
Biomass power plants: operation, advantages and disadvantages
Biomass is becoming increasingly well known as the main source of renewable energy on Earth. Biomass is the production of electricity and heat through the combustion of plant or animal matter. The main interest of this solution of energy production is the fact that the material used is inexhaustible, as long as it is produced in an ecological way, contrary to fossil fuels.
The operation of a biomass plant
A biomass power plant produces electricity from the steam that is released during the combustion of plant or animal matter in a combustion chamber. This process is done in several steps:

1. Combustion: The biomass is burned in a combustion chamber.
2. Steam production: The biomass releases heat that heats water in a boiler. The water is transformed into steam, which is sent under pressure to turbines.
3. Electricity production: The steam turns a turbine which in turn drives an alternator. Thanks to the energy supplied by the turbine, the alternator produces an alternating electric current. A transformer raises the voltage of the electric current produced by the alternator so that it can be more easily transported in medium and high voltage lines.
4. Recycling: At the exit of the turbine, part of the steam is recovered to be used for heating. This is called cogeneration.
The rest of the steam is again transformed into water thanks to a condenser in which cold water from the sea or a river circulates. The water thus obtained is recovered and recirculated in the boiler to start another cycle.
The advantages of biomass

The main advantage of biomass power plants is simple: they allow to create energy without using fossil fuels, thanks to ecological resources. With biomass, it is also possible to recover waste and reuse it to create energy.
This mode of electricity production has, in principle, a neutral carbon balance, because it rejects a relatively low quantity of CO2, similar to the quantity consumed by the plants during their growth phase.
In a world where ecology and respect for the environment are increasingly important, the use of natural fuels is necessarily a welcome solution. However, this solution is contested by many associations...
Different mechanisms allow to create energy with biomass:

1. Combustion of raw material:
This is the most frequently adopted method. It relies on the combustion of raw material, such as wood, in order to create steam, which is necessary for the turbine to function.
One detail is particularly pointed out by environmental associations: deforestation.
Wood being the main material consumed by biomass power plants, the increasing presence of this mode of energy production will potentially cause a need in trees more and more important. It will be necessary to be careful that the exploitation of the resources is not too intensive.
Example of use: from residue of sugar cane production: bagasse. This form of biomass is used instead of coal to fuel thermal power plants. This practice allows to use the natural resources of the islands in the DROM-COM (Reunion, Guadeloupe, ...).

2. Gasification:
This is an innovative alternative that consists, through a thermochemical process, of transforming solid biomass into combustible gas that can be used in multiple ways. With this process, the raw material is transformed into a gas, which will then be used as fuel.
Example of use: Gasification can create a biogas, for example thanks to hemp. Gasification is a high-temperature thermo-chemical process (between 800°C and 1400°C) that can be used for various inputs such as dry biomass, solid recovered fuels or wood waste. Hemp can therefore be used in this process.
Similarly, there is an association in Japan called HySTRA, which aims to develop a reliable and economical hydrogen supply network. Thanks to this association, a terminal for unloading this fuel is being built in Japan, and a lignite gasification plant is also being built in Australia.

3. Methanization:
The methanization process is sometimes used by biomass power plants. In this case, the organic materials used, such as household waste, paper, cardboard or manure, are not burned, but fermented.
Example of use: Methanization will create a biogas used for the operation of cars and trucks. It is a technique in full expansion! The number of methanization sites injecting biogas into the gas networks has largely increased in 2020. As of December 31, 2020, France had 214 biogas plants.
A national information portal for the general public dedicated to methanization has recently been created. Called MéthaFrance, its objective is to provide educational answers to questions that French people may have about the development of methanization in our territories.
Guaranteeing the safety of workers in biomass power plants
Risk prevention and the sustainable improvement of working conditions are issues to be taken into account in biomass power plants. Several risks are present: manual handling of heavy loads, the presence of awkward postures, potential contact with dangerous chemical agents, and the sometimes high noise level.
In order to protect the employees of biomass plants, several Personal Protective Equipment (PPE) must be put in place and used. Depending on the sector of activity, the recommended PPE is different. For biomass, the recommended equipment is :
Respiratory protection

Respiratory protection is mandatory to protect an operator, in case prevention is not enough.
Choosing a respiratory protection device must be done after a complete analysis of the workstation. Then, it will be possible to choose the appropriate protection from those that exist (disposable or reusable masks, half-masks and masks with filtering cartridges, respirators, ventilation devices, etc.).
Fall protection

Fall protection encompasses several elements: connection, holding, anchoring, lanyards, reels, ropes, lifeline, ties, harness, etc.
The equipment is selected according to European standards and must be CE marked.
Gas detection, portable or fixed

Several gas detectors exist, and it is necessary to analyze them in detail to know the different functions and characteristics. It is therefore necessary to be well aware of your needs and to evaluate the gas risks related to your activity.
Our selection of equipment for biomass plants

Single gas detector GASMAN Crowcon

REGARD 3900 gas detection system

REGARD 7000 detection unit

Fixed gas detector POLYTRON 7000

Fixed gas detector POLYTRON 3000

BIOSCAPE escape breathing apparatus

Honeywell H-DESIGN Safety Harness

EDGE MILLER fall arrest lanyard

Tie Strap TITAN Honeywell Miller
Sources: EDF, Lendopolis blog