Saint Paul, MN

District Energy St. Paul

Partnership and Innovation

SERVICES PROVIDED
Operations, maintenance, and management including business planning, project management, engineering, and construction oversight
Owner
District Energy St. Paul, non-profit utility
Start-up
heating 1983; cooling 1993

District Energy St. Paul is a non-profit utility providing energy services to downtown Saint Paul. The core heating and cooling network serves 200 buildings in the central business district and across the river to a secondary area of commercial, light industrial, and residential development. The customer base includes higher education, hospitals, Fortune 500 companies, residential apartments, condos, and townhomes, as well as hotels, entertainment and sporting venues.

District Energy is the largest hot-water district energy system in North America and is recognized globally as a leader in integrated and dynamic energy systems. Since its transition from steam to hot water in 1983, this system has incorporated district cooling, thermal storage, solar thermal, and a biomass-fired combined heat and power plant.

Public-Private Partnership

Developed as a public-private partnership, District Energy has worked closely with the City of Saint Paul, Saint Paul Port Authority, local businesses leaders, and civic partners to offer competitive energy solutions and cost-based rates that have played a critical role in development for the city. District Energy has become a showcase for energy efficiency through continued efforts to evolve, to reinvent, and to integrate sustainable solutions that have earned the operations a global reputation, including recognition from the United Nations Environment Programme.

Studying, testing, and demonstrating emerging technology has been key to system achievements. Just as importantly, the people inside this operation are committed to bringing customers and community stakeholders into the story to share in their success. Whether it is multifaceted efforts to bring combined heat and power to this downtown area or to build the Saint Paul EcoDistrict sustainability education platform, District Energy is dedicated to merging partnership and innovation to advance St. Paul’s community energy model.

Ever-Green Energy’s Role: Ever-Green provides comprehensive operation and management services, energy engineering, and project management, as well as business operations, finance, legal, and outreach and education services.

Milestones:

  • 1983 steam to hot water conversion complete and heating system start-up.
  • 1993 cooling service start-up.
  • 2003 District Energy became a green energy service provider following construction of an affiliated combined heat and power (CHP) plant that is fueled by a renewable resource—clean, urban wood residuals. Using renewable fuel, the CHP plant simultaneously produces about 65 megawatts of thermal energy for District Energy and 25 megawatts of electricity for the local utility. It is the largest wood-fired CHP plant serving a district energy system in the nation.
  • 2011 the system was advanced further with the installation of the Midwest’s largest solar installation. It is one of the country’s largest hot water solar projects and the first in the United States to be integrated into a district heating system. The system peaks over 1.5 MW (thermal equivalent) and provides hot water and space heating to the Saint Paul RiverCentre, as well as exporting to serve other District Energy customers.
  • 2013 first phase of conversion of an existing 2.5 million gallon chilled water thermal storage tank to be able to store hot water.
  • 2015 commitment to end use of coal after the 2020-21 heating season. The transition from coal reduces the heating system’s CO2 emissions by 27 percent or 21,000 tons. This is the equivalent of removing 4,400 cars from the road each year.

Technologies Implemented: Hot water district heating, steam to hot water transition, district cooling, combined heat and power, waste heat recovery, thermal storage, biomass, solar thermal, snow melt

DISTRICT ENERGY ST. PAUL HOT WATER SERVICE DATA

Buildings served with district heating 195 Buildings
Single Family Homes 298
FY 2015 energy sales 322,000 MWh
Current billed demand 171 megawatts
Total Building Area Served 31.8 million square feet

HEAT SOURCES

Two coal/gas-fired boilers 88 MW
Four gas/oil-fired boilers 106 MW
Combined heat and power plant 65 MW
Regions Hospital Plant (gas/oil-fired)  25 MW
 Mobile boilers (temporary and/or backup)  7.5 MW
Solar thermal  1.2 MW
TOTAL  292.7 MW
Piping Materials  prefabricated steel pipe with polyurethane
insulation encased in polyethylene jacket
Diameter  3/4-inch to 28-inch
Length  40 miles
Volume  915,000 gallons
Supply Temperature  190-250 degrees F
Return Temperature  140-160 degrees F
Supply Pressure  180 psi
Reliability rate  99.99%

DISTRICT ENERGY ST. PAUL CHILLED WATER SERVICE DATA

Buildings served with district cooling 111 Buildings
FY 2015 Energy Sales 39,588,241 ton-hours
Building Area Served 21 million sq. ft.

CHILLED WATER SOURCES

Main plant, 76 West Kellogg Boulevard
Six electric chillers 12,737 tons
Two absorption chillers 1,000 tons
10th and Sibley Plant
Three electric chillers 7,000 tons
Chilled water storage systems 10,800 tons
Satellite chillers 3,900 tons
TOTAL 35,437 tons
Piping Materials steel pipe wrapped in protective coating with cathodic protection
Diameter 3-inch to 30-inch
Length 15 miles
Volume of distribution system 1,055,000 gallons
Volume of storage system 6,700,000 gallons
Supply Temperature 42 degrees F
Return Temperature 56 degrees F
Supply Pressure 150 psi
Minimum pressure differential 15 psi
Reliability rate  99.99%

Work with Ever-Green

Call 651.290.2812 or email info@ever-greenenergy.com to chat with an Energy Systems Expert.