Can We Do It?

At this point we have looked at a number of chapters from David's book to understand how he arrives at his numbers. Hopefully you get the general sense that the numbers are reasonable and you accept the data on which they are based. In Chapter 18 David totals up all the parts of the red and green stacks (the ones we looked at as well as the ones we didn't) to clarify the big picture.

1) What is an appropriate first interpretation of the size of the red and green stacks from Britain? Are the essentially the same size (less than 25% different) or are they very different? What does this tell us about the simple answer to the question "Can we meet our (Britain's) energy needs with only renewable energy resources?"?

2) Does the data that David generated in his book for the red stack agree with measurements of national consumption that are captured in Figure 18.4? What is the primary factor which explains the difference between the energy consumption per person per day for Britain shown in the figure and the red stack as David determined it? How much more energy do we use per person in the US according to the figure? Where do you think the differences come from?

3) What percent of the green renewable stack seemed like it could actually be constructed at some reasonable level of cost? How can you explain the remarkable variation in the different predictions shown in Figure 18.6? How does this affect our answer to question #1?

4) On page 204 in Chapter 27 David suggests that we could reduce our need for energy (the red stack) by a bit without compromising our lifestyles. This reduction in need is mostly through improved transportation and insulation in our homes. What is the percent reduction that he thinks we might be able to accept?

5) We talked a bit about how this all connects with energy use in the United States. Here is the most current (should be linked) energy picture (from the Lawrence Livermore National Lab - LLNL) for the US. Given that a Quad is 2.9^.10¹¹ kWh and the current population of the US is 330 million calculate the average energy use per person per day in kWh and compare it with the data point on Figure 18.4 in David's book.

6) What percentage of the energy put into the generation of electricity actually comes out as usable energy based on the LLNL data from the previous problem? This actually complicates our understanding of energy flows. When I use 10 kWh of electrical energy in my house how much energy have I actually "used" as a citizen of this country?

7) The block on the right side of the LLNL data represent where the energy is going. LLNL has divided the pie up differently than David did. Calculate the kWh per person per day for each of the catagories (there are 4) and compare them to the appropriate categories in the red stack. Don't forget to add the energy correction from step 6 to any electrical energy used in each catagory. Does this clarify your answer to the last part of #2?