Comments on Next Big Future: Carbon sequestering in cities, Calera cement, and ...

In my blog article , I explain the main impediments for the process Calera is targeting.

The upshot is that forming calcium carbonate from sea water consumes energy and requires basic conditions. Additionally, sequestering 1 T of CO2 would require 360 T of sea water. I cannot see how this process would work with sea water, unless someone is using ultra-efficient, ultra-stable membranes to separate just the calcium and magnesium ions from the water.

Oh, and forget trying to form sodium carbonate from sodium hydroxide, I think this process emits more CO2 than it actually sequesters as Na2CO3.

In another article, I examine GreenFuel's algae (algal) biodiesel process, and conclude that a doubling of yields and/or a doubling of oil prices will make it a justifiable investment.

Analysis: Algae for CO2 capture - II

For those who are interested, my post on the PeakOil forum also led me to analyze Carbon Sciences' concrete-carbonation process as well. The conclusion is that this process at best, can be CO2-neutral but cannot reduce additional CO2 in the atmosphere. (You can only put in as much as you can took out).

"Curing concrete is an exothermic process"<...

2008-08-15T18:28:00.000-07:00

"Curing concrete is an exothermic process"

Yes, but making concrete is an endothermic process; The energy released during curing is some of the energy which was consumed during the manufacture of the cement. I suppose it's not entirely out of the question to make a cement that net absorbs CO2, as weathering reactions typically do that, but I'd really like to see the chemistry being used here, starting from mining raw materials.

Another promising development is mineral sequestra...

2008-07-21T07:44:00.000-07:00

Another promising development is mineral sequestration. Mining and crushing two square miles per year of olivine mineral and then dispersing it over the oceans sequesters pretty much all of that 27 GT/year. This would require a couple percent of the world's oil production; whenever possible, mining and transportation would have to be electrical in order to reduce this oil consumption.

Brian,
Curing concrete is an exothermic process...

2008-07-20T13:44:00.000-07:00

Brian,
Curing concrete is an exothermic process, in that the concrete heats up during the curing. I would assume that concrete has never been used as an energy source, because it would be too difficult to get the waste product out of the boiler. If this inherent chemical energy is sufficient for carbon sequestration, is, the $64,000,000.00 question.

I see. Impose higher taxes on people (uh, I mean b...

2008-07-20T12:04:00.000-07:00

I see. Impose higher taxes on people (uh, I mean businesses), call the taxes Carbon Credits, and give the money to Vinod to make cement. We can have all the cement we want or ever could need. Free! (except for the taxes).

If you start with "carbon is death", then there is a whole world of things that we can do "profitably" with the carbon taxes. What do we need with all of those luxuries, anyway?

Yeah but the claim is that this is a carbon seques...

2008-07-20T09:58:00.000-07:00

Yeah but the claim is that this is a carbon sequestration process. Just producing less carbon dioxide isn't equivalent to having a net use of carbon. I don't see any information on that.

What's the exact chemical process they are using here? They are obviously chemically reducing carbon somehow using magnesium oxide but I'm not sure how.

It's perfectly believable that you can generate less CO2 just not sure how they are going negative. That is, how are they consuming more CO2 than the entire stream of materials including those used to mine and heat the periclase (magnesium oxide)?

That's what is fishy. They are claiming to have a perpetual motion but seem only to have a more efficient engine.

It looks like they're building a demonstration fac...

2008-07-20T07:57:00.000-07:00

It looks like they're building a demonstration facility right now so it's a bit more than just a hypothetical. I'd put it in the category "something to watch for".

Fast company has coverage on the Calera startup The pilot plant should be open by the end of 2010.

Making cement without also making carbon dioxide seems impossible; the basic chemistry of the process releases the gas. But maybe that's not really true, Stanford University scientist Brent Contstantz began thinking last year.

Calera is typical; it is only now preparing to open its first cement plant, on a 200-acre site next door to a gas-fired electric-power utility. Carbon-dioxide-laden exhaust from the power plant will be captured and used to make and dry the cement. Calera plans to be in pilot production by the end of the year, in commercial operation by 2010, and running 100 sites in North America five years later.

wikipedia has information on how others are working on cement that absorbs CO2

Eco-Cement sets and hardens by sequestering CO2 from the atmosphere and is recyclable. The rate of absorption of CO2 varies with the degree of porosity and the amount of MgO. Carbonation occurs quickly at first and more slowly towards completion. A typical Eco-Cement concrete block would be expected to fully carbonate within a year.

Other carbon sequestration startups and methods and background

Calera website. Almost no info

Startups:

* GreatPoint Energy - Their main product is natural gas derived from coal called “bluegas.” Using a chemical catalyst to break down low-grade, and low cost, carbon fuels (tar sands, petroleum coke, etc.) in a process called “catalytic coal methanation” GreatPoint produces pipeline grade methane. The resulting emission stream is nearly all CO2 that GreatPoint recommends can be used in EOR operations. GreatPoint has raised $137 million in three rounds of funding and have announced a pilot plant and R&D program. Investors.
* PowerSpan - Maker of pollutant controls focusing on SOx and NOx, PowerSpan is working on CCS as part of its ECO2 program. ECO2 is an ammonia-based scrubber system that can be added to existing plants ad remove CO2 from flue gases after other pollutants have been scrubbed. PowerSpan has plans for two different pilot programs, one in a partnership with BP Alternative Energy and the other with NRG Energy to prove the commercial scalability. Investors.
* Blue Source: A carbon middleman, Salt Lake City-based Blue Source orchestrates sales of carbon emissions along their gas pipelines between polluters and EOR projects. MIT Technology Review lauded them as financially innovative for coupling CCS with carbon offset sales.
* Skyonic: Skyonic’s “SkyMine process” is a post-combustion system that can be implemented in existing plants. The process reacts flue effluent with sodium hydroxide and pulls CO2 out to form sodium bicarbonate (”better-than-food-grade baking soda”) while also removing heavy metals and acid gases. The process uses energy in the form of waste heat from the plant. Oh, and it’s profitable since emitters can sell off the chemicals byproducts. Skyonic has installed a pilot project on a Luminant (formerly TXU) plant in Texas and are planning on installing a system on a large plant (500 MW) in 2009. Skyonics has raised $4.25 million in two rounds of funding, including investment from TXU.
* Calera: There are few details on this Silicon Valley startup, but the company was founded by Stanford earth sciences professor Brent Constantz and has received funding from Khosla Ventures. Calera looks to make cement, a carbon-intensive undertaking, by taking CO2 out of the atmosphere.
* GreenFuel Technologies: Looking to sell biomass to biofuel makers, GreenFuel plans to take CO2 from flues and use it to grow algae. The “emissions-to-biofuel” process pulls flue gases through an algal farm to grow the algae and released a performance summary in September. They have raised $18 million in Series B led by Polaris and are raising more funding now.

Wait a second. Somehow this process needs to tak...

2008-07-20T07:26:00.000-07:00

Wait a second. Somehow this process needs to take CO2 and break the carbon atom from the two oxygen atoms so that the carbon can be sequestered.

That takes energy and energy requires an energy source. So the real breakthrough here would have to be a new fossil fuel free energy source.

The only other possibility is that after having separated the carbon from the oxygen there is some chemical reaction that uses a carbon source and releases more energy than was require to separate the CO2 and also produces as a side effect some kind of concrete. If that is the case then why not use that directly on fossil fuels?

Sounds very fishy to me.

Followed the various links. Seems it's hypothetic...

2008-07-20T07:17:00.000-07:00

Followed the various links. Seems it's hypothetical at the moment, not a startup underway.