Scientific American presents "A Path to Sustainable Energy by 2030" in its November issue. In many ways, it sounds good. But let's think about the details: What would the end result look like? Would it really be sustainable? What would the costs really be? Is there any way we could afford to do what is proposed?

The authors of the article, Mark Jacobson and Mark Delucchi, propose substituting wind, water, and solar (WWS) energy for all other forms of energy by 2030, not for just the US, but for the world. The types of energy sources that would be eliminated include the following:

• Petroelum (including gasoline, diesel, propane, heating oil, etc.)
• Natural gas
• Coal
• Liquid biofuels, such as ethanol
• Wood and other biomass
• Nuclear

All that would remain would be wind, wave power, tidal energy, hydroelectric, geothermal, and solar. Because of the ambitious timeframe, the only techniques that can be used are ones that work at large scale today, or are very close to working.

This is a guest post by Kris De Decker. It was previously published by Low-tech Magazine (a very interesting web magazine) and by Energy Bulletin.

In the 1930s and 1940s, decades after steam engines had made wind power obsolete, Dutch researchers obstinately kept improving the – already very sophisticated – traditional windmill. The results were spectacular, and there is no doubt that today an army of ecogeeks could improve them even further. Would it make sense to revive the industrial windmill and again convert kinetic energy directly into mechanical energy?

The Netherlands had 5 times more windmills in 1850 than it has wind turbines today.

The energy use by the agricultural sector of the economy has been widely discussed and debated in the peak oil community.  The amount of energy used directly at farms is not very large; typical claims for the fuel required to cover a field with a plow or other implement are in the range of one gallon of diesel per acre per pass.  Assuming seeding, harvesting and 3 other passes per year, the total comes to approximately 750 MJ per acre per year.  Nitrogen fertilizer applied at 200 pounds of nitrogen per acre would account for another 4600 MJ per acre¹.  Residues from many crops such as corn can supply over 20 GJ per acre and energy sources such as wood chips and fuel grasses are even more productive.  Farming operations such as dairies have already become net exporters of energy as electricity.  This suggests that even a mechanized farm can be self-sufficient in energy, and "fast crash" doom scenarios involving the collapse of farming are not very likely.

Introduction

I got quite a few interesting e-mails and comments following my previous essay: Biofuel Pretenders. I probably should have mentioned - but I thought it went without saying - that pretenders usually don't think they are pretenders and will therefore protest mightily at the characterization. A number of people who e-mailed assured me that they have really cracked the code to affordable biofuels, and that we would be hearing more about them soon. Another person who wrote to me about algae said that he has been following algae since 1973, and he wrote "In spite of all the hype and non-stop press releases, no one to my knowledge is producing algae on a commercial basis for biofuel production."* Ultimately, I would be happy to be proven wrong on this, but I am just calling it as I see it.

On the other hand, there are some renewable fuel options that have either proven themselves as solid contenders, or have not yet demonstrated fatal flaws that would disqualify them at this point. In this essay I will cover some of those. First, I will cover a pair of first generation biofuels that have proven that they can compete with oil on a cost basis, and then a pair of next generation biofuels that I believe will be competitive.