This paper makes several points about the use of EROI as an indicator of future potential.
First, for comparability it is important to limit comparisons to specific end-use a products, such as gasoline for cars or electricity for the grid, or perhaps hydrogen for fuel cells. Comparisons between different end-uses are very dubious.
Second, it is important to avoid comparing EROIs for fossil fuels stored by geochemical processes in the Earth’s crust vs nuclear power (based on a single element, uranium) vs technologies based on energy directly or indirectly from the sun.
– Robert U. Ayres. Paris, 29 October 2014
Photosynthesis was (and is) the biological process that removed carbon dioxide from the primitive atmosphere and left some of the oxygen in the atmosphere and sequestered CO2 in the earth’s crust. That happened as living organisms, such as diatoms, in the oceans attached carbon dioxide to calcium ions to make shells for themselves and left them as chalk or limestone. This went on for billions of years. When the oxygen level in the atmosphere rose enough, the new ozone layer cut the UV radiation level and made life on land feasible. Plants moved onto the land, and thrived spectacularly during the so-called Carboniferous era, several hundred million years ago when the CO2 level was still quite high by present standards. For over a hundred million years immense accumulations of dead plant biomass were covered by silt from erosion of the land surface. Meanwhile the bodies of dead marine organisms accumulated in some places under the sea. These accumulations were gradually compressed and “cooked” (pyrolized) releasing some of the hydrogen and converting the rest of the mass successively into peat, lignite and coal or (in the case of marine biomass) into bitumen and petroleum.
These accumulations constitute an energy (exergy) resource that currently drives industry and human civilization. We humans are now “un-sequestering” those stored hydrocarbons, combining them with oxygen and putting CO2 back into the atmosphere. Moreover, we are doing this at a rate thousands or even millions of times faster than the original accumulation. This ultra-rapid dissipation of stored exergy in the form of hydrocarbons clearly cannot continue indefinitely, not because we will run out of carbon fuels immediately, but because the atmospheric buildup of CO2 cannot continue much longer without catastrophic climatic consequences (IPCC 2007, 2014).
– For Exernomics. Robert Ayres, Paris. 25 October, 2014
The future of energy will be driven by a combination of price and availability, as it always has. But in an uncertain world one thing is very sure, and that is that this combination is already in rapid transformation, so we are looking at a very different future indeed.
In my recent book (“The Bubble Economy”) , I have argued that the rising price of oil, in particular (because of its unique role as a fuel for mobile applications) together with the declining price of “renewables” creates an opportunity for long-term investors. It is estimated that $2 trillion/year must be invested in renewable energy to meet future energy demand without increasing carbon dioxide emissions. Surprisingly, perhaps, current trends suggest that – contrary to widespread assumptions – such investments can be very profitable.
New York City skyline during power outage