| Local Policy Description: | Biomass District Energy
The development of a biomass-fueled district energy system is the single largest measure for reducing greenhouse gas emissions that is identified in Burlington’s Climate Protection Action Plan. The estimated annual reduction in CO2 emissions of a biomass district system, compared to natural gas heat systems in individual buildings, ranges from 32,000-50,000 tons, depending on the extent of the distribution system.
The proposed district energy system reduces emissions through two mechanisms. First, the central plant, in this case the McNeil generating station, would be retrofitted to take advantage of cogeneration—also referred to as combined heat and power (CHP).
This significantly improves the overall efficiency of fuel use. When operating in an electric generating mode only, conventional thermal power plants are typically 30-40 percent efficient. Capturing waste heat and using it to supply heating loads can raise their overall efficiency to more than 70 percent.
Second, the proposed system will rely primarily on renewable biomass fuels. The McNeil plant consumed approximately 220,000 green tons of low-quality wood fuels in 1996. Implementing the district energy system is estimated to increase this consumption by an additional 200,000 green tons per year. In the first year, this is projected to offset roughly 394,000 million BTUs of fossil fuel combustion, resulting in 32,000 tons of estimated CO2 reductions.
The projected increase in biomass fuel consumption falls within state projections for the amount of biomass energy that is easily and readily available for new sustainable wood-to-energy projects.
The two largest potential consumers for thermal energy from the proposed system are the University of Vermont and Fletcher Allen Health Care. Other institutions, including the Red Cross and Champlain and Trinity Colleges, become important under a potential second phase of development, in which the distribution system is expanded.
The project’s economic feasibility depends, in part, on the ability of these and other institutional consumers with significant thermal energy loads to make facility modifications and energy purchasing commitments. For this reason, institutional decision makers are critical to the further development and implementation of a district energy system.
A number of issues will continue to receive attention during efforts to develop a viable implementation plan for the district energy system. These issues include:
- the community’s acceptance of the increased McNeil plant operations and required fuel transport and
- the negotiation of contracts and financial arrangements acceptable to all major parties and sufficient to provide the foundation for project finance.
Buildings and Operations
The climate protection opportunities in institutional buildings and operations are similar in many ways to those described in the commercial and industrial sections of this plan. Many institutions have undertaken significant energy efficiency projects, most frequently in lighting, motors, and heating, ventilation and air conditioning systems.
Along with preventing thousands of tons of greenhouse gas emissions each year, these projects bring economic savings, comfort and productivity improvements, and significant environmental benefits.
By continuing and strengthening their commitments to identify and capture all economically achievable energy efficiency savings, institutions directly benefit their constituents while freeing resources for investments in other critical activities. As in the past, efficiency measures can be undertaken independently, with assistance from utility-sponsored efficiency programs, and/or in collaboration other partners such as Climate Wise.
Plans for new construction, facility renovation or expansion, and the replacement of failed equipment present important opportunities for investment in energy-efficient and environmentally-sound structures and equipment. These are often prime opportunities for comprehensive investments that would be less attractive under retrofit conditions.
Helping customers capture opportunities for cost-effective investments that would otherwise be lost is a fundamental component of Vermont’s plan for a statewide energy efficiency utility.
Institutional administrators and facility managers who aggressively seek these opportunities before they are lost are making an important contribution to the community’s overall climate protection objectives.
Combined Heat and Power; Fuel Switching
Large industrial operations often have big-enough thermal and electric energy loads to justify investments in combined heat and power (CHP or cogeneration) systems. The overall system efficiencies attainable with CHP—up to 80 percent—can reduce emissions by up to two-thirds, compared with conventional power supplies. CHP technologies can be implemented at the facility, or can be community-scale. Section C, Institutional Opportunities, gives more detail on the potential for district heating based on CHP.
Switching to lower-carbon or renewable fuels is another strategy that can help industrial firms reduce emissions. Transpired air collectors for ventilation air preheating is one example of a simple, cost-effective renewable energy technology that is suitable to Burlington’s climate and can help reduce heating costs for buildings with large ventilation requirements, such as vehicle maintenance barns or ventilated warehouses. These systems rely on a dark-colored, south-facing wall with small perforations. Air passing through the perforations is preheated by as much as 40 degrees in a simple, low maintenance means of reducing both emissions and heating costs.
Solar water heating, the sustainable use of biomass energy, and solar photovoltaics are other renewable energy technology options for companies seeking cleaner energy solutions. Information and resource contacts for these technologies are provided in the residential and commercial sections of this plan.
Light-Emitting Diode Traffic Indicators
Light-emitting diodes (LEDs) are highly efficient alternatives to the bulbs that have been used in traffic signals over the years. A 20-watt LED lamp has the same light output as a 135-watt incandescent bulb, resulting in energy savings of 115 watts. LED lights have also been estimated to last 6 to 10 times longer than incandescent lamps.
LED technology for traffic signals is ready for use on a large scale. The Burlington Public Works Department installed its first LED signals in 1995 at Plattsburg Avenue and Sunset Drive. These indicators proved successful, and Public Works targeted 28 intersections with a total of 118 red indicator signals to be replaced with LED lamps. Energy savings from replacing these signals are estimated at 77,268 kWh a year, or around $11,590.
The Burlington Electric Department is financing this project through its energy savings program, and the payback period is around two and a half years. Carbon dioxide reductions from these initial 118 red-signal replacements are above 34 tons per year.
The first signal in the city (and in Vermont) to have been converted totally to LED, with all colors outfitted, is at the corner of Pine Street and Flynn Avenue. With just this one signal, the city is saving around 8,000 kWh a year and about $1,200. Each signal thus retrofitted will prevent almost four tons of emissions per year. Since installation the intersection traffic signal has been virtually maintenance free.
Energy Star Procurement and Bulk Purchase Program
Recent years have seen a significant increase in the number and quality of environmentally sensitive office products and office equipment. Establishing standards for purchasing these types of products, and making sure that energy saving and climate-friendly shutdown procedures for office equipment are established and followed, can reduce the city’s emissions of CO2 by an estimated 50 tons per year.
Investigating the opportunity to acquire efficient office products through bulk purchases is also recommended.
Energy Efficiency Improvements for Municipal Building
Heating, Ventilation and Air Conditioning Systems for Municipal Buildings
Bring all systems up to a minimum operating efficiency level, perform building and system seal-up, install efficient control systems, analyze cost-effectiveness of heat recovery ventilation, establish a comprehensive maintenance protocol and train/inform building employees on energy efficiency strategies.
Water Heating Systems for Municipal Buildings
Analyze systems for cost-effective efficiency improvements and fuel conversions, insulate piping and tanks, reduce temperature set-points where appropriate and install low-flow fixtures.
Lighting for Municipal Buildings
Perform lighting assessment and implement alternate lighting strategies where appropriate, improve task lighting, install occupancy sensors and lighting controls where appropriate.
Motors for Municipal Buildings
Implement protocol to install premium efficiency motors at time of replacement, and analyze motors larger than 1HP for proper sizing and efficiency, replace where cost-effective.
Office Equipment for Municipal Buildings
Implement buying strategy of Energy Star equipment and Products and environmentally sensitive office products, and implement awareness campaigns to encourage “thoughtful” consumption of equipment and products.
New Technologies for Municipal Buildings
Investigate and support cost effective heat recovery, renewable fuel and cogeneration opportunities, while providing leadership for the development of a municipal energy system.
“Energy Star” Office Equipment
Purchasing office equipment that has received the Energy Star designation is an easy way to lower your bills and reduce greenhouse gas emissions. Energy Star office equipment listed in the following table includes power-down features that allow a device to “sleep” during extended periods of inactivity, thereby reducing energy consumption by 25 to 60 percent. If a typical office, including 10 computers, one fax machine, two printers and one medium-sized copier, were to replace its office equipment with Energy Star models, it would reduce its CO2 emissions by 5,000 pounds per year. If 50 Burlington offices this size were to upgrade their equipment to Energy Star models, the total annual CO2 reductions would equal 125 tons.
Renewable Energy Supplies
Renewable energy systems are a great way to demonstrate your commitment to environmental protection, help to educate the public about solar technologies, reduce your emissions of greenhouse gases, and cut your spending on conventional fuels. Systems can also be designed to provide you with backup power—and can provide an important degree of risk management for critical loads in case of temporary grid power outages.
In Burlington, solar hot water and photovoltaic (PV) technologies are the most commonly feasible options for customer-sited renewable energy systems. Investing in a renewable energy system can provide your business with clean, reliable, affordable energy for years to come.
Solar hot water heaters for commercial applications can often provide better customer economics than residential-sized systems, due to economies of scale. Depending upon your type of business, water heating may represent a significant share of your annual energy bills. Solar collectors use the sun’s free energy to heat your water, reduce your energy bills and reduce greenhouse gas emissions. Most systems use a conventional fuel for backup, to guarantee your hot water supply.
Depending on site conditions and hot water consumption patterns, a new solar hot water heating system in Burlington can meet up to 70 percent of your business’s annual hot water needs.
Photovoltaic systems produce electricity directly from sunlight. They can be tied directly to the existing utility grid, and can power regular electronic loads. They can also be used to charge battery banks, or to feed your business directly in case of a utility power outage.
By reducing consumption of conventionally produced electric power, each kilowatt of PV power installed in Burlington prevents roughly 24 tons of greenhouse gas emissions over 20 years.
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