Utility Energy Services and Customer Use

Utilities provide energy services. Each energy service is a single type of energy (electricity, natural gas, etc). The goal of selling solar and energy efficiency is to reduce the amount of energy that your customer purchases through one (or more) utility energy services, avoiding costs.

To calculate how much money can be saved by reducing these bills, you must first define how much the customer currently spends by inputting the customer's current utility, tariff (or rate schedule), and energy use throughout the year.

Current Energy Use

Define Service: Utility / Tariff / Usage

After creating a project, you can add one (or more) energy services on the Energy Use screen. This screen is where you define the customer's current energy services and the customer's usage of that energy service (typically from their past year's bills).

After clicking "Add" on the Energy Use screen, you will see the screen below:

Select the type of energy, the utility, and the customer's current tariff (also known as rate schedule).

Many larger utilities have tariffs with a variety of rate criteria that affect how the bills are calculated. Tariff rate criteria include options like:

• baseline territory (default value is set by zip code, although some zip codes span more than one territory)
• medical allowance (Input daily kWh quantity. See info rollover which in some cases provides quantity per allotment for the utility. Most customers have a single allotment, but its possible to have more than one, in which case you mutiply the base daily allotment by the number of allotments)
• etc

If your customer's bill has options, we recommend clicking to reveal the tariff rate criteria and reviewing the option. The screen shot below shows an example of a tariff with a whole set of rate criteria:

Define Customer Energy Demand

Many commercial utility tariffs charge customers for their highest instantaneous demand, in kW, during the billing period. This is a charge for highest power (kW), not energy (kWh). This charge accounts for the maximum service load that the utility provides to the customer. It is calculated as a given rate ($ / kW) times the highest instantaneous demand that the customer had during the billing period. 

When you select a rate tariff that has a demand component to the billing, SolarNexus adds a section within the Tariff Rate Criteria section where you can input the customer's monthly demand numbers in kW. If you do not input the customer's actual monthly demand, SolarNexus will estimate it for you based on the zip code and "building type" from the Project Information.

If you do not input the customer's actual monthly demand, and the SolarNexus estimate is off, even a small amount, the difference in bill estimates can be significantly off from actual since demand is often a substantial portion of the customer's bill amount.

Define Customer Energy Consumption

There are multiple options for inputting the customer's current energy consumption, depending on the availability of information you have. The more complete your input, the better the analysis will be for the customer. Options include:

• Green Button - Best choice if your utility provides ability for customer to download a "Green Button" file of their use. Be sure to get the trailing 12 months for a time range and specify the output is XML format, rather than CSV. You can simply upload this file into SolarNexus. (note - if you get multiple years of data, SolarNexus just uses the most recent 12 months in the file, so there is no benefit to downloading more than 12 months of usage).
• Billing Periods - Second best choice - if you can get 12 trailing months of customer utility bills and input consumption and optionally cost by billing period.
• Billing Periods with Time of Use - Same as billing periods, but includes separate fields for peak/part-peak/off-peak periods. Note that this option is only available if you have selected a Time of Use tariff.
• Calendar Months - Like billing periods but assumes the periods match calendar months. This is rarely the case so it causes some inaccuracies due to billing period days not matching months. This option simplifies inputs by leaving out "billing days" as well as a start date for a consecutive set of 12 trailing months.
• Average Monthly Use - Use this when you only have some estimate of kWhs. This option does not reflect seasonal variations in usage.
• Average Monthly Bill - Use this when you only have a rough estimate of dollars spent per month for that energy service. This produces a very rough estimate, and is not suggested for regular use.

Define Proposed Tariff for Analysis

When you first click on Analysis screen for a solution, you'll be presented with a popup to select the proposed electricity tariff. The customer's current tariff is pre-selected by default, but you may change it (for example, propose moving customer to a time of use rate).

An example is shown below:

Notes:

• For solutions with PV systems, net metering is automatically applied if the selected tariff supports it.
• If no electric service is defined, then this popup step is skipped. Non-electric tariffs are assumed to remain the same for the proposed case.
• Select the "Feed In Tariff" box if your utility compensates PV electricity using a Feed-In-Tariff (FIT) rather than with net metering check . The customer's post-project electric tariff is unchanged in a FIT scenario. To model the FIT compensation, use a performance based incentive (PBI) in the incentives section of the Analysis Parameters section shown below.

After selecting the proposed master tariff, you can view more electric utility tariff options by expanding the "Analysis Parameters" section and then clicking on the section titled "Electric Tariff." 

Select the desired options, and you'll be ready to complete the Analysis process.

Proposed Demand

If your tariff includes a demand component, SolarNexus will automatically assume a modest savings to demand levels when analyzing demand savings for the proposed post-project case. But these will not be very significant (~ 10-15%). On the Analysis parameters, Electric Tariff section, SolarNexus gives you access to manually input post-project demand values that will override the SolarNexus estimates. For example, if you are proposing the installation of a demand management system, you may input the planned demand limit that the system will manage.

In the Utility Bills tab of the Analysis results, you can see the demand values and rates used in the bill calculation.

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2016-05/05 Change Notes:

Deployed the following significant updates to tariff selections:

1. List of available tariffs has been significantly simplified to only show the "master tariff" list.
2. The system no longer has separate "Net Metered" tariffs. When a PV system is included in the solution, net metering is assumed for proposed tariffs (that allow net metering). As a result, the "Show All Tariffs" checkbox is no longer needed, and has been removed.
3. Instead of incorporating various tariff rate criteria and options into the tariff names, these options are now broken out into separate fields and only shown if desired within the "Tariff Rate Criteria" section. Defaults are set for all options.
4. Contract rates for customers in deregulated markets like Texas and Pennsylvania can now be entered in the Tariff Rate Criteria section. The selected utility tariff provides the transmission and distribution portions of the bill calculations.