When I'm not busy thinking about garbage (or rooting through it), I think a lot about energy. A few years ago, I had a cochamamie idea that if there were a wind turbine on every utility pole, it would be a great additional source of energy without polluting the environment or screwing up the viewshed or infringing on any one's rights. Eventually I discarded this idea as utopian and unrealistic. If it would work, I thought, someone would have suggested it already. Well... someone did, actually. I've since learned that Buckminster Fuller proposed the same idea in the 70's. I don't know why it never took off. Seems like a no brainer to me. Later (last year, I think), I hatched another energy scheme, even wilder than the last. Single celled organisms are awfully good at taking sunlight, water, and carbon and converting it into hydrocarbons. Why not tweak their genomes to maximize the process? Couldn't they convert the atmospheric CO2 that's cooking the planet into oil? If we produced all of our carbon based fuels this way, carbon emissions would become a closed system, and we might be able to make some real headway on global warming. Once again, I dismissed the idea as fanciful and science-fictiony. But a few months ago, I read in the New York Times that there's a start-up company in the desert southwest that's doing pretty much exactly what I'd envisioned. So part of the lesson here is clearly that I should always act on my every idea, no matter how ridiculous it seems.
I also had a thought that the problem of birds flying into wind turbines at night and dying could be ameliorated by placing LED's on the blades (of the turbines, not the birds). LED's hardly draw any energy, and they could be produced to illuminate at a wavelength that's visible to birds but not humans.
We're all taught in gradeschool that all of our energy (or most of it, anyway) comes from the sun. And by the second law of thermodynamics, the closer to an energy source you get, the less loss there is. Take fossil fuels for example: first photosynthetic life had to evolve, then it had to die en masse and be compressed for millions of years before becoming a fuel source. So the end product (oil, natural gas, coal) is really, really far removed from the original energy source (the sun), which is why this energy source is so easily depleted. Lots of loss along the way. So the best solution to our energy woes is to use solar energy, right, since it comes directly from the source? Well... no. Or not yet, anyway. Solar panel technology is still very, very inefficient. Only a few percent of the energy that hits a solar panel gets converted into electricity. Until solar panels can be built to harness more of the sun's output, they're really just going to be a novelty item.
Hydrogen - also problematic. It's a great way to store energy, but you still need to produce it somehow. The most obvious source of hydrogen is water, but it's awfully difficult to split it from that oxygen atom. Takes a lot of energy, so we're back to square one - trying to find an efficient, non-depletable energy source.