There are two sides to energy use:
- the embodied energy (an LCA term discussed in more detail below) associated with the manufacturing, transportation, use and ultimate disposal of all the materials in a building
- the energy used to heat, cool, light and generally operate a building.
Embodied energy represents the total energy used in making a product, including cement production, energy used to extract and process aggregates, transportation energy, and energy used in a precast plant. Energy is required for machinery, concrete curing and for heating the plant.
It is possible to utilize manufacturing energy very efficiently as production of precast concrete elements takes place mainly in enclosed factories. For example, the heat used for accelerating the strength development of concrete can also be used in heating the plant. When producing massive elements, the exothermal reaction (hydration) of the cement may reduce heating requirements. The energy consumption of the manufacturing process depends on the type of production.
Equipment, like cranes, transport equipment for aggregates and cement, bending equipment for reinforcement, vibrators etc., can, due to their repetitive operations, be reduced to only what is absolutely necessary to perform the task. The energy required to produce concrete can be improved by rationalizing energy consumption in plant production.