Fossil fuel power station is also beneficial to the environment. In some instances, torrefaction of biomass may be needed if biomass is the material the converted fossil fuel power plant will be using. Improving energy efficiency of a coal-fired power plant also reduces emissions. For example, emissions can be reduced by upgrading existing plants or building new high-efficiency, low-emissions plants. Such plants emit almost 20% less CO than a subcritical unit operating at a similar load. Over the longer term, HELE plants can further facilitate emission reductions because coal-fired plants operating at the highest efficiencies are also the most appropriate option for carbon capture
Evolutionary history of plants also formed shallow rooting systems during the Famennian. The rhizophores of the lycopods provide a slightly different approach to rooting. They were equivalent to stems, with organs equivalent to leaves performing the role of rootlets. A similar construction is observed in the extant lycopod "Isoetes", and this appears to be evidence that roots evolved independently at least twice, in the lycophytes and other plants, a proposition supported by studies showing that roots are initiated and their growth promoted by different mechanisms in lycophytes and euphyllophytes. A vascular system is indispensable to rooted plants, as non-photosynthesising roots need a supply of