Photovoltaics might provide us some relief. Efficiency of the panels themselves though has not really improved that dramatically. It's a good thing sunlight is free.
25 years ago, silicon PV cells were about 11 or 12% efficient. Fast forward to 2020 and they're up to what, 16%? Yes, that's a 50% improvement which is not trivial, but it means that football field array in the documentary could power 15 homes rather than 10. Note that the homes would still need to be connected to the grid if you want heat, lights, food, etc. when the sun's not shining, so you cannot actually shut down any conventional power plants, and running them at 70% efficiency for 8 hours while the sun is shining means they were operating at substantially less than optimal efficiency. [as an aside, anyone guess why Caterpillar would sponsor shows promoting alternative energy? Do a Google search on Solar Turbines, A Caterpillar Company. Guess what power companies use to meet short term energy demands. Gas turbines. So you can optimize your big units and meet short term, peak load fluctuations by having a bunch of small, aero-derivative turbines waiting in the wings that can be started up and shut down fairly easily. Caterpillar have benefited substantially from the shift away from coal and over to intermittent wind and solar.]
Here's a graph showing the efficiency of PV cells. Note that the Thin Film panels are just now getting up to the efficiency of Silicon from 25 years ago. All of them are much cheaper than they were 25 years ago. I believe the "Concentrator" they list is the system that uses mirrors to focus sunlight on a central tower, core, rod or what ever. Ultimately, you use the sunlight to make steam. Steam to make electricity. I'm always somewhat amazed that the theoretical maximum efficiency of this process (Carnot Cycle) is better than for photovoltaic cells. But it requires a lot of moving parts (turbines ... generators...).
For home production of Hydrogen, separating O2 and H2 from water is only half the problem. Using electricity from solar to turn water into O2 and H2 makes sense (I think this is still done by electrolysis, isn't it?). However, a bag full of hydrogen at atmospheric pressure won't get you far, so you're going to need to compress the H2. From an energy perspective, compression is a pig. Lots of energy input and lots of heat generated as a by-product (you put 1 Watt of power in and get +/-1.2 watts of power out as heat). If this were integrated in with a heating system for the house, you might kill 2 birds and improve the overall efficiency, at least in winter, but more pieces = more cost. Still, I can envision a refrigerator sized appliance that could accomplish this, so it should be doable. The net benefit is going to suffer due to the amount of energy consumed to compress the H2, but sunlight is free, and PV cells are becoming cheaper and cheaper.
Some of the fuel cell systems do not use compressed H2. From what I have read, many (most?) fuel cell systems store hydrogen by adsorbing it into (onto) special materials. I've never heard of this option being used in conjunction with an internal combustion engine, but I could be wrong.
I think the single biggest source of hydrogen is still natural gas. Take a methane molecule, remove two H2's from one Carbon, and voila. Done in a large scale and we should be able to do something useful with the carbon too.
I like the hybrid option. To me this seems to make the most sense. As technology improves, the size and efficiency of the systems will improve. For all, or at least the vast majority, of our daily transportation, we could get by on electricity only. But, long weekend comes along and we can drive 400 kilometres to visit the in-laws without taking an 8 hour charging break along the way.
Or, battery packs could be universal. You pull in, they swap the battery pack out for a charged one and you're back on the road in a couple minutes. In this scenario, I figure you would not own the battery pack, you'd be leasing it and all EV's would have compatible, modular battery packs. So Tesla needs to talk to Nissan and GM and Ford and Fiat and ... As long as the battery module fits into the agreed-upon space, and electrical connections are standard, the evolution of battery tech should be fairly easily accommodated. It's a big suitcase that slides into/out of a rack on the car or charging bay. What is inside the suitcase could change over time. If you drive a Suburban pulling a 5,000 kg trailer, you swap out 8 battery packs. A two-seater econo-box takes one. How tough is that?
In BC, I am somewhat amazed. I am pretty sure that the same people demonstrating against the pipelines are also demonstrating against Hydroelectric expansion (Site C). These people are either incredibly stupid, or they are simply anarchists. I suspect many are the former and our education system needs to do a better job. But, as has been pointed out previously, to most of the greens, its a religion and there is no place for actual facts - and science is what got us into this mess in the first place, isn't it? Unfortunately, it seems some of our 'leaders' are also scientifically challenged and do not want to upset the tinfoil hatters by basing decisions on real science.
We live in exciting times. To which I remember reading somewhere (Readers Digest I think) that "May you live in exciting times" is an old Chinese curse.
