The Cost of Compressed Air

Electrical energy is the most prevalent energy source for industrial compressed air production. In many compressed air installations there are often significant and unutilized energy-saving possibilities including energy recovery, pressure reduction, leakage reduction and optimization of operations through correct choice of a control and regulation system as well as the choice of compressor size.

Energy costs are clearly the dominating factor for the installation's overall cost. It is therefore important to focus on finding solutions that comply with demands for performance and quality as well as the demand for efficient energy utilization. The added cost associated with acquiring compressors and other equipment that complies with both of these demands will be perceived over time as a good investment.

As energy consumption often represents approx. 80% of the overall cost, care should be taken in selecting the regulation system. The significant difference in the available regulation systems exceeds the significant differences in types of compressor. An ideal situation is when compressor full capacity is precisely matched to the application's air consumption. This frequently occurs in applications. Most types of compressors are supplied with their own on-board control and regulation system, but the addition of equipment for shared control with other compressors in the installation can further improve operating economy.

Speed regulation has proven to be a popular regulation method because of its substantial energy-saving potential. Think carefully and allow your application requirements to govern your selection of regulation equipment in order to obtain good results. If only a small amount of compressed air is required during the night and weekends, it may be profit-able to install a small compressor adapted to this off-peak requirement.

If, for some reason, a particular application needs a different working pressure, this requirement should be analyzed to find out whether all compressed air production should be centralized in a compressor central plant, or whether the network should be split up according to the different pressure levels. Sectioning of the compressed air network can also be considered to shut down certain sections during the night and on the weekends, in order to reduce air consumption or to allocate costs internally based on airflow measurements.

Investment costs are a fixed cost that include the purchase price, building infrastructure costs, installation and insurance. The share of the investment cost as a part of the overall cost is determined partly by the selection of the compressed air quality level and partly by the depreciation period and the applicable interest rate. The share of energy costs is determined by annual operating time, the degree of load/unload utilization and the unit energy cost. Additional investments, for example, equipment for energy recovery, offer a direct payoff in the form of reduced operating and maintenance costs.