The snowmaking process has evolved from a crude novelty 60 years ago into an industrial process involving a complex array of sophisticated machinery and technology. Modern systems can pump huge volumes of water and convert it to machine-made snow distributed over hundreds of acres. In turn, the costs of snowmaking have escalated by orders of magnitude, with the peak energy demand for major systems now measured in multiple megawatts. All this raises the importance of using energy efficiently. And that's the goal of the new Snowmaking Energy Index (SEI).

On a national scale, the magnitude of seasonal energy usage for snowmaking purposes has not been precisely quantified. However, it can be roughly estimated to be somewhere between 500,000,000 kWh to 1,000,000,000 kWh.

The current worldwide emphasis on energy conservation continues to spotlight snowmaking-not only from an equipment perspective, but also from an energy management viewpoint. The SEI methodology, as presented here, provides the means to quantify the snowmaking process. It is an important step toward intelligent and consistent energy management.

Careful energy management is commonplace in other industries. Most sophisticated industrial processes, for example, rely on computers and system data to control production costs and track energy use. These are an essential part of modern technology management-they minimize operational costs and energy use while maintaining profitability.

These tools rely on real-time displays and reporting systems to spot system anomalies. They enable operators and managers to make swift adjustments and correct the process. The days of monthly and seasonal reviews are so last century!

With the above in mind, consider the state of snowmaking reporting methods and metrics. The majority of snowmaking systems produce huge volumes of seasonal system data. In most cases, this information lies fallow, for want of appropriate methods for simple evaluation and review. This is a consequence of the sheer complexity of the snowmaking system and associated technology. For some, there may be the fear of appearing technically ignorant, too.

To meet and overcome this challenge, the Snowmaking Energy Index (SEI) was developed over the past two years, then tested last winter with actual ski area data and information. The SEI relies on the three most important snowmaking variables-water consumption, energy use, and wet bulb temperature-to demystify the snowmaking process and produce easily-understood real time information.

The SEI is defined as Energy Consumed/Snow Produced (total snowmaking system energy consumption, divided by actual production snowmaking water). This can then be plotted as a function of wet bulb temperature or time. The data is collected on an hourly basis over the course of the snowmaking season, and then used to establish a baseline SEI curve for the individual snowmaking system (see Chart 1).

This baseline curve, when normalized to a simple standard within the SEI methodology, allows disparate snowmaking systems at different ski areas to be easily compared, irrespective of size and snowmaking equipment types.
To provide valid comparison data, three critical variables must be accurately measured and recorded simultaneously on at least an hourly basis:

1) individual electrical consumption of snowmaking equipment (pumps, compressors and electric fan guns). Most areas do not directly collect or track this, but taking individual hourly amperage readings and calculating instantaneous kW or hourly kWh will suffice. For diesel air compressors, it's simple to create "virtual electric compressors" for the rated capacity, and then, track hourly online time. The same logic applies to electric fan gun systems that are not individually metered.

2) water flow data. It must be measured with accurate instrumentation, with water losses subtracted. Only the water used in actual snowmaking production is relevant for the calculation, or the resulting SEI value will be overly optimistic. The energy losses from parasitic water losses can be individually tracked for later evaluation and system energy impacts.

3) wet bulb temperature. At most areas, a weather station positioned around mid mountain or inversion-layer elevation is ideal. Weather instrumentation is widely available that will output ambient temperature, relative humidity, and wet bulb temperature.

The SEI methodology can become a powerful and valuable tool for management, financial and planning purposes. As a simple example, Chart 2 displays the energy impact of snow gun selection on a snowmaking system once a baseline SEI curve is established for a ski area. SEI performance curves can be established for any type of snowmaking equipment, and then overlaid on an existing system baseline-allowing a more definitive analysis of the energy impact of the equipment.

The snow gun performance curves and SEI baseline values can be incorporated into current snowmaking computer control interfaces for a real time display of system energy performance, and to enable immediate response to divergence. A daily performance report can be created for supervisory and management review. This report can be e-mailed automatically to the staff, or posted on an internal company network for immediate access.
Utilizing seasonal data, an average SEI value can be established for a snowmaking system. This creates a powerful tool for estimating seasonal energy costs for given volumes of water use. For expansion and planning purposes, this will provide an immediate seasonal energy cost estimate, which can be easily translated into operating expenses.

The SEI baseline can be normalized to a given standard, allowing resort companies with multiple areas to easily compare energy performance characteristics on an "apples to apples" basis (see chart 3). This procedure can be applied regardless of physical size and snowmaking equipment types. This tool gives corporate management and financial officers a powerful means of assessing performance and furthering managerial accountability.

The creation of the SEI methodology is a small step in demystifying the snowmaking production process, and a bold step in acknowledging the huge energy expenditures in a play product that eventually melts away.

For more information, e-mail ystanchak@the-snowman.com.