This required rate of return is of course denominated in fiat currency eg $, €, £ - issued as a claim over debt.

The required rate of return by an investor in gold or in energy, on the other hand is zero per cent. These investors are not aiming to make a profit: they are aiming to avoid a loss.

There are currently tens of billions invested in energy markets - typically through futures markets and structured finance, but occasionally directly "peer to peer" (eg Shell's transaction with ETF Securities) - at zero percent in dollar terms.

Such funds could easily be deployed as direct investment in future energy production. Renewable energy, and energy savings, then have an advantage over all other forms, since it is possible to monetise energy which is essentially free.

"The future is already here -- it's just not very evenly distributed" William Gibson