Aquanovis’ technology is an evolution of run-of-river hydroelectric generation. The invention is built entirely with pre-existing and proven components in order to reduce engineering and investment risk.
The invention was developed to meet four primary objectives:
- Reduce ‘environmental impact’
- Reduce ‘construction cost’
- Increase resilience
- Open new sites for hydroelectric development
By creating an almost completely subterranean infrastructure, environmental impact is avoided. The technology works to minimise the required water extraction, to further reduce environmental damage. Undulating surface topography is ignored for penstock design. The overarching engineering objective is to maximise the electricity output of every cubic metre of water per second that is extracted, by creating high ‘heads’ (vertical distance between water intake and the hydroelectric turbine) in locations where current technology can not be utilized.
The installations are purposefully small scale, ranging up to a maximum of five megawatts of output. If larger power output is required at one location, a second (and or third) unit are built in parallel.
The technology is an ideal solution for decentralised renewable electricity generation. As well as opening up new sites for hydroelectric development the technology can be used to retrofit hydroelectric generation at non-powered dams. The invention provides an option for revenue from power generation in areas of outstanding beauty. It is a new, clean and compelling technology to satisfy the need for electricity in remote and mountainous regions.
There are three options of turbine design that can be employed within Aquanovis’ installations. The choice is determined by the mix of head (vertical height of the system) and flow as can be seen from the following table:
The Pelton turbine consists of a number of water jets which can be controlled independently. This enables this turbine design to operate efficiently with the greatest variations in water flow. Pelton’s can handle higher ‘head’ than any other turbine type. Pelton turbines are a member of the ‘impulse’ family of turbines.
The Francis turbine is cheaper to install than the Pelton and has a different ‘head’ and ‘flow’ range. It is also better at dealing with water that has a higher volume of sediment than the Pelton. However the efficiency of the Francis turbine drops off quite rapidly as water flow decreases below the design flow-rate.
Turgo turbines are similar to the Pelton design; they are also a member of the ‘impulse’ family of turbine designs. They operate with a lower ‘head’ and ‘flow’ variation than Peltons.