Gasification processes: levers of a renewable and low-carbon energy mix

Pyro-gasification consists in heating organic waste to very high temperatures of between
800°C and 1500°C, in an oxygen-free or low-oxygen atmosphere. This process can be used
to transform waste into gas in two stages:

1. pyrolysis, which breaks the matter down in 3 phases: solid, liquid and gaseous

2. gasification, the addition of small quantities of air, oxygen, water or carbon dioxide
   transforms the solid and liquid phases into synthetic gas (or syngas)

_{*Source : Panorama des gaz renouvelables 2023 publié en avril 2024}

For which type of inputs?

Pyro-gasification can be used to recycle a wide variety of dry waste from forestry,
agriculture, industry or other local authority activities, which would normally be buried or
incinerated:

• Wood: forestry and timber industry residues, cork residues, etc.

• Green waste: branches, wood cuttings and parts, etc.

• Lignocellulosic crop residues: straw, stalks, vine tendrils, etc.

• Non-hazardous wood waste: packaging, pallets, furniture waste, etc.

• Non-recyclable waste: non-recyclable plastics, used tyres, etc.

• Solid Recovered Fuels (SRF): refuse resulting from the sorting of wood, cardboard,
  plastics, etc.

Development prospects

In 2022, a CEI (Call for expression of interest) highlighted a French pyro-gasification industry on the verge of industrialisation: 49 projects were identified, equating to an estimated total gas production capacity of 4.1 TWh/year, equivalent to the consumption of more than 900,000 new homes.

By 2030, the long-term assessment of the recycling capacity of pyro-gasification based on
the goals of regional plans for land use, sustainable development and territorial equality
(SRADDET) and specific studies is around 3 million tonnes of waste per year, enabling 6
TWh of gas to be injected annually into grids and reducing CO2 emissions by approximately
1 million tonnes.

Hydrothermal gasification recycles wet organic waste, either on its own or in a mix, by
combining high temperatures (from 360°C to 700°C) and high pressures (from 210 to 350
bar). The process produces a gas containing high amounts of methane and hydrogen. It can
also be used to separate and recover from metals, minerals (phosphorous, potassium, etc.)
and nitrogen that can be reused in particular in agricultural fertilisers but also clear and
drinking or irrigation water.

_{*Source : Panorama des gaz renouvelables 2023 publié en avril 2024}

For which type of inputs?

A very wide range of wet waste from industrial, urban or agricultural activities can be treated
by hydrothermal gasification:

• Sludge: dredging, urban and industrial water treatment plants

• Agricultural and food residues: dairy byproducts, manufacturing of sugar, fruits and
  vegetables, etc.

• Pharmaceutical residues

• Urban organic waste

• Agricultural effluent and waste: molasses, vinasse, etc.

• Non-spreadable methanisation digestates

Development prospects

In 2024, the French Hydrothermal Gasification working group supported by the “New energy
systems” Sector Strategic Committee launched a CEI (Call for expression of interest) to
identify projects and the interest of project owners for this technology, then to consolidate
and share a vision of the sector with public authorities and stakeholders.

The initiation of the first industrial pilot projects will be used to confirm the relevance of the
technology before a larger-scale roll-out with a view to achieving industrialisation by 2027.
The potential production of synthetic methane that can be injected into the grid is estimated
to be 2 TWh/year in 2030 and 12 TWh/year in 2035. By 2050, the sector is expected to be
able to produce 50 TWh/year of renewable and low-carbon gas.

Through the local treatment of many types of waste, which are not recycled or are scarcely
recycled, pyro-gasification and hydrothermal gasification form part of a circular economy and
energy transition drive.

Renewable and low-carbon gas obtained locally can be injected into the gas transport grid
for local use:

• domestic uses: heating and cooking;

• mobility: NGV or bioNGV;

• industry: energy and raw material;

• and can also be stored;

• or converted into heat and electricity.

These two gasification processes constitute processes that respect the regulatory prioritising
of energy recovery, replacing incineration and burial, and supporting the decarbonisation of
uses by strengthening national energy sovereignty and by multiplying renewable resources.

One example of synergy is the association of a methanisation unit and a hydrothermal
gasification unit to treat biogenic CO₂ produced as well as the digestate that could not be recycled through land application due to risk of water logging.

In addition, these processes involve a wide range of stakeholders: manufacturers, local
authorities and their waste and wastewater syndicates, environmental and waste treatment
companies, farmers and energy sector stakeholders.

Are you developing a pyro-gasification or hydrothermal gasification project? We can offer
you solutions and help you to ensure compatibility and inject this new gas into your grid.

Patrice Couget
Territorial development officer
Tel. : +33 (0)5 59 13 34 69
Mob. : +33 (0)6 07 09 46 67
patrice.couget@terega.fr