A New Alchemy: Turning Heat into Power
Look at the sky over any city or town on a winter day. See those columns of steam or smoke rising from the chimneys? What you’re looking at is wasted energy. Amazingly, at least 56% of the energy produced in the U.S. is wasted. It escapes as heat, radiating out of boilers, leaking through the roofs of power plants, and billowing out of smoke stacks and steam pipes.
Here’s a little math lesson that doesn’t add up: 3 + 2 = 1. No, I didn’t make a mistake. To generate 1 Watt of power, a utility company needs about 3 Watts of heat input and dumps into the environment the equivalent of about 2 Watts of power in the form of heat. Not very efficient, is it?
According to the U.S. Department of Energy, 20 to 50 percent of the energy of the 24 quadrillion BTUs generated by industry across the nation is lost in waste heat. That figure may be as high as 70 percent in coal-fired power plants.
Loy Sneary, CEO of Gulf Coast Green Energy, thinks that’s got to change. Sneary’s company sells the ElectraTherm “Green Machine,” a generator that transfers waste heat directly into electricity, while using no fuel and creating no emissions. Sound too good to be true? It did to me, too, until I saw it in action on the campus of Southern Methodist University (SMU) in Dallas, Texas, where the first 50 kw Green Machine was installed.
Gulf Coast Green Energy was a sponsor for SMU’s Geothermal Energy Utilization conference in June of 2008. During the conference, Sneary showed off the Green Machine’s power-generating capabilities for its first-ever test run. I watched as he switched it on, and the meter shot from 0 kW to 50 kW in a matter of seconds. That’s kW out, feeding power to the campus grid.
Sneary, a Texas farmer, businessman, and former judge, has been busy in the intervening months since that demonstration, making presentations to industries and municipalities throughout the South. He’s also working with the Texas Legislature and the Texas Renewable Energy Industries Association to classify waste heat as a renewable energy resource for the first time ever.
What follows is an interview with Sneary while he was stopped along the road somewhere between Houston and Oklahoma.
BPGL: I understand that the Green Machine takes industrial heat and transfers it into electricity. How does it accomplish this?
SNEARY: In the back of the 50 kW machine, a 6-inch supply hose feeds in cold water, and another feeds in hot water or a hot fluid. Inside the machine is a closed-loop, organic Rankine cycle system.
The temperature differential (delta T) between the hot water and the cold water causes the refrigerant in the system to expand and contract. Two things come out of the machine: lukewarm water and electricity.
BPGL: Most heat that industry wastes is in the form of hot air. How do you transfer the industrial hot air into the hot water/fluid that you are pumping into your machine?
SNEARY: To capture the hot gas, we hook a heat exchanger (economizer) up to the exhaust. A fluid, either water or glycol and water, runs through the economizer’s coil tubing. As hot air goes through the stack, it heats up the fluid in the coil tubing. That hot liquid is pumped into our waste heat generator, where the refrigerant is pressurized and vaporized. The resulting hot vapor drives the twin-screw expander, which drives the generator.
BPGL: What are the best applications for your waste heat generators?
SNEARY: There are so many uses. The best way to answer that question would be to describe the projects we are working on.
Let’s start with methane gas from landfills. If a landfill is flaring excess methane, we can tap into that heat source and make electricity.
We’re working at a gas turbine and compression station in Louisiana with the goal of putting the Green Machine on the exhaust system.
We’re also working on a couple of projects where excess steam is vented off. We’re taking that steam and turning it into electricity. In each of those cases, a single machine will generate 50 kW. That company is trying a simple application first, but they have a number of applications within that one plant and they have similar plants all over the world.
For another company in Louisiana, we will be taking geothermal fluids out of non-producing gas wells. We expect that site to produce 100 kW.
We’re working with a company that uses hardening furnaces. This is a foundry that makes steel, and we’re using the heat from those furnaces to make electricity.
BPGL: Loy, today I talked with Jeff Voorhis of the Texas Commission on Environmental Quality. I asked what he thinks about capturing waste heat and turning it into power. He said, “This kind of technology has great potential. But it needs to be evaluated by companies to see if it’s technologically and economically feasible.”
As the CEO of Gulf Coast Green Energy, you’ve already given us your opinion on the technology. What about economics? If a company were to purchase one of your machines, what would be their return on investment, or ROI?
SNEARY: Depending on the job, there’s a lot of variables. We need to know the cost of power at that location. We have one customer in the ship channel in Houston that overhauls barges. They pump out the gas and flare it. We take that flare gas and use it as a heat source. In their case, the ElectraTherm Green Machine will pay for itself in 2 ½ years.
But every situation is different; other sites may require quite a bit of ancillary equipment. The ROI could be anywhere from 2½ to 5 years, depending on the cost of power and how complicated the job is. There a lot more at 2½ years than there are at 5 years. And that’s not including any carbon credits or incentives. In the new bailout, there are investment tax credit provisions for equipment like ours. But our equipment stands on its own without any subsidy.
BPGL: You described your generators as “plug and play.” What does that mean?
SNEARY: Right now, our systems come in two sizes, 50 kW and 500 kW. If the location emits enough waste heat to generate, say, 20 megawatts of electricity, we can just hook these up in a series. It gives us the flexibility to pull one out to work on it, while the others keep running.
BPGL: Combined heat and power (CHP) is getting discussed in a few state legislatures and now, finally, at the federal level. If you were to be standing in front of a state Senator right now, what would you tell him or her?
SNEARY: The first thing you have to do is educate them. I testified to the Texas House Energy Resources Committee. Everyone there knows a lot about wind, solar energy, and geothermal energy sources. But no one had even heard of waste heat generation, because no one’s been educating them.
BPGL: Loy, I see that your waste heat generators have been getting a lot of attention lately in the press. Where should our readers go looking for you?
SNEARY: Well, Popular Science just named the ElectraTherm Green Machine one of the top new green technologies for 2008. And we were interviewed on television on the 700 Club as an alternative energy source. The Green Machine has also been talked about by Gizmodo, Green Tec, EnergyCurrent, and Ecogeek. It was even on Fox News the other day.
BPGL: That’s huge, Loy. With such great press, you’d think people would be beating down your door trying to get the Green Machine. Why doesn’t every factory have at least one?
SNEARY: The ElectraTherm Green Machine is relatively new in the marketplace. We have the technology right now to not only capture some of that waste heat, but also to reduce carbon emissions that are going up the chimney and becoming greenhouse gases.
By reducing the heat, we slow the gas molecules in the chimney. By slowing the molecules, stack scrubbers can work more efficiently, keeping more greenhouse gases out of the air. So, it’s a winning proposition not only for a company’s ROI but also for the environment and the air that we breathe.
BPGL: Thank you Loy, for what you are doing to save the planet and for the time you have given me.
SNEARY: Glad to do it, Joe.
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