Big, centralized energy systems, like the one allowing you to hear this, have lots of power: extra capacity, back-up for big demand.
Small systems balance energy, efficiency and expense more carefully. They have to be smart -- like your phone is.
Maybe the smartest energy system anywhere is being tested this summer in the most demanding sites in the world...combat outposts in Afghanistan, where costs are measured in more than dollars. Because these combat outposts, they really are out, a long way.
Resupplying them means convoy routes -- a hundred miles maybe. To normal road hazards - fatigue, breakdowns, flat tires - add roadside bombs, an ambush, a rocket grenade.
In Afghanistan and Iraq, the convoys became the great vulnerability. The chance of getting hit: one in 50...maybe okay if you go once, but these guys go a lot.
What is it they resupply? Lots of things, but two real essentials: water, and diesel fuel.
It's not hard to produce power.
A diesel generator, some fuel - electricity. The trick is in managing the power, because sometimes you want to be very, very efficient. At an experimental site on a gunnery range near Fort Bliss, El Paso, Texas, I'm learning this from a diesel mechanic named Allen Easterling.
"What you have here is six 30KW diesel engine-driven generators, and they're all tied into what we call a bus ring," Easterling says.
Bus ring...I'll come back to that, and to Allen, but let me revisit that cell analogy from a moment ago. Smart energy is to energy as your cell phone is to an old fashioned telephone.
The way things have been at remote army outposts, many generators run most of the time, each for one purpose...power the kitchen or mess hall, for instance.
That's bad. For efficiency, diesel generators should run at 90 percent of capacity. A lot of diesels run at 20 or 30 percent, because that's the load they're carrying...well, you waste fuel, and pretty soon the generators clog and stop working.
What you need is a micro-smart-grid robust enough to operate in a really hostile environment. And that's what the army is getting. It's been redesigning the basic combat outpost, and the new designs are assembled and built by a company called Berg based in Spokane.
"And that's when I talk about energy efficiency, no one else has done that," says Berg's CEO, Don Myers. Berg makes camps for extreme needs: disaster relief, mining, the military. The systems for what the army is testing now, he says, are the most efficient camps in the world
"Other ones have little bits and pieces and little satellite operations that are under very restrictive conditions here in the states," he says. "They have certain types of water and power and all sorts of engineers and technicians tweaking it and making it work. No one can field it like this to this point."
Let's go back to the test site, and diesel guru Allen Easterling.
Remember what he said about the array of generators?
"And they're all tied into what we call a bus ring."
A bus ring is a configuration of parts and sensors and a control device to read them. Instead of six generators limping toward the junkyard at half speed, the smart grid connects them all to each other, and then loads all the demand onto one generator until it needs another. And everything works fine.
"What we have here is the new X Camp," Easterling says.
X for experimental...the combat outpost model they were testing at Fort Bliss in February, and that the army is deploying now in Afghanistan.
"It's a 100-man base camp," he says. "It comes with the billeting containers..."
Billet - army speak for where you live. A billet container is a living space for 10 people.
"It comes with a small kitchen with a dining room."
Well, in another container...the X-camp has to feed its 100 soldiers. And care for them, so there's also one for sanitation.
"And we have a power grid. It supplies the power for the camp."
Yeah. The grid. Because a smart-grid cuts fuel needs by at least 50 percent, probably more. That's why they are maniacal about efficiency, and its sometimes-tricky balance.
"These are the most energy efficient machines that I believe they make," Easterling says.
Allen Easterling was a soldier for a dozen years, a consultant now for more than a dozen, the lead tech for assembling the X-Camps. He is telling me about the washers and dryers, the ones in the sanitation unit for soldiers to do their laundry.
"But they're too efficient for the soldiers. They're too efficient."
What does he mean by that?
"It takes six hours for one person to wash their clothes and dry their clothes in this machine. Soldiers don't have six hours to wash their clothes at any time."
Even efficiencies come at a cost...the washer/dryers use very little power and water, but they pay for it with time.
The combat outposts are in an early stage. Eventually, they'll lose the diesels, go solar/battery renewable...smart grids can get much smarter.
But for these people, cutting fuel demand by 50 percent means you can cut convoys by 50 percent. And that is huge...just ask Easterling, currently in Afghanistan to build the first X-camp and make sure it all works.
"Because that guy's having to drive that truck miles and miles just to get to you, to bring you fuel," he says. "So when you can cut fuel down, have fuel savings, you're saving lives. Really, you really are.
He'll be home again in August, he says, and probably back to work on a new, more efficient X-camp.