Summary: Modeling the Energy Consequences of the Cell Phone Revolution Introduction
Note on “U.S. Population Projections”
Download 0.57 Mb.
|
- Navigate this page:
- Note on “Number of Cell Phone Subscriptions”
- Note on “Percentage of Population with Cell Phones”
- Note on “Total Energy Used by Cell Phones (Barrels of Oil per Day)”
- Appendix F: Calculating projections of % of households with landlines
- Total 14 79.5 699.9
- X= 29.150 years.
- Appendix D 12 See Appendix B
Note on “U.S. Population Projections”: The U.S. Bureau of the Census published figures of their projections for the population in the United States between 2000 and 2050 (As indicated by the boxed in region of the above chart). After determining that the data follows a linear model, we used a linear regression to extrapolate the data beyond the date ranges presented by the U.S. Bureau of the Census. Note on “Number of Cell Phone Subscriptions”: The Global Wireless Matrix 4Q07 Report published by Merrill Lynch gives the total number of cell phone subscriptions for the U.S. between 1998 and 2007 (As indicated by the boxed in region of the above chart). After determining that the data follows a linear model, we used a linear regression to extrapolation the date beyond the date ranges presented by The Global Wireless Matrix 4Q07 Report. Note on “Percentage of Population with Cell Phones”: These figures were calculated by taking 90% of the number of subscriptions (taking of 10% because of our assumed number of people with multiple cell phones) and dividing by the number of people within the population. Note on “Total Number of People with Cell Phones”: These figures were calculated by taking the percentage of population with cell phones and multiplying the by the forecasted population of the United States. Note on “Total Energy Used by Cell Phones (Barrels of Oil per Day)”: The figures in this data set are derived by the method described in Requirement 1 using the data from Table 1.5 and using the conversion rates found in Bio-energy Conversion Factors. Appendix E: Household Phantom energy consumption
Appendix F: Calculating projections of % of households with landlines: Estimates the time period in which cell phones will become the sole means of communication.
X = # of years from 2004 (data measured bi-annually) Y1 = % of Households with wireless only Y2 = % of Households with Landlines Simple Linear Regression Model (Least Squares Estimate): We will assume that the errors of this models are normally distributed with mean 0. Thus our model will become:  
Calculations for  ,  ,  
 , 
Thus: We can use this linear approximation to calculate the time for Households to become completely wireless (0% Landlines). 100 = 4.450 + 3.136 We can predict that at the year 2034 (2004 + 30.47), Households will have become 100% wireless. To check this approximation, we will also use a linear regression model to extend the data trend on percentage of households with landlines. We would like to see this data trend correlate with the percentage of wireless only households, and approximate the same year. Calculations for ,  , 
 , 
Thus: Now we can use this model to check our calculation that households will become completely wireless in 2034. 0 = 93.075 – 3.193X, solving for X yields: X= 29.150 years. Therefore, both calculations have shown that households will have completely made this shift from landline phones to wireless by the year 2034. Thus it is most likely that the US will spend another 25 years transitioning from a combination of landline and wireless phones to just relying on wireless phones. After 2034, the US will be in a steady state in which, assuming no new technological breakthroughs, its sole means of telephone communications will be wireless devices. Graphical representation of changing trends from landline telephones to wireless cell phones. 2 "Energy use of set-top boxes and telephony products in the U.S." by the Lawrence Berkeley National Laboratory 4 Bio-energy Conversion Factors 5 “Global Wireless Matrix 4Q07” by Merrill Lynch 6 See Appendix B 7 Batteries4Less.com 8 See Appendix A 9 Charging Lithium-ion batteries" by Battery University 10 “Standby Power Summary Table" by Lawrence Berkeley National Laboratory 11 See Appendix D 12 See Appendix B 13 Charging Lithium-ion batteries" by Battery University 14 See Appendix A 15 “Standby Energy Power Table” - by Lawrence Berkeley National Laboratory 16 See Appendix D 17 “Standby Energy Power Table” - by Lawrence Berkeley National Laboratory 18 “Petroleum Basic Data” by the Energy Information Administration Download 0.57 Mb. Share with your friends:
|
where
: 
, solving for X yields: X= 30.47 Years. 
: (Using 