A renewable energy system which simultaneously utilizes wind, wave, and solar energy is being developed in Bosnia and Herzegovina by Josip Bilic, an innovator who aims at building a cost-effective device that can produce energy from more than one source.
Device Using Multiple Renewable Energy Sources (DUMRES) is based on a synergy between the installed devices, allowing for the utilization of as much energy as possible per square meter of occupied space and the reduction of investment required per kWh.
Specifically, the DUMRES comprises a plant for storing and using wave energy with buoyancy force regulation, Integrated System of Bearings and Power Transmission (ISBPT), Vertical-Axis Wind Turbine (VAWT) with two large-diameter rotors that rotate freely around the cylinder, and a dual-axis sun tracker with staggered platform.
As every component of the device can be used independently, they are being developed and tested individually before the first working prototype of DUMRES is assembled.
Currently, the second (improved) version of a vertical axis wind turbine is ready to be put to the test, while a solar tracker is now in the design phase and is expected to be built and tested soon, Bilic told Offshore WIND in an interview. “I expect the test results will show that this version of the turbine is a little less efficient than the previous one, but it is designed to have significantly lower manufacturing costs,” Bilic said.
After the testing of these two systems, a working prototype of the vertical axis wind turbine will enter design and construction phase.
A wave energy device had already gone through significant modifications compared to the one described in the patent application, which resulted in a major improvement of the system. “I think that the new version, on which I am still working, could fully meet the goals that are set. Therefore, this part of the DUMRES will be developed last,” Bilic added.
The installation and assembly of the DUMRES are very easy and do not require any specially-made equipment. With maintenance that is required only periodically, the system will prove to have lower investment requirements and minimized operation and maintenance costs.
He explained: “At the beginning of my work, I aimed at developing devices that are highly efficient in energy exploitation. However, after gaining experience through the development of the first vertical axis wind turbine, I am primarily aiming to find technical solutions to lower investment per kWh as much as possible.”
The device can be built in three sizes, depending on its purpose: the small DUMRES (5-60 kW) is planned to supply electricity to individual households and residential buildings with flat roof; the medium-sized one (110-300 kW) would be used to power industrial facilities and the large DUMRES (5 MW) is intended for use on large offshore/onshore energy producers.
Regarding materials that will be used to build the DUMRES, Bilic said: “Parts of the structure that will be underwater or in contact with seawater will be built out of already proven materials. Wind turbine blades would not be manufactured by using molds and composite resin, but rather by implementing a new manufacturing process that would allow serial production and lowering manufacturing costs.”
Right after the patent application was published on April 17, certain interest was shown for the development of the device, Josip Bilic revealed to Offshore WIND. Nevertheless, he pointed out that it is too early to speak about any agreements.
Bilic said that he remains open for any business cooperation on the project, adding: “I would be glad if I could gather a cluster of partners who would supply components.”
Besides being technically challenging, the project also requires financial support, which would speed up the design and building of the operational prototype.
When asked about the estimated overall price of the prototype fabrication and its demonstration phase, Bilic said: “Besides the work that I am doing on my own, the design and construction of the prototype will require around EUR 150,000. Expenses for the demonstration phase will be easier to assess after the prototype is built.”
In addition to its main purpose of producing renewable energy, the DUMRES can be an integral part of seawater desalination plants, which makes the system an important product for areas that are facing water scarcity.
Offshore WIND Staff, August 5, 2014; Images: Navingo