Conservation of energy and energy resources GapFill

In any process, energy is conserved, meaning that energy  can be created but cannot be destroyedcannot be created or destroyedcannot be transferredis always stored in the same way. However, energy can be transferred between stores; if energy is transferred irreversibly in a way we don't consider useful (often to thermal energy lost to the environment), we say that this energy has  radiatedtravelleddissipatedbeen destroyed.  PowerDissipationRenewabilityEfficiency is a measure of how much energy has been transferred in a way we consider useful, and can be calculated by useful energy transferred ÷ total energy transferred.
If less energy has been transferred usefully than we'd like, there are a few ways we can reduce the wasted energy. If a moving part is dissipating energy because of friction,  lubricationincreasing the speedincreasing the powerinsulation will cause more energy to be transferred usefully. If a heated building is losing a lot of thermal energy to its surroundings, the walls can be  broken apartthinnedinsulatedlubricated.

The modern world depends on energy resources for a variety of applications, including electricity generation, transport and heating. Energy resources are categorised as either  perishable or non-perishablerenewable or non-renewableenvironmental or non-environmentalgood or bad, based on whether or not there is a finite amount of a resource or whether more of the resource is produced continuously.
Some energy resources, such as  tidal powergeothermal powernuclear powerfossil fuels, give off a lot of by-products, and can contribute to pollution and climate change. Others don't have these same by-products, but might have other drawbacks, such as  costing too muchbeing difficult to minereleasing greenhouse gasesbeing dependent on weather or location.