Although coal and petroleum are produced by degradation of biomass, yet we need to conserve them. Why ?
Coal and petroleum have been produced from large amounts of biomass entrapped inside the earth under high temperature, pressure and
anaerobic conditions. Such a situation develops only rarely like big upheavals on earth. At present no more coal or petroleum is being formed. All
that is available has been formed millions of years ago. Being rich source of energy, coal and petroleum are being consumed in ever increasing
amount in industry, transport, kitchens, etc. If the trend continues, soon they will be exhausted. Therefore, they must be conserved by developing
more efficient machines, hybrid engines and using hydrogen as a fuel.