Slashdot Mirror

We are not rapidly running out of natural gas. We're running out of domestic natural gas, but world natural gas supplies are still quite plentiful.

And, GW emissions aside, how exactly does this helps our energy security and balance of trade situations? There is considerable resistance to LNG terminals also.

Note that the US used to use a significant amount of oil for electricity generation.

A point I've made frequently. (Note that "petroleum" in that table includes refining byproducts such as petroleum coke, so the total of liquids is even less.)

The primary replacements for oil-fired electric plants were nuclear and coal. Recently we've added a lot of gas-fired capacity. We can't add more gas due to supply limits, coal is a pollution and GHG nightmare and nuclear has a 10-year or so planning horizon. The immediate problems require other solutions, and I think the primary ones are going to be wind, efficiency and cogeneration.

When it became expensive, we switched, and now oil is almost unused in this country for power generation (except for backup power). Barring some instant, "ooops, we're out of natural gas -- when the heck did that happen?" moment (which is essentially impossible), there's not going to be an electricity shortage.

Impossible? It happened to New Zealand:

The Maui gas field has been responsible for 25% of New Zealand's electricity generation. When it runs out in a year or two, not only will a multibillion dollar infrastructure become essentially obsolete overnight but New Zealand will have lost 25% of it's electricity generation capacity. If you thought New Zealand's electricity crisis was a concern it is about to get a whole lot worse.

It ain't what you don't know that'll get ya. It those things you know that ain't so.

As for a charcoal fuel cell: it's not about whether or not you can get energy from charcoal in a variety of manners. Feeding it and removing the byproducts, even in a slurry, is the problematic element -- especially when you factor in the cost of making your charcoal consistent enough.

Consistent? It only has to be fine enough (and ball mills are very good at guaranteeing that). The actual feeding is an engineering problem; if engineers can build gravimetric feeders for powdered coal in furnaces which require steady flames, the management of a carbonate bath which needs feeding every half-hour or so can't be all that difficult. And here's what the originators say about ash:

The ash in coal may be chemically extracted and thereby reduced to levels below 0.5% at minimal cost and energy penalty. At this level, its impact on electrolyte life no longer limits cell economy.

In other words, you're going to need to deal with other things before the electrolyte composition changes enough to bother you. More about ash on pages 11-12 of this PDF.

As for charcoal itself, its production is a lossy process. Much of the original energy is contained in the released gasses -- namely CO, H2, and volatile oils/tars -- but they're mixed in with lots of CO2 and H2O, making for less efficient combustion (not to mention the energy loss involved with the process heat).

Quite right! Charcoal produced by flash carbonization yields about half the input energy as gas and heat (a pyrolysis process driven by external heat would convert more to carbon and le

For instance, I postulated 50% efficiency for the fuel cell end of the biomass processing system, but some people are already talking 80%.

I also didn't postulate any liquid-fuel production from the charcoal pathway. Feeding the charcoal to direct-carbon fuel cells yields CO2, which can be fed to algae same as at the biomass-processing stage. The algae produce fats (biodiesel feedstock) and carbohydrates (ethanol feedstock). The only issue is that the products will almost always wind up in the atmosphere rather than sequestered, but that's an issue of priorities. Roughly 2/3 of the carbon winds up as charcoal, so you could potentially triple the liquid fuel output beyond my basic analysis.

Are you saying that ethanol SHOULD be a source of electricity (at what net efficiency from the source material?) or that it shouldn't be?

I propose ethanol as one of several storable products of an energy-production process which begins with non-edible biomass. The other storable products are charcoal and biodiesel (formed by transesterification of algal fatty acids) or light hydrocarbons (formed by thermochemical processing of the same fatty acids). The non-storable (but easily transported) product is electricity, which is the product of equally non-storable (and non-transportable) pyrolysis gas. Please see the section from "Bi-cycles and re-cycles" down to the bubble diagram before the next section header.

I don't think we should use ethanol to make electricity. Too many losses in the pathway, and far more complicated than starting with charcoal.

A nuclear plant has a 10-year planning horizon. The current spurt of license applications just started in 2006, so we're looking at 2016 before the first ones come on-line... assuming they stay on schedule.

Nine years to go before we get perhaps 2-5 GW. We don't have nine years! We are looking at serious problems much sooner.

Wind farms have a planning horizon of around two years; the installed base is growing at about 25%/year, doubling every 3 years. Small-scale fuel-cell generators (250 kW-1 MW) literally fit on flatbed pallets and can be put into operation in days. The problem is going to be coming up with enough fuel to feed them. If we can start making direct-carbon fuel cells running on charcoal, we can make one hell of a lot of fuel from agricultural and forestry wastes, or even tree-trimming wastes in forested cities.

I have literally nothing against nukes, but we can't sit on our hands until they light up.

Also, I don't appreciate this article's attempt to conflagrate electricity generation with fuel production.

Few are worried about us running out of sources of electricity, due to coal, nuclear, and decreasing costs of renewables. It's vehicle fuels that are the issue of concern.

And some of the proposals are just plain stupid, like running vehicles on charcoal that it's embarassing that they even mentioned them in passing.

A long-term solution, in this rapidly-moving technological environment, is 50 years.

You can bet that, absent massive climate change (which my proposal is crafted to help prevent), we won't have plants stop growing and cease generating organic wastes from diverse sources in the next 50 years. Before 50 years are up, I expect that solar PV will be cheaper than wind power and will be the principle source of electric power in most of the world. Wind and wave power look good to cope with night, clouds and other difficulties for PV, and storable energy of some kind (e.g. charcoal for direct-carbon fuel cells) will fill any gaps left over from hydro, nuclear and the rest.

H2 can be acquired one of two ways. First, invest lots of energy into dissassociating h2o where the h2 is merely an energy storage means.

The other is to 'crack' hydrocarbons to get it from.