second.
If sufficient flow is available, this design can
be used with larger heads and will produce considerable power.
For example, with a 3 m head, it should produce about 10kw.
The power output is very
dependant on the turbine diameter and the available head. It
is proportional to the diameter2 and the head1.5. The graph on
the left illustrates some examples based on derivatives of our small
consideration is the water flow necessary to achieve maximum powe
from the turbine. The requirement can be quite high, and must
be a reasonably small proportion of the total flow if secondary
environmental problems are to be minimised. The graph on the
right gives an indication of the flows necessary for our turbines.