Off-grid usage holds promise, as this Fortune article describes:

Stunning Solar-Powered Homes
http://www.forbes.com/2007/08/16/solar-energy-homes-forbe ...

Rather, by opting for a photovoltaic (PV) solar-power system, which relies on roof-top solar panels to convert sunlight directly into electricity, a homeowner can, depending on the time of year and the climate in which he lives, cover his monthly energy bill and in some cases, even sell surplus energy back to the grid.

This is due in large part to state and federal subsidies, which homeowners are increasingly embracing. Residential solar installations have tripled since 2002, according to the Solar Energy Industries Association (SEIA), a trade group for solar energy-related businesses.

Why?

SolarThermal, GeoThermal, and Wind are already very cost competitive.

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Building new coal plants is 120% more expensive than old coal plants, and new nuclear much more than that. Fossil Fuels are already priced out of the market.

That said, this article does make a good point that of one source of liquid hydrocarbon fuel is too expensive, they will merely switch to a harder  to acquire dirtier liquid hydrocarbon fuel.

-David Ahlport

The lesson for policy makers is that economics alone won't help solve the world's greenhouse-gas problems. The markets care about money, not the environment, so the most important alternatives to oil will be the biggest and cheapest, not the greenest.

What's needed, say many clean energy advocates, isn't just high oil prices, but high carbon prices. If fuels were taxed on their carbon content, climate change would be priced into the economics of energy production.

"If you have a carbon tax, or some other concerted carbon policy," says Mike Jackson, an energy analyst with Stanford University's Freeman Spogli Institute for International Studies, "then high oil prices drive industry toward clean technologies."

Otherwise, he says, "you're just going to see more people building these wacky projects that are a disaster for the environment."

But it's worth parsing between those whose high costs are dominated by capital investment vs. those whose high costs are dominated by greater operating costs.  If a commodity can earn $100/unit in the marketplace, then technologies to produce that commodity with $90/unit production costs all look good.  But there is a natural dichotomy about how we get there.  In the long run, I'd like to own the technology that is dominated by capital costs (since volatility on the Opex side might move my profit up and down, but are unlikely to make me unprofitable).  But in the short run, it is much easier to build technologies that are dominated by high operating expense, since they are proportionally easier to raise capital for.  Albertan tar sands are in the latter camp, while traditional renewables and energy efficiency are in the latter.  And when your dominant operating costs are fuel, the high capex/low opex technologies are generally going to be more ecologically desirable.  (I say generally because fuel switching - such as in the electric industry - can lead to lower opex with a poorer environmental signature.  But even in this case, efficiency and renewables trump all in terms of minimizing opex.)

I mention this not to be overly financial, but because the economic conditions that are currently  encouraging fuel-intensive oil extraction technologies like Albertan oil sands are also those which are also encouraging less fossil fuel intensive pathways like biofuels, HEVs, etc.  And when the inevitable economic shakeout happens, the lower opex stuff is going to be much more competitive.

This is a point that the coal industry has long understood - coal is cheaper than gas on an opex basis, but much more expensive on a capex basis.  Thus, even while coal plants may not earn great returns for their investors, they at least earn returns, since they rarely have an economic incentive to shut off.  It is a point that will soon be understood by the ethanol industry, which is building lots of low capex, but comparitively inefficient corn dry mills, and when the margins in that business cyclically come down, I'd much rather be an investor in a more efficient (but also more capital intensive) wet mill.  (e.g., I'd rather be ADM than VeraSun).  

What's interesting in these cycles though is that you always see people flood into both classes of investments (low capex and low opex).  The former get praised for their ability to respond quickly to markets, while the latter ultimately get rewarded for their long term vision.  (Calpine's experience here is instructive: their bankruptcy was driven in no small part by their rush into relatively cheap gas-fired generation stations, which penciled beautifully until the power margins collapsed and the capacity factor on their fleet fell off.  And when you're not running your gas turbine, the investment starts to look rather expensive no matter what you paid for each installed kW.)  From a purely financial perspective, one ought to anticipate similar results in Albertan tar sands.

Anyway, I don't want to appear overly optimistic, or suggest that I can predict the future - but the history of economic cycles suggests that the dirty investments now being made could well prove to be a temporary blip on a path to a cleaner future.

i think your fortune story is referring to on-grid homes.  if they have an electric meter and energy bill, they're on the grid.  pv off grid is a different animal, more $$$ because you're buying battery storage and maybe generator backup in addition to panels to produce electricity.  on grid pv is booming in many places where legislation mandating renewables provides financial incentives to help defray the significant front end costs of pv.  

jon becker