With the continuous depletion of fossil fuels and the aggravating effects of climate change, the world is being pushed towards an energy transition. In the process of development, Hybrid Renewable Energy Systems have been emphasized, especially those combining solar and wind technologies, and have become a prominent solution to the energy problem.
Hybrid renewable energy systems can alleviate the intermittency problems of individual renewable energy systems and can improve the overall reliability and stability of energy production.
For example, the combination of solar and wind systems, where the solar system reaches peak output during the day and wind energy can be utilized when the solar energy supply is reduced, allows for a more stable energy supply by integrating different sources of energy, reducing the consumption of fossil energy sources and decreasing the problem of power shortages during inclement weather.
Moreover, hybrid renewable energy systems are often combined with energy storage systems, which can store the remaining energy from the hybrid renewable energy system and feed the stored energy into the grid during peak periods, improving the stability of the grid and making the hybrid renewable energy system more adaptable to the existing energy infrastructure.
Hybrid renewable energy systems can be categorized into 3 types: grid-connected, off-grid, and microgrid systems, which are described as follows
HRES (Hybrid Renewable Energy Systems) are directly connected to the centralized grid, the main advantage of grid-connected systems is that they are easier to implement and can take advantage of the existing grid infrastructure, the disadvantage is that they will receive the impact of the grid, they are mainly suitable for urban or suburban areas where the grid connection is reliable and stable.
These systems operate independently of the centralized grid, off-grid HRES (Hybrid Renewable Energy Systems) typically require energy storage (e.g. batteries) to store power and can provide energy independence when the renewable energy system is not generating power or the grid is unavailable, but off-grid systems require storage and more complex control systems, with higher upfront investment costs.
Microgrid systems are between grid-connected and off-grid systems and are systems that can operate independently or in conjunction with the grid, microgrids typically combine multiple types of renewable or conventional energy sources and energy storage, microgrid systems are highly flexible and can provide resilience in the event of a grid failure but are more expensive to use.
Hybrid renewable energy systems can use a combination of solar panels and wind turbines. Wind turbines can have more output when the wind is strong, and in the hot season the solar panels will produce peak output, which can combine the systems to feed the grid and ensure a more stable and continuous supply of energy to the grid, which can be useful in areas where solar and wind resources are complementary. Controllers can also be utilized to divert surplus power for charging batteries to be stored for later use.
Hybrid renewable energy system can be combined with wind turbines and pumped storage power generation, using the energy generated by wind energy to pump reservoirs at low elevation to high elevation reservoirs, and when needed, the water is then released from high elevation to the hydroelectric plant to generate electricity, but this hybrid renewable energy system is limited in terms of implementation conditions and high cost.
The utilization of solar energy is mainly photothermal utilization and photovoltaic utilization of two kinds of solar thermal energy and solar panel combination, can improve the comprehensive utilization of solar energy, and can meet the user’s demand for high-quality electricity and thermal energy. It is mainly the conversion of solar energy into electricity at the same time the heat of the solar thermal collector is utilized to produce both electrical and thermal energy gains at the same time.
The utilization rate of this hybrid renewable energy system is higher than that of the solar system, but there is an intermittent problem, the supply of energy is unstable, and storage devices need to be added to improve stability.
Hybrid renewable energy systems have great promise for the future, and in combination with energy storage technology, they can greatly reduce the consumption of fossil energy to cope with harsh climate impacts.
