Is Your Organic Waste Worth Anything? Five Questions Before You Commission a Study

Most sites we assess believe they have more usable organic waste than they do. A few discover they have far more value than they thought. Both are expensive mistakes to make late.

Before commissioning any study, five questions will tell you most of what you need to know.

1. How much, and how steadily?

Annual tonnage is the number people quote. It is the least useful one.

What matters is the daily rate and how much it varies. A digester or a boiler is sized for a feed rate, not for a yearly total. A site producing ten tonnes a day every day is a far better prospect than one averaging the same figure through a three-month harvest peak and nine quiet months. If the material is seasonal, the project has to be designed around the low season or around storage. Both cost money.

2. What is actually in it?

Composition decides feasibility more often than volume does.

Moisture content sets how much usable energy is left after evaporating the water. Contamination (plastics, grit, metal, cleaning chemicals) determines whether a process runs or blocks. For anaerobic digestion, the share of readily degradable material matters more than the mass. When we sampled mall and household waste for the Biosfair digester, two thirds to three quarters was digestible, a sixth of the mall stream was free liquid, and almost all the plastic sat in pieces larger than five centimetres; a screen, not a sorting line, made the feed usable.

This is why a clean, segregated process residue and mixed municipal waste are not the same problem, even at identical tonnage. The route you can use depends on it.

3. Who actually controls it?

A surprising number of projects fail here.

The waste may already be contracted to a hauler. It may belong to a tenant rather than the site owner. In agro-processing, residues are often sold informally to neighbours as feed or fuel, and that arrangement is invisible until you try to displace it. If you cannot secure the material for the life of the plant, you do not have a feedstock. You have an intention.

4. What does disposal cost you today?

This sets the value of the project before a single kilowatt-hour is counted.

Hauling fees, tipping fees, labour, lost space and regulatory exposure are all avoided costs. On many sites the disposal saving is a larger and more certain benefit than the energy, and it is the part that survives changes in fuel prices.

5. What do you need on site?

Energy you cannot use has little value.

A site with a steady thermal demand can use biogas directly and displace purchased fuel. A site with no heat demand has to generate electricity, which is less efficient and brings grid and permitting questions. Matching output to on-site demand is usually the difference between a strong project and a marginal one.

What comes next

If the answers look promising, the next step is a waste characterisation study: sampling over enough days to establish real composition, moisture and variability, rather than relying on records. If the numbers support a plant and you would rather not fund one, a leased containerised digester is one route.

If the answers do not look promising, that is a useful outcome. Knowing early costs very little. Finding out after procurement costs a great deal. Tell us about your site and an engineer replies with what we would need.

Sources

IEA Bioenergy, Task 37, anaerobic digestion and biogas.

US EPA AgSTAR, feedstock characterisation and digester suitability.

REURASIA, Biosfair waste analysis and characterisation study, June 2026.