There is a important difference between the carbon dioxide (CO2) emitted by heating diesel, natural gas and other fossil fuels and CO2 emitted by renewable energy sources such as biomass. Both emit CO2 when burned, but in terms of climate change, the impact of that CO2 is very different.
To understand this difference, it is useful to think small and scale. It is useful to think in your own garden.
A tree, every year for 30 years.
Imagine you are lucky to have a garden with space for 30 trees. Three decades ago, you decided to plant a tree every year, every year. In this example, each tree grows to maturity for thirty years, so today you find a flowering grove with 30 trees in different stages of growth, ranging from one year to 30 years.
At 30 years of age, now, the oldest tree has reached maturity and you cut it, for example at the end of winter, before the sap rises, and you let the wooden logs dry during the summer. Plants a new seedling in its place. During spring, summer and autumn, the 29 trees and the new seedling continue to grow, absorbing carbon from the atmosphere to do so.
Winter comes then and to combat the cold, dry wood is burned to keep warm. Burning it will emit carbon into the atmosphere. However, at the end of winter, the other 29 trees plus the sapling he planted will be in exactly the same stage of growth as the previous year; They contain the same amount of wood and, therefore, the same amount of carbon.
Whenever a tree is talented and replanted every year in a 30-year cycle, the atmosphere will not see additional CO2 and will have used the energy captured by its growth to heat your home. Using only what grows is the essence of sustainable forest management.
If you didn't have your dry wood to burn, you may have been forced to burn coal, diesel or gas to heat your home. In the course of the same winter, these fuels would have emitted carbon into the atmosphere that accumulates endlessly, causing climate change.
Your tree management not only provides you with an endless renewable fuel supply, but you can also enjoy other benefits, such as the shelter provided by their trees and the diversity of wildlife they attract.
No carbon added
This is a simplified example, but the principles are valid if your forest contains 30 trees or 300 million; The important point is that with these renewable carbon emissions, as long as less wood is extracted from the one that is growing and the trees that are cut down are replaced, new carbon is not added to the atmosphere. That does not happen with fossil fuels. To be equally renewable it is true that he could have chosen not to have trees, and instead, he could build a wind turbine or install solar panels in his garden. That would be another perfectly reasonable option, but you will still need to use other fuels when the sun does not shine or when the wind does not blow. Worst of all, you don't get all the other benefits a forest brings: seasonal beauty and habitat that maintains wildlife.
In Europe, biomass comes from our forests that we deal with Sustainable Forest Management.
Source: Matthew Rivers, Group Special Advisor23rd February 2017 https://www.drax.com/sustainability/biomass-carbon-story/