Energy Monitoring with RETScreen

As part of the RETScreen Clean Energy Management Software, a Performance Analysis Module is provided to help the user monitor, analyze, and report key energy performance data to facility operators, managers and senior decision-makers.

Implementing an energy monitoring, targeting and reporting (MT&R) system can be a powerful way to better manage energy project investments as well as identify additional project opportunities. In addition, the measurement and verification (M&V) of actual savings (or production) achieved by a clean energy project is an important final step in the energy decision chain.

To help address this need on a global basis, RETScreen International, in collaboration with the Renewable Energy and Energy Efficiency Partnership (REEEP) and the NASA Langley Research Center, has developed the RETScreen Performance Analysis Module. This energy management software tool, which integrates near real-time satellite-derived weather data from NASA for the entire surface of the planet, can be used worldwide to track a facility’s actual energy performance versus predicted performance.

The fundamental approach to energy monitoring, targeting and reporting (MT&R) involves determining what factors will have an influence on energy use (or production), typically recorded by an energy meter. These factors are sometimes referred to as "drivers" or "factors of influence" (e.g. weather, production level, occupancy). For a building heated with a natural-gas-fired boiler, the driver will typically be the heating requirements expressed as the number of heating degree-days. For a building with air-conditioning loads and an electric chiller, the driver is often cooling degree-days. And the drivers for an industrial plant might be the production level for a particular manufactured product, while for a photovoltaic power system, the driver would likely be the amount of solar radiation hitting the solar collectors each day.

Data Worksheet

The RETScreen Performance Analysis Module has a Data Worksheet that enables the user to create, import, calculate, filter, merge and store various datasets needed to prepare the analysis of the project.

Key to successful application of MT&R is the availability of a consistent set of accurate historical and current environmental data. The NASA Langley Research Center has developed an automated database of satellite-derived daily values of surface meteorological parameters for a 30+ year period and in near real-time, for the entire surface of the planet. Parameters include, for example, daily temperature from July 1983 to present with a maximum delay of one week relative to real-time. The RETScreen user is able to automatically download historical and near real-time data from NASA’s web servers and directly upload it into this data section of the Performance Analysis Module. This makes weather-related data collection a simple task for projects anywhere in the world.

Analytics Worksheet

Once the factors of influence are identified, the relationship between these drivers and energy consumption (or production) can be established by a technique known as regression analysis. Regression analysis attempts to describe the relationship between consumption / production and its drivers with a mathematical equation (i.e. model). An advanced regression model is integrated directly into the RETScreen Performance Analysis Module.

The first step is to determine graphs to be included into the dashboard in order to prepare the performance analysis. The next step is to establish a baseline period for the analysis. Often, a Time Series Graph is used to help identify the baseline. Once the baseline is set, it can be used to predict future energy consumption or production during a period for a specified set of conditions described by the drivers. Then, future use (or production) can be compared with the prediction to determine whether the use (or production) is higher or lower than predicted. The difference between actual and predicted values is calculated for each period and added together, creating a "running total." This is referred to as the CUSUM, or CUmulative SUM, of the differences. The CUSUM is also referred to as the cumulative savings total. This, and other capabilities, such as Control Charts for tracking actual performance of a project in comparison with the targeted performance, is also incorporated into the Performance Analysis Module.

Intro Video - Performance Analysis with RETScreen Expert

Example Use - Photovoltaic Project Monitoring in The Netherlands

Numerous organizations are using RETScreen Expert to measure and verify the ongoing energy performance of their facilities.

One recent example includes work by Vanhout and Ovvia in The Netherlands, who are using RETScreen Expert for a portfolio of photovoltaic (PV) power projects. This work is led by Jan van Hout (photo), with key facts listed below.

Photo credit: OVVIA-directeur Jan van Hout. ? Fotomeulenhof - click to see Dutch article

• Located in Eindhoven, Netherlands
• Photovoltaic system
• Feasibility analysis & performance analysis for three client facilities
• Ovvia was interested in learning how to do this kind of work themselves for other client facilities.
• Use of the electricity/energy production tool in RETScreen (Facility Type = Power plant)
• 1.1 MW of PV monitored and modelled (total initial costs 1.25 million Euros)
• These three facilities represent around 700,000 kWh of electricity produced in 2017
• Electricity export revenue of more than 110,000 euros in 2017 and a net present value of more than 1,000,000 Euros.
• Total gross annual GHG emission reduction of over 400 tCO2 (from feasibility analysis)

This is just one example of how RETScreen Expert is proving to be an excellent tool for organizations implementing more comprehensive energy management systems (EnMS).

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