Periodic Reporting for period 3 - Hydrolowhead (PROFITABLE LOW HEAD HYROPOWER)
Reporting period: 2017-03-01 to 2017-10-31
Hydroelectric power plays a key role in power generation worldwide through production in big plants, however conventional turbines installation at a micro level is currently unattractive because of large initial investment and their low efficiency.
HydroLowHead Project pretends to overcome this efficiency problem and promote the use of micro turbines for energy production. Our “regenerative variable speed control system” works at variable speed to produce as much energy as possible according to available water flow (See Figure 1. Micro Turbine). This project's goal is to develop a product able to make profitable energy recovered from small water falls, which would mean generating several gigawatts in Europe which are being currently wasted.
Installation time is between 1 and 2 months, reducing civil works by 35%, and payback for final clients is between 2 and 4 years.
Typical applications for our micro turbines would be arquimides screws, and ecological flows from mini and big hydro dams, that are forced by law to release large flows of water downstream of the dam, reducing notably the amount of energy produced. Hydrolowhead has been designed to help them to recover the full hydraulic potential of the facility.
As a result of simulation, maps of pressure and velocity were obtained as well as efficiency of the designed rotor. Also, thanks to the static study, the efforts and deformations of the rotor could be studied. With this studies, we also obtained the hydraulic losses in the pipe line.
Based on previous hydraulic and mechanical calculations and axial turbine designed, a turbine prototype at scale 1:5 has been built, in order to take tests and evaluate several performance features. Results obtained from this prototype will be extrapolated to prototype at scale 1:1.
Manufacturing a prototype at scale 1:1 was planned, however, during project progress, it was decided to perform a prototype at scale 1:5 previously. This decision does not modify project development and budget and its implementation is based in improving the design, costs saving and the possibility to study failures easily.
The validation at scale model 1:5 was performed in order to correct any mistake that may have committed during the conception of the machine design or drawing elaboration and not reproduce it in the prototype 1:1, since this would represent a great cost and huge waste of time. (see figure 3: Model 1:5 Hydro Low Head turbine).
Functional behaviour of the turbines built are being validated in laboratories from the University of Seville, obtaining the yield curves characteristic of the turbine (flow variation, behaviour under pressure variations, water speed, etc.) and analysing its vibrations as well as material resistance of the turbine and the piping system.
On the other hand, in order to develop the power stage system for operating turbine in variable speed mode, we have defined and designed, in a first approach, a system at smaller scale, in order to check that calculations were correct and control system was stable. This software was designed to be scalable in future real turbines. Software design was divided in four steps: software technical specifications, functional rules definition, final components selection and user interface creation.
Once the electronic stage system was totally defined and designed, a prototype of the electrical cabinet that manages the HydroLowHead regenerative turbine was built.
Functional behavior of the power cabinets was subsequently validated, obtaining the following results:
- The regenerative equipment is working within expected performance and efficiency;
- The base of the closed control loop works properly, although it needs to be improved, as well as adapted for real hydraulic conditions;
- The carried out design base are correct;
The installation of conventional turbines requires associated civil works for acquiring, unloading and assembling the turbine, typically representing between 40 to 50% of the costs of such projects, resulting in a high time cost for installation, assembly and space requirements. Also, the mechanical complexity of these devices makes acquisition costs high.
Usually most locations susceptible to exploitation of mini and micro hydraulic exhibit great variability in flow and pressure drop available. Mechanical control elements regulate the rotational speed of the turbine generator so that its speed is synchronized with that of the grid (50Hz), thus the regulation range is very limited and insufficient for the variability present in most locations with micro and mini hydraulic power.
In this project TECNOTURBINES and SENDEKIA have developed new concept of hydraulic turbine: the hydraulic turbine with regenerative variable speed electronic control.
In this period, an electronic control system prototype for micro turbines was built based on based on the electronic control system patented by TECNOTURBINES. This technology takes advantage of the effect of the electric motors which, acting as generators connected to a load, generates a resistive torque onto its axis. By coupling this axle to a hydraulic turbine, and changing the braking torque exerted on the turbine generator, we can control the amount of power draw, and therefore the operating point of the turbine.
During this period, we have performed hydraulic and mechanical calculations and the axial turbine design. Once these activities were ended, a prototype at scale 1:5 has been developed, in order to take tests and evaluate several performance features. Results obtained from this prototype will be extrapolated to prototype at scale 1:1.
Using this disruptive concept of hydro turbine (a control system based on regenerative braking had not been used before in hydro turbines) mixed with the advantages of using an axial shaft turbine (low head applications), allows our solution to reduce the installation costs, assuming this as a savings of 85%.
According to the European Small Hydropower Association (ESHA), installed capacity of small hydropower should increase nearly 30% by the year 2020. Worldwide only 5% of the world's small-scale hydropower has yet been exploited, the technical potential of small hydropower is estimated at 150 GW to 200 GW.