Building Green Report

Building Green Report

This month:

PVs Emerging As Option For Big Buildings

When people think of photovoltaics (PVs), they might get an image of fields of bracket-mounted solar arrays facing skyward. They might also think of them only in sunny areas of the country, such as California and New Mexico. Certain words may come to mind, such as “semiconductors” and “alternative energy sources.” And after the word “alternative” pops up, many people might think that PVs are a really good idea that never really amounted to much in the way of serious energy generation; it’s one thing to run your calculator on a photocell, but a large facility is quite another, right? Not necessarily.

PVs have been popular for the past 30 years in applications where grid power just isn’t practical, like pumping stations for cattle farms in remote regions of Colorado or in third-world countries where grid power doesn’t exist. And there is a small but dedicated core of homeowners who have installed solar panels on their houses to meet their personal energy needs. But until recently solar power just wasn’t practical for large-scale commercial use. Most facilities lacked the space needed to house large solar arrays, and battery storage units were too expensive, didn’t last very long and required too much maintenance to be practical.

Now, a combination of developments in PV technology and energy legislation in many states has brought PVs back on line as a viable solution for reducing energy expenses in an unpredictable energy market.

To begin with, new thin-film PV technology is becoming a popular alternative to older silicon crystal PVs. In silicon systems, the crystal is grown, or cast, in a process that wastes about 40 percent of the material produced. Only about 10- to 12-thousandths of an inch of the semiconductor’s surface is used to produce electricity, while the rest of the material behind it simply acts as backing. Thin film, on the other hand, is produced using only enough semiconductor to generate electricity. This process cuts down on production expenses, thus bringing down the cost of PVs while making them far more versatile as a building material.

Thin films can be used as stand-alone panels or building-integrated PV (BIPV) arrays, which are incorporated in windows, integral roof modules, roofing tiles and shingles, modules for vertical curtain wall facades, sloped glazing systems and skylights. In the last stage of the production process for window applications, or anywhere light penetration is desired, the opaque film can be laser-etched to allow a specified amount of light through.

Another attractive aspect of the thin-film production process, according to Steven Strong, president of Solar Design Associates, Harvard, Mass., is that it is the same as that used to produce metallic oxide or low-e window coatings, so there is no need for additional equipment to produce this new generation of PVs. “I believe that in a three year period,” says Strong, “this production method will allow thin films to compete head on in cost with high-end architectural glass.

“And to make BIPVs even more attractive, the federal government presently offers two tax incentives to encourage private investment in solar energy equipment and systems: an investment tax credit and an accelerated depreciation allowance,” says Strong. “Both of these incentives apply to building-integrated photovoltaic systems.”

Many states also offer incentives in the form of tax exemptions for the value added to a property through the installation of alternative energy-generating devices, including PVs and other systems such as fuel cells and wind power. Some of these exemptions are indefinite while others are for a fixed number of years, and most of them apply to both commercial and residential properties.

Strong is quick to point out that the purpose of a BIPV system is not to generate all of a building’s power needs, but to reduce the amount of electricity purchased from a power supplier, especially during peak periods. He sees the building power equation as being two sided: In order to deal effectively with high-energy costs, facilities need to combine energy efficient building systems with PVs.

Because BIPVs are not intended to meet all of a facility’s energy needs, modern PV systems do not rely on onsite storage. Instead, facilities with these systems employ net metering, so that the electric utility credits a BIPV system owner for surplus solar power produced. With net metering, surplus solar power in excess of instantaneous loads spins the revenue meter backwards.

According to the American Wind Energy Association, 33 states have mandated net metering, and another six states have proposed legislation. However, all states limit production capacity to 100 kW or less.

— John Sieracki is assistant editor of Building Operating Management



New Building Simulation Will Be Best, But Not Yet

A new and improved building energy modeling tool is almost here.

U.S. Department of Energy recently released EnergyPlus, the successor to the popular but somewhat limited DOE-2. And early testers have given EnergyPlus high marks for its ability to better simulate loads, run more accurate analyses and be easier to use. It combines the best of DOE-2 and another program called BLAST, developed by the U.S. Department of Defense.

EnergyPlus provides methods to analyze new kinds of systems such as radiant heating and cooling, electrochromic glazings and daylighting. EnergyPlus will be a much better tool for tracking and analyzing energy use in existing buildings.

It also will be much easier to add modules to, and this can be a big benefit for existing buildings, says Adrian Tuluca, principal with Steven Winter Associates.

“It is practically impossible to think of all types of operations that are encountered in the field,” he says.

But EnergyPlus is not yet fully developed.

“EnergyPlus is just an engine, and it needs front end programs,” says Tom McDougall, vice president of The Weidt Group. “But five years from now, most everyone will be using EnergyPlus.”

— D.K.



North Carolina Counties Set Building Guidelines

After eight months of work, a consortium of North Carolina municipal and county government agencies, including Orange, Chatham, Durham, Johnston, Lee and Wake counties, released a document titled “High Performance Guidelines: Triangle Region Public Facilities,” which includes measures to save energy and water, reduce the use of materials, improve indoor air quality and improve work environments.

The group also devised a rating system to compare the energy efficiency of government buildings.



Lighting Pollution Going Down And Out In Texas

Alpine, Texas, looks to reduce light pollution while also providing cheaper, more efficient outdoor lighting.

The city, located about 450 miles west of Austin, worked with officials from the McDonald Observatory, the Big Bend Astronomical Society and American Electric Power to produce the measure, which allows existing lighting to remain in place but requires full cut-off lighting for new public and private installations.

The law ensures that light will be directed down rather than into the sky, helping to counter the light pollution. Furthermore, because the light is concentrated downward, energy can be saved by using a lower wattage bulb.



Council Perspective: New Rating System Offers More Than Certification

LEED for Existing Buildings Helps Facility Managers Rate Their Building While Offering Template For Operations

This fall the U.S. Green Building Council will begin a pilot program for the country’s first green building rating system for existing buildings.

LEED (Leadership in Energy and Environmental Design) for Existing Buildings is a set of sustainable standards based on whole-building performance for operating and upgrading commercial and institutional facilities. It draws upon its increasingly popular forerunner, LEED 2.0, a green building rating system for new construction and renovation, and the U.S. Environmental Protection Agency’s Energy Star Building Label program.

Included in LEED for Existing Buildings are standards for making green improvements to the building’s systems and building operating practices by both occupants and owners. The rating system addresses energy and water efficiency; indoor air quality; recycling programs; cleaning and maintenance practices; and ongoing monitoring, measurement and management of all building systems.

In pulling together this comprehensive rating system, the Council was very cognizant of what is affordable and what is doable in making an existing building a green building. As a result, a building owner can take the leap and change a building to a green building in one fell swoop or take substantive incremental steps over years.

But even more than a rating system, LEED for Existing Buildings will provide a template for the continuous operations and maintenance of a building. It will help building owners significantly reduce their energy costs and improve the environmental health and impact of their buildings.

There are 4.5 million existing buildings in the United States that can cut their energy use up to 25 percent with a program of operations and maintenance focused on energy efficiency. A reduction of that amount eliminates the need to build 85 500-megawatt power plants, according to the Leonardo Academy in Madison, Wis., which translates into a reduction of 275 million tons annually of carbon dioxide.

LEED for Existing Buildings will not only help achieve this, it will also improve the performance and marketability of a building and save a building owner money.

— Paul von Paumgartten, Co-chair, LEED Steering Committee



LEED Helps Guide Organization Toward a Better Building

YARMOUTHPORT, Mass., October 15, 2001 – In any growing organization, there comes a time when needs overtake the facility's footprint. When the International Fund for Animal Welfare (IFAW) needed to relocate due to space constraints -- some of its departments were working out of rented space nearby -- every possible location was considered. It had hoped to recycle an existing building but could not find one that met its space needs.

After an exhaustive search, the decision was made to stay in Yarmouthport, Mass., where it has been since 1977. IFAW purchased 16.5 acres of land right around the corner from its original location.

LEED Plays Lead Role

IFAW wanted an environmentally sustainable facility that reflected the organization's mission of promoting animal welfare and conservation policies that advance the well being of both animals and people. At the same time, it needed to adhere to specific Cape Cod building restrictions.

IFAW had mentioned four overriding concerns: traffic, wastewater, water usage and the presence of open space. It was from this initial meeting that the design concept really materialized.

"When they brought up three of the five components of LEED, we began discussing incorporating LEED into the design," says project manager Ray Bourcier of William A. Berry & Sons. The two remaining LEED categories - material usage and IAQ - were equally important to IFAW.

A design team who was familiar with the Cape and had a good deal of sustainable experience was selected.

Building Up Bare Bones

The design team initially developed a price for a bare-bones building. They then used this as a baseline so that they could consider the three levels of LEED: platinum, gold and silver. They decided that the gold rating would be their goal after estimating that this level would cost about $25 more per square foot and that the payback would be 15 to 20 years.

"The biggest cost was actually the composting toilet system," says Bourcier. "That added $7 per square foot to the total cost, but the system was one of their priorities."

The facility will also boast a grey water treatment facility, which will cut water usage by 65 percent. The southern face of the building will be 50 to 70 percent glass, making use of passive solar energy and reducing energy consumption significantly.

A flat roof will house solar panels, and a geothermal heating and cooling system is planned. Recycled building materials were used whenever possible, and paints and carpeting that meet green industry standards will minimize emissions.

Rather than level the undulating landscape, IFAW will attempt to make the least impact possible on the area. It purchased more land than needed, allowing the majority of the land to remain open space. The land includes a kettle hole, which will be utilized as a wetlands habitat for native plants and animals as well as an area to contain and clean storm runoff from the building's roof and parking areas.

One challenge the design team faced was building a facility that was not only big enough to support all of IFAW's employees, but one that also had the smallest footprint possible. Vertical rather than horizontal expansion would seem an obvious solution, but zoning restricts Cape buildings to two levels.

Working With The Site

The solution was a three-story facility sited on the edge of the kettle hole. The third level of the facility extends into the depression, giving a two-level profile to the northern, street-facing side of the building. The proposed facility will be just less than 39,000 square feet, but the actual footprint will be closer to 13,000 square feet.

Bourcier notes that there have not really been any unforeseen changes to the design because the team has kept a good handle on the budget. "We didn't want to put in front of the owner a project they couldn't afford," he says.

Bourcier has also learned from others' mistakes: The green elements often come up too late in the design process.

"This experience has been great," says Bourcier, "because we've all been there since day one."

- Angela Maas is managing editor of Building Operating Management

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Building Operating Management is a GreenBiz News Affiliate. This story appears by permission. Story copyright 2001 Building Operating Management, all rights reserved.