In March, Jackalyne Pfannenstiel took office as the assistant secretary of the Navy in charge of environment and energy, just as that role took on more prominence. A few months earlier her boss, Navy Secretary Ray Mabus, laid out an aggressive plan to increase the Navy's use of renewable energy. The goals include:

- Demonstrate a Green Strike Group in local operations by 2012 and sail it by 2016.

- Reduce the use of petroleum in vehicles by 50 percent by 2015.

- By 2020, get half of installations' energy from renewable sources, and have half of installations be net-zero in energy usage.

- Source half of the Navy's energy from alternative sources by 2020.

Pfannenstiel spent most of her career at Pacific Gas & Electric, the California utility, and also served as chair of the California Energy Commission. She has no prior military experience. I sat down recently with Pfannenstiel in her office at the Pentagon to discuss how the Navy will meet its ambitious goals.

This interview is in two parts, the first delving into the Navy's energy strategy, and the second looking at lessons the that strategy might offer to other businesses and enterprises. Look for the second part tomorrow.

Matter Network: When it comes to saving energy, the U.S. Navy isn't the most likely crusader. Why did the Navy set these goals?

Jackalyne Pfannenstiel: We're doing it for energy independence, national security and cost. Energy independence, because this country and the military burn a lot of fossil fuels. The military accounts for 2 percent of the U.S.'s oil energy use, and 93 percent of the federal government's energy use. If we move away from our own use of fossil fuels, we could help the country move. So that's energy independence. National security is related in that we're held hostage, in a planning sense, to something going wrong somewhere else in the world. Some other nation has the ability to affect our economy and our ability to take care of ourselves. Cost is related to both of those.

Those are the strategic reasons, but there's a tactical focus that I think people may miss with the military, and that's how much energy it takes to forward deploy -- to have people in the field. Energy gets there usually through long fuel convoys which are dangerous and labor intensive as well as expensive. So to the extent we can find practical ways of doing what we do in the field without moving this much energy, the better off we are.

Matter Network: One of the Navy's new goals is to have the entire Navy -- ships and planes and bases -- get half of its energy from renewable sources by the year 2020. That's a more ambitious target than just about any company or government has tried to reach. How is it going?

Pfannenstiel: One of our goals is an overall 50 percent reduction in use of fossil fuels, including at sea on ships and underwater as well as on bases. That will be very hard because we need to replace our current fuels with something else. There are some technical options we can pursue -- for example, you can fly in simulators instead of planes for training. But we still need to fuel our ships and planes. That's a really hard nut to crack. The technologies haven't yet caught up with where we will be in 10 years.

Matter Network: The energy initiative that's gotten the most attention is the "Great Green Fleet," which includes projects like the "Green Hornet" FA-18 fighter jet that has flown half on biofuel from the camelina plant, and the U.S.S. Makin Island, which has a hybrid engine. Could you explain what a "Green Fleet" really means?

Pfannenstiel: It's some combination of different kinds of ships -- aircraft carriers, other ships, and the aircraft that go with them -- running on non-fossil fuels, on biofuels. With the aircraft carriers, that's not possible because they're already nuclear. We are testing biofuels now. You know about the Green Hornet test. We're trying them on ships next. We both need to have enough biofuels that have been tested and found to be acceptable to us, and we have to have sufficient quantities. How far are we? We're testing. If we find some, I don't think it's rocket science to make a lot of it.

Matter Network: By that same year, 2020, half of the Navy's bases are supposed to be net-zero. What does that mean exactly?

Pfannenstiel: That means we can produce as much energy through renewables as we use, so we don't need to buy as much from the grid anymore.

People find that the most challenging but I find it the most exciting because it brings together not just the supply side -- using renewable energy -- but also the demand side, on reducing the amount of energy that you burn. Reduce your denominator and you don't need as much for your numerator. That's really challenging, but those technologies exist. It's a matter of thinking of which 50 percent of our bases are most likely to do this.

Matter Network: What's the low-hanging fruit to make a naval base more efficient?

Pfannenstiel: There's a lot of bases around that are capturing that low-hanging fruit. A lot of the basic, boring efficiency stuff, with lighting and windows and insulation and better heating and air conditioning systems -- that's happening everywhere. Everybody's starting to get that, that you have to get all that really basic energy efficiency stuff onto the bases, even though it takes some upfront money, the payback on that usually is pretty fast. Once you do that, you can go to the more exotic, sexier stuff, like renewables.

Matter Network: Speaking of renewables, where are the biggest projects?

Pfannenstiel: The different bases all have different geographical assets vis a vis renewables. China Lake (Naval Air Weapons Station) has great geothermal, all over Hawaii you see solar thermal, all over Camp Pendleton and Miramar (Marine Corps Air Station) you see solar. You're not going to see as much solar in the Great Lakes area.

The newer buildings are all being built to LEED Silver (standard). Because it's a good market to be building in, they're getting some savings on the construction and are upgrading to LEED Gold. Everyone is putting in smart meters, and the base energy people are trying to determine how to use that data.

Matter Network: Another goal is to reduce use of petroleum in vehicles by 50 percent by 2015. What is the Navy doing to get there?

Pfannenstiel:It's the same issue in terms of biofuels, though the second part for bases is electric vehicles. Some of the bases can use practically golf-cart things to get around. Some bases have bigger expansions but can use electric vehicles that already exist, with central places where they can recharge. The bases are incredibly creative. I'm always in awe of the things they have in mind. I think that again this is one of those things where the technology sort of exists but they're really isn't enough mass at this point to make it viable. The biofuels and the electric vehicles exist, but they're pretty expensive still.

David Ferris is managing editor of the Matter Network.