Which has the lower lifecycle impact, palm leaf or PLA plates?

What does each material go through before it becomes a plate?

The two lifecycles look nothing alike. PLA is a plastic made from plant sugar. Palm leaf is a fallen leaf sheath that has been washed and pressed. That difference shows up at every stage.

What do the published carbon figures say?

There is one peer-reviewed lifecycle study of areca leaf plates that I would point a buyer to. Gautam, Mata, Martins and Caetano (Energy Reports, 2020) looked at areca plates, bowls and boxes made in India and shipped 12,320 km by sea to Lisbon. Their figure for plates was about 1,033 kg CO2e per tonne. That covers collection, processing, shipping to Europe and disposal, which they assumed was 80% landfill and 20% incineration.

For PLA, the most quoted source is the eco-profile of NatureWorks’ Ingeo resin. Vink and Davies (Industrial Biotechnology, 2015) give 0.62 kg CO2e per kg of resin for 2014 production. That stops at the factory gate of the resin plant. It does not include turning pellets into plates, trucking them or shipping them.

So the PLA number looks smaller, but it covers much less of the journey. The same Gautam paper quotes an earlier study of foamed PLA trays at about 4,826 kg CO2e per tonne, and foamed polystyrene trays at about 5,110. Those are trays, from a different study with its own boundaries, so treat them as a rough guide and nothing more.

Why can’t you compare lifecycle numbers straight from two reports?

Because each study chooses its own boundary and unit. One counts per tonne, another per plate, a third per meal served. One stops at the factory gate, another includes the ocean leg and the bin. ISO 14040 and 14044 set out how a lifecycle study has to be done and reported, and they make the author state these choices. They do not make two studies comparable.

Weight matters too. A palm leaf plate and a PLA plate of the same diameter do not weigh the same, so a per-tonne figure has to be converted to a per-plate figure before you compare. If a supplier hands you a neat per-plate comparison, ask which study it comes from and whether both sides were measured the same way.

Where does most of the footprint of a palm leaf plate come from?

In the Gautam study it was not the ocean. Local trucking in India and grid electricity at the factory were the biggest contributors, together more than half of the impact in the categories studied. The electricity was modelled on the Tamil Nadu grid. Shipping to Portugal was below 15% in most categories.

That is useful for a buyer, because it points at things a manufacturer can change. Our 90+ pressing units are spread out close to where the sheaths are collected, and the 20,000 sq ft hub in Bhadravathi is solar-powered. We have not commissioned our own lifecycle study, so I will not claim a lower number than the published one. What I can say is that the two biggest items in that study are the two we have worked on. If you need a figure for your own reporting, the Scope 3 page shows how to work one out from the study.

How much land does each material use?

PLA needs a field of maize, sugarcane or cassava for the sugar, so every tonne of PLA has a land footprint and the fertiliser that goes with it. The size depends on the crop and the yield.

Palm leaf adds no land. The orchards are farmed for the nut, and the sheaths fall whether or not anyone collects them. In lifecycle terms, the leaf is a by-product, and most of the burden of growing the palm belongs to the nut. A careful study will say how it split that burden.

What happens to each plate at the end of its life?

This is where the choice often gets made in practice. Compostable PLA is tested in industrial composting conditions; the EN 13432 biodegradation test runs at 58 °C. If the customer’s waste service does not collect it for composting, it goes out with general waste.

Palm leaf is plant fibre. It goes into the food waste or compost stream with the leftovers on it, and it breaks down as leaves do. Our plates passed EN 13432 testing, and we send the report on request.

For EU buyers there is a legal point as well. The Single-Use Plastics Directive defines plastic to exclude only natural polymers that have not been chemically modified. PLA is made by polymerising lactic acid, so it is a plastic under the directive, and single-use plastic plates are banned from the EU market. Pressed leaf is a natural material and sits outside that definition. More on the material side in palm leaf vs PLA plates.