Biomass Heating Facility – The Hotchkiss School, Lakeville, CT


Quick Facts

Name: The Hotchkiss School Biomass Heating Facility, CT

Year of Implementation: July 2012

Area: 16500 sf

Cost: $14 million

Location: Hotchkiss School, Salisbury, Connecticut

Built Context: suburban

Climatic Conditions: Cold

Type of System: Biomass central heating facility/ thermal method

Scale: Regional

Annual Energy Production: 9.9 million kWh/yr


Associated General Contractors (AGC) Build Connecticut Award for Mid-Size New Constructions, 2014.

Connecticut Green Building Council Alexion Award of Excellence, 2013.

The third LEED-certified power facility in the US

1.1 Background

The Hotchkiss School is a boarding private school, sitting on 827 acres of woods, fields, and farmland in one of the most extraordinary landscapes in the Northeast. The School’s state-of-the-art facilities combined with these surroundings. (Hotchkiss, 2016)

The school is a member of EPA Green Power Partner (Environmental Protection Agency) and Green Schools Ally. Hotchkiss requires all campus buildings to acquire LEED certification and as of 2009 uses 34% green power. (Wikipedia, 2016)

The campus includes many historic and notable landmarks and buildings, including the award-winning Biomass Facility. (Hotchkiss, 2016)

In 2012 the school decided to replace an aging steam plant with a state-of-the-art biomass central heating facility. (Greenroofs, 2015)

The facility is part of a commitment to becoming a carbon-neutral campus by 2020. In order to merge with the surrounding landscape, the new building will have a low profile and an undulating, sloped green roof.  (Greenroofs, 2015)

photos source:


Connecticut belongs to the clod climate zone which has an average year temperature of 65°F. According to IECC(International Energy Conservation Code), the site is in the 5 climate zone. (source:

2.1 Type of system – 2.2 Scale – 2.3 Dimensions

The case study is a biomass central heating facility. Biomass is organic matter derived from living organisms. Biomass can be used as a source of energy and it most often refers to plants or plant-based materials that are not used for food or feed. As an energy source, biomass can either be used directly via combustion to produce heat, or indirectly after converting it to various forms of biofuel. Conversion of biomass to biofuel can be achieved by 3 types of methods: thermal, chemical, and biochemical methods. In this case, the method is thermal. (Source: Wikipedia, Biomass)

The scale of this case is both within the building and the regional. The energy produced by the plant is used mainly for the school building and also the regional area. The provision of wood chips is from the regional area.

Located at the bottom of a sloping landscape, the building on the Hotchkiss school site sits in between a golf course and marshes. The total area of the site is about 16500 square feet, with 190 feet length and 80 feet width.

type of system.001.jpeg

3.1 System description

The plant burns around 5,500 tons of wood-waste chips annually. The wood chips are the biomass in this case. After preparation and processing procedure, the biomass enters 2 boilers. After the fire boiling, some parts are exhausted, some turn to the ash. The waste ash from the burning is used as vegetable fertilizer around the school. The rest energy is converted to the electricity and used by the school and other buildings.

The 16,500-square-foot building burns locally sourced wood chips—a byproduct of FSC forests(Forest Stewardship Council)—and serves 85 buildings, 1.2 million sf, aka about 600 residents.

Other facts:

  • Woodchips collected from managed timber stands are considered a “carbon neutral” fuel by the International Panel on Climate Change because the CO2 produced by their use is reabsorbed by the ecosystem through regrowth of the forests where they originate. (Way, Rick. “Hotchkiss School ‘s Sleek Heating System.” (n.d.): 16. Web.)
  • These woodchips collected are thus transported to the biomass heating plant at the Hotchkiss school.
  • The energy produced from Biomass plant provides heat to 85 buildings i.e. 1.2 Million Sq.Ft.

4.1 Energy production – 4.2 Feasibility

Energy Production: 14 million BTUs per hour*24*365*81%(80-82% efficiency)/10000 (heat-electricity conversion rate)=9.9 million kWh/yr (Annual Energy Production)

As the facility serves about 600 residents, the average energy consumption is 16500 kWh per resident.

Feasibility: The average electricity consumption in PA household is 10402 kWh/yr (source EIA: while the annually Energy Production of Hotchkiss is 9.9 million kWh/yr. So it can provide 955 households with their annual electricity. The East liberty scheme is supposed to provide 1000 units within the site which needs about 1.05 Hotchkiss School Biomass Plant.



Note: For the feasibility study there has been used the sources of the U.S. Energy Information Administration.

5 Other benefits

The facility was built not only to produce heating to the school but also to generate a friendly space where students, teachers, parents, visitors, can visit and personal experience the benefits of such equipment. Thus, the place becomes a “Living Classroom” as stated in the sources. More benefits include the production of fertilizer and the external landscapes facilities.


6 Stakeholders



11 Bibliography

Other sources:










Group members

paul Moscoso – ankita Patel – chun Zhung






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