AM makes parts by joining, which requires energy. If it were only joining, it might not have required much energy—all pieces must be brought together to apply heat on them, which happens in sintering. But AM joins in a selective way. Considering powder bed fusion, when heat is applied, some of the heat that gets squandered is not utilized to join powder. The squandering is due to the lack of absorption of heat, over-absorption, absorption by the other area of the bed, etc.; it is the side effect of joining. AM, compared to sintering, thus requires more heat to do the same amount of joining, which makes AM an energy-intensive process. For example, AM consumes 97 MJ/kg, while sintering consumes 2.4 MJ/kg to make a steel part. Therefore, AM requires more electricity than CM.