Techno-Economic Feasibility and Operational Emission Assessment of Hybrid Renewable Energy Systems for a Large Educational Building: A Case Study in Türkiye
This study evaluates the techno-economic feasibility and operational emissions of grid-connected and off-grid hybrid renewable energy systems for a large educational building in Türkiye, finding that while biomass and solar configurations significantly reduce emissions, their cost-effectiveness depends heavily on local resource quality and the specific grid electricity price.
Original paper licensed under CC BY 4.0 (https://creativecommons.org/licenses/by/4.0/). This is an AI-generated explanation of the paper below. It is not written or endorsed by the authors. For technical accuracy, refer to the original paper. Read full disclaimer
Every building needs electricity to light its rooms, power its computers, and keep its climate comfortable. For decades, this energy has come mostly from large power plants that burn fossil fuels, releasing gases that warm the planet. In recent years, engineers have looked for ways to generate power right where it is needed, using sunlight, wind, or even organic waste. This approach, known as a hybrid renewable energy system, mixes different sources together to create a more reliable and cleaner supply. The challenge lies in figuring out exactly which mix works best for a specific building, considering how much sun and wind are available locally, how much waste can be collected, and how much all of this costs compared to simply buying electricity from the grid.
Researchers in Türkiye recently tackled this question for a large university classroom building. They wanted to know if it made sense to power the building with a custom mix of solar panels, wind turbines, and a generator that runs on biogas made from animal manure. To find the answer, they built a detailed computer model of the building's electricity use, tracking exactly how much power was needed every hour over several years. They then simulated different combinations of renewable equipment to see which setup would be the cheapest to run and which would produce the least pollution. The study focused on a specific campus in northwestern Türkiye, a region with moderate sunshine but relatively weak winds, and an abundance of cattle that could provide the manure needed for biogas.
The team discovered that the most cost-effective way to use renewable energy for this building was to stay connected to the main power grid while adding solar panels and a biogas generator. In this scenario, the building would generate about 70 percent of its own electricity from the sun and the manure, buying the rest from the grid. This hybrid setup cost about 19.9 cents for every kilowatt-hour of electricity it produced. While this was the cheapest option among the renewable designs, it was still more expensive than simply continuing to buy all the electricity from the grid at the current local rates. The researchers found that adding wind turbines to this mix did not lower the cost; because the wind at this specific location is often too weak to turn the turbines efficiently, the wind energy contributed very little to the total power, making the extra equipment an unnecessary expense.
The study also explored what would happen if the building tried to run completely off the grid, cutting its ties to the main power lines entirely. To do this, the system would need a massive battery bank to store energy for cloudy or windless days. The simulation showed that while this fully independent system was technically possible, it was far more expensive, costing about 55.5 cents per kilowatt-hour. In this off-grid scenario, solar panels provided nearly half of the power, the biogas generator provided about 40 percent, and the wind turbines provided the remaining 12 percent. Even with the wind contributing a small amount, the low wind speed meant the turbines ran at a very low capacity, acting more as a small supplement than a primary power source.
Beyond the costs, the researchers looked at the environmental impact of these different setups. They found that switching to the renewable systems dramatically reduced the amount of carbon dioxide released into the air. The off-grid system cut emissions by more than 99 percent compared to using only the grid, while the grid-connected hybrid system reduced emissions by about 80 percent. However, the study noted that burning biogas does produce other types of pollutants, such as carbon monoxide and tiny particles, which would need to be managed with proper exhaust equipment. The researchers were careful to point out that these numbers represent the emissions from running the system, not the total environmental cost of building the equipment or transporting the manure.
Ultimately, the study highlights that there is no single perfect solution for every building. For this specific university, the best balance of cost and clean energy involved using solar power and manure-based biogas while keeping the safety net of the main power grid. The wind, despite being a popular renewable resource, was not a strong player at this location. The findings suggest that while going fully independent is possible, it comes with a steep price tag, and that the most practical path to cleaner energy often involves a smart mix of local generation and the existing power network. The work serves as a realistic guide for other educational institutions, showing that local conditions like wind speed and waste availability are just as important as the technology itself when designing a sustainable energy future.
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