Volume 27, number 2, September 2013

Hercule : Tariff simulator

Hercule was launched some twenty years ago and has since been updated in order to be adapted to today’s IT realities.

Hercule is an application that can simulate different energy scenarios for the transfer of loads from another energy source to natural gas.

The software includes energy calculators, integrates all tariff parameters for natural gas, electricity and other energies, and can automatically transfer energy, whether that is propane, fuel oil No.2 or No.6, or electricity, to natural gas. All these parameters are kept up to date and a customized report is available in PDF format.

The importance of rate-setting

Rate-setting consists in fixing a price for the supply of a quantity of energy, given certain parameters. Depending on the case, creating a rate structure may be relatively simple (with just one parameter, such as litres of propane or fuel oil), but sometimes it is more complex, calling for the input of several variables (such as number of days, maximum power demand, electricity supply voltage, minimum obligations, load factor (LF) from the previous year, etc.). Hercule indicates what is needed to determine the monthly price of the energy delivered.

Here is an example by way of illustration. At Gaz Métro, a load factor equal to or higher than 60% signifies that the client has a relatively stable consumption profile and is thus eligible for preferential Rate D3. Load factor (LF) equals the ratio between the daily average consumption and the peak daily volume in winter (from November 1 to March 31). Thus, a customer who already consumes natural gas and who has a LF below 60% could have access to this rate by converting the electrical load of a process to natural gas. With a LF above 60% after the conversion, this same customer would thus be eligible for Rate D3 which, under certain conditions, offers rebates on the cost of distribution on the natural gas bill. Consequently, the energy bill after conversion could be lower than initially, with the customer realizing substantial savings.

In light of the above, it would appear justified to question the evaluations of savings from conversions that are calculated using an average rate, since they do not necessarily correspond to the actual prices of all the energies surveyed. However, Hercule maintains up to date electricity rates and natural gas tariffs, so it is therefore easier to calculate the effect on bills as a result of the conversion of one or more electrical loads to natural gas and so see the advantages. The real price of each annual energy profile is thus obtained, versus an approximate price based on an average unit cost for all energies combined.

Functionalities of Hercule

Load factor (LF) optimizer

When seeking solutions to reduce a customer’s overall energy bill, it is first worth evaluating the customer’s eligibility for Rate D3, which has many economic advantages. To qualify for this tariff, customers must meet the following three criteria:

  1. have a subscribed volume of at least 333 m³/day;
  2. have an annual volume above 75,000 m³;
  3. have a load factor equal to or above 60% (LF ≥ 60%).

To facilitate access to Rate D3, Hercule has a function that can propose three scenarios in order to achieve a load factor of 60% or more:

  1. add natural gas from a monthly or regular process;
  2. add natural gas in summer only; and
  3. improve the energy efficiency of a seasonal load, i.e., one that depends proportionally on degree-days.

Hercule suggests the monthly breakdown of volumes for each of the three cases.


By using Hercule’s database, the consumption of a load called seasonal (e.g., heating or ventilation) can be spread over twelve (12) months using degree-days. This option can correctly quantify the value of the energy attributable to a particular period. Hercule has a database of all the degree-days registered daily for the last 50 years in the nine (9) different administrative regions in Gaz Métro’s distributorship. These data can be used in the different calculation bases by also generating the various temperatures at which a building starts to be heated. This aspect may be specific to each type of building and may vary, depending on its use. The data on degree-days are taken from Environment Canada’s database.

Energy calculators

Hercule also has calculators that can evaluate the quantity of energy attributable to a specific load, based on the load’s significant parameters. These are essential since the quantity of energy specific to a particular appliance must be defined in Hercule when describing the load to be converted to natural gas. Once these data have been input, Hercule directs the energy needed to the appropriate units. For example, in order to calculate the energy consumption of a make-up ventilation generator, Hercule will require the following parameters:

  1. relevant air flow in cubic feet per minute (ft³/min);
  2. weekly hours of operation;
  3. efficiency rating of the appliance;
  4. percentage of fresh air in the air supply.

The software then takes into account the region where the building is located and the degree-days calculation base in order to evaluate the consumption of energy related to the load involved. It is worth noting that there are different types of calculators within Hercule, both or seasonal loads and for stable processes.

Study report

Once the various existing energy bills have been input, as well as the electricity withdrawals and fuel conversions duly recorded, Hercule calculates the new energy bills. The results are presented in the form of a report, supported by summary tables that clearly show the annual savings achievable following the various conversions proposed. It is thus a very attractive turnkey option to present to potential customers.

To learn more

This is a flexible tool that offers concrete solutions in order to make significant savings and, most importantly, it is readily available.

Discover the many functionalities of Hercule right away! Go to our Website and consult the “Practical tools” section under partenaires.gazmetro.com.

Daniel Laurier, Eng.