This is a guest post by Tom Murphy. Tom is an associate professor of physics at the University of California, San Diego. This post originally appeared on Tom's blog Do the Math.

Breathe, Neo. I’ve been running a marathon lately to cover all the major players that may provide viable alternatives to fossil fuels this century. Even though I have not exhausted all possibilities, or covered each topic exhaustively, I am exhausted. So in this post, I will provide a recap of all the schemes discussed thus far, in matrix form. Then Do the Math will shift its focus to more of the “what next” part of the message.

The primary “mission” of late has been to sort possible future energy resources into boxes labeled “abundant,” “potent” (able to support something like a quarter of our present demand if fully developed), and “niche,” which is a polite way to say puny. In the process, I have clarified in my mind that a significant contributor to my concerns about future energy scarcity is not the simple quantitative scorecard. After all, if it were that easy, we’d be rocking along with a collective consensus about our path forward. Some comments have asked: “If we forget about trying to meet our total demand with one source, could we meet our demand if we add them all up?” Absolutely. In fact, the abundant sources technically need no other complement. So on the abundance score alone, we’re done at solar, for instance. But it’s not that simple, unfortunately. While the quantitative abundance of a resource is key, many other practical concerns enter the fray when trying to anticipate long-term prospects and challenges—usually making up the bulk of the words in prior posts.

For example, it does not much matter that Titan has enormous pools of methane unprotected by any army (that we know of!). The gigantic scale of this resource makes our Earthly fossil fuel allocation a mere speck. But so what? Practical considerations mean we will never grab this energy store. Likewise, some of our terrestrial sources of energy are super-abundant, but just a pain in the butt to access or put to practical use.

In this post, we will summarize the ins and outs of the various prospects. Interpretation will come later. For now, let’s just wrap it all up together.

This is a guest post from Dolores García, an independent researcher based in Brighton, UK.

Recently Jorgen Randers (best known for being one of the co-authors of The Limits to Growth, 1972) asked me to do some modelling work on the World3-Energy model, an updated version of the classic World3 computer model that was used in The Limits to Growth that includes a much larger amount of information about energy. He’d like to use it for the next book that he intends to publish sometime in 2012.

I have published on The Oil Drum before the details of World3-Energy (a dynamic systems model), can be found in:

A New World Model Including Energy and Climate Change Data

And a few answers to reader’s questions can be found here:

New World Model – EROEI issues

Part of the work I’m doing for Jorgen Randers is comparing the results of World3-Energy with IEA’s results. I thought the readers of The Oil Drum would be interested in this.

Below the fold is a proposal written by Chris Clugston relating to developing a better analysis of our non-renewable resources, that he would like our assistance on, in three ways:

1. Finding an organization that would be willing to conduct such a study.
2. Finding organizations that would be willing to fund such a study.
3. Providing feedback on the proposal itself. Should it be modified in any way?

Today, we are featuring two different posts on closely related topics. (1) This post, which relates to a proposal for an analysis which would cover a wide range of minerals, and (2) A report by Rembrandt about a group in Europe which seems to be doing at least some things fairly closely related to what Chris is discussing in his proposal, but probably on a more limited basis.

When I published the results on The Oil Drum of my New World Model, based on World3 (the “Limits to Growth” model) – see here, many of the questions and issues that people had were around EROEI. So I’m writing this article to clarify how the model uses EROEI and the results in some alternative scenarios where EROEI is changed in different ways.

Total energy production and industrial output in the New World Model.