16. 1 Why Is Energy Efficiency an Important Energy Resource?



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Notes Chapter 16.1 APES



16.1 Why Is Energy Efficiency an Important Energy Resource?

What is energy efficiency? 84% of all commercial energy used in the U.S. does not produce useful work. What happens to 41% of this energy? What about the other 43%? What are some reasons that many homes are considered to be “energy hogs”?

Energy Efficiency is how much useful work we can achieve from each unit of energy. Basically, more capable work provided by a clean, abundant (high net energy yield not amount needed to put in), and cheap source of energy means better efficiency.

• 41% of energy used in a system usually ends up as low-quality waste heat emitted into the environment because of the second law of thermo.

• Other 43% is usually needed just to operate an inefficient system (non-LED light bulb, nonhybrid motor vehicles, and nuclear/natural gas operated power plants)

• Many homes are not made with high-quality energy efficient materials/systems such as being poorly insulated, run with a low-quality furnace/AC unit, cheap quality windows, etc. Thus, homes are using more energy sources to heat them in the winter and cool them in the summer.

What are four energy-inefficient devices that the U.S. economy depends on and how much of the energy from each device is lost and not being provided to do useful work? Why do most analysts believe developing machines/technology to run more efficiency is our best source to improve our economy and environment? What are some benefits both economically and environmentally for improving energy efficiency?



• Data/Telecommunication centers where only 10% is used to run the system and the other 90% ends up as low-quality heat into the environment

• Internal combustion engine used to run most motor vehicles where 80% of the energy is lost as heat into the environment (20% of the fuel is actually useful energy to operate the vehicles).

• Nuclear power plant where from 75% up to 82% of the energy is wasted to run nuclear fuel cells and is turned into low-quality heat in the atmosphere.

• Coal-fired power plant where 65% is lost to the environment (possibly up to 80% if you include the energy needed to mine the coal)

•Analysts believe improving the machines/technology to become more energy efficient is usually the quickest, cleanest, cheapest way to provide more energy, reduce pollution and environmental degradation, and slow projected climate changes.

• Economically – Lower fuel costs, create more local jobs, prolong fossil fuel supplies, reduce oil imports and improve energy security, improve overall net energy yields of the systems

Environmentally – Reduce air, water, and nuclear pollution that will help increase biodiversity for maintaining the natural habitats many native species are accustom to.

What percent do industries account for towards power consumption in the U.S.? What are five ways most industries can improve their energy efficiencies and save money in the process? Give an example for each type.



• Industries account for 33% of energy consumption in the U.S. (30% for industries worldwide).

• 1.) Use cogeneration by involving a combined heat and power (CHP) system that can capture the steam used to generate the system and reuse energy released from the system again through another generator to provide more useful work (electricity). Has an energy efficiency of 90%. CHP Benefits CHP vs. Conventional

2.) Energy-efficient electric motors that run at the minimal rate for the required task instead of running at full speed for any task.

3.) Recycling materials to produce new materials such as producing steel by using recycled scrap iron.

4.) Energy-efficient lighting such as LED light bulbs.

5.) Redesign the software and cooling systems in government and private electronic data processing systems Bloomberg Telecommunications System

What type of grid system does the U.S. currently have? What type of grid system is the U.S. proposing to use in the future and what type of impact would it have on our economy?



• High-voltage grid system

• Ultra-high-voltage smart grid system would adapt to natural disasters loss in one area and hopefully bring power in from another area elsewhere in the country. Could also make more use out of other renewable resources such as solar and wind if power is connected country wide.

What percent does transportation account for towards power consumption in the U.S.? In 2040, what goal is the U.S. government proposing for cars and light trucks to have for their fuel economy standards? What are three hidden costs most motorists are not aware of with the type of vehicle they drive daily? What is one way the government is trying to encourage motorists to purchase more energy efficient vehicles? Besides just motor vehicles, in what ways can we improve our mass transit system?



• 28% of the energy consumption comes from transportation with two-thirds being from the use of oil in the U.S..

• Be able to have a fuel economy of 100 mpg for cars and light weight vehicles

• Three hidden costs: 1) Tax breaks and subsidies from government to oil companies 2.) Idling in traffic due to poor road design 3.) Road builders and contruction

• By giving tax breaks or economic incentives to encourage citizens to purchase more energy efficient vehicles.

• Providing more mass transit systems to the public (especially between cities) and more freight transportation through mass transit instead of in large motor vehicles.

What is one (most popular) type of vehicle that has already been in production for the last couple of decades in achieving the goal of being a more energy efficient vehicle? What makes these vehicles more efficient? Also, what is their fuel economy value and what greenhouse gas does it decrease?



Hybrid Vehicles Top Ranked Hybrid Cars

• Have both a gasoline-powered engine and a battery-powered motor (used primarily for acceleration and uphill terrain) in one car.

• Fuel economy of up to 50 mpg and emits upwards of 65% less CO2 than a traditional combustion engine motor vehicle.

What other type of energy efficient vehicle is being used that is a little more inconvenient, but still decreases CO2 levels by 27%? What addition are they proposing to make that decreases the CO2 levels to be 80-90%?



• Plug-In Hybrid Electric Vehicle Best Plug-In Hybrid Car (both plug-in and diesel electric hybrid)

• Most common typically get 30-60 mpg on electricity alone (problem is where they obtain the electricity from *hint hint*). Have back up/supporting fuel motor that kicks in when electricity is low.

• Have the electricity being used to power these vehicles from wind, solar, or hydroelectric dam systems.

Would a fully electric car not emit both directly and indirectly CO2? Explain why or why not. What is one other type of energy efficient vehicle that might be massed produced in the future if the negative net energy it produces were to change? How do both ultralight and ultrastrong materials improve a cars energy efficiency?



• Directly it significantly decreases CO2, but indirectly there is little to no change, possibly even more CO2 produced in the manufacturing of complex materials to build the vehicles. CO2 is also emitted with these plug-in cars in the way they acquire their electricity mainly from nonrenewable, heavy air/water polluting systems (coal, oil, and also natural gas). In short, it’s not possible

• Possibilities in the future are electric vehicles that use a fuel cell such as a hydrogen fuel cell. They are said to be twice as efficient as internal combustion engines, have no moving parts, and require little maintenance. The way to charge the fuel cells are similar to electric plug-in cars. Rough Concept of Hydrogen Fuel Cells Model of a Hydrogen Fuel Cell and Vehicle

• Ultralight and ultrastrong composite materials use lighter and stronger materials that are not on traditional cars. Do not require painting on the material but cost is currently high to use on standard cars. Examples are fiberglass, carbon fiber, and graphene. Graphene Template

Globally, what percent do homes consume in terms of energy, CO2, and solid wastes produced? What is one simple way that a home can reduce its consumption of energy simply when under its construction phase? You can save up to 75% of heating costs by making sure what is up to date in your household?



• Consist of 25 – 40% of energy consumption globally for homes that have an average life span of 50 to 100 years.

• If a building is oriented to face the sun with the most optimum window coverage area (facing south) and not obstructed you can obtain natural solar energy and cut heating costs by up to 20%

• Making sure the house is properly insulated and has airtight roofs and windows in place. Standard Insulation Injected Insulation

What are the benefits of using green architecture in households? What are the benefits of having green roofs (also called living roofs) placed on top of a building? What is superinsulation and what are its benefits for a more energy efficient home?



• Uses environmental friendly concepts such as insulated windows, energy-efficient appliances and lightening, electricity from solar cells, and even windows that darken to deflect heat during warmer days.

• Green roofs are covered with specially designed soil and vegetation that can reduce the costs of cooling and heating a building by absorbing heat from the summer sun and help insulate the structure during the winter. Green Roofs

• Superinsulation is when the insulation is so airtight that just the body heat from those living in the residence can naturally keep the structure warm. An example would be using straw-bale. Straw-bale Homes

What are four types of energy audits a homeowner can have done to their home to make their home more energy efficient and what benefits do both the homeowner and environment gain from these audits?



1.) Insulate the building and plug leaks such as small crakes and crevasses and updated insulation by using less AC in summer and heat in the winter (less greenhouse gases emitted).

2.) Energy-efficient windows can pay for themselves in a few years, cut heating/cooling expenses, and reduce the need of CO2 emissions from heating the home.

3.) Heat water more efficiently by using a roof-mounted solar hot water heater or tankless instant water heater that uses less electricity (less CO2 emitted). Solar-Mounted Water Heater Tankless water heater

4.) Automatic motion sensors to turn lights on and off can cut the energy used for lightening purposes by 90% by shifting to LED light bulbs that only turn on when motion activated and with dimmers.


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