The power bill at Fort Knox has been steadily declining due to upgrades in infrastructure and the addition of some high tech "green"--but not the dollar bill kind of green.

Between usage of geothermal wells, solar panels and the heat exchange pond at Human Resources Command, Knox continues to be more ecologically friendly while saving money.

For instance, the heat exchanger at HRC harnesses the excess heat coming from the Data Center to heat all of the other five buildings that form the Lt. Gen. Timothy J. Maude complex, home of the Human Resources Command.

Currently, Fort Knox is constructing generators that will produce electricity from the natural gas that is found underground on post. That power will be used to meet electrical and cooling demands. Not only will the generators produce electrical energy, but a byproduct of that process is heat, which will also be captured for additional heating and cooling needs. Known as Combined Heat and Power, the CHP feature is most efficient when meeting a constant demand, so those will be installed at the hospital, the Exchange and HRC--both of those facilities use power constantly, 24/7.

The chronology of energy improvements began with the big ice storm of 2009; the crippling effects led to the Department of the Army directing all military bases to develop 90-day emergency plans. Fort Knox realized how vulnerable the power supply was because the power for the cantonment area came through one substation on three power lines that are side by side. Soon after, the Army designated five posts to achieve Net Zero energy. Although Fort Knox was not one of those five, a former commander saw that omission as a challenge and determined that Fort Knox would surpass the DA goals and, in fact, may even achieve net zero status before the five that were designated to do so.

DA directed that all other installations reduce their overall energy consumption by 30 percent by 2015, a goal that Fort Knox has already easily exceeded. Since 2003 when peak usage was nearly 120 MBTU/ksqft (million British thermal units per thousand square feet), the projection for this year is roughly half that number.

"Of course energy usage projections are highly dependent on weather," said RJ Dyrdek, the Knox energy manager. "Last year, we had a mild winter, while this winter has been especially harsh. But if the temperatures are moderate this summer, we can easily compensate for the higher winter usage, so we should be right at 60 MBTUs this year, barring anything unusual."

"Fort Knox is committed to enhancing Army capability and operations through energy and water efficiency and security," said Pat Walsh, director of Public Works. "Energy and water are key enablers of Army readiness, in preserving our freedom of action and in being good stewards of the nation's financial and natural resources."

According to Dyrdek, when the construction of the six generators sites is completed--which should be soon--Fort Knox should realize an annual savings of nearly $8 million on the power bill. That savings will come through shaving demand during peak usage hours and minimizing the long term average loads. Additionally (and ironically) the waste heat from operation of the generators at three sites can be used to provide free cooling through a process known as absorption cooling. This significantly lowers the electric bill.

The generator towers will be fairly tall in order to help dissipate the sound they will produce while they're creating energy. The sound at ground level should be comparable to a motorcycle engine and to occupants indoors, it's expected the generators will produce a steady drone that sounds something like a food processor.

Each of the generators sites is being built next to existing power substations in order to take advantage of the current electrical distribution systems.

Each of the major energy requirements--power and natural gas--will have three potential suppliers, another layer of security so that post citizens should never face another power outage like the one seen after the ice storm of 2009.

"We'll use our own natural gas first, the secondary supplier--Texas gas--second and if need be, we could ask for gas from LG&E," Dyrdek said. "With electricity, we also have backups; we will be generating our own electricity from the natural gas generators, we have sufficient diesel generators that could be used in an emergency situation (like the ice storm of 2009) and finally, we could always request electricity from LG&E."

The entire system will eventually contribute to the installation's goal to reach a net zero energy usage; in other words, becoming totally independent of outside providers. The post's energy will be secured within the gates, removing the uncertainty of supply and demand, which can only force rising prices as the population around Louisville grows. The first year the generators are online, the reliance on LG&E should be cut by 50 percent and should continue for every year thereafter. Eventually, Fort Knox should be totally independent of any outside source of energy.

"That's an achievable goal," Dyrdek said.