Question

Coal is said to be formed from the wood of trees. Then why is coal considered to be a non-renewable source of energy whereas wood is a renewable source of energy ?

Answer 1

Coal is a flammable black or brownish-black sedimentary rock that is found in the form of coal seams. Coal is mostly made up of carbon, with varying quantities of additional elements such as hydrogen, sulphur, oxygen, and nitrogen. Coal is created when dead plant matter decays into peat, which is then transformed to coal over millions of years by the heat and pressure of deep burial.

Complete answer:
A non-renewable resource (also known as a finite resource) is a natural resource that cannot be replenished at a rate fast enough to keep up with use by natural methods. Carbon-based fossil fuels are one example. With the use of heat and pressure, organic matter transforms into a fuel like oil or gas. Non-renewable resources include earth minerals and metal ores, fossil fuels (coal, petroleum, natural gas), and groundwater in specific aquifers, however individual components are always maintained (except in nuclear reactions).
Coal is a non-renewable energy source since it has been collected in the ground over a very long period and cannot be generated rapidly in nature if it is depleted. Natural resources like coal, petroleum (crude oil), and natural gas require thousands of years to produce and cannot be replenished at the same rate as they are consumed. It is expected that fossil-based resources will become too expensive to gather at some point, and mankind will be forced to rely on other energy sources such as solar or wind power.

Note:
Another possibility is that carbon-based fuel is practically limitless in human terms if all sources of carbon-based energy, such as methane hydrates on the seafloor, are included, which are substantially bigger than all other carbon-based fossil fuel resources combined. Although the pace of formation/replenishment on the seafloor is unknown, these carbon sources are likewise considered non-renewable. However, it has yet to be discovered how to extract them at commercially feasible costs and rates.