Which renewable-energy technology uses organic waste to produce both biogas and digestate?

Anaerobic digestion uses organic waste to produce both biogas and digestate.

In an oxygen-free digester, communities of microorganisms break down materials such as animal manure, sewage sludge, food scraps, and agricultural residues. The process produces biogas, whose methane can be burned for heat or electricity, and digestate, the nutrient-containing material left behind.

Digestate may be separated into liquid and solid portions and used in agriculture when regulations and contamination controls permit. Capturing biogas can reduce uncontrolled methane emissions from waste and displace fossil fuels, although the climate benefit depends on construction, leakage, transport, and how the digestate is managed.

Anaerobic digestion differs from composting because composting generally uses oxygen and produces a stable aerobic compost rather than methane-rich biogas. It also differs from landfill decomposition, which is less controlled and can allow methane to escape.