I'm going to try to lay out a kind of import replacement based on the kind of cities we have in Canada - specifically, Calgary. I like Calgary a lot, but it has something of a sprawl problem. This makes utilities stretch to the limit and makes stuff like garbage collection and snow removal really expensive. So, instead of starting at the city level, I thought it would be really useful to go right down to the very basic building block of Calgary: suburban subdivisions.
Developers in Calgary develop land in bite-sized chunks, each chunk designed from the ground up with a type of house layout in mind. The houses are mainly cookie-cutter mirror images of one another and very little imagination goes into their layout. What a subdivision does have in abundance is surface area. Lots and lots of surface area. Specifically, the place is covered in a wide spaghetti-mess of roads that are altogether too wide for their purposes. Also, people have pretty big houses. All of this is a disadvantage from the standpoint of cheap utility services. So I propose to handle all utilities from the subdivision level. In essence, you'd be replacing the import of utility services from the central processing centres that are currently in operation. This would make the subdivision a wholly independent entity (and, as you'll see, it will actually create exports from the subdivision). I was mentioning before that I wanted to create a business plan that would create development in phases, but would make money in each phase. Here is phase number one.
The number one import of every part of every city would have to be petrol. I propose the replacement of petrol entirely through the use of algae biodiesel. Every house in the subdivision would be able to maintain an algae bioreactor. It could be built just the same as a solar hot water heater, and each unit would take up only a percentage of total roof space. Since this kind of technology is possible for hobbyists to construct (see here and here) it's mature enough for the big time. Those worrying about freezing pipes in the -30 degree winters we know and love in Calgary need to read about Solaroof technology - an open source technology that uses low power photovoltaics to power soap bubble generators that produce insulation that is not only seethrough but provides R-40 insulation values for negligible cost. In other words, this technology is mature, cheap, and feasible.
Every house, devoting only four square meters of biorector surface could produce between 18.7 and 56 L of oil per year. In essence, one litre of algae oil is equal to one litre of biofuel (minus trace glycol). Home kits such as the patriotically-named Freedom Fueller indicate that biodiesel production is not only possible for small-scale purposes, it's already mature enough for the consumer market. I cannot imagine a high rate of conversion given the very long duration of the batch-based (more labour-intensive) production method; however, using modern ultrasonic cavitation techniques, not only is constant throughput possible, but the speed of conversion is reduced 90%. Using ultrasonic cavitation and direct plumbing from the subdivision to a local processing plant, continuous production of algae biofuel would be possible.
This does not produce the full amount of gas required by one car for one family per year, but it does make a start at producing it. Plus, this is only on a single unit covering four square metres of bioreactor surface area. The design of bioreactors allows for a lot greater surface area of algae to sunlight, and four square metres of algae surface area would conceivably take up much less than four real square metres of roof. Finally, if the units were modular (as in the above-linked example of the biofence), they could be added over the usable area of the roof, which is an average of anywhere from 120-220 sqm. Using the rough estimate of 600 gallons (2270L) of fuel per car per year, between 40-121sqm of bioreactor would produce the gas for one car per household per year (depending on the yield of the algae strain). Since the bioreactor surface area is far greater than its footprint, this is doable on most average rooves. Heck, it would be doable at the lowest efficiency even if the footprint and bioreactor area were 1:1!
This is simply for a regular 2008-era car. If driving a hybrid, at the current levels of fuel efficiency (assuming 24,000km/year at the Toyota Prius 2010 model in-city fuel efficiency of 51mpg or 21.7km/L), and assuming the lowest yield for algae, only 59sqm of bioreactor area is required (which is equal to much less roof space). Through the use of a production coop, people who chose to save gas and take public transport would be given cash credits from shares in the local biodiesel cooperative. Persons who chose to drive would use their production credits to offset the cost of their own petrol. Persons who were not members of the cooperative would pay full price and profits would go to the fuel cooperative.
Since the design of the roof units could be modular, the cooperative members would only add capacity when they had the free capital to do so. Producers would be able to gain payback on their investment through selling their algae production, so the infrastructure has a real return on investment. Added capacity would not strain a continuous throughput system. The project could be implemented piecemeal without undoing the integrity of the investment: initial production of biodiesel could be mixed with regular petrol in order to have enough supply for the cooperative. The purchase of petrol for mixing, however, adds an overhead to the enterprise that would encourage early addition of production capacity in order to offset costs. In the end, it would likely be best for the cooperative to be established with seed capital, and extend generous buy-in terms and rebates to early adopters in order to avoid ongoing outlays for mixing petrol.
One import replaced, and on a local level. Not only would the product be carbon-neutral (it would not create more carbon dioxide than it removed from the atmosphere), but it would no longer necessitate the entire logistics chain required to get gas to the pump: exploration, drilling, refinement, transportation. Once initial costs were paid back, the system would continue to supply fixed-price fuel for the cooperative so long as there were cars to use it. If there were no cars, the fuel could equally be used in fuel cells for the generation of electricity... but that's a few phases down the road.
The Green Gap
In the Cold War, we feared a Missile Gap was a strategic weakness. Nowadays, we must awaken to the fact that the Green Gap is true strategic weakness: the nations whose economies will thrive in the coming years will not be those with the biggest factories, but those with the most sustainable, efficient, and ecological markets. What we require is a Strategic "Green Reserve" of ecological design to weather the coming changes that both climate and resource scarcity will force on the international economy.