Competitive Energy Insight, Inc.

Phone: (858) 566 - 0221

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Evaluate Hourly Time-of-Production Value from Commercial and Rooftop Photovoltaic Projects

On-site Photovoltaic (PV) projects can be complex requiring a thorough understanding of the comparative economics of displacing electric energy that would otherwise be purchased from the utility (behind-the-meter).

The savings associated with this type of PV are tied directly to utility tariffs, typically involving time-of-day pricing, demand charges, standby charges and excess sales rules or net metering. A true understanding of the economics of PV requires an accurate insight into the factors that influence those economics including:


  • The host’s current and future electric demand and usage profiles
  • Facility operating characteristics and costs
  • The solar radiation profile at the site and the resulting PV electric production, and
  • The workings of the applicable tariff.

These factors, when properly evaluated, will reveal the true value proposition of a PV investment. With this valuable insight, the site owner, engineer, developer and investor can each gain a better understanding of:

  • Cost/benefit trade-offs associated with PV
  • The optimum size of facilities and their related electric operating profiles
  • The risk factors facing the facility owner
  • The true economics of PV ownership.

EconExpert-IAT for PV is a fully automated Excel-based production simulation model that predicts the hourly interval production and energy savings achieved with PV. The model evaluates the hourly profile of energy production by a PV facility and compares that with the alternative of purchasing electricity under the utility’s tariff. Basic inputs to the model include:

  • Solar radiation data that can be downloaded from published sources (i.e. NREL TM3Y)
  • 15, 30 or 60-minute interval electric metering data for the host site. The data can be copied and pasted from utility metering data, or “proxy” data can be generated and matched to electric bills using EconExpert-EnergyShape*.
  • PV Facility operating data provided by the equipment vendor, and
  • Electric tariff rates published on the Internet, and

EconExpert-IAT for PV evaluates each hourly interval over the course of a year, and reports the comparative economics of producing energy with PV versus buying energy from the utility. It then reports hourly, monthly and yearly aggregated results including simulated billings, usage / production profiles, excess sales and savings associated with the utilization of PV.  EconExpert-IAT for PV is easy to use and very powerful. The model is:

  • Fully Customizable. A unique architecture allows you to customize your analysis for any PV project or technology.
  • Wizard Driven. The model walks you through the inputs needed to analyze the solar radiation profile, PV facility performance, operating and maintenance costs and electric tariff.
  • Fully Integrated with EconExpert-DG. Results from EconExpert-IAT for PV can be automatically exported to the EconExpert-DG financial model allowing you to perform full discount cash flow and financial analysis based on hourly load profile and interval analysis.

Hourly Electric Load Profiles for a particular site can be analyzed based on actual metering data from the site or from proxy data developed using EconExpert-EnergyShape

Load Duration Curves provide insight into the complex behavior of hourly profiles

Results are aggregated into time-of-production categories that match the electric utility tarriff and solar profile 

* EconExpert-EnergyShape is a database product offered by CEI that allows users to generate simulated/electric load profiles for commercial buildings in various regions of the US. It is used when actual metering data is not available. EnergyShape is a product licensed by CEI from EPRI Solutions.