- Joined
- Jan 26, 2002
- Messages
- 2,737
By "easier to convert electricity to useful work than it is to convert heat," I meant also that the conversion of electricity to work is more efficient than the conversion of heat to work. It's much more difficult to prevent loss the product, heat, to the environment than it is for electricity.
I do agree that current electric motors have a ways to go before being comparable to internal combusution engines. Perhaps a hybrid utilizing a hydrogen turbine/steam engine instead of gasoline combustion engine would help.
The problem with photovoltaics is low energy-density and low efficiency. Oil is ultimately the result of plant's storage of solar energy as energy-rich molecules via photosynthesis. Last I heard plants were much better capturing and utilizing solar energy than photovoltaics.
How many year-acres of plant growth does a tanker of gasoline represent? What area of photo-voltaics is needed to generate that same ammount of energy in a reasonable time? How long must a photo-voltaic array operate before it generates an ammount of energy equal to that used to produce the photo-voltaic from raw materials? How do the ecological implications of covering a large swath of land and depriving it of sunlight compare with say, strip-mining coal? What would be the implications of the by-products and pollutants of producing a huge ammount of the semi-conductive materials utilized in photovoltaic cells?
I seldom see these types of questions asked. They are difficult ones. Even trying to follow and assess the parts of the energy equation that are currently valued in dollars is nearly impossible, due to it's convolution with subsidies, politics, hidden costs like projecting military power elsewhere in the world, etc. How much have I paid for a gallon of gasoline or the infrastructure to make it available before I even buy it at the gas station? And many parts of the energy equation aren't currently valued in dollars.
I'm not saying it's hopeless, but I seldom see more than tiny bits of the equation discussed. It is entirely possible that a large conversion to an alternate technology could create new, worse ecological problems or effectively place us in overall "energy debt" and/or monetary debt for an unacceptably long time before net break-even. The dollar break-even for supplimenting house-hold heating of water with photo-voltaics can be many years.
Trying to reduce the size of the problem certinly can't hurt though, even if does mean scaling down expectations away from 7,OOO lb personal vehicles, 10,OOO sq foot residences with heating/cooling plants, or yes, even less "punchy" acceleration on the car, at least if one must have one the size and weight of most current ones.
Rant completed.
I do agree that current electric motors have a ways to go before being comparable to internal combusution engines. Perhaps a hybrid utilizing a hydrogen turbine/steam engine instead of gasoline combustion engine would help.
The problem with photovoltaics is low energy-density and low efficiency. Oil is ultimately the result of plant's storage of solar energy as energy-rich molecules via photosynthesis. Last I heard plants were much better capturing and utilizing solar energy than photovoltaics.
How many year-acres of plant growth does a tanker of gasoline represent? What area of photo-voltaics is needed to generate that same ammount of energy in a reasonable time? How long must a photo-voltaic array operate before it generates an ammount of energy equal to that used to produce the photo-voltaic from raw materials? How do the ecological implications of covering a large swath of land and depriving it of sunlight compare with say, strip-mining coal? What would be the implications of the by-products and pollutants of producing a huge ammount of the semi-conductive materials utilized in photovoltaic cells?
I seldom see these types of questions asked. They are difficult ones. Even trying to follow and assess the parts of the energy equation that are currently valued in dollars is nearly impossible, due to it's convolution with subsidies, politics, hidden costs like projecting military power elsewhere in the world, etc. How much have I paid for a gallon of gasoline or the infrastructure to make it available before I even buy it at the gas station? And many parts of the energy equation aren't currently valued in dollars.
I'm not saying it's hopeless, but I seldom see more than tiny bits of the equation discussed. It is entirely possible that a large conversion to an alternate technology could create new, worse ecological problems or effectively place us in overall "energy debt" and/or monetary debt for an unacceptably long time before net break-even. The dollar break-even for supplimenting house-hold heating of water with photo-voltaics can be many years.
Trying to reduce the size of the problem certinly can't hurt though, even if does mean scaling down expectations away from 7,OOO lb personal vehicles, 10,OOO sq foot residences with heating/cooling plants, or yes, even less "punchy" acceleration on the car, at least if one must have one the size and weight of most current ones.
Rant completed.