Smart solutions for isolated power systems
Author: Francisco Cubillo | Title: Product Line Manager | Published on: Energetica International
Technological development of renewable energies makes possible the decrease of CO2 emissions in conventional power generation plants. It offers, as well, future sustainable alternatives to the traditional energy sources based on fossil fuels, whose extraction is becoming more difficult and expensive.
This technological development offers the possibility of power supply in areas where there is no connection to the electric grid. An example would be the power supply in islands far off a continent. In these cases, there are some features that usually concur:
- Electric generation is carried out, mainly, by means of diesel systems which, usually, are outdated and offer low efficiency and high number of accumulated operating hours. This also means upward CO2 emissions in areas with high environmental value.
- High cost of fuel. It has to be added to the fuel base price all the costs associated with the necessary logistic for the transport of fuel to remote areas.
- The control of the generated energy distribution is, oftently, very rudimentary and is not very much automated, what means an inefficient management.
- Power outages due to failures in the power generation or distribution are very frequent.
To avoid these situations, it is highly advisable the introduction of generation systems based on renewable energies, mainly on photovoltaic and wind energies, but also on mini-hydraulic and geothermal energies in determined cases. First, it is necessary to carry out a study of the existing resources in the island where the generation system will be developed. As a result, we will have a first idea about the most appropriate technology to be installed. After that, it has to be carried out a technical and economic study in order to establish the most suitable percentage of each technology that needs to be set up.
Even though it can be considered extremely attractive, hybridization between conventional and renewable generation systems in isolated power plants presents several technical difficulties that have to be resolved. The integration of renewable energies implies a large variability in power generation. Such variability is independent of the variability of the loads connected during the day. Thus, it is necessary to provide a dynamic stability system to the grid.
The system should behave like a small-scale grid. Generally, it requires a supervision system which is responsible of an optimal management of the power flows in order that no charge runs without supply. Similarly, it is essential to have some energy storage system that allows the reserve of generated energy during off-peak hours to enable the consumption at peak hours.
GPTech has developed solutions for power and control electronics that enable a reliable energy supply for isolated facilities. These solutions mix conventional and renewable generation systems, and present varied profiles of charge. The company has worked on the Smart PV inverters series which, among other features, offer high versatility to operate synchronously with other generation devices through a centralized control. This control is carried out by GPTech’s Power Plant Controller to guarantee an optimal performance of the hybrid power plant. The control strategy of the plant is flexible, with modular control, and allows modifications to achieve different objectives, as minimizing the total cost of power generation or the fossil fuel consumption, as well as achieving an uninterrupted supply of determined charges with the lowest losses, among others.
Isolated hybrid plants may require, as well, energy storage systems in order to supply power temporally. The central control system, along with the BPCS (Battery Power Conversion Systems) developed by GPTech can handle the charge or discharge of energy from different batteries technologies or ultracapacitors.
In short, the technological difficulties associated to this type of facilities could be solved with smart devices as those developed by GPTech. Until now, the proliferation of hybrid isolated generation systems had been hampered by technical and economic aspects since the implementation of such a facility means a major investment. Nevertheless, the technological advances have enabled a reduction of the required investment, as well as an optimal operation of the final installation. Additionally, these improvements produce a faster recovery of the mentioned investment. Therefore, it is expected a larger rise of hybrid generation systems in the coming years.
