District Energy Systems

Metro Nashville District Energy System
On Time Project Completions

Mayor
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Deaderick Street Projects

During the fall of 2008, NDES became aware of the Department of Public Works’ Streetscape project for Deaderick Street.  This Streetscape Project involves the refurbishment and revitalization of the Streetscape along Deaderick Street between 3rd Avenue North and 6th Avenue North.  This Streetscape Project began construction during the fall of 2008 and the Department of Public Works notified all underground utilities that if work was required within the Deaerick Street boundaries, it need to take place right away and not impact the schedule of the Streetscape Project which was scheduled for completion during the summer of 2009.  NDES had four projects that fell within the boundaries of the Streetscape Project:

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  1. The replacement of 350 feet of 6" condensate piping between Manhole 5 (at Union and 5th Avenue) and Manhole 9 (at Deaderick and 5th Avenue)
  2. The enlargement of Manhole 9 to allow the repositioning of manways out of the street and into the sidewalk
  3. The replacement of the 2" condensate service piping to the Citizen’s Plaza (on Deaderick between 4th and 5th Avenues) and repair of the existing steam piping
  4. The enlargement of the manway access to Manhole 13 (in the intersection of Deaderick and 3rd Avenue) to enable the insertion of a new 16" steam valve to replace a leaking valve.

These projects were completed in the first three months of 2009 so there was no negative impact to the Streetscape Project.

Ryman Auditorium Project

The condensate service line to the Ryman Auditorium from the main in 4th Avenue was in very poor condition and needed to be replaced.  After analyzing options, it was determined that the replacement of this line could be cost effective.  Therefore, a design for a replacement line was completed and put out to bid.  The pricing received was within the payback parameters so construction began in April of 2009.  With the Annual Country Music Festival beginning in early June, this line replacement needed to occur at a fast pace.  Approximately 290 feet of new 2" was installed by the end of May of 2009 and there wasn’t any conflict with the Music Festival.

Nashville (DES) Underground

Mayor
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The Nashville District Energy System Distribution System is comprised of four primary pipes; chilled water supply, chilled water return, steam supply and condensate return. These pipes account for approximately 84,000 feet of piping contained in four miles of direct-buried trenches or tunnel systems. There are three independent tunnel systems within the distribution system: the main tunnel system which is comprised of the 4th Avenue Tunnel, the 7th Avenue Tunnel and the Broadway Tunnel; the State Tunnel System and the AA Birch Tunnel.

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These tunnel systems account for some 31,000 feet of piping of the 84,000 feet total. These tunnel systems vary in depth from approximately 20 feet to 40 feet. All of the four miles of direct-buried piping and tunnels are installed underneath Nashville's street and sidewalks and the majority of the tunnel systems are bored through solid rock. The tunnel systems are accessed from buried manholes and vaults and special confined space certification is required for any personnel who enter these manholes or tunnel systems.

The underground tunnel piping and all of the manhole piping is inspected on a monthly basis to ensure timely repairs are made in order to maintain the overall system performance and efficiency.

The construction of these tunnel systems minimized the impact on traffic and businesses in the downtown area during the installation of the piping systems as opposed to a conventional open-trench, direct buried construction. In addition, the tunnel systems provide a means of inspecting and maintaining the piping systems on a regular basis that is not afforded by the direct buried method.

Customer Fixed Charges To Remain Flat for FY2010

Before the beginning of each fiscal, DES customer charges tied to the fixed costs for system operations are adjusted upward for inflation per the steam service agreement based on changes in the Consumer Price Index (CPI). As a result of the current CPI turning negative, there will be no upward adjustments of customer fixed charges for FY2010.

Mayor
Mayor Karl Dean

Happy 5th Anniversary Metro District Energy System!

On Friday, January 16, 2009, the Metro District Energy System celebrated its Five Year Anniversary of operations at the DES Plant with a reception to express appreciation to the DES customers. Mayor Karl Dean and other Metropolitan Government officials and Metro Council Members joined DES customers at the event.

Mayor Karl Dean recognized several individuals for their contribution over the past five years including DES Plant Manager Tim Hestle and Metro Project Administrator Harry Ragsdale of Thermal Engineering Group. Addressing those in attendance, Mayor Dean shared that Metro DES services have helped to lower the city of Nashville’s energy consumption and reduced the city’s electricity costs, and because the city decided to install additional future capacity when the plant was constructed, DES has been able to service new downtown developments. In doing so, the city's costs to support the DES system have been reduced, while at the same time reducing the capital investments of new developments.

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“As we work to get new businesses to call Nashville home, these factors become increasingly important,” added Dean, “We want businesses to know that Nashville is among the leaders when it comes to offering greener, more efficient and cost friendly alternatives.”
Since 2003, DES has been responsible for providing heating and/or cooling of 39 downtown buildings with a reliability rating of more than 99 percent. Metro DES will officially commemorate five years of service in downtown Nashville on December 16. DES plays an important role in the city's infrastructure, here are a few points:

  • Metro DES has a proven track record of being a greener, more efficient and more sustainable source of heating and cooling than in-house heating and cooling systems.
  • District Energy Systems' heating and cooling services improve the community's carbon footprint by helping to reduce CO 2 production by approximately 46,600 tons per year.
  • DES provides its customers with one of the nation's lowest chilled-water costs of service.
  • Metro DES consistently maintains a reliability rating of more than 99 percent, and because Metro has budgeted for capital projects, DES can ensure a high reliability rating for years to come.

Customers' variable costs have steadily decreased over the past several months due to operational changes within the customer's buildings and at the Energy Generation Facility.

Music City Center Closer To Becoming a Reality

One of the most exciting projects that has moved forward under Mayor Karl Dean's administration – with support from the Metro Council and leadership from the Metropolitan Development and Housing Agency – is the planning and design of a new state-of-the-art downtown convention center – the Music City Center. Read More

Tips for Customer Energy Savings

As you prepare your buildings for the approaching heating season, we would like to take this opportunity to present to you a few suggestions on saving energy whether heating or cooling. Energy conservation is beneficial for everyone. In addition to saving you money, energy conservation reduces the consumption of hydrocarbon-based fuels, and reduces the amount of greenhouse gas emissions. We hope the following list proves helpful to you this heating season.

Did You Know District Energy Offers More Favorable Carbon Footprint?

In cases where buildings are considering electric resistance heat or heat pumps, utilizing District Energy for heating results in a more favorable “Carbon Footprint.” Read More
View the Comparison of the Production of Carbon Dioxide.

Schermerhorn Symphony Center
Schermerhorn Symphony Center
The Symphony started with a design
to accept DES because of the
lower capital costs.
Photo by Marie Lancaster

Incorporating District Energy at the Design Stage of a Project Yields Greatest Savings.

Incorporating district heating and cooling services (DHC) from Metropolitan Nashville District Energy System (MNDES) into a new development at the design/conception stage can achieve reduced capital costs and reduced operating costs over the life of the development.

Perhaps the most significant economic benefit is in the form of avoided capital costs. Capital cost avoidance can have a material affect on the customer’s project viability. This is particularly true if the proposed facility is large enough to warrant chilled water generators. When DHC is designed into the project, the total building area, as well as the costs, can be reduced as a result of removing the chillers, cooling towers and a portion of the pumps and related piping and electrical. There are also structural savings, as well as aesthetic benefits, by not having to locate cooling towers atop or adjacent to buildings and by avoiding cooling tower plumes. Read More

Capital Projects Provide Condensate Savings

Three completed capital projects and two projects currently in the design stage will complete refurbishment of the condensate line for the District Energy System. Read More

Pesky Leak Discovered and Repaired

A sonic listening device operated by Metro Water detected a chilled water leak that has eluded CEPS for more than a year. Read More

DES Paying Dividends, Subsidies Continue to Shrink

The Metro Finance Department recently reported that the Metro DES facility provides the city with significant value. An audit released by the department found that the facility's value comes from declining subsidy and solid waste costs, combined with a more efficient energy source.

DES building photoThe Metro Nashville District Energy System (DES) provides energy for heating and/or air conditioning of 39 buildings in downtown Nashville.

The city has used district energy services for three decades, pioneering the waste-to-energy method of district energy in the early 1970s via the Nashville Thermal Transfer Corporation (Thermal).

The DES facility replaced the aged Thermal facility in December 2003 to provide its customers with more reliable, efficient, cost-effective and environmentally friendly heating and cooling.