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Hybrid Systems in Remote Areas
The use of renewable energy systems to supply electrical power in remote, off-grid areas is fairly well established throughout the world.
Depending on the resources available, such systems typically rely on wind turbines and/or photovoltaic (PV) modules as the primary renewable power source. These systems usually also employ batteries for short-term back-up power. The recent technology advancements in hydrogen electrolyzers, fuel cells, internal combustion engines, and storage in the past five years have made the storage of excess renewable energy as hydrogen an intriguing alternative to established backup power systems. Assuming that reliable, low maintenance, systems can be designed, they are expected to first become competitive in remote locations, which have expensive electricity because they are not linked to power grids serving the main urban areas.
Studying the feasibility of adding hydrogen systems to the locations considered requires defining and optimizing the size and number of the system components. There are many different size possibilities and hardware configurations to be determined. For example, the size of the wind turbines, electrolyzer, hydrogen storage tank, fuel cell, must all be determined to ensure that the system is able to meet the required load at the least possible cost.
A usual structure of such systems can be seen in the following figure (Click picture to enlarge)
Power Flow Diagrams of Renewable Energy systems using Fuel Cell (Click picture to enlarge)
The theory of operation is to use the wind turbine or PV system to meet the load directly whenever possible to minimize the losses in the battery and fuel cell. When excess wind or PV energy is available, power is supplied first to the batteries, then to an electrolyzer, which consumes water to generate hydrogen for storage. The batteries or the fuel cell is then used to meet the load when the wind or solar energy is insufficient.
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Fuel Cell Canada[3] Fuel Cells 2000