What a Tonne of Biomass Pellets Costs in Electricity

Ask for a pellet plant quotation in India and you will get one within the day. Machine price, motor rating, rated tonnes per hour, delivery schedule, sometimes a payback estimate built on numbers the supplier chose.

What almost nobody gives you is the electricity bill. Yet across a pellet line's working life the power it draws will cost several times what the machines cost, and it is the one number that decides whether a plant survives a bad pellet price — because it does not fall when your margin does.

The figure is recoverable, though. Manufacturers publish rated motor power and rated output for every model, and dividing one by the other gives specific energy — kilowatt-hours per tonne. That division gives a ceiling, not a measurement, and the distinction matters enough that it is repeated beside every number below. Motors are sized for the worst moment a machine will ever have, not for its normal one, and lines of this class now ship with variable-frequency drives that cut the draw at part load.

Still, a ceiling you can calculate beats a number nobody will give you. Here is the arithmetic, worked on one manufacturer's published table, with the parts you have to fill in yourself marked clearly.

A pelletising line is not one machine. Residue arrives too coarse and too loose to press, so it goes through a shredder, then a hammer mill, and only then the pellet mill. Each stage has its own nameplate, and each one draws power on every tonne that passes.

Taking the published ratings of one Indian manufacturer's line — Trio Renewable Engineering, whose full specification tables are online — and dividing rated kW by rated TPH:

Power figures include the ancillaries the manufacturer lists against each machine — the ID fan on the hammer mill, and the kickout motor, oil pump, grease pump and mini cyclone on the pellet mill. People costing a plant routinely forget those and they are not trivial: the hammer mill's induced-draught fan alone is 18.5 to 37 kW, a fifth to a quarter of the mill it serves.

Two things fall out of the table immediately. The pellet mill is the expensive stage, accounting for roughly half to two-thirds of the line's electricity. And the shredder, which looks intimidating at 180 kW, is the cheapest thing on the site per tonne, because it moves material fast.

The instinctive assumption — buy larger, run more efficiently — does not survive the arithmetic. Work through the pellet mills one by one, rated power over rated output:

Across a range where installed power nearly triples, the energy ceiling per tonne moves only between roughly 55 and 94 kWh — and the largest machine on the list is not the most efficient one. The best ratio belongs to the 700-160, a mid-sized mill with a larger die on the same motor as the model below it.

That is not a quirk of one catalogue. Pelletising energy is set by what the material does inside the die — friction, compression, the heat that softens the lignin and binds the pellet — and that physics does not care how big the machine around it is. Scale buys you fewer operators per tonne, fewer shifts and headroom to grow. It does not buy you cheaper electricity per tonne. Anyone being sold a larger mill on an efficiency argument should ask to see this division done on the actual models being compared.

Add the three stages at their rated ceilings and a line runs roughly 100 to 165 kWh per tonne of pellets. Derate for the fact that motors rarely sit at rated load and that a VFD trims the rest, and a working expectation of 85 to 135 kWh/t is reasonable for a well-fed line — though only a meter on your own plant settles it.

Industrial tariffs in India broadly sit in the ₹7 to ₹9 per unit range depending on state, voltage level and time of day, and they move every tariff order, so re-quote from your own DISCOM rather than trusting that band. At ₹8, the middle of it:

• A tonne of pellets carries roughly ₹700 to ₹1,200 of electricity.
• A 1 TPH line running 20 hours a day for 25 days makes about 500 tonnes a month — around ₹4.8 lakh a month in energy at 120 kWh/t.
• Every 10 kWh/t you shave is worth about ₹80 a tonne, or ₹40,000 a month on that same line.

Then there is the part of the bill that has nothing to do with production. A line of this size needs a connected load in the region of 300 kW, which means an HT connection and demand charges billed on sanctioned capacity whether the plant runs or not. A plant that idles half the month pays those in full, which is why utilisation, not efficiency, is usually the first thing that kills a small pellet operation. Ask your DISCOM what the demand charge is per kVA per month before you size the connection, and read it as a fixed cost, not a variable one.

For readers who want the method rather than the answer, this is the same arithmetic we ran on what a power weeder actually costs to run per acre — build the number from components you can verify, and mark the ones you cannot.

Planning a pellet line?Tell us your feedstock and tonnage — we will size the lineSend the desk your feedstock, the tonnes an hour you are aiming at and your state. You get back the machine sizes that actually fit, the power draw to plan the connection around, and who supplies them.Get a plant costingWhatsApp +91 92093 28498Agpro Consulting, which publishes IndianAgri, advises on biomass projects and may earn a fee on an introduction. The arithmetic above is independent of that and cites its source.

Everything above is the electricity. It is not the energy.

A pellet die needs feedstock at roughly 10 to 15% moisture. Below that the material will not bind and you get fines; above it, steam in the die and pellets that crumble in the bag. Almost nothing arrives in that window. Sawdust from a working mill might; paddy straw off a field, bagasse from a crushing season and freshly chipped wood certainly do not.

Closing that gap means drying, and drying is usually the biggest energy consumer in a pellet plant — frequently more than the pelletising itself. It also mostly does not appear on an electricity bill, because the heat generally comes from a biomass furnace burning residue, or in many cases burning some of the plant's own pellets. The cost lands as feedstock consumed rather than units metered, which is exactly why it goes missing from comparisons.

So the honest form of the headline number is this: 100 to 165 kWh per tonne is what the machines draw, on a manufacturer's own ratings, assuming the material is already dry enough to press. Any project report quoting a specific energy figure without saying where drying sits in it is either describing dry sawdust or is incomplete. When you are handed one, that is the first question to ask.

It is worth stepping back from the die for a moment, because a pellet plant is one answer to a question — what to do with several tonnes of residue an hour — and it is not automatically the best one for a given field, feedstock or balance sheet.

The same paddy straw can be pyrolysed rather than pressed, which turns it into biochar and a soil amendment with a durable carbon story attached; we have written about what that does to a field in its first season and about the residue-fire problem it is meant to solve. Our sister site India Biochar works on that route specifically, including the carbon-removal side of it.

And whichever route the residue takes, the carbon arithmetic underneath it is increasingly monetisable in its own right — soil carbon, agroforestry, methane reduction in rice — which is the ground AgriCarbon Credits covers, from measurement and verification through to who actually pays.

The reason to raise it here is arithmetic, not advocacy. A tonne of residue has a pellet value, a biochar value and possibly a carbon value, and they are not the same number in every state or every season. Sugarcane trash is the clearest illustration — we looked at the scale of what is currently burned or left — and anyone about to spend a crore on a pelletising line should have priced at least the other two before signing.

We are working through this category post by post — sizing the front end, choosing a die diameter, what paddy straw does to a line built for sawdust, what the subsidy routes actually pay, and who is buying the output.

If you are costing a plant and hit a number you cannot source, the desk will help you find it. Write to us through the contact page or on WhatsApp with your feedstock, your target tonnage and your state. Questions that arrive that way also decide what gets commissioned next, so the answer comes back to you either way.