Variable Speed DrivesCosts & Benefits
|Parent Process: Cement Plant General|
|Energy Savings Potential||
The savings VSDs provide can vary between 7 to 60% depending on the flow pattern and loads. (ECRA, 2009).
Other sources estimate that the potential savings are 15% for 44% of the installed power, or roughly equivalent to 8 kWh/t cement (LBNL, 2008).
In a Canadian plant, replacing the kiln ID fans with VSDs saved 6 kWh/t.
|CO2 Emission Reduction Potential|
The specific costs depend strongly on the size of the system. For systems over 300 kW the costs are estimated to be 70 €/kW (75 US$/kW) or less and for the range of 30-300 kW at 115-130 €/kW (120-140 US$/kW). Based on these, the specific costs for a modern cement plant was estimated to be roughly US $0.9 to 1.0/annual ton cement capacity.
VSDs for clinker cooler fans have a low payback, even when energy savings are the only reason for installing.
Variable Speed Drives Publications
The U.S. Environmental Protection Agency’s (EPA) energy guide, Energy Efficiency Improvement and Cost Saving Opportunities for Cement Making, discusses energy efficiency practices and technologies that can be implemented in cement manufacturing plants. This ENERGY STAR guide provides current real world examples of cement plants saving energy and reducing cost and carbon dioxide emissions.
The report represents the independent research efforts of the European Cement Research Academy (ECRA) to identify, describe and evaluate technologies which may contribute to increase energy efficiency and to reduce greenhouse gas emissions from global cement production today as well as in the medium and long-term future.