Why Not Use Water or Solar Energy to Power Hydrogen Vehicles?

While the concept of using renewable energy sources like solar power or water to power hydrogen vehicles is intriguing, there are significant practical challenges that make these options impractical. Let's explore these constraints and why electric vehicles (EVs) remain the preferred choice for green transportation.

The Feasibility of Using Solar Energy for Hydrogen Production

It is technically possible to convert solar energy into hydrogen and then use that hydrogen to power a vehicle. However, the current technology and infrastructure make this approach far from cost-effective. The process of producing hydrogen from solar power involves converting sunlight into electrical energy through photovoltaic (PV) cells, which is then used to separate water molecules and extract hydrogen.

The efficiency of PV cells is typically around 20-25%, meaning that a considerable amount of energy is lost during the conversion process. Additionally, to produce enough hydrogen for a car, a vast array of PV cells would be required, making the system both expensive and inefficient.

Vaccuuming Jet Stream: The Realistic Challenges

Even if we disregard the cost and efficiency issues, the challenges do not end there. A typical car requires around 15 to 20 kilowatts (kW) of power to overcome friction and maintain speed on a straight, level road with no wind, traveling at about 50 mph (approximately 80 kilometers per hour). To generate this amount of power, a 20 kW PV array would need to be positioned directly at the sun and in full sunlight continuously. However, the practical limitations of PV efficiency and surface area requirements make this approach unfeasible.

For example, a 100% efficient PV module, covering the roof, hood, and trunk of the vehicle, would only produce about half the required power. Moreover, the most efficient PV cells are around 25% efficient, which means the array would need to be much larger, possibly several times the surface area of the car, and continually aligned precisely in both azimuth and elevation to remain directly facing the sun. This is impractical for an on-road vehicle with dynamic driving conditions.

On the Other Hand: Water and Its Limitations

Water, being fully oxidized hydrogen, cannot provide any energy itself. Even if we were to consider using water, the process of extracting hydrogen from water through electrolysis is energy-intensive and not practical for vehicle power. Converting electrical energy from solar panels into hydrogen and then using that hydrogen in a vehicle is far less efficient than using the electrical energy directly in an EV.

The Energy Wastage of Hydrogen Fuel

Even if hydrogen is used efficiently, such as in fuel cells to generate electricity and drive an electric motor, the overall efficiency is still lower than that of battery-operated vehicles. Fuel cells can convert hydrogen into electricity, but they cannot provide the high power that batteries can, which is a critical factor in EV performance.

One of the primary advantages of EVs is their instant torque and acceleration. A well-built EV can easily outperform a traditional gasoline-powered muscle car. Batteries can provide high current at a stable voltage, delivering rapid acceleration and a robust driving experience. In contrast, fuel cells, even if they are efficient in converting hydrogen to electricity, cannot provide the same level of power. They struggle to even provide enough power to climb a mild incline.

Conclusion

In summary, while the idea of using renewable energy sources like solar power or water to power hydrogen vehicles seems promising, the practical challenges make it less viable compared to electric vehicles. EVs, especially when powered by renewable energy, offer higher efficiency, better performance, and a more practical driving experience. As technology advances, the focus continues to shift towards improving battery technology and infrastructure for green energy solutions, making EVs the future of sustainable transportation.