Originally Posted by xyzdonna  Why continue to pour money into carbon energy when the other stuff is safer, cheaper and easier. Is it laziness, we just don't want to learn how to do the new stuff, the old ways are more comfortable? |
Why then isn't "easier" chosen if "laziness" is the reason? Sillier yet is comfortable "old ways" and learning "new stuff". Do brief review of the last 100 years.
Why not ask the question again but give it some thought before offering a reason. Maybe you'll find a problem with the question, perhaps the assumption it's "safer, cheaper and easier".
Non-renewable energy is fossil fuel and nuclear. Renewable energy is solar-cells, solar concentrators, biomass, ethanol, hydroelectric, windmills, wood-burning stoves, etc. All renewable energy is solar energy and that is a major problem. In fact it's a show-stopper for a technological civilization.
Solar energy is feeble. It is at best (noon, clear day, on the equator) 1kW per square meter. 10% of that is recoverable as usable energy so make it 100W per square meter.
Let's use it in a car. A car needs 75kW minimum at 100 kM/hr. To get that, 750 square meters of collector area is required. The collector diameter is 31 meters (about 100 feet) sitting atop your vehicle. OK, not practical.
Let's grow corn, convert it to ethanol and put it in the car. You drive 15,000 km a year, your car gets 10 km/l so you need 1,500 liters of ethanol a year. A square meter of land produces 0.3 liters of ethanol from corn a year. You need 5,000 square meters of farmland for your personal transportation needs.
That's 10,000 miles a year, 25 MPG, 400 gallons annually, 300 gallons ethanol per acre or 1.3 acres of corn. That's a lot of corn.
Solar energy conversion efficiency for ethanol is a not so hot 0.1%. A square meter receives 8 X 10^9 Joules of solar energy a year. A square meter produces 0.3 liters of ethanol a year whose energy content is 7 X 10^6 Joules.
The bigger picture. US per capita energy consumption is 4.5 X 10^11 Joules per year. Solar energy is 8 X 10^9 J / m^2 / yr. Assuming a very optimistic 5% conversion efficiency, every man, woman and child would need over 1000 square meters of solar "collector area". That's over a 1/4 acre per person of very expensive technology. Get it all from low-tech corn? Now you need 50 times more land; 50,000 m^2 or 12.5 acres per person.
Conclusion: There are no "alternative energy sources". It's oil or it's nuclear or we go back to a primitive agrarian existence.
I did the math myself. I hope I didn't slip a decimal point somewhere.
Mariss