This is putting the cart in front of the horse. Is like thinking about this awesome car concept that can run as fast as an F1 car but also work the land as a tractor and carry heavy loads like a truck. You design it and build the body yet the main underlying problem is you have no fkin engine for it to meet all these demands.
As jazzc said problem is not space but the fact technology is not there yet. If you'd have the technology then you could do whatever you want with it. Put it in a roadway, on a field, in the desert, wherever.
Another aspect with the video is the fact it presents certain advantages as being awesome while completely ignoring the problems. How much will a panel cost and how much money will it produce. That aside, what will be the damage rate, lifespan, infrastructure cost, technical requirements for the underlying pavement and buildings? Even if you'd have a great panel that is cost effective and has high lifespan, the other costs would make the entire project an economic aberration.
Another aspect is that expecting from the private sector to come up with alternative energy tech is just being naive. NASA invests millions into this type of technology because they need it. Yet, they're nowhere near close to having discovered a breakthrough that would make solar panels a good investment.
Another thing is, the solar technology with highest efficiency and lifespan is not based on panels but on heat. Parabolic dishes powering Stirling engines, solar power plants that produce steam that turns turbines, etc. A panel is great for a satellite in space, to put on your house or to recharge your iphone. Far from great for nation-wide or global energy production.
Another thing is, even with super high efficiency panels, you obtain good energy production only in areas with sunlight spanning over most of the year. There are areas that work well for solar (e.g. deserts, Equator region), areas that work well for wind, ones that work well for geothermal and ones that work well for sea.
Thinking that you can invent one single green and safe technology for energy production across the globe is a bit being naive given the level we are at currently. Besides nuclear, nothing can be used everywhere and nuclear is not safe or green even if it works flawlessly (produces horrible waste).
Another aspect is inefficiency and waste of energy. But from an economic perspective that's meaningless because when it will be a major economic problem it will be dealt with. But even so what i mean is - you have massive waste of energy and is not at the level of final user/household but at city and industry level - street lights being on 24/7 regardless if anybody is there to need them, inefficient power consumers in the industry, etc. Civilians account for a tiny fraction of the power consumptions, even though there's a huge media campaign making it look otherwise (e.g. Earth's day, turn off your lights/water/whatever in the home to save energy). A steel plant consumes the equivalent energy of a small city. If you add up all household consumers I doubt you will even account for 10% of global energy consumption.
Another aspect is the mafia commonly known as "the government" - they have their own interests and in many smaller countries corporations have enough reach to dictate legislation through corrupt politicians, thus producing a fake demand for certain technologies (e.g. green energy) generally at the expense of those country's citizens.
There are enough technologies to produce green energy. What we lack is leaders who work with each other for the well being of everybody. Generally what we have is wars, fight for power, corruption, X trying to screw Y to gain some advantage or more power. In this process we as a civilization end up functioning in a way that is far from the optimal level that current technology would allow. But is not a problem just with the leaders because they're placed there and allowed to function by the masses that essentially find it ok to function as cattle in a farm with no wish for greatness.
At the end of the day, a civilization reaps exactly what it seeds. If you seed hate, war, pain, ego, corruption, lies, then don't expect to reap something good.