So, almost a couple months ago, I found myself in the strange position of having to agree with Anthony Watts and Roy Spencer. Yeah, I know. I'm still trying to shake the creepy feeling. In my defense, however, I only agreed to a degree, and drew a clear line exactly where they started acting like the King Trolls they truly are (you'll need to click on the link for further elaboration/clarification).
In that post, I also referenced a very lucid takedown of solar roadways by Thunderf00t. Sorry, solar roadway fans, but they ain't what they're cracked up to be (pun definitely intended). Interestingly, in that video, Thunderf00t estimates that if we cover all of America's roadways in these proposed hexagonal solar panels, the tempered glass component alone will cost close to what I estimate the present price tag for space-based solar power (SBSP) to be ($20 trillion vs. $10-$300 trillion). Now, forgetting for a moment that a recent NASA-funded research project came up with a much lower total than I did, let's just assume the two ideas would cost roughly the same. With the amount of either bill being essentially a wash, and assuming no show-stopping deployment/feasibility issues, we are only left deciding which is a more productive and beneficial concept (i.e.: which gives us more bang in the form of energy for our buck).
To start the decision-making, we should first consider perhaps the most important factor: efficiency. The solar roadway folks claim about a 15-20% efficiency. Nice, but once you remove/polish away the snow/dirt/dust/opaque scratching/etc., get your solar panels above the shadowing/interference caused by cars/trees/buildings/clouds/weather/other atmospheric disturbances/etc., you might just find the biggest issue is transmission difficulties, and even detractors put the worst-case RF/microwave-beaming scenario at about 50% efficiency. What are your most problematic power production levels in space can't even be achieved in the best of situations on good ole terra firma.
Secondly, that efficiency estimate for solar roadways will NOT hold in higher latitudes and/or during the winter due to the fact that the sunlight is less direct and has to travel through greater stretches of scattering atmosphere resulting in further attenuation of its strength, as Thunderf00t points out in his video. In space, however, you need not worry about your distance from the equator or seasonality. The sun shines with equal power all the time, which is nice.
Finally, though I said the cost of either shouldn't weigh into the decision here, I really meant initial investment, because, when the price of maintenance is considered, I don't think there can be any doubt that the wear-and-tear of vehicle traffic will far surpass anything the vacuum of space can throw at properly-designed, autonomous satellite systems. To the best of my knowledge, once SBSP is up in geosynchronous orbit, it will be well beyond most of the corrosion issues faced in low-earth orbit, as well as threats from man-made space junk. If I'm wrong about that, I welcome the schooling, so let me have it. Fair warning, however, I'm not terribly interested in long dissertations about the dangers posed by micrometeorites. I never claimed SBSP was perfect and invulnerable (in fact, systems like the one proposed by John Mankins are biologically-inspired, modular, no-single-point-of-failure designs whereby broken components are replaced, if necessary, rather than repaired...see section "3.3 Concept Description" of the SPS-ALPHA final report), and, I think we can all agree, no power system we make ever will be.
Thunderf00t makes a snarky and rather valid point toward the end of his video about existing parking lot solar panels. For good reasons, you don't find them under the cars, where the solar roadway folks would have us put them. Well, I'm just asking that we take that point to its logical conclusion and place our solar panels in the ultimate "above it all" location: 35,000km over our heads.
Let's go, solar roadways folks, before all that money you received gets wasted on R&D for a less practical, less productive idea, donate it to SBSP projects which promise to deliver more energy per dollar invested. Instead of looking down, start looking up, because, like it or not, that's where we're headed, anyway.
