Biomass is a term that has gained popularity recently, but the concept it originated from has been around for centuries: burning residues to generate energy. The difference between burning twigs and logs to cook and heat homes, still a routine practice for populations living in rural and isolated areas, and using biomass, is that the second option is a clean energy, coming from renewable sources, and does not harm the health of people or the planet.

The raw material can come from sugar cane or corn, used in the production of biofuels, residue from reforested timber, planted forests, manure, residue from agricultural production, such as cobs, cane pulp, the straw and husk from corn, rice, wheat, soy and coconut, and even organic urban waste. They are viable alternatives to fossil fuels, such as carbon and oil, which are responsible for 80 percent of global greenhouse gas emissions. Biomass is also a renewable source of energy: it can meet a demand that keeps growing.

Each year, the planet gains 83 million inhabitants. There will be almost 10 billion people by 2050, according to the United Nation’s World Population Prospects 2017. More people on the planet means more demand for food and energy. The challenge is to supply this population in a sustainable manner, with a smaller impact on climate change.

1. The use of agricultural waste solves an important environmental problem: it takes care of what is not used in farms, refuse that is normally discarded through decomposition or burning. These processes release carbon gas, which contributes to global warming.

2. Unlike hydropower, which constantly generates power, and solar and wind sources, which depend on weather conditions, biomass can produce energy on demand, in a predictable fashion.

3. During growth, plants and trees store carbon. The burning of this biomass to produce energy returns this stored-up carbon gas to the atmosphere. The continuous capture and release of carbon between the atmosphere and plants, combined with energy efficiency and cogeneration processes, lead to a compensation in emissions. When this equilibrium is reached, the amount of carbon emitted is zero.

A large metal structure with pipes that run in every direction, surrounded by a short yellow fence. A street runs around it, and in the back is a clear blue sky with a few clouds.

Steam biomass power plant belonging to the Combio company at Votorantim Metais in the city of Três Marias (Thiago Meira / Combio)

According to the World Council of Energy’s World Energy Resources 2016 report, bioenergy – the term used for energy generated from biomass – is currently the biggest source of renewable energy in the world, corresponding to 14 percent of renewable energy and 2 percent of global production. The World Bioenergy Association estimates that the use of biomass could increase threefold by 2035. At that point, renewable sources could supply 50 percent of the world’s energy demand.

In Sweden, Finland, and Germany, the bioenergy share of the energy matrix is between 20 and 30 percent. The world’s three most populous countries are headed in the same direction. In India, the share is at 10 percent. China has promised to increase the share of non-fossil fuel energy from 11 percenttoday to 20% by 2030. And the United States is building 115 biomass energy plants, according to data from World Energy Resources 2016.

In Brazil, biomass provides 8.4 percent of all electricity and is growing constantly, as shown in the Mining and Energy Department’s Monthly Energy Bulletin from July of 2017. One of the country’s bioelectricity companies is Raízen, which runs thermoelectric plants in its 24 mills in the state of São Paulo. They add up to a potential 2.8 megawatt-hour of electrical energy sold every year, enough to supply a city of 5 million.

Industry is another important market for biomass, which can be burned in boilers and take the place of fossil fuels, helping companies reduce greenhouse gas emissions. But this is still an expensive investment. The solution found by some businesses is to contract with companies that produce and sell steam from biomass, such as Combio Energias Renováveis.

In 2017, the eight boilers installed by Combio in the states of São Paulo, Pará, Rio Grande do Sul and Minas Gerais will be responsible for less than 210 thousand tons of carbon gas in the atmosphere, according to information from the company. The fuel used to produce the steam comes from rice husks, timber residue, and açai pits collected in locations near the industries where it will be used.

Biomass has also gained ground on a smaller scale, with biodigestors generating energy from food waste from homes, hotels and restaurants.