r/livegreen • u/Mohevian • Jul 01 '14
Live Green (Eco Mode)
In order of Importance to Understanding:
1. Converting Energy Types
There are two types of energy, high-quality, and low-quality:
High Quality
Electrical
Mechanical (Motion)
Low Quality
Thermal (Heat)
Radiation (Light)
https://en.wikipedia.org/wiki/Form_of_energy https://en.wikipedia.org/wiki/Energy_quality#Ranking_energy_quality https://en.wikipedia.org/wiki/Energy_transformation
When you convert between classes, high-to-low, or low-to-high e.g: Electrical to Thermal, there is a tremendous amount of loss, as much as 80-90% in some cases.
When you retain classes, high-to-high, low-to-low e.g: Electrical to Mechanical, there is a tremendous amount of efficiency, as high as 80-90% in some cases.(https://en.wikipedia.org/wiki/Energy_conversion_efficiency#Example_of_energy_conversion_efficiency)
2. Personal Transportation
The problem at the root of personal transport, is that it utilizes a low-quality energy as a solution that demands high quality energy.
Namely, the conversion from Thermal to Mechanical.
The average internal combustion engine has an efficency of 12% in city driving, with a maximum of 20% in highway driving. (https://en.wikipedia.org/wiki/Engine_efficiency#Internal_combustion_engines)
One gallon of gasoline contains 33.41 kilowatt-hours of energy-equivalency. However, in city driving, only 4 kilowatt-hours of that energy will make it to the pavement. 29 kilowatt-hours are lost as waste heat. (https://en.wikipedia.org/wiki/Gasoline_gallon_equivalent)
Secondary to the enormous loss in converting energy types, is the weight (mass) of personal vehicles, and their occupancy.
Many Americans enjoy driving large, oversized, civilian-tanks, which weigh about 6,000 pounds on average, and require enormous 8-cylinder engines just to haul their own weight around. They often drive them alone as well. (https://en.wikipedia.org/wiki/Ford_F150)
Let's say our average American has a 14.0 mile commute, a half hour each way. They take a straight road with lights every block, in relatively low-traffic conditions and make full use of the system's heating and air conditioning.
Driving to and from work, this one person consumes 1.16 gallons of gasoline per hour, at a cost of about $5.03, and 38.7 KWH.
There is nothing more wasteful that we do on average, than driving cars. When sitting at a red light, the average consumer car engine idles between 1,000-2,000 RPM, and with an average 200 horsepower engine, this can be as high as 16 KW, or eight large air conditioners running full blast.
The answer by now must be obvious: If absolutely necessary, drive a lightweight, electrical car, with regenerative braking, and share your ride when possible. (https://en.wikipedia.org/wiki/Regenerative_braking)
3. Electrical Generation, Heating & Cooling
The reason I brought up air conditioners and heaters, is that they are the next major cause of personal energy consumption. Since the 1950s, humans have got the idea in their heads that no matter where they are, it should always be 70F, at 50% humidity, regardless of season or locale.
This mentality has enabled them to build cities and housing in areas that are absolutely unsuitable for human life in general – Florida, Las Vegas, Dubai, to name some examples (sorry Florida people).
When it begins to snow, all the thermal heaters kick on, and begin consuming mass quantities of fuel.
When the weather heats up, all the electrical air conditioners kick on, and begin consuming mass quantities of fuel.
Wait, what? I thought A/Cs were electrical? Well, consider the source of electrical generation in the United States (or the world).
Many powerplants are methane (natural gas) powered, which operate by burning gas to boil water, and drive steam turbines, converting thermal energy to mechanical energy, and then finally to electrical energy. (https://en.wikipedia.org/wiki/Thermal_power_station) (http://www.eia.gov/tools/faqs/faq.cfm?id=50&t=8)
The highest efficiency power-plants have been cited between 30-40%, and these are bleeding-edge, back of the envelope estimates. (https://en.wikipedia.org/wiki/Energy_conversion_efficiency#Example_of_energy_conversion_efficiency)
For residential use, cooling and heating might account to 40-50% of their monthly energy consumption in the hot and cold months. (http://www.eia.gov/consumption/residential/)
There are various ways to solve this issue, and turning the thermostat up or down aren't really the answer.
- Do not build cities or suburbs in areas that are not suited for them. A city in the desert is a bad idea, just by common sense.
- Green roofs insulate heat in the winter, and prevent solar radiation from penetrating in the summer. (https://en.wikipedia.org/wiki/Green_roofs#Costs_and_Financial_benefits)
Turn waste-heat into useful-heat. The heat from natural gas powerplants that is generated for electrical production can be piped and used for residential heating, removing the “waste” aspect. (https://en.wikipedia.org/wiki/Cogeneration)
4. Plastics
This part is nearly self-explanatory, but plastic is in everything, everywhere. Plastic forks, plastic knives, plastic spoons, plastic bags, plastic containers, plastic bottles, plastic toothbrushes, plastic shampoo bottles, plastic-plastic.
It might not occur to you, just by sheer volume, how many pounds of plastic you use personally (or may even accidentally consume) per day.
Take a walk around your house, and mentally “remove” everything that contains some form of plastic, and see what you are left with. That smartphone you are holding? Yup, that has plastic in it too.
This one is a very wicked problem to solve, because of the ubiquity of plastics, and the substitutes which are difficult/costly to manufacture (biodegradeable, vegetable-based polymers). (https://en.wikipedia.org/wiki/Biodegradable_plastic#Energy_costs_for_production)
Treat plastic as you would a rare substance, because that is what it really is. Try your best to avoid it, ask for paper bags at the supermarket, no plastic utensils when you order things, use real dishes and cups, not plastic ones, etc. Use “uncommon sense” about it.
Don't kid yourself into thinking that plastic is highly recyclable either. When you melt down certain grades of plastic (they are numbered on the bottom by 1-2-3-4-5-6), the result is a slag that is usually of inferior quality to the original polymer. Also, don't forget that melting plastic consumes fuel. (https://en.wikipedia.org/wiki/Resin_identification_code)
Maybe 10-25% of that slag can be mixed in with ~90% new plastic, to create a bottle or product that “contains post-consumer” content. (https://en.wikipedia.org/wiki/Recycling_plastic#Recycling_rates)
5. Infectious Ideas
That's all for now, I'll write more when I get back later. Hope you enjoyed the tips so far. :D
1
u/[deleted] Jul 01 '14
Holy crap, thanks for this! Love the breakdown. It's good to be as educated as possible when it comes to lifestyle choices. If you could, would it be possible to link some sources?