By Christine Laue, Omaha World-Herald, Neb.

Dec. 30--The World-Herald featured a unique structure rising from a residential neighborhood, the Zero Net Energy Test Home, in a story last month.

Readers were so curious about the cutting-edge, "green" house that they wrote to us with more questions, which were passed to Avery Schwer, a Kiewit Institute professor overseeing the project.

First, a quick recap:

The Zero Net Energy Test Home at 6454 Woolworth Ave. is a partnership of the University of Nebraska Kiewit Institute, Green Omaha Coalition and Nebraska Flatwater Chapter of the U.S. Green Building Council. Its purpose is to serve as a teaching tool and to inspire students to seek solutions to energy issues. Construction started in June and is scheduled for completion by August 2009.

Now, the reader questions:

Q. Are the photovoltaics very sturdy? I heard they will break very easily in a hail storm. Also, does a roof have to be metal?

A. The photovoltaics are durable. The new ones are more durable than ones that were developed years ago. But you can always have a situation where they can break, just like a normal roof.

You don't have to have a metal roof to have the photovoltaics. You can install them in panels. The photovoltaics come in a number of different types. The type we are looking at putting on the ZNETH house is a standing-seam steel roof. A typical standing-seam steel roof has ridges about 16 inches apart. The roof I'm looking at putting on the ZNETH house will have the photovoltaics between those seams. They are adhered to the roof in a factory. You can have regular, separate photovoltaics panels and install them over your asphalt or cedar roof shingles. You can put photovoltaics on any type of roof.

Because the ZNETH house is a new house, a good way to do it is on a metal roof. You see more and more (metal roofs), like on a McDonald's. They are becoming more popular because they are a lifetime roof; they are very durable.

Q. Can you break down the cost of each key element in the ZNETH home?

A. 1. Solar collection device: $15,000

You want to have 700 square feet of surface area devoted to PVs in order to get a return on your investment. There are a lot of different types out there now, which is good, but it's also manufacture- and model-type dependent as far as cost.

2. Wind turbine: $7,000

Because we're building the wind turbine on top of the house, we don't have the cost of building the base. (The base in this case is the house itself.) So this estimated cost is probably lower than what a wind turbine with a base might cost.

3. Geothermal energy: $3,300

There are two main costs: excavation and materials. Because we laid the pipe in the horizontal well when the foundation was dug, the price of that well is just the pipe: about $300. The vertical well had to be dug down to 235 feet, so the cost for that excavation and pipe totaled about $3,000.

You've got to have an electric pump to circulate the fluid through the geothermal pipes as well as a system that makes these power sources work together. That system cost is what we're investigating now. I don't have the cost of tying it all together and the monitoring. I think there's going to be significant cost there because what we're doing is not very common.

Q. One reader called the cost of going green "maddening." Do you think the average person can afford implementing all three systems?

A. I think the average person will probably commit to one technology. And I think the ground-source heat pump is the most accepted already. PVs are second most accepted. The wind application is kind of wild. Having a wind turbine on top of a roof, that is the one that is probably going to be ridiculed the most. That's why I have to demonstrate that it is practical.

There's a real financial incentive for ground-source heat pumps. As far as practicality, you have to have the room around the house for that vertical well -- you have to have the area to put that pipe in. For a new house, that's not as difficult as for an old house.

Wind has got a lot of potential for return on investment. I'm projecting that the wind is going to be a real good investment, because as far as that vertical axis is concerned, it's good for blustery-type winds.

Photovoltaics right now are kind of expensive, but if you compare that to the cedar shaker roof, it's comparable. I'm terribly biased. People will get a cedar shake roof -- it's very expensive but doesn't do anything for the environment. But if you got a (less expensive) asphalt roof and photovoltaics, if you have a ground-source heat pump, I think you're on the way to saving some fossil fuels.

I would say for the cost of a cedar shake roof, you could get a regular roof with photovoltaics. If people would spend the money they do on granite countertops or cedar shakes on a wind turbine or photovoltaics, then that's a lot better investment for society. If that happens, then everything will come down in price. It's coming down in price already. But the more demand there is for the product, then the demand will make it more competitive, and that will drive down the cost.

A problem that we have in this area, in the Omaha area, is the energy costs are lower than in places like Arizona and California. If you're paying more for energy, the cost of investing in green fuel sources is not expensive -- it's a good investment.

Q. Will the Zero Net Energy Test Home be open for viewing by interested people soon?

A. Formal tours will be given as early as July. We'll have enough of it done so they can see the technology. We're still hoping graduate students will be living in it this fall. Once the graduate students are living in it, they will conduct tours for elementary, junior high and high school students.

Q. May I stop by the house?

A. I've had a number of people stop by, and we've tried to accommodate them. Students work on the house throughout the week, so Fridays are the best time to stop by.

Q. Can I get a floor plan of the house?

A. The plans will be available on our Web site when our Web site is completed. I plan to have it up in February.

Q. Do you know where I can get additional information on the wind turbine?

A. There are a number of companies producing wind turbines, but the one we're considering is Helix Wind. More information is available at the Web site: www.helixwind.com.

--Contact the writer: 444-1183, christine.laue@owh.com

-----

To see more of the Omaha World-Herald, or to subscribe to the newspaper, go to http://www.omaha.com.

Copyright (c) 2008, Omaha World-Herald, Neb.

Distributed by McClatchy-Tribune Information Services.

For reprints, email tmsreprints@permissionsgroup.com, call 800-374-7985 or 847-635-6550, send a fax to 847-635-6968, or write to The Permissions Group Inc., 1247 Milwaukee Ave., Suite 303, Glenview, IL 60025, USA.

NYSE:MCD,

A service of YellowBrix, Inc.