Tag Archives: energy

Blogging Theme, week 3

The blogging theme for this week is Penn State Campus.   A brief reminder about blogging requirements: you may post on anything related to the course (the “theme” for the week is only a suggestion), and your postings will be graded according to the rubric that appears in the syllabus,  The rubric involves five grading elements: frequency of posting, mathematical content, thematic content, organization and presentation, references and connections.

It is suggested that you post about some measurement or estimate related to sustainability on the Penn State (UP) campus. Example topics (many more are possible).

  • Waste and recycling – see http://sustainability.psu.edu/mobius, and listen and respond to Al Matyasovsky’s presentation on Wednesday.
  • Over the winter break (approx December 24th – January 5th), the Office of Physical Plant “sets back” temperatures in most PSU buildings from their normal 70 degrees (F) to about 50 degrees. How much difference does this make to PSU’s energy consumption?
  • Estimate the environmental impact of a big football game.
  • Learn about the UP campus’ water consumption. Where does our water come from? Is the supply sustainable (define this term how you wish, but make sure you answer the question in terms of your definition). What activities on campus use the most water?
  • Blog about the work of Penn State’s Consortium for Building Energy Innovation at the Philadelphia Navy yard (http://cbei.psu.edu) What is their goal? How do they plan to achieve it? Is it realistic?
  • Conversion of the PSU steam plant from coal to natural gas. (http://www.opp.psu.edu/planning-construction/penn-states-switch-from-coal-to-natural-gas)
  • Estimate how many showers per day are taken on the Penn State campus.   How much energy is used to heat the water for them?
  • Interview some faculty members about their academic travel.   Estimate the number of barrels of oil per year used by faculty academic travel. Are there alternatives?
  • If we covered the roof of a dorm with solar panels, what fraction of that building’s energy needs might they realistically supply?

Energy balance of the Global Photovoltaic Industry

One can estimate the energy payback time of a solar panel (that is, the length of time for the panel to yield more energy than was consumed in its manufacture) fairly easily.  But the energy invested to make the panel is a “down payment” – all at teh beginning of its lifetime – whereas the energy it yields back is a trickle that flows over many years.  Because the global solar industry is growing at a rapid (exponential) rate, it is not obvious that the industry as a whole has yet been a net energy benefit.   This paper gets to the bottom of that question.   Its conclusions might surprise you!

Dale, Michael, and Sally M. Benson. 2013. “Energy Balance of the Global Photovoltaic (PV) Industry – Is the PV Industry a Net Electricity Producer?” Environmental Science & Technology 47 (7): 3482–89. doi:10.1021/es3038824.

You can access the paper online using your PSU credentials

How Much Water Does it Take to Make a Pair of Jeans?

Water rights and accessibility is no doubt a global issue. Despite it being in the news, day to day when we wash our face or dishes we rarely think about how much we are wasting. However even if you are water conscious at home its more likely that you do not think about how much water is being wasted when you buy products.

Indirectly we can waste water, whether its buying agriculture from fields which do not have a efficient irrigation systems, or from buying a pair of jeans.  ” It takes around 1,800 gallons of water to grow enough cotton to produce just one pair of regular ol’ blue jeans.” That’s more water than it takes to make a ton of cement or a barrel of beer (although I’m sure some of you do not consume this yet).  And that’s just in terms of growing cotton, when you take into account the dye process as well as the machine wash almost 9,982 gallons of water are used.

How can we fix this?

1. stop purchasing so many jeans

2.  Buy levis, they are built to last, and its strongly recommended to not machine wash them. They suggest freezing them instead, it kills all the germs. however, if  there is a grass stain that you would like to get off all it takes is a sponge and a cup of water opposed to 40 gallons ( a typical machine wash).


sources: http://www.treehugger.com/clean-technology/how-many-gallons-of-water-does-it-take-to-make.html

Greenhouse Gases, Overpopulation, and Agriculture

One of the most energy and resource intensive human activities is harvesting food, mostly because we have so many people to feed. And the population is only growing. There have been a variety of responses to this dilemma, three of the big ones being

  1. to genetically engineer crops and livestock to produce more food with less resources,
  2. optimize farming practices to reduce waste (e.g. organic farming), and
  3. reduce the consumption of foods that are energy intensive (e.g. beef) or whose harvesting lead to unacceptable levels of environmental degradation (e.g. palm oil).

Unfortunately, each of these approaches faces major obstacles. The public is reticent to embrace genetically engineered foods, primarily because of perceived risks. Organic farming is not only expensive, but requires more space for the same crop yields as conventional farming. Reducing the consumption of energy intensive foods like meat and dairy–something advocated by the United Nations and the Environmental Working Group— is wildly unpopular. In the case of detrimental crops like palm oil and bananas, most people aren’t even aware there is an environmental problem.

Sustainable Energy Without The Hot Air

From the preface: “This is a straight-talking book about numbers… I’m concerned about cutting emissions of twaddle – twaddle about sustainable energy”.  (This is a British book, so you will need to think about how his examples translate to the US context.  The word “twaddle” means “silly, idle talk”, according to the online Merriam-Webster dictionary.)  Many helpful calculations about energy resources, efficiencies, and the possibility of meeting our consumption from renewables.

Book reference: MacKay, David JC. 2009. Sustainable Energy – Without the Hot Air. 1 edition. Cambridge, England, 2009

Online: The whole book is downloadable for free from http://www.withouthotair.com/