BUILDINGS - Smarter Facilities Management

11/01/2014

6 Considerations for Wind

Learn about the breezy benefits of this renewable power source

By Jennie Morton

 

Geothermal heating and cooling? Hidden beneath your feet. Rooftop solar array? Placed out of sight. A utility-scale wind turbine? Visible from miles away.

You don’t need gale-force winds to invest in a turbine. This form of renewable energy is breezing its way onto schools, hotels, office parks, and college campuses. As long as you have available land and an eye for a long-range payback, wind can help you secure clean energy in your own backyard.

Spinning with Success
Imagine long white blades stretched across a blue sky and gracefully rotating in the wind. It paints a pretty picture, but turbines aren’t for architectural interest. These renewable energy generators can significantly offset the amount of electricity your facility normally draws from the grid.

“There’s no silver bullet for renewable power – we can’t meet all of our energy goals with one technology. You have to use what’s most appropriate and feasible for the particular resource of your location, and wind can deliver for many regions,” explains Trevor Atkinson, sales and business development manager for Northern Power Systems, a turbine manufacturer.

INFORMATION AND IMAGES COURTESY OF NORTHERN POWER SYSTEMS

Case Study #1: McGlynn Elementary and Middle School

This municipality-owned turbine at the McGlynn Elementary and Middle School was identified as an opportunity for energy independence by Medford, MA.

Installed in February of 2009, the congested city site was predicted by AWS Truepower to have an average wind resource of 4.6 m/s (10.3 mph), but in actuality has experienced winds of 4.3 m/s (9.6 mph). As a result, the annual energy output has been lower than anticipated but well within expectations for this type of urban installation.

The low height profile of the 37-meter tower and quiet permanent magnetic direct-drive (PMDD) operation ensure that the school’s neighbors are not adversely affected. A web monitoring program tracks energy output, carbon emission offsets, cost savings, and other historical data that can be accessed online by classrooms and the community.

“The opportunity with wind for schools is not only to educate tomorrow’s leaders about energy and the environment, but also to gain real savings that can translate to teacher positions, arts programs, facility improvements, and even other renewable energy projects,” noted Michael J. McGlynn, mayor of Medford at the time of installation.

The city obtained incentives from numerous sources, such as the Massachusetts Renewable Energy Trust LORI grant, Massachusetts Energy Consumers Alliance grant, Clean Energy Choice grants through the National Grid GreenUp Program, annual renewable energy credits, state appropriation general laws, and Chapter 312 of the Acts of 2008.

Whether adding a wind turbine to an existing property or a new development, you need to extensively research your options before committing to an installation. To ensure a successful project, do your homework using these six factors:

1) Understand Your Goals
Before you even consider wind, take care of efficiency projects first. There’s no sense in adding renewable generation if it will only lull you into wasting power elsewhere in your facility.

“You need to understand your load and how you can improve it,” Atkinson stresses. “If you’re generating your own power, you don’t want to be throwing away your green energy on incandescent lighting and leaky windows.”

Once you get your energy usage as lean as possible, determine what goals you want a wind turbine to satisfy.

“Do you want to be 100% powered by renewable energy or just 10%? Do you want to create a microgrid so you reduce power quality issues? Do you want to earn LEED credits? Do you simply want to put up a green flagpole to announce your company is sustainable?” Atkinson asks. “Each of these goals directly impacts the size of the turbine you need.”

Beyond diversifying their energy sources, the majority of owners use wind to manage their utility spend. It’s key to know how much your building is consuming so you can appropriately match the turbine output, says Adam Miller, founder of Summit Design + Build. Even better, use submetering throughout your facility. This will lay the groundwork for ROI if you can concretely say your wind generation in a given year will satisfy 100% of your lighting needs or 85% of your HVAC consumption.

2) Calculate Your Wind Resource
Wind resource is the amount of wind your site receives annually. Sure, you can step outside and feel the direction of a stiff breeze by licking your finger and sticking it in the air, but that’s only good for movie characters, not real life.

“If you’re going to spend seven figures on a turbine, you want to make sure the wind is going to be there,” says Ari Killian, project manager for Summit Design + Build.

Note that the viability of wind power is dependent on geography, adds Killian. Solar is likely to have an edge in southern and western states, but wind is more prevalent in the plains and coastal areas. And even if your region has strong wind throughout the year, performance varies on a daily basis, even more so than sunny days.

“Wind speeds can fluctuate between 20 to 25% each year, whereas solar is within 2 to 3%,” Atkinson explains.

There are two ways a commercial property can assess its wind resource. The most common is to use national weather data.


“There are a number of online databases that utilize hundreds of weather stations. While they are a pay-for service, you can put in your building location and it will give you a highly accurate assessment of your wind resource,” says Atkinson. “For a single distributed-scale turbine project that’s 100, 200, or even 300 kW, the online data is extremely reliable. We’re talking about a nominal 3 to 4% accuracy range from what is measured on-site to what was predicted.”

The other option is to install a wind tower that uses anemometry to document wind speeds, says Miller. This is the same technology a wind farm developer uses to study the microclimate of a potential site. These feasibility studies are an added expense and typically run for several years, but they may save you from installing a wind turbine that ultimately won’t meet your goals.

“Every year you collect data, you radically reduce the uncertainty of your wind resource,” emphasizes Atkinson.

INFORMATION AND IMAGE COURTESY OF NORTHERN POWER SYSTEMS

Case Study #2: Wausau East High School

Wisconsin’s first high school renewable energy center is proud to have this turbine complement textbook lessons on renewable power.

Installed in 2009, the gearless design offers 24/7 monitoring capabilities and students can access power data through web portals. The information is used across curricula and throughout all grade levels to track wind speed, historical data, and energy efficiency.

The school is projected to save almost half a million dollars on utility bills and has thus far offset more than 208 metric tons of carbon emissions. The site’s five-year wind resource has averaged 4.23 m/s (9.9 mph).

The educational benefits of the wind system to the students was the primary motivation and purpose for this renewable energy installation. The project was funded with support from the Walter Alexander Foundation, Focus on Energy, and the Wisconsin Public Service Response Rewards.


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