La Encantada silver mine is a remote site in northern Mexico, close to the Texas border.  It is located in the Sierra Madre mountains at a fairly high altitude.  It is a fascinating site, where silver ore is mined and refined to a certain level of purity.  From La Encantada, the product is further refined at other facilities.

La Encantada had previously run their mine exclusively on diesel power generation.  In years past, this was a relatively economical solution.  More recently, high diesel fuel costs have made diesel power generation a more costly endeavor.  What to do?

Our client proposed a solution to the mine to use natural gas power generation to provide the bulk of the power to the mine.  Natural gas power generation can cut fuel costs in half or even more.  There were several obstacles to overcome to make this happen:

1. There is no nearby natural gas pipeline. Our client elected to truck in LNG to site and utilize a regasification solution to power the new generators.  Taking the LNG from a liquid state to a gaseous state is endothermic in nature.  This produced the unusual effect of producing small quantities of snow in the desert!
2. The existing diesel generators are Caterpillar machines, utilizing DEIF paralleling and load sharing controls.
3. The new gas generators are MTU machines, utilizing MTU paralleling controls. Getting the MTU machines to play nicely with the Caterpillar machines was a challenge.  Not only were we mixing makes of generators – we were mixing fuel types and transient response characteristics.  No pressure!

The objective was to run the new MTU generators at high load factors, and then to use the Caterpillar diesel machines as fast responding machines to “swing” and deal with rapid load changes.  How does one do all of that?

LEC provided medium voltage switchgear, metering equipment, automation equipment and SCADA equipment to make it all happen.  Talk about a science experiment!  After ironing out a few wrinkles, the power plant continues to operate today providing a more economical solution to power the mine.