Mammoth Mountain Tracks Energy Use with E-Mon D-Mon Submeters
Located on the eastern slope of California's majestic Sierra Nevada range, Mammoth Mountain Ski Area (MMSA) is one of the world's premier year round resorts. From its humble beginnings 66 years ago with a single portable ski tow, founder Dave McCoy's vision of a winter wonderland for the people has materialized beyond his wildest dreams. Today, Mammoth Mountain is owned by Starwood Capital Group, which is responsible for three large day lodges, 29 lifts, three gondolas, four hotels, three restaurants, a large maintenance facility and scores of other 45,000-180,000 square foot (ft2) buildings and structures spread over 3,200 acres. Not just a winter resort, in the summer MMSA offers hiking trails and more than 90 miles of mountain-bike paths that draw nature lovers from around the world. As Mono County's leading electrical power user, MMSA is not only conscious of its energy profile but is equally conscientious about tracking consumption and demand to save energy, use it more efficiently, and lower operating costs in the wake of the California energy crisis that peaked a few years ago. Headed by CEO Rusty Gregory, MMSA has succeeded in that regard thanks to the vision of Senior VP Bill Cockroft who saw electrical submetering as the cornerstone of a broader effort to seriously reduce energy consumption by all means possible—from high technology to patching holes in the buildings.
As a way to understand how and where the electricity was being used and as a first step to controlling it, Cockroft spearheaded the installation of an electrical submetering system from the market's leading supplier, E-Mon of Langhorne, PA. According to Energy Manager Ray Bradbury, who also runs the resort's preventative maintenance program, MMSA's initial $12,000 submetering system currently collects data from 13 meters at key locations around the mountain, including six main buildings and six cellular communication sites that are being monitored by E-Mon D-Mon submeters.
Submeters like the E-Mon D-Mon Class 3000 are highly flexible in operation, offering compatibility with third-party water, gas, steam and other pulse output meters. 0-2V output split-core current sensors allow safe and easy remote connection of the meter to the monitored circuit without interrupting power. Recording kWh, kW and kVARh on two channels, the meter is capable of storing demand and consumption data in five or 15-minute intervals for up to 12 or 36 days, respectively.
Most of the submeters in the MMSA system incorporate an inexpensive Ethernet communications interface that converts the RS-485 meter output to a 10 Mbps data stream for download to the host computer via the facility's existing Ethernet infrastructure. This allows Bradbury to import the data into the E-Mon Energy software to output graphs and other reports for charting energy usage/demand, cost allocation by tenant or department, billing or other functions, including measurement and verification of energy initiatives. Of the 13 meters in the current MMSA installation, eight are plugged into the Ethernet backbone, while the remaining five stand-alone devices are due for upgrade as the Ethernet network spreads.
MMSA's submetering system has proven invaluable in verifying energy savings and identifying other energy conservation opportunities.
Mammoth Submeter Installation
MMSA's submetering system has proven invaluable in verifying energy savings and identifying other energy conservation opportunities. All buildings in the complex are connected via an Ethernet backbone that is also networked through fiber optic, which allows meters to be put just about anywhere the need arises. The installation crew, led by Mike McGonical, experienced no major glitches while completing the install and getting the software and communication links up and running.
Now in its fifth year of operation, system results have been very positive. "We now understand how, where, and how much electricity is being used," said Bradbury, who pointed out that the real savings came, not from the submetering system itself, but by the ability they now have to "drill down into the building to watch the loads to see what equipment is on and at what time, and to review the results from changes and additions to the building control system."
Tangible System Benefits
One such case involves building emergency-lighting systems, which stay on all the time. Changing T12 double lamps luminaries to single-lamp T8 lamps, for example, resulted in a substantial cost reduction. Submetering allowed facility engineers to actually measure the impact of those changes on the bottom line. "We were able to use the system as a tool to reduce our electrical consumption in different ways. In one very electrically dependent building, we reduced usage by over 23% in three years. just that one reduction has paid for the submetering system many times over," Bradbury said.
Not long ago, the supervisor of one large building reprogrammed the HVAC to shut down at 11:00 p.m. instead of 4:00. The submeter's profiling capability enabled the E-Mon Energy software to catch the discrepancy and the building's EMS was returned to its normal time schedule. Without such visibility, the problem and its associated higher cost might have continued indefinitely. For Bradbury, the bottom line is always the bottom line: "Because of E-Mon, I can zero in on any building to find total usage and how much we saved."
MMSA supplies electricity to the Village at Mammoth for holiday lighting and other seasonal events. The E-Mon's revenue-grade accuracy allows MMSA to recover costs by allocating all utility services to the actual user, while providing energy reports that let the various users know if they are operating within budget.
Energy Grant Compliance
Submetering is also being used to track the electricity that pumps water around the mountain. Electrical profiles of energy usage helped the Facilities Department determine that its existing 60 horsepower (hp) well pump could be safely downsized to 20 hp, lowering operating cost by two-thirds. According to Bradbury, "Electrical usage on that SCE (Southern California Edison) meter is very minimal in the summer months, so we can really zero in on the pump's usage." Installing a more energy-efficient replacement pump also earned MMSA points toward applicable state energy-conservation initiatives.
As part of MMSA's financial reporting system, Bradbury prepares a monthly report that details electrical and heating energy usage throughout the Ski Area. He runs E-Mon Energy software on his laptop and uses it daily to export data into a spreadsheet that tracks propane and electrical usage for his comprehensive utility report. This report typically includes data for the reporting month, the month prior and year-to-date usage totals. Each report integrates the utility's electrical bills with the results from the E-Mon system to show budget vs. actuals for the current and previous year. The bottom line is shown in terms of cost and millions of BTUs. According to Bradbury, "Converting our data to BTUs allows us to compare total energy usage over different report periods by factoring out fluctuating energy costs, especially propane and fuel oil."
Interestingly, the resort's three gondolas, 29 chair lifts, and its snow-making equipment have not been metered. "We already know what their loading is," said Bradbury. "By taking the information from all of the E-Mon submeters we have, and using the utility meter information, we're able to estimate the total electrical usage from our chairlifts, snow-making system and other non-metered users to give a pretty exact figure for those usages."
"We'll also be using information from our E-Mon system at the Canyon Lodge to program our control system at the Canyon Lodge to program our control system to limit total electric demand in that building," Bradbury said. Time of day usage, total heating demand at any given time, how long it takes to heat the building in the morning, and what time to turn on the HVAC to take advantage of cheaper early morning rates, etc., are all factors in the energy management equation for Bradbury and the eight mechanics of the Facilities Department.
Results have all been dramatic at Canyon Lodge, an all-electric facility. According to Bradbury, "Over the last four years we've reduced the electrical costs in this 100,000 ft2 building by $72,000 per year, which we track with the E-Mon system."
Several projects are in the works, including a possible demonstration wind turbine at McCoy Station, located about halfway up the mountain. With a Class 3000 series submeter installed nearby on the Ethernet backbone, engineers will be able to watch the generator in real-time and download data for graphing and analysis in order to determine if a larger scale system would be feasible for energy generation under potentially sever icing conditions. Other projects will be to install E-Mon electrical submeters on buildings under 45,000 ft2 to start tracking usage in those locations, the philosophy being: "What you can measure, you can influence."
At 11,053 feet, Panorama Lookout is MMSA's highest gondola station. Construction was just completed for a new food service, nature center, special events area and other amenities. However, doing business is difficult at more than two miles above sea level, where sustained winds of 140 miles per hour (mph), gusting to 180, are common in winter. Exhaust gases do not vent in high winds, so the entire facility runs off a 480V feed that is metered by an E-Mon Class 3000 through the Ethernet backbone to factor those operating costs into the bigger picture.
MMSA's submetering experience has proven extremely positive, contributing in no small part to significant energy conservation on the mountain. Since MMSA started tracking its energy usage in calendar 2001, Energy Manager Bradbury says that they have trimmed overall electrical consumption by more than nine percent, which at that scale of operation translates into a substantial reduction in overhead cost. mammoth Mountain Ski Area and its surroundings are in the midst of a major renaissance, fueled by planned capital investments that will exceed $1 billion over the next decade. As MMSA grows, the demand for energy will grow with it. And so, too, the need will grow for advanced energy management tools like the E-Mon submetering system that has so positively impacted the bottom line of this conscientious, high-volume energy user.
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