The Wave – July 2013

President’s Letter

District Energy has a proud history of serving the downtown community. As a community-based, non-profit energy company, we aspire to support our customers in their philanthropic and educational efforts, serve our community-based partners, and work with others to improve the quality of our environment. Each year, committed to supporting the organizations that improve the livability and vitality of Saint Paul, we align our giving strategy with our company values, outreach strategies, and customer-invested resources.

We provide sponsorship to customers in Saint Paul who improve the lives of others and the livability of downtown including the Ordway’s Circle of Stars, Music in Mears, Aeon, Greater Saint Paul BOMA, the Saint Paul Public Libraries, and our local hospitals. In addition to our financial giving, we have a strong commitment to education. My team enjoys sharing the story of District Energy St. Paul. That story includes the important partnerships forged in our community in the late 1970s to launch this community-energy system and expands to include the technologies we use to deliver our chilled and hot water services to our customers. These educational efforts are strengthened through partnerships with important community institutions like the Science Museum of Minnesota and Visit Saint Paul. Environmental responsibility is part of our daily operation, but we also value participation in community-based environmental conversations such as the one led by the Citizen’s League. Our company is one of many utilities at the table with policy makers, citizens, environmental organizations, business leaders, and institutional leaders to address the policies needed to more authentically and effectively promote energy efficiency in all parts of our state’s energy system.

We strive to use our organizational resources in these and other ways to help our customers and our neighbors keep Saint Paul strong. In this edition of The Wave, you’ll read more detail about some of our community-based efforts.

Celebrating 30 Years of Service

Triple Anniversary LogoThis year, District Energy celebrates three decades of energy service to the downtown Saint Paul area. Inspired by European technology and launched in 1983, District Energy was Saint Paul’s response to the energy crisis of the 1970s. Through the vision of then Mayor George Latimer and expertise of the company’s first president, Hans Nyman, the system was successfully designed to be energy efficient and fuel flexible, which would translate to stable rates for its customers.

The system’s capabilities have grown throughout the last thirty years to include integration of cooling services, an adjacent combined heat and power plant, and successful installation of the Midwest’s largest solar thermal array atop of the Saint Paul RiverCentre. In addition to growth of the system’s capabilities, the service area has grown to serve beyond the downtown core.

Thirty years ago, a group of dedicated civic and business leaders convened to strategize a new energy future for the city of Saint Paul.  Today, District Energy now operates the largest and most successful hot water district heating system in North America. This heating system now serves more than 32 million square feet of building space and operates at twice the efficiency of the former steam district heating system while using the same amount of fuel. Customers who have been with us since inception have experienced significant savings by choosing our community-based energy system over a stand-alone system.

Our commitment to community energy for Saint Paul remains strong through collaborative effort. We thank all of our partners, customers, and hardworking staff for their support and shared belief in our ability to provide exceptional heating and cooling services to this community. As we move forward into our fourth decade, we will continue to evaluate emerging technologies and partnership opportunities to benefit our customers, our community, and the environment.

Ask the Engineer – Domestic Hot Water Heat Exchanger Maintenance

Pressure GaugeOne thing many people may take for granted is their ability to get hot water at the turn of a faucet. In a district heating system, the key piece of equipment for keeping hot water running is your domestic hot water heat exchanger (DHW Hx). When properly designed and maintained, a DHW Hx should have a life expectancy of ten to fifteen years. If a DHW Hx is not properly maintained, the life expectancy can shrink to as short as a year or two. This can be a very expensive proposition, so here are a few tips to keep your DHW system running optimally.

Since you cannot fix what you do not measure, your DHW Hx should have common pressure gauges across the supply and return ports in order to check the pressure drop across the Hx.

This will allow you to monitor the most common cause for premature failure: hard water deposits. Your DHW Hx should also have clean-in-place ports installed to facilitate flushing with citric acid at a minimum of every two years, preferably annually. Do not use muriatic acid, as chlorine is highly corrosive to stainless steel. If not performed regularly, the narrow pathways through the DWH Hx will clog entirely, and even the cleaning agent will not circulate.

Pre-mix cold city water in the tank before sending it to the DHW Hx for heating. Sending 50°F city water directly to a DHW Hx that has 250°F water from the district heating system running through it will cause the Hx to warp, leak, and eventually fail. Finally, if there are dishwashers or washing machines utilizing the hot water, it is important to have a properly sized hammer-arresting system in place. Pressure spikes caused by the supply valves on the equipment could ultimately cause the Hx plates to separate and water to accumulate on the floor.

Please contact us if you have any questions about maintaining your domestic hot water heat exchanger so that you can achieve a long life out of this compact, yet important, piece of mechanical equipment.

Bronze Space Award Recipient

Since 1990, the International District Energy Association (IDEA) has been recognizing members who have demonstrated increases in the number of buildings and the area in square feet committed or recommitted to local district energy systems each year. At the 2013 IDEA Annual Conference and Trade Show, District Energy St. Paul earned a Bronze Space Award for increased space committed to our district heating and district cooling services. We credit the system’s dedicated and creative employees who assure District Energy St. Paul’s high-performing day-to-day operation and exploration of opportunities to implement best-in-class innovations for the continued success of our system. Many of our customers have extended their long-term agreements for heating and cooling after 20-30 years of positive experiences with our service. Our strong outlook for reliability, energy efficiency, and rate stability continues to be valued by existing and new District Energy customers.

State of Minnesota Extends Commitment

MN State CapitolThe State of Minnesota has extended its commitment to reliable and local district heating service for another 29 years. One of the original customers, district heating was extended to Minnesota’s State Capitol Building and the State Capitol Complex in 1984. Officials in public service at the time of District Energy St. Paul’s launch were important advocates for this system, working with the local officials and the business community to promote the development of our unique utility as a community asset with important service to the public and private sectors. The state capitol building was the first in the nation to use district heating generated by biomass-fired combined heat and power. Other buildings in the capitol complex include the Administration Building, the Judicial Center, the Veteran’s Service Building, and the Transportation Building. The nine state office buildings offer an important anchor to the northern edge of our current service area. As the State of Minnesota’s administration continues its efforts to be energy and cost efficient, we look forward to on-going opportunities for collaboration on effective energy solutions.

Local Partnerships – Tours and Programs Advance Shared Goals

Every month, dozens of visitors come to District Energy St. Paul’s facilities to experience energy production first-hand and learn more about how our unique integration of technologies leads the way for utility management, business growth, and policy development. In June, District Energy hosted tours of volunteers and staff members from the Minnesota Department of Natural Resources (DNR), City of Saint Paul, Science Museum of Minnesota, and Minnesota Association of Environmental Educators. Each group has a unique partnership with our business and has expressed diverse interests regarding a more in-depth understanding of our plant operations, solar installation, system delivery, fuel procurement and processing, and approaches to balancing environmental and economic benefits.

The DNR and Saint Paul staff work with our affiliates Environmental Wood Supply (EWS) and St. Paul Cogeneration to repurpose urban wood residuals as fuel in our combined heat and power (CHP) plant. The DNR’s Woody Biomass Harvest for Habitat program has helped many local, private landowners and public entities manage downed or damaged trees, invasive species, and general land improvements involving clearing of woody biomass.

The Science Museum has been an important neighbor and educational partner so we were thrilled to have their volunteer docents tour the plant and challenge our staff with informed and interesting questions about our machines and processes. We partnered with the Science Museum again to host educators from around the state for a discussion of CHP’s role in both energy efficiency and the operation of our system. The tour also included the seven solar installations located near our plant, including District Energy’s internationally recognized solar thermal installation.

Our team enjoys creating educational experiences for our community based on their specific needs and interests.

News In Brief

District Energy Recognized for Innovation
The International District Energy Association recognized District Energy St. Paul for its ongoing integration of renewable energy sources and efficiency-monitoring technologies at its 2013 Annual Conference and Trade Show.

We’d Like Your Input for Upcoming Communication Topics
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Operating Engineers Seminar
Hold the date! The next Operating Engineers Seminar will be held October 15, 2013 at Amsterdam Bar and Hall. Stay connected, more information will be forthcoming.