Whenever I see something a wildly create idea like the solar road idea, it renews my faith in the power of innovation and its potential to address our toughest sustainability problems. Given the number of people who sent me links to this project, the idea seems to have captured the imagination of a good number of folks.
I'll be up front: in the case of solar roads, I actually don't believe that it will make sense to widely deploy them today (more on this at the end of this post). But that doesn't mean that the idea won't have important value, either by sparking a related idea that has a better chance of making it big, or by catalyzing someone's thought process, enabling them to have a totally different, off-the-wall idea. It's also possible that I'm wrong, and this is a killer idea.
The beauty of the US innovation "system" is that a rich pool of new ideas gets broad visibility. Many will get an initial investment of some kind. The ones that best solve real problems in a cost-effective manner will get to live on, and the ones that don't will eventually not get the investment they need, and will fade away. We don't rely on my opinion, or that of some government agency, or anyone any specific company. The open market makes the ultimate decision.
Ideas flow through our "system" and build on each other. As mentioned above, the real value of an idea may be the other ideas that it helps foster. Or maybe the time just isn't right for a specific idea, but at some point in the future someone will notice that the conditions that previously doomed an idea have changed, and its time to reconsider it. For example, some future solar technology may have just the right characteristics to radically change the viability of the solar road idea.
This is why eye-opening ideas get me charged up, even if the commercial viability isn't obvious at a given moment in time. Solar roads may or may not make sense with current technology, but I'm confident that 1) our innovation system will come to an appropriate answer to that question, and 2) the idea will get broad visilibity, with the potential to ultimately create value that is much bigger than the obvious implementation we see today.
Initial Thoughts on the Viability of Solar Roads
Two thought experiments lead me to believe that solar roads don't make sense right now.
The first revolves around the following question: if you had today's state of the art solar panel, would you embed it in a road? The answer is clearly "no". With today's panels people do serious work to make sure that they are well sited, with clear view of the right parts of the sky, deployed at angles optimized for that geo-location, and organized in groups to optimize maintenance and common infrastructure. Even with all of this careful work, today's panels only make financial sense with serious government subsidies.
Solar roads will be very suboptimal from the persective of all of these siting criteria. Compared to other options, solar roads won't make economic sense until we've deployed panels on every available warehouse, megastore, mall and factory; a state which we are a long way from.
The second thought experiment revolves around the obvious follow-up question: would solar roads have unique features that would justify the very expensive electricity that they would produce? The two that have been suggested are heating roads for snow and ice removal, and dynamic road lighting for pedestrian and animal visibility at night.
A first observation is that these both add to our national electricity requirements so better have a high value or replace other, comparable energy usage. Based on having lived in a few northern climates, my sense is that road heating would work in such a narrow band of temperature and conditions that it would not be generally useful. I'd be interested if anyone has a study or examples that show that this is actually an effective strategy for clearing roards.
Lighting roads for pedestrians and animals seems cool, but it's hard to imagine that it would justify the infrastructure and energy required.
If I'm wrong about something, its most likely that there's a niche application where these features are valuable, and can justify the inefficient solar deployment. I'll be interested to see if such a scenario emerges, and, if so, how large it is. In the meantime, I'm will remain skeptical of the viability of this solar roads given current technologies.