Biofuels create several serious problems, but the most significant is their impact on food prices and food security. More than 40 percent of U.S. corn now goes toward producing biofuels rather than feeding people or livestock, and energy mandates in the United States and European Union have driven food prices up by an estimated 20 to 60 percent depending on the crop and region.
Rising Food Prices and Competition for Land
When farmland shifts from growing food to growing fuel, the global food supply shrinks and prices climb. In the United States, roughly 60 million hectares of farmland (about a third of all agricultural land) has moved from food production to biofuel crops. The result: U.S. food production has dropped by nearly 27 percent due to energy mandates, and food exports have fallen by more than 80 percent, from 75 million tons to just 13 million.
That squeeze ripples worldwide. Research from Resources for the Future estimates that biofuel mandates add roughly 17 percent to global food prices on top of increases already caused by population growth. Without any biofuel mandates, food prices would rise about 15 percent between 2007 and 2022 from population changes alone. With mandates, that figure jumps to 32 percent. The people hit hardest are those in low-income countries who spend the largest share of their income on food.
Carbon Debt From Land Clearing
Biofuels are marketed as a way to reduce greenhouse gas emissions, but clearing natural land to grow biofuel crops often makes climate change worse. A landmark study published in Science found that converting rainforests, peatlands, savannas, or grasslands to biofuel cropland releases 17 to 420 times more carbon dioxide than the biofuels save each year by replacing fossil fuels. This upfront burst of carbon creates a “carbon debt” that can take decades or even centuries to repay through the modest annual emissions savings biofuels provide.
In middle-income countries, biofuel mandates are projected to push an additional 74 million hectares of new land into farming by 2022. Each hectare converted from forest or grassland releases stored carbon that had been locked in soil and vegetation for centuries.
Habitat Destruction and Biodiversity Loss
Palm oil, a major biodiesel feedstock, is one of the clearest examples. Indonesia and Malaysia supply 85 percent of the world’s palm oil, and on the island of Borneo, at least half of all deforestation between 2005 and 2015 was tied to oil palm development. Globally, palm oil production threatens at least 193 species on the IUCN Red List, and expansion could eventually affect 54 percent of all threatened mammals and 64 percent of all threatened birds.
Around 10,000 critically endangered Bornean orangutans currently live in areas allocated to oil palm plantations. Tigers face similar pressure. Future expansion is most likely to target Africa and South America, regions especially rich in biodiversity.
Water Pollution and Fertilizer Runoff
Growing biofuel crops at industrial scale requires heavy fertilizer use. Nitrogen applied to fields doesn’t stay put. It leaches into rivers and groundwater, fueling algal blooms that choke aquatic ecosystems, a process called eutrophication. Roughly 0.3 to 0.4 percent of nitrogen applied to farmland escapes through leaching, runoff, or evaporation and ends up in waterways or the atmosphere.
Some of that nitrogen also converts to nitrous oxide, a greenhouse gas about 265 times more potent than carbon dioxide over a 100-year period. The main source of these emissions is fertilized agricultural soil, and biofuel crops contribute to this problem just like any other heavily fertilized crop.
Massive Water Consumption
Biofuel production is extraordinarily water-intensive. Producing one liter of corn-based ethanol in the United States requires about 541 liters of water. Brazilian sugarcane ethanol is even thirstier, at roughly 1,115 liters of water per liter of fuel. In regions already facing water stress, scaling up biofuel production puts additional strain on supplies needed for drinking, sanitation, and food crops.
Poor Energy Return
A fuel’s usefulness depends partly on how much energy you get back compared to what you put in. Corn ethanol barely breaks even, with an energy return on investment (EROI) of about 1.0 to 1.6 in U.S. distilleries. That means for every unit of energy spent growing, harvesting, transporting, and processing the corn, you get back only slightly more than one unit of ethanol energy. Sugarcane ethanol performs better, with an EROI around 1.8, but even that is modest compared to conventional petroleum, which historically returns far more energy per unit invested. Wood-based ethanol actually produces less energy than it consumes, with an EROI below 1.0.
Engine Damage and Compatibility Issues
Biodiesel is more corrosive than petroleum diesel, particularly when it absorbs moisture from the air and begins to oxidize. This degradation attacks engine components that come into contact with the fuel, including piston rings, bearings, fuel injectors, gaskets, and fuel pumps. Copper and brass parts are the most vulnerable, followed by aluminum and steel alloys. Over time, this corrosion increases the wear rate of engine parts and shortens their lifespan.
Biodiesel also performs poorly in cold temperatures and is less volatile than conventional diesel, which can cause starting problems in winter. Fuel consumption tends to increase slightly when running on biodiesel, and overall engine performance drops. These compatibility issues limit how much biodiesel can be blended into existing fuel supplies without requiring costly engine modifications or new infrastructure.