1 Volumetric Energy Density Use Case

  • What are some questions you can ask and answer with a volumetric energy density?
  • Come up with an example of where a high volumetric density would be desired.

2 Gravimetric Energy Density Use Case

  • What are some questions you can ask and answer with a gravimetric energy density?
  • Come up with an example of where a high gravimetric density would be desired.

3 Energy Efficiency Use Case

  • What are some questions you can ask and answer with an energy efficiency?
  • Come up with an example of where a high energy efficiency would be desired.

4 Energy Density Calculation

Assume it takes about 2 MJ of energy to boil a large pot of water. Assume coal has an energy density of 20 MJ per kg. What mass of coal in kg when burned will release this much energy? (Assume 100% of the energy is absorbed by the water.)

5 Energy Efficiency Calculation

Assume a coal plant is 37% efficient at transforming thermal energy into electrical energy. If you need 50 MWh of electricity, how many MWh of thermal energy from the coal do you need?

6 SSU Digs Coal Planning

Consider the following thought experiment. Suppose our electricity provider is significantly raising our cost of electricity and we are under pressure to find an alternative source of electricity. Now imagine our good fortune as we find an enormous coal deposit under the campus and decide to create a coal plant to provide for all of our electricity needs. In this exercise, we’ll estimate the amount of coal we must mine per year and the carbon dioxide emitted.

Please answer the following in complete sentences. (There are no calculations expected.)

  • What quantities will we need to estimate to determine our coal use and carbon emissions?
  • Which of our analytical tools are we likely to use and why?

7 SSU Digs Coal Discussion

  • What questions do you have about this proposed plan?
  • How do we determine which of our analytical tools are relevant to the problem?
  • How would you explain and document an overall strategy for this estimation?
  • What other related estimations and calculations might be interesting?

8 SSU Digs Coal Estimation

Based on our discussion, write up an estimation of:

  • the coal use per year in kilograms
  • comment on changes to your mental models

9 Next Industrial Revolution Reading

Please answer the following questions in a brief essay. You can find a link to a copy the reading here. You can also find the entire text here.

  • What do you think the author’s main point is in the chapter?
  • Explain the types of scarcity that the author talks about and why they are important.
  • Can you think of an energy service that interests you or that you would be willing to purchase?

10 Conservation of Energy Reading

Please read H&K chapter 3, linked here, on Conservation of Energy and answer the following:

  • What is the difference between a unit conversion and an energy conversion?
  • What energy conversion(s) interest you and why?

Natural Capitalism Services

Please read Natural Capitalism Chapter 7, “Muda, Service, Flow” and in a few sentences answer the following questions:

  • What does the author mean by a solutions or service economy?
  • How does this service economy differ from our current one?
  • What is a specific example of a service economy you would be interested in and how is it different from what you currently do?

Efficiency Reading

Read the H&K chapter with energy efficiency and answer the following questions.

  • State a definition for efficiency in your own words.
  • Would you say automobiles have high or low efficiency? Why?
  • Would you say electric motors have high or low efficiency? Why?
  • What is the difference between “energy conservation” and “conservation of energy”?

Estimation Description

Imagine you have been asked to estimate the carbon dioxide emissions released by students commuting to campus. Without performing a numerical estimate, describe the approach you would take.

Multiple Choice

The fraction 30MJ/kg expresses the fact that if I burn 1 kg of diesel I release 30 MJ of heat energy. Is this a

unit conversion energy density carbon intensity energy efficiency

The fraction 4186J/kcal expresses the fact that 4186 Joules are the same quantity of energy as 1 kilocalorie. Is this a

unit conversion energy density carbon intensity energy efficiency

For a valid unit conversion fraction

top and bottom units are different top and bottom dimensions are different

For an energy density

top and bottom units are the same top and bottom units are different

A battery converts

chemical energy to electrical energy thermal energy to chemical energy thermal energy to electrical energy

The internal combustion engine in a car converts

electrical energy to mechanical (kinetic) energy chemical energy to mechanical (kinetic) energy

  • Name an energy service and the energy conversions used to provide that service.
  • What is the difference between efficiency and efficacy?
  • The world uses about 500 EJ (500 Exajoules) in a year. What size power plant (it watts) will generate that much energy if it is on 24 hours a day for an entire year? Recall that energy delivered is equal to the power multiplied by the time.
  • Burning a gallon of gasoline emits 8.9 kilograms of CO2 emissions per gallon. If a car gets 30 miles to the gallon, how much carbon dioxide is emitted per distance? Give your answer in both kg per mile and kg per km.
  • A high power stove delivers 20,000 BTU per hour. What is this power if you express it in units of kilowatts?

The amount of carbon dioxide emitted per gallon of gas depends strongly on the mileage your car gets.

True False

Burning a gallon of gasoline emits 8.9 kilograms of CO2 emissions per gallon. If a car get 30 miles to the gallon, how much carbon dioxide is emitted per mile?

  • 3.3 kg CO2 per mile
  • 0.30 kg CO2 per mile
  • 266 kg CO2 per mile