President Barack Obama and Canadian Prime Minister Stephen Harper this week have been enjoying each other's company. The two have discussed tar sands, the goopy, sandy and dirty source of fossil fuels up there in the Great White North. But how valuable are tar sands and can they be extracted? Hyperion Power Generation, the nuclear-in-a-box people, say yes. The company's sealed reactor can produce 70 megawatts of thermal energy, which can be used for separating the sand from the oil. The reactor, as the company has emphasized, is also not made to power condominium complexes and subdivisions. It is made to provide energy to remote, secure, and somewhat off-grid facilities like military bases and oil fields. The company expects to start delivering its reactors, developed at Los Alamos National Labs, in 2014. Using nuclear -- which does not generate fossil fuels -- could play a important role in improving the greenhouse gas balance with tar sands. Canada's tar sands contain 173 billion barrels of recoverable oil, according to proponents. (Critics put the figure much lower.) The world consumed 84.3 million barrels of oil a day in 2005. At that rate, tar sands could provide enough oil for 2035 days, or 5.58 years. (Oil consumption is expected to rise to 112.5 million barrels a day by 2030.). If you count the tar sands that can't be recovered by existing means, the estimate of the reserves jumps to 1.7 trillion barrels. That's quite a bit. U.S. manufacturers are expected to only produce 250 gallons (gallons, not barrels) of cellulosic ethanol a year by 2011 and that is if everything works as planned. So far, cellulosic ethanol providers are behind schedule. Total ethanol production in 2007 worldwide from all feedstocks comes to 13 billion gallons. Divide by 42 to get barrels and factor in a discount because ethanol doesn't provide the same energy per gallon that gas does and the figures for ethanol begin to look really small. Finding ways to produce tar sands cleanly would still, however, leave the problem that you are burning fossil fuel. True, but liquid fossil fuels still aren't our biggest problem. Transportation, where most liquid fuels go, account for only 26 percent of the total energy budget in the U.S. In other words, it might make more sense to tackle the coal problem first and use clean tar sand extraction as an interim step in what will be a decades-long quest for cleaner car fuels. And Canada is more democracy friendly than Kazakhstan. Just a thought.