Mature pongamia pinnata trees stand up to 50-feet high, and their dense canopy can be almost equally wide. They sport hearty, dark-green leaves that retain moisture even under intense heat. Small clusters of white, purple, and pink flowers blossom on their branches throughout the year, maturing into brown seed pods that litter the ground. When the seed pods are pressed, the oil that is extracted can be used as biofuel to power pumps, generators, and even heavy machinery like tractors, cars, and trucks.
A Tough, Reliable Tree
Extreme weather conditions are no obstacle for the pongamia. The tree is well suited to the intense heat and sunlight of places like south India. Its dense network of lateral roots and thick, long taproot make it drought-resistant.
The tree can even help rehabilitate the land. The dense shade it provides slows the evaporation of surface water. Its root structures promote nitrogen fixation, which moves nutrients from the air into the soil. Once established, the pongamia can give a reliable harvest of seeds for fifty years.
One Seed, Many Products
Vegetable oils can be used to supplement or even replace traditional petroleum fuels. Raw pongamia oil can be used in stationary generators, and after some refinement, it can be used to be used to power motorized vehicles. The refining process, known as transesterification, involves heating unrefined oil and agitating it with a catalyst for a few hours to separate the pure vegetable oil from other constituents, such as glycerol. This transforms 90 percent of the dark-brown unrefined oil into a light-yellow liquid that can properly be called biodiesel. The glycerol in the remaining 10 percent has a wide range of applications, including use in cosmetics and pharmaceuticals. In fact, almost every step in the life cycle of pongamia seeds results in a safe and useful product.
Once the oil has been extracted from the seeds, the remaining seedcake can be mixed with water and placed in an airtight environment where it ferments, producing a flammable gas and a slurry, which is a safe and highly effective organic fertilizer. The gas can be compressed and stored in small tanks for use as cooking fuel. (Biogas burns far cleaner than wood or cow dung, the traditional cooking fuels, and so causes fewer respiratory disorders.) Widespread use of gas for cooking could also help curb the rampant deforestation common to areas where wood is used as a primary fuel.
The seedcake has other uses as well. The toxic compounds that make pongamia seeds repellent to grazing livestock can be extracted to create a potent natural pesticide. Once these toxins are removed, the seedcake makes a cattle feed rich in amino acids.
Biofuel is vastly superior to its fossil-derived counterpart when it comes to the effect it has on the environment. Engines running on biofuel emit almost no sulfur dioxide and particulate emissions are typically reduced by more than 50 percent.
On a global scale, biofuels reduce the net emission of greenhouse gases, especially carbon dioxide. While it is true that any burning fuel releases carbon into the atmosphere, fossil fuels are composed of carbon previously stored below the earth’s surface in the form of oil, natural gas, and coal, and as they burn they release a new load of carbon into the air. On the other hand, the carbon content of biofuels, like pongamia oil, has been taken directly from the atmosphere as the tree grows. On average, one hectare (2.47 acres) of pongamia absorbs 30 tons of carbon per year. Thus burning pongamia oil instead of fossil fuels has the overall effect of reducing carbon dioxide emissions by about 75 percent and carbon monoxide emissions by almost 50 percent. So planting millions of acres of pongamia will help slow global warming.
Our History with Pongamia
The Himalayan Institute first began working with pongamia in 2003 in order to aid farmers in drought stricken south India. A crop was needed with huge sale potential that could be cultivated on dry, marginal land. Pongamia fit the bill as it has the ability to grow in harsh conditions and, since there is a great need for petrol alternatives, pongamia’s capacity as an energy producer makes it a very viable cash crop. Today, the Institute’s work with pongamia has expanded to include Cameroon, Mexico, and the Tibetan Settlements. Learn how you can support our pongamia plantations and the Tibetan culture at Trees for Tibet.