Biomass Energy Calculator

The calculator starts with a base calorific value for each biomass type (e.g. ~4,000 kWh/tonne for dry wood waste), then adjusts for moisture content — water in the fuel reduces the net calorific value. The adjusted figure is then multiplied by your system efficiency percentage to give the usable energy actually delivered as heat or power.

Water in biomass must be evaporated before combustion can produce useful heat, consuming a significant portion of the fuel's gross energy. For example, wood at 10–12% moisture yields around 4,000 kWh/tonne, while the same wood at 40% moisture may yield only 2,800 kWh/tonne. Drying your biomass before combustion can substantially increase output.

Dry wood waste and wood chips typically contain around 4,200–4,800 kWh per tonne on a dry-weight basis. Most wood manufacturing and packaging waste runs at 10–12% moisture content, giving a net calorific value of approximately 3,800–4,200 kWh/tonne. Wood pellets, being highly processed and dry, can reach 4,600–5,000 kWh/tonne.

The calculator estimates CO₂ avoided by comparing the emissions factor of your existing fossil fuel against the biomass alternative. For example, natural gas emits roughly 0.185 kg CO₂/kWh and coal around 0.34 kg CO₂/kWh. Because sustainably sourced biomass is considered broadly carbon-neutral over its lifecycle, displacing fossil fuels with biomass reduces net atmospheric CO₂ emissions.

Modern industrial biomass boilers typically operate at 70–85% efficiency. Older or less well-maintained systems may be 60–70%. Combined heat and power (CHP) systems can achieve overall efficiencies of 75–90% when both heat and electricity outputs are captured. If you are unsure, 75% is a reasonable mid-range default.

Yes — set the Biomass Fuel Cost per Tonne to $0. In this case, your cost savings come entirely from avoiding your existing fuel purchases plus the disposal costs you no longer pay. The disposal cost saving field lets you factor in the gate fees or haulage costs you currently spend to remove wood waste.

In most markets, biomass fuel (wood chips, pellets) is cheaper per kWh of heat delivered than heating oil or LPG, and often competitive with natural gas. The exact saving depends heavily on local fuel prices and biomass supply costs. When biomass is a waste by-product with associated disposal costs, the economics are even more compelling.

This is debated. Burning biomass releases CO₂, but if the biomass comes from sustainably managed forests or agricultural residues, the carbon is reabsorbed as new growth over time. The IPCC recognises that biomass is not automatically carbon neutral — the full lifecycle, including harvesting, transport, and forest regrowth timescales, must be considered. Biomass from waste materials (sawdust, straw) generally offers the most straightforward GHG benefits.