WASHINGTON (Army News Service) -- Asked what stands out as her biggest achievement, Katherine Hammack replied, "I'm proudest of the Net Zero Program."Since taking the reins in 2010 as assistant secretary of the Army for Installations, Energy and Environment, Hammack said, the Army has saved a ton of money in the energy sector, improved the overall resilience of its utilities and, as a result, Army readiness has increased.Hammack spoke here Thursday at what she said will probably be her last public venue before departing. The event was The Pew Charitable Trusts-sponsored panel: "Power Begins at Home: Assured Energy for U.S. Military Bases."Net Zero consists of three parts, she explained: net zero energy, net zero water and net zero waste.NET ZERO ENERGYNet zero energy has a two-part strategy, Hammack said: producing as much energy on site as possible -- preferably with renewables like wind and solar -- and reducing consumption.The reducing consumption component boils down to common sense, she said, comparing it to turning lights off at home and lowering the thermostat in winter when not at home. The reducing consumption message has gained ground in the last five or six years, but more can still be done, she noted.Hammack's office has been responsible for much of the Army's energy savings through energy savings performance contracts (ESPCs). Such a contract represents a partnership between an agency and an energy service company. ESPCs allow for the Army to procure energy savings and facility improvements with no up-front capital costs or special appropriations from Congress."[With ESPCs], someone else brings in their technology and you pay them back through savings," she explained, adding that if the Army had more new dollars to invest, even more savings could be realized."If we had the money to implement these efficiencies and improvements, we'd do it, because then we'd receive all of the savings dollars ourselves," she said. "But with the Budget Control Act [of 2011], our budgets have been going down."She likened the Army's strategy to that of a home buyer. While some home buyers with enough cash might purchase a house outright, she said, most don't; they take out a mortgage and pay the principal and interest over time.The authority to use ESPCs was granted in 1992, but the contracting methodology -- along with legal and acquisition issues -- wasn't completely worked through. Nonetheless, the Army executed $1.2 billion in ESPCs between 1992 and 2010, she said.When Hammack began in 2010, she recalled, she made ESPCs a priority and her team explored ways to streamline the process. Each installation was tasked with looking for ESPC opportunities. The result: over the last five years, another $1.2 billion in ESPCs were executed.As a result of ESPCs and energy conservation by units and Soldiers, the Army saw a 4.7 percent decrease in energy consumption between fiscal years 2015 and 2016, even as more Soldiers returned home from overseas to U.S. installations.She called it, "the greatest drop over a one-year period that we have seen in our records."Hammack credits the Army's Office of Energy Initiatives, or OEI, with overseeing large-scale energy projects. In the past, the Army might undertake one or two large projects over a 10-year period. Since OEI stood up in 2011, it has undertaken four or five per year.ENERGY RESILIENCEWhile saving energy is important, so too is energy resilience, she said.Extreme weather conditions and accidents can cause the electrical grid to lose power, she noted. For instance, an extreme windstorm at Fort Carson, Colorado, recently damaged roofs on 400 buildings. Add to that the aging utility infrastructure on installations that can lead to power failure."Over the last 10 years," she said, "we've seen a four-fold increase in the number of power outages."Fort Drum, New York, is particularly prone to wintry events that could take down the grid, she said. That installation has begun producing energy on site using biomass, an OEI initiative. The installation has put into place grid disconnect controls and has demonstrated disconnecting from the grid during a simulated ice storm. It has enough biomass fuel on site to power its internal grid for three months in the event of an outage.Besides biomass, solar energy technology today provides the lowest cost energy, even without the government rebates, she said. Once perceived as a luxury, solar tech is the "workforce of any utility portfolio.""We've identified over 2 gigawatts of potential renewable energy projects," she said, adding that she hopes her successor follows through with those projects.The challenges with those projects aren't technical in nature, she added. Rather, they face a myriad of regulatory and legal requirements, sometimes four per state, "so you have to work each on a project-by-project basis."OEI monitors the regulatory environment of each state, she said.Currently, the Army also is partnering with the Air Force in OEI endeavors.MICROGRIDSWhen the electrical grid does goes down, Army units are accustomed to relying on their standalone generators. The problem is they're expensive to fix and maintain. The solution, according to Hammack, is to replace them with microgrids. As the name implies, a microgrid is a small grid that's connected to the larger grid used by local communities. If the larger grid goes down, the microgrid can still supply electricity.Additionally, a microgrid can actually save money and energy, as it makes use of "smart" generators that link with one another to intelligently manage the power supply and operate at peak efficiency. Microgrids also enable the use of alternative energy sources and energy storage. In fact, with microgrids it is possible not to consume any energy from the main grid at all.Currently, microgrids are being used in Iraq and Afghanistan and some installations, but it will be the task of the next assistant secretary to oversee their adoption Army-wide, Hammack said.To do that, the culture must shift, she suggested. Some units today view microgrids as taking away their energy security."Because it's no longer my generator behind my building and I can look out the window and see it," she said. "It's not there. It's somewhere else, and someone else has energy security. It's a very emotional, visceral response."NET ZERO WATER AND WASTEThe Army has also reduced its water consumption considerably, and that strategy has helped in communities facing drought conditions, particularly communities out west, Hammack said."We're the largest consumer of water in many communities," she noted. "They look at us first to reduce consumption."In fact, according to Hammack, the Army has been leading in water conservation, ahead of other industries, most notably in California. "It's part of our culture," she said. "It's about being a good partner with the community."Regarding waste, Hammack said sending all of it to landfills taxes the community. Instead, the Army has explored ways to recycle, and is often the biggest recycling customer in the community."Leading by example is what we've done," she said.THE FUTUREHammack feels confident that the new administration will continue her energy-resilience efforts. She cannot comprehend why a new administration would choose instead to increase costs and consume more energy and water."That is counterintuitive to me," she said. "Our strategy is one that will sustain these programs through this next administration. We're focused on the right measures to ensure that the Department of Defense is prepared to do whatever mission it's asked to perform."Hammack added that she is impressed with the passion and quality of people working in her organization."We have competent professionals who understand why we're doing what we're doing" she said.It will be up to them to continue the work, she said, and explain to the rest of the Army and to the American public what they're doing and why.(Follow David Vergun on Twitter: @vergunARNEWS)