In the previous lesson, we learned about the drivers moving us from traditional fossil fuels to renewables in terms of generating electricity to meet the energy demands of society. In this lesson, we will explore some aspects of how we can use the energy provided, regardless of source, as efficiently as possible. We will also learn that efficient use of energy is not only about how well we use it, but also how efficiently it gets to you.
By the end of this lesson, you should be able to:
Read | Lesson 5 Content and all assigned readings/videos |
---|---|
Discuss | Demand Side Management |
Create | Infographic |
*Contributions to this lesson by Vera Cole.
If you have questions, please feel free to post them to the Questions about EGEE 401 Discussion forum in Canvas. While you are there, feel free to post your own responses if you, too, are able to help a classmate.
There are several terms related to this topic that are important to know. For this lesson, we will touch on energy efficiency, distributed energy and microgrids, and the future of the way energy is delivered, which includes smart grids and demand side management.
Credit: Eight Electrical Metric Meters by Tim Mossholder [1] is licensed under CC BY-NC-ND 2.0 [2]
Energy efficiency is the amount of useful energy you get from any type of system. It is calculated as the useful energy output divided by the total energy input. For example, a light bulb converts electricity to light and heat. Typically, the light is the "useful" output, and the heat is a byproduct. Because only five to eight percent of the energy used by a standard incandescent light bulb is converted to light, the rest is dissipated as heat.
Stated another way, energy efficiency generally means how effectively we use energy to accomplish a function. For example, a refrigerator that uses less energy than another model to keep the same amount of food cold is said to be “more efficient” than the other model. Another aspect of energy efficiency is how much of the energy provided is used as compared to that which is wasted. For example, with a steam boiler, the higher the percentage of the heat generated by burning fuel that is translated to the heat output in steam, the more efficient it is said to be.
The traditional grid is relatively inefficient because so much energy is lost in transmission between the power plant and the ultimate user. This is in part due to heat loss generated by the resistance of the transmission lines. Without getting into physics here, suffice to say that long distance transmission and traditional power plants lose energy as waste, usually as heat, between initial generation and delivery to your home. These losses average 6 to 8%, and minimizing these losses, combined with managing how much energy you use, serves as the foundation for the energy use efficiency movement. This doesn’t sound like much, but when you consider the losses at the power plant simply from burning a fuel to generate power, you will start to get a sense of how much energy it takes to make electricity and how important it is to be as efficient as possible from generation to transmission to end use.
The term "energy efficiency" is also used with a more broadly scoped meaning, such as this previously published definition from the World Energy Council: "energy efficiency improvements refer to a reduction in the energy used for a given service (heating, lighting, etc.) or level of activity. The reduction in the energy consumption is usually associated with technological changes, but not always, since it can also result from better organization and management or improved economic conditions in the sector ('non-technical factors')."
In this sense, a programmable thermostat may help with "energy efficiency." Simple steps such as remembering to turn off the lights is a non-technical behavior that can also improve energy efficiency. These are examples of energy efficiency in its broader meaning, related to the smarter use of energy for a specific purpose.
Energy efficiency helps in many ways. Recall our four attributes- security, reliability, accessibility, and sustainability. Energy efficiency, which fundamentally is using less energy when possible, is one of the few approaches that supports all four. By using less energy, there is more in the system increasing reliability and accessibility (in part, due to reduced cost of power from lower demand). Needing less energy means less use of fossil fuels and other environmental impacts. And using less energy makes us less dependent and therefore more secure.
Some content on this page came from an earlier version of this course and was written by Vera Cole.
EGEE 401: Energy in a Changing World by Vera Cole via the Pennsylvania State University is licensed under CC BY-NC-SA 3.0 [3]
If energy is lost by simply moving it through long transmission lines, then logic tells us that if we can use the energy closer to where it is generated, the better off we are. The concepts of distributed energy and microgrids are based on that notion- that it is better when energy is generated and managed closer to point of use.
According to EPA, distributed energy is defined as follows:
“Distributed generation refers to a variety of technologies that generate electricity at or near where it will be used, such as solar panels and combined heat and power. Distributed generation may serve a single structure, such as a home or business, or it may be part of a microgrid (a smaller grid that is also tied into the larger electricity delivery system), such as at a major industrial facility, a military base, or a large college campus. When connected to the electric utility’s lower voltage distribution lines, distributed generation can help support delivery of clean, reliable power to additional customers and reduce electricity losses along transmission and distribution lines.”
A microgrid is simply a “small scale grid.” It does the same thing as the larger regional and national grids, but on a geographically more limited scale. It can be connected to the main grid, but once it obtains the power, it manages it through a smaller, more localized grid. Alternatively, the microgrid can have its own generation capability.
Watch the short video on distributed energy. It is from a company in the UK, but the concepts are directly applicable here in the USA. This video is also helpful in that it relates distributed energy benefits to several of the four attributes we have been exploring this course (reliability, accessibility (including affordability), security, and sustainability.
As additional reading, please read the features and benefits page on microgrids provided by the Microgrid Resources Coalition [7].
Electricity is not easily or efficiently stored in large amounts. In an electricity grid, power generation and power consumption must be closely matched at all times. If power generation and power consumption get out of balance, blackouts and other systemic failures occur. Hence, electricity must be produced on-demand, as needed. Naturally, demand changes throughout each day and throughout the year. Demands are met with a combination of power plants that are used all the time (base load) and others that are used when needed to meet peak demand. Together, they must have the collective capacity to meet actual demand, real-time.
Large swings in demand are expensive and problematic. When demand is low, expensive generating facilities (built to meet peak requirements) are sitting offline idle. When demand is high, all available generators are online, running full tilt, stressing the system, and risking reliability. Reducing large swings in demand allows for the more cost and energy-efficient design and operation of the electricity grid and its generators.
To achieve this balance, widespread efforts are being made to involve the consumer in the management of electricity demand. Overall, the umbrella term for working with customers to balance their electricity usage with the available supply is called demand response. The essential component is some form of communication with the customer or the customer’s systems so that they know when a change in their demand is desirable (supply is low, use less or supply is high, good time to use more).
There are many ways to accomplish this using tools and methods described as demand-side management (DSM). EIA defines DSM [9] as follows:
"Demand-side management (DSM): A utility action that reduces or curtails end-use equipment or processes. DSM is often used in order to reduce customer load during peak demand and/or in times of supply constraint. DSM includes programs that are focused, deep, and immediate such as the brief curtailment of energy-intensive processes used by a utility's most demanding industrial customers, and programs that are broad, shallow, and less immediate such as the promotion of energy-efficient equipment in residential and commercial sectors."
Because of seasons and weather patterns, the United States' electric grid is built for capacity we almost never use. A report from Advanced Energy Economy [10] (AEE) finds that 10% of the country's electric system is built to meet demand in just 1% of a year's hours. And reducing those demand peaks – typically met with the costliest, dirtiest electricity generation – can have a significant impact on consumers' bottom lines. UtilityDIVE (Nov 4, 2015) [11]
Other terms related to this topic are load shifting and load leveling (both refer to rescheduling electricity usage to reduce peaks), time-of-day or time-of-use pricing or real-time pricing (customer is charged more for electricity used during peak periods) and smart grid (see below).
Some content on this page came from an earlier version of this course and was written by Vera Cole.
EGEE 401: Energy in a Changing World by Vera Cole via the Pennsylvania State University is licensed under CC BY-NC-SA 3.0 (https://creativecommons.org/licenses/by-nc-sa/3.0/ [3])
The Energy Storage Association explains the importance of grid energy storage: "Energy storage fundamentally improves the way we generate, deliver, and consume electricity. Energy storage helps during emergencies like power outages from storms, equipment failures, accidents or even terrorist attacks. But the game-changing nature of energy storage is its ability to balance power supply and demand instantaneously - within milliseconds - which make power networks more resilient, efficient, and cleaner than ever before.” (FAQs [12])
We also know that electricity is not easily or efficiently stored in large amounts. The Energy Storage Association identifies five categories of Energy Storage Technologies [13]:
Batteries – a range of electrochemical storage solutions, including advanced chemistry batteries, flow batteries, and capacitors
Thermal – capturing heat and cold to create energy on demand or offset energy needs
Mechanical Storage – other innovative technologies to harness kinetic or gravitational energy to store electricity
Hydrogen – excess electricity generation can be converted into hydrogen via electrolysis and stored
Pumped Hydropower – creating large-scale reservoirs of energy with water
Primitive as it may seem, the grid-tied energy storage technology with the largest capacity is simply to pump water to a higher elevation, storing it as potential energy. Called pumped storage, or pumped hydropower, the energy is recovered when the water from the higher elevation is used to drive turbines for hydroelectric power conversion. This process uses more electricity than it produces. So why do it? When a power plant has extra capacity, it generates electricity used to pump water uphill. Then, when the plant is stretched to capacity and electricity is at its highest price, this pumped storage can be used to generate low-cost hydroelectricity.
Some content on this page came from an earlier version of this course and was written by Vera Cole.
EGEE 401: Energy in a Changing World by Vera Cole via the Pennsylvania State University is licensed under CC BY-NC-SA 3.0 (https://creativecommons.org/licenses/by-nc-sa/3.0/ [3])
We have discussed distributed energy that relates to the physical nature of the grid- its geographic expanse and where power is generated relative to the user. But these grids, be they the large national scale or microgrids and distributed energy, need to be able to “think and make decisions” in order to optimize power generation and distribution. We refer to this as a “smart grid.”
Watch the short video and read the page found at https://www.smartgrid.gov/the_smart_grid/smart_grid.html [22] This website is managed by the U.S. Department of Energy and has a good overview of what we mean by smart grid.
In this lesson, we learned some aspects of how we use the energy provided, regardless of source, as efficiently as possible. We also learned that efficient use of energy is not only about how well we use it, but also how efficiently it gets to you. To determine how well you understood the points discussed in this lesson, you will create an infographic which relates to your personal use of energy.
To successfully complete this assignment, you will create an infographic that illustrates how your home could ideally benefit from concepts of this lesson.
Illustrate points where and how energy efficiency and the smart grid would relate, and how your home could connect to distributed energy features such as microgrids. You can show both the interior elements, as well as how the home relates to the grid in map diagram format. In your illustration, show connections, if any, to the national grid. Illustrate which elements of your home that would be part of the smart grid.
To help you in thinking of what to show, the U.S. Government has simplified energy efficiency shopping for customers with the ENERGY STAR [23] rating system, a joint program of the U.S. Environmental Protection Agency and the U.S. Department of Energy that awards Energy Star status to highly efficient products. If you'd like more information, visit the Energy Star website [24] or read through How Energy Star Works [25].
For other ideas, once again go to the Project Drawdown [26] page, click on the Electricity icon, and explore some of the innovative projects dealing with efficiency and distributed energy. Some cases have been around a while, like green and cool roofs, but others are quite cutting-edge like dynamic glass and building automation.
If you haven’t done so already, review the foundational resources provided in the Orientation lesson. They are titled Creating Infographics and Overview of Infographic Assignments. The rubric used for grading this assignment is provided on the following page in Canvas.
If you have any questions, please post them to the Questions about EGEE 401 Discussion Forum.
Links
[1] https://www.pexels.com/photo/eight-electrical-metric-meters-942316/
[2] https://creativecommons.org/licenses/by-nc-nd/2.0/
[3] https://creativecommons.org/licenses/by-nc-sa/3.0/
[4] https://www.pexels.com/@life-of-pix
[5] https://creativecommons.org/share-your-work/public-domain/cc0/
[6] https://www.centrica.com/
[7] https://www.districtenergy.org/microgrids/about-microgrids97/features
[8] https://www.pexels.com/@jplenio
[9] https://www.eia.gov/tools/glossary/?id=D
[10] https://blog.advancedenergyunited.org/in-new-report-and-before-the-supreme-court-demand-response-is-in-the-spotlight
[11] https://www.utilitydive.com/news/the-value-of-less-quantifying-the-benefit-of-peak-demand-savings/408565/
[12] http://energystorageassociationarchive.org/resources/thought-leadership/faqs/
[13] http://energystorageassociationarchive.org/why-energy-storage/technologies/
[14] https://commons.wikimedia.org/w/index.php?title=User:Munna_Aawara&action=edit&redlink=1
[15] https://creativecommons.org/licenses/by-sa/4.0
[16] mailto:simmon@climate.gsfc.nasa.gov
[17] http://www.nasa.gov/
[18] http://www.gsfc.nasa.gov/
[19] http://www.noaa.gov/
[20] https://ngdc.noaa.gov/ngdc.html
[21] https://www.ospo.noaa.gov/Operations/DMSP/index.html
[22] https://www.smartgrid.gov/the_smart_grid/smart_grid.html
[23] https://www.energystar.gov/about/
[24] https://www.energystar.gov/
[25] https://home.howstuffworks.com/home-improvement/construction/green/energy-star.htm
[26] https://drawdown.org/