Saturday, December 12, 2009

Could You Run a Smelter with Renewable Energy?

This morning I was doing my normal surfing of the Interweb Tubes and I came across lots of posts about global warming. I started to wonder about renewable energy and how you might use it to power things that are mammoth energy hogs like smelters. I did only the most casual of research and came across these two bits of information.

In Iceland, Rio Tinto, an Australian metals company, is setting up a new aluminum smelting plant at HelguvĂ­k. The smelter will require about 1,000 MW to run. In all of California, since 1998 the government has helped develop only 489 MW of renewable power sources.

In other words, a single aluminum smelter would devour the output of twice as many renewable energy sources as have been installed in the last 10 years under the New Renewables program.

This promotional video for Rio Tinto gives you an idea of the scale of the mining,shipping and smelting operations required to produce aluminum.

Again, I haven't done any more digging than this, but I would bet that those government figures on energy production are goosed to make it look better for them. They're probably aggregate peak power numbers which would mean that you might need three to four times as much to run the smelter reliably. If the wind dies down or it's cloudy or, God forbid, both happen at the same time (fog!) then you'd be sitting around with an idle smelter, paying labor costs on workers who were playing cards.

Green jobs? Not so much.

Nope.

5 comments:

Tim Eisele said...

Yep, tell me about it. Like I tell my extractive metallurgy class, if you think of aluminum, in particular, as being essentially crystallized electricity, you won't be far wrong.

On the other hand, historically the preferred electricity source for aluminum smelting[1] has been hydropower, because it is pretty common for big hydropower projects to have really cheap power. This is because areas with good terrain for hydropower are frequently thinly populated, so there's not enough people locally to use up all that is available. And, what do you know - hydropower is renewable! Of course, it is also widely reviled by environmentalists, almost as bad as nuclear . . .


[1] This is for the Hall electrolytic process to produce metal from aluminum oxide, which specifically needs electricity. The preceeding step (the Bayer process for making pure aluminum oxide from bauxite) is also an energy hog, but it mainly needs heat, which can be provided even more cheaply by isolated natural gas sources that would otherwise be flared off. So what we have is bauxite being mined wherever it might happen to be, which is then shipped to a Bayer plant which is located near an oilfield that supplies lots of natural gas, and then the alumina is shipped to someplace with cheap hydropower to run the Hall plants.

Anonymous said...

Iceland has lots of geothermal power, and it works. There are several national parks with undisturbed pools of hot water (very cool), the preferred method is to drill a hole, pump seawater in, then use the steam to power turbines. The water is then used for tourist resorts (see: Blue Lagoon in Grindavik), then finds its way back to the ocean.

The whole process releases a lot of sulphur stink.. it's the first thing you notice when the airplane lands. And you stop noticing in about ten minutes.

The Icelanders pretty much have unlimited hot water, so outdoor swimming pools that are open year-round are common.

Iceland's renewables aren't comparable to California, unless you're ready to drill in Yosemite.

(criters)

K T Cat said...

Anon, what was interesting in the Iceland link was the claim that at the rate of power generation they were planning, the geothermal was not renewable and the effort was going to tap out the power source. I don't know if it's true or not, but it would probably be worth a look.

Anonymous said...

OK, I either completely misread your post or you did a horrible job expressing the point of the Islandic article.

Your point seemed to be that the required power in Iceland is more than California can handle. What you were trying to say is the required power in Iceland is more than Iceland can handle, never mind California.

K T Cat said...

Anon, actually you hit upon great points all the way around. The only point I was trying to make was about the differences in scale between production and consumption.