Look at the incredibly low energy return on investment (EROI) for tar sands oil in this graph from American Scientist - in some conditions a negative return on the energy invested. This is what people are referring to when they say burning natural gas (EROI of close to 20:1) to extract and process tar sands bitumen is like spinning gold into straw. We're not even talking about the greenhouse gas emissions involved. In an increasingly carbon constrained world, one where electric car owners and their societies will favour the cleanest, most efficient conversion of energy sources into electricity, there won't be a place for tar sands.
Energy return on investment (EROI) for different energy sources. Lighter color indicates range of EROI, depending on conditions. Source: Charles A.S. Hall and John W. Day, Jr. in "Revisiting the Limits to Growth After Peak Oil" in American Scientist, May-June, 2009.
Here's what the original article has to say about investing in sources with a lower EROI, like solar:
"There are situations in which investing in energy resources with very low EROI values can make sense — for example, if most of that energy investment is front-loaded and the subsequent operating energy requirements are relatively low. This is the case with solar water heating. It takes a lot of energy to produce copper absorber plates, piping, and other solar collector components — but most of those energy inputs are "upstream" (that is, they have already been expended by the time your solar water heating system is hooked up).
It can make good economic sense for an individual — or a society — to invest in that energy producing system as long as the ongoing energy input is renewable (sunlight, wind, or wave power, for example) and as long as the system can be maintained and operated for a long time."
It also makes good environmental sense, investing in energy systems that don't continually release carbon dioxide into the atmosphere.