Solar panels vs sugar beets: which powers clean cars better?

Jules Nova

Solar panels vs sugar beets

As the world shifts towards cleaner energy solutions, the question of how to fuel our vehicles without relying on fossil fuels remains a hot topic. Electric cars, bioethanol from sugar beets, and other renewable options are often debated, but one interesting way to assess their environmental impact is by evaluating how much land is needed to power these cars. If you had an acre of land, which option would give you the most autonomy while avoiding fossil fuels? Let’s explore the potential of a sugar beet biofuel-powered car versus a solar-powered electric car.

Option 1: The Bioethanol Car

Imagine you decide to plant sugar beets on your acre of land. In France, sugar beet farming is a significant industry, historically nurtured by Napoleon during the 19th century as a response to the British sugar blockade. Today, it’s primarily concentrated in regions like the North, Ile-de-France, and Normandy.

Sugar from these beets can be converted into ethanol, which is then used as a substitute for gasoline. Vehicles running on E85, a bioethanol blend containing up to 85% ethanol, are increasingly common, though many cars can handle a lower mix like E10.

Here’s the catch: ethanol provides less energy per liter than gasoline. A car that consumes 7.5 liters of gasoline per 100 kilometers will need approximately 11 liters of ethanol to travel the same distance. On your acre of land, you could expect to produce between 6,000 and 9,000 liters of bioethanol annually. This means you could drive up to 70,000 kilometers per year, which is more than seven times the average distance driven by a typical car in France. You’d have enough biofuel to share with your neighbors!

Option 2: The Electric Car Powered by Solar Panels

Alternatively, you could cover your land with solar panels to charge an electric vehicle. An average electric car consumes around 17 kWh per 100 kilometers. To generate enough electricity, you’d install a photovoltaic system that can produce 400 kWc per hectare. Depending on the climate and panel efficiency, this could generate between 800 and 1,400 kWh per kWc annually.

With this setup, your acre could produce about 400 MWh per year, enough to power a car for 2 million kilometers. In other words, the amount of energy generated by the solar panels could allow you to drive 25 times more than with the bioethanol. And here’s the kicker: with just 400 square meters of your land dedicated to solar panels, you could drive the same 70,000 kilometers annually, while leaving the rest of the land for biodiversity, like a forest or pond.

Agrofuels vs. Electricity: A Matter of Efficiency

Clearly, the electric car powered by solar energy is far more space-efficient than a car fueled by sugar beet-based bioethanol. But this comparison is only part of the picture, as it simplifies some of the complexities involved. There are environmental costs to both options.

For example, sugar beet farming relies heavily on fertilizers and pesticides, which can have negative environmental impacts, especially when produced from fossil fuels. On the other hand, the production of solar panels and electric vehicle batteries requires energy, and their lifecycle—starting with the extraction of raw materials—can also be environmentally damaging.

Photosynthesis vs. Photovoltaics: The Real Difference in Efficiency

The key difference between these two options lies in their energy efficiency. The process of photosynthesis, which allows plants to convert sunlight into energy, is inherently inefficient—typically around 1% for crops like sugar beets. In contrast, solar panels have an efficiency rate of 18-24%. This means that photovoltaic panels are 20 to 25 times more effective than plants at converting sunlight into usable energy for vehicles.

Why is this? Plants aren’t designed to produce energy for human use—they create energy to survive, reproduce, and adapt to their environments. Their efficiency in energy conversion is secondary to their survival, whereas solar panels are specifically designed to maximize sunlight absorption and convert it into electricity.

Conclusion: Which Option is Better?

While both bioethanol and solar energy have their merits, the numbers are clear: solar panels offer a much higher energy return per unit of land. By harnessing solar energy, you can power an electric car for a fraction of the land area required to grow sugar beets for bioethanol. However, both options have their trade-offs, and further developments in both technologies may change the equation in the future. For now, though, the solar-powered electric car seems to be the winner when it comes to land efficiency.