At the moment, it is often cheaper to process virgin materials, despite the extra energy required, because collecting and sorting recyclables is so labour-intensive.
目前，尽管原材料加工需要额外的能源，但往往很便宜，因为回收时收集和分类需要更多劳动力。
2
The vaulting gives the house plenty of structural strength but does away with the need for energy-intensivematerials such as reinforced concrete.
拱形结构为房屋提供了足够的结构强度而无需混凝土这样的能源密集型材料。
3
This would be a departure from the current approach, where strong bonds, expensive constituents, and energy intensive processing (at high temperatures) are used to obtain high-performance materials.