Over at dieoff.org, which is the scariest peak oil site bar none out there, one of the main tenets is that there are "no substitutes" and that renewables contribute only a little and will never contribute more than a little.
In fact, there are many substitutes and they are contributing all over the world and in many industries.
The main area where peak oil is likely to be a problem is transportation.
Do we have a substitute for oil in transportation?
Well yes we do.
Batteries and electrified transit systems.
There are at least five examples of huge electrified systems that I can think of off the top of my head (and several lesser ones). They are: The New York Subway, The Paris Metro, The London Underground , The Tokyo Subway and the Mexico City Underground. Smaller systems include the Dublin Bart, The Glasgow Underground, the Portland Light Rail system, the BART system, The Toronto Underground and Streetcar system and The Calgary C-Train among others. I'm sure others could list several more electrified systems.
Now, that's all well and good, but the electricity to power these systems has to come from somewhere.
Dieoff.org posits that when oil peaks, the lights will go out and then we will end up a few years later back at "olduvai gorge" levels of technology.
In fact, electricity doesn't come from oil in the majority of cases.
There are five main sources worldwide: coal, natural gas, hydro-electric, wind and nuclear. Others such as solar are neglible but fast growing.
The dieoff crowd, however, would try to backpedal the argument "but electricity doesn't use oil in most cases" by saying, "yes, but trucks use oil and the electric grid needs trucks to service the infrastructure. When enough parts wear out and there are no trucks to take the maintenance crews out there, the grid will eventualy fail".
Perhaps if there really were no alternatives to petroleum powered trucks. And right now, they are indeed mostly petroleum (gasoline or diesel) powered.
There are alternatives, however, especially electric trucks.
Although there are not huge volumes of them in operation or in production, they could be produced in large volumes and they certainly do work as an acceptable substitute, especially examples from outfits like Smith Electric Vehicles with 13.5 ton trucks which have a top speed of 65mph and a range of 150 miles. Not too shabby. This is admittedly a new technology and to be fair to dieoff.org it wasn't available at the time the original site was put up, but the technology works for sure.
That said, we have had functional electric trucks for decades. This is not a new and untested technology. In the UK, milk was commonly delivered by electric trucks called "milk floats" from the end of the second world war up until the early 80s. Hardly a novel technology that "does not work". Sure they are based on decades old lead-acid batteries, but it would be a stopgap for transporting parts from a warehouse to any sub-stations on the grid.
As for energy sources for the grid, as said we have coal, natural gas, hydro-electric, wind and nuclear.
Of coal, we have pessimistically another fifty years worth at current rates of consumption and optimistically a hundred years worth. Of natural gas, there have recently been new technology breakthroughs that permit far better utilization of stranded natural gas than was possible before. This is especially the case with shale gas. Natural gas will of course peak, but there is sufficient for at least the next decade if not globally then certainly in North America and other areas with abundant shale formations. Nuclear is a good case in point too and was actually the solution posited by Hubbert himself to the then impending global peak in oil production that he foresaw. Hydro-electric is old technology like lead-acid batteries, and significant resource is already in place and going nowhere when oil peaks. Large scale examples of this are Ontario Hydro and Quebec Hydro as well as the Hoover Dam. China is building massive new hydro resource as we speak. Wind and Solar are interesting and ultimately we must depend on them.
According to dieoff, renewables such as wind will never make much of a difference. I beg to differ.
In a handful of regions, 20% of the electric power is supplied by wind and there's no real reason it couldn't go higher. Right now wind power is on parity with new coal and new nat gas plant on a lifecycle basis which makes it both a technical substitute and a price based substitute.
The big argument against wind is that due to it's intermittency it cannot ever get higher than a 20% penetration.
In fact, this is not the case. Even though it's true that a single geographic windfarm could conceivably be without wind, this is very unlikely to be the case with many geographically dispersed windfarms. The solution to the problem is more grid connections to make sure power can move from where the wind is blowing to the centers of consumption. Recent studies by a scientist named Gregor Czisch have shown that not only can this be done, but the cost is favorable. To quote an article in new scientist magazine "The wind is always blowing somewhere, just as the sun is always shining on half the globe. So with a large enough grid, variations in generation should even out, giving a reliable supply.
The project would cost more than €1.5 trillion, of which €128 billion would go on the lines and equipment for the supergrid itself, and around €1.4 trillion on renewable-generating capacity. To put this in context, the International Energy Agency forecasts that the global power industry will have to invest $13.6 trillion on fossil-fuel-based power generation by 2030."
So sure, we are currently not in the position where we have a continental or even a global super grid capable of taking renewable power from where it's generated to where it's needed, but it roundly debunks the point that it will never be done because it cannot be done.
So the remaining argument is this: What resilience is left in the system to get substitutes online quickly if depletion sets in starting tomorrow?
Well to answer that we need to ask the following question:
Are there any regions of the world that are currently significantly supplied with either nuclear or renewable electricity that also have a reasonable manufacturing base or at least the capability to ramp up quickly.
As it happens there are.
Ontario is mostly hydro and nuclear as is Quebec. Both are heavy manufacturing regions.
France sources most of it's electricity from nuclear. Switzerland sources most of it's electricity from hydro. Germany is in a relatively weaker position, but it is the largest user in the world of both solar and wind and is also a heavy manufacturing superpower. Japan, though it has no fossil fuels of it's own, supplies most of it's electricity from nuclear and tokyo which is a huge manufacturing region, just happens to have a world class metro system. Norway, which has abundant hydro power, also has one of the world's most electrified mass transit systems in the form of a high speed electric rail network, electric streetcars in oslo and an electric metro system. It is also home to the manufacturing facilities of Th!nk Electric, one of the two well known brands of electric cars with reasonable price and performance (the other is Tesla of California).
So it seems that even if depletion comes calling and it is severe, there are at least a handful of regions that have the ability to substitute. I'd wager that in such a scenario, rather than a global collapse back to the stone age and mass dieoff we'd really be facing what would amount to a transfer of manufacturing to these regions that are powered by renewables and nuclear. From there a bright renewable future would eventually emerge. And that's the WORST scenario.