April 6, 2022

Managing Electrical Energy Costs with Time of Use (TOU) Limitations

By:
Professor Steve
Linthicum
Guest Author

According to the United States Bureau of Labor Statistics, San Diego has the highest energy rates in the United States. In 2017, recognizing continued increases energy costs were likely, I made a decision to take steps to damper consequences by following a pathway that incorporated both a reduction of energy use and the incorporation of a solar energy system for my home. To facilitate this effort, I purchased a Toyota Prius Prime, a plug-in hybrid vehicle along with a roof-top solar system composed of 15 panels. The system was sized in a manner to provide electrical energy for my home, automobile, and an electric spa. In deciding upon this course of action, I specifically focused on electrical rates, recognizing the likely best rate offered by San Diego Gas & Electric was designated as EV02 (designated for electric vehicles). For the summer of 2018, the “on-peak” rate from 4:00p.m. to 9:00p.m. was $0.53/kWh. As noted on the table below, that rate has increased for this summer to $0.68/kWh. 

2022 SDG&E EV-TOU-2 Pricing Plan
TOU On-Peak
(4p.m. – 9p.m.)
Off-Peak
(Other Times)
Super Off-Peak
(12a.m. – 6a.m.)
Winter (Nov-May) $0.45/kWh $0.40/kWh $0.24/kWh
Summer (Jun-Oct) $0.68/kWh $0.42/kWh $0.24/kWh

To achieve an accurate understanding of costs and usage, we are fortunate here in San Diego to be able to utilize products manufactured by Emporia, a Colorado based company built on ideals associated with “customer satisfaction, optimization, innovation, and making the world better.” Detailed below are the steps I took utilizing Emporia products that enabled me to make data driven decisions relating to energy use and conservation designed to reduce overall energy costs. While some of the decisions I’ve made may be ecologically beneficial, the primary motivation is economically driven. 

Project Plan 

I’m a fan of always completing a “cost/benefit” approach when considering how to proceed with a project. While it would be nice to have an unlimited budget, that simply was not the case when I approach this project. I’ve found the best way to begin is to identify project goals. For this project I identified the following goals: 

  • Take advantage of Time of Use (TOU) energy pricing. 
  • Adjust energy usage patterns to identify savings opportunities. 
  • Determine the potential continued energy use even though an appliance is turned off (vampire electricity use). 

Achieving these objectives requires utilization of technologies that: 

  • Control the times that electrical devices operate (controlling both the power-on and power-off for devices in a scheduled manner). 
  • Identify the amount of electrical power utilized by devices, both in terms of watts consumed and the cost of that power. 
  • Identify whether devices utilize power while they are turned off.

While not necessary, more often than not I follow an approach that focuses on a lower cost when possible. For energy management purposes, Emporia provides a broad range of equipment at a variety of price points. What keyed my focus was the fact that their “Vue: Utility Connect” product works with a limited number of utilities that include San Diego Gas & Electric. A necessary first step is determining if this product can communicate with the smart meter your utility company has installed on your home. An amazing aspect of the “View: Utility Connect” is it measures overall electrical consumption along with my solar system production of electricity. All this at the amazing cost on Amazon’s website of $29.99 for this device.

For consumers who are not located in areas where communication with your electrical meter is not possible, there are a number of monitoring devices can be used. Costs identified on Emporia’s website, depend upon the number of electrical circuits being monitored and currently range from $70 to $159. Monitoring, while providing necessary data to make informed decisions, does not provide the ability to schedule devices and incorporate utilization to avoid the higher energy costs during peak usage hours. 

The companion Emporia device available to control appliance utilization is an amazing “Smart Plug.” Admittedly there are a variety of manufacturers of similar devices that provide the ability to turn power off and on through command features as well as setting a schedule base upon the times of day. The Emporia device provides these features as well as detailing energy use both in terms of watts (kWh) and dollars. The cost for their “Smart Plug” ranges from $7.50 to $10.00 per plug, depending on quantity purchased.

The ability to utilize scheduling provides the ability to develop “device use rules.” Examples below illustrate the rules and their basis: 

For my Prius Prime EV 110 volt charging cable, I have scheduled electrical power to be turned off from 4:00p.m. until 11:55p.m. The car charging process begins at midnight, and typically takes 5.5 hours to completely charge. This avoids charging during On-Peak hours and eliminates vampire electricity use after 4:00p.m. until power is restored before midnight. 

For my entertainment center, with the exception of the cable provider’s DVR, the television and other center devices are turned off at 11:00p.m. and turned on at 6:00a.m., reducing vampire electricity use. Rationale for this timeframe is we are generally asleep during this time period. 

For my devices charging station, electrical power is turned on at midnight and turned off at 6:00a.m. This ensures charging is accomplished during “super off-peak” hours when electrical rates are at their lowest cost. 

Information relating to the decision-making process is accessible through both a website and a smart phone application. The screen below details my Bosch dishwasher’s one-hour express cycle. During this time I was able to determine a cost, based upon the super off-peak meter rate of $0.22.

Dishwasher while running

Dishwasher while not running

Based upon the information provided above, it appears the dishwasher does not consume power when it is turned off, thus eliminating concerns about vampire energy loss for this appliance. 

The information provided below shows, both in monetary terms and power (kWh), the main circuit on a cloudy day here in San Diego where the solar system is providing more electricity than we are consuming. Hence the negative values.

Solar generation in Watts

Solar generation in Dollars

The unanswered question is how difficult is it to install the “Vue: Utility Connect” along with the Emporia Smart Plugs. Truthfully it is relatively simple, even for those not technically inclined. If you’ve attached other devices to your wireless network (e.g. phones, gaming devices, etc.), you should not have a difficulty. The instructions are fairly automated and must be done utilizing the Emporia application available for iPhones and android phones. It is important, before purchasing the “Vue: Utility Connect” to be sure your utility company’s smart meter can communicate with it. This will likely mean communicating with your utility company (process details are contained in the installation instructions).

Steve Linthicum is a retired professor who holds a variety of industry recognized certifications that focus on information technology and cybersecurity. He serves as a technical advisor and currently provides services on a periodic basis to members of his senior community.

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