Stack Exchange Network

Stack Exchange network consists of 175 Q&A communities including Stack Overflow, the largest, most trusted online community for developers to learn, share their knowledge, and build their careers.

Visit Stack Exchange
15

Simply put biochar is charcoal made by burning biomass and using it to enhance soil and/or capture CO2. The idea is that the charcoal improves the soil's carbon content and functions as a carbon sink for atmospheric CO2. This would be especially useful for depleted soils. The idea of using charcoil to enhance to soil was derived from the Terra Preta found in ...


8

A ton of coal is roughly 240 kWh of electricity. At present, the coal mine north of me charges the local power company something like $1.90 /ton for coal. So the fuel cost is about a cent per kWh. The wholesale price of electricty is about $.03/kWh. The retail price of that power is $.15/kWh. A $24/ton carbon tax would be 10 cents/kWH. That's enough to ...


8

Ecologists refer to this as 'gross productivity' and define it to be dry weight plant matter per area per year. In temperate climates this is likely to be a grass. Switchgrass has been proposed as a bio feedstock, both because it's highly productive, and the plant pulls most of the necessary trace nutrients back into the roots in fall. Poplar and willow ...


5

One way to look at it to compare like with like is to look at the photosynthetic efficiency since carbon is fixed through photosynthesis. By this measure, sugar cane comes on top, converting about 8% of the incomming sunlight energy into stored carbon energy.


4

The short answer is no, not anywhere close to 200ppm and not appreciably lower than ambient conditions. The modern standard for buildings is a full air change every three hours. This means your houseplants would need to achieve your target level on a full house volume of air every three hours. There is no practical arrangement which will achieve this. ...


4

I think you're up against two three at least four separate problems: The scale: rallying 1M people to plant 16k trees apiece over 20 years is no way a "guerrilla" operation; it's a mass movement. It won't be covert: everyone will know about it, and landowners will probably object more or less strenuously. The distribution: if you have anywhere near 1M ...


4

No, and no. Current production costs of biochar are in the hundreds of dollars per tonne. (It shouldn't be that expensive.) By comparison the mining costs for coal at my neighbor, the coal mine, run about 90 cents (canadian) per ton. It will be a while. General paper about biochar with nominal $200/ton wholesale price from a unit that processes 2000 ...


4

As soon as you plant a forest it starts to decay. Initially the growth rate is faster than the decay rate. At some point it reaches equilibrium. To maximize carbon capture you want to plant something that adds biomass quickly. To keep it sequestered, you need long life. Your best strategy is to plant fast growth trees for your area, coupled with shade ...


3

Air travel sustainability problems, even if you limit the category to climate change impacts, are not limited to greenhouse gas emissions. Atmospheric transport of emissions is difficult and, since jet fuel isn't a pure (or even homogeneous) substance, it's not always possible to know what is coming out of the aircraft in what concentrations. Biofuels were ...


3

An unexploited forest has many benefits but carbon sequestration is not an exclusive driver. You can invert the logic and argue that any wood used for making durable things is an additional carbon storage opportunity. To capture carbon, plant growth must be sustained while preventing burning or decay in the open. Once the growth/decay equilibrium is ...


3

Gail Taylor's team at the University of Southampton is looking at almost exactly this question. Their primary focus is on fastest-growing bioenery crops, but the answer is going to be pretty much the same as for your question, as carbon sequestration is roughly the same as bioenergy accumulation. They are concetrating on three species currently: poplar, ...


3

Since grass and switchgrass already been mentioned; Hemp and Paulownia tree may be the alternative answer. They are among the fastest growing plants. For hemp, one unit land area of hemp(s) can produces as much cellulose as 4 unit land area of trees.


2

I'm going to focus on the potential for enhanced oil recovery, permanent sequestration and government support for active projects. Carbon capture technology is a whole other beast. Projects Currently Underway sequestration.mit.edu has a great database of active and cancelled CCS projects in the US. I was surprised how many projects are on the burner now. ...


2

I found this article regarding lawns. It suggests that lawns could be regarded as carbon sinks only if they are not (frequently) mowered, and do not use pesticedes. Also: An acre of established temperate forest can hold from 2,000 lbs. up to 6,000 or more lbs. of carbon per year, depending on the age of the trees and other conditions. Mature ...


2

For all-electric passenger jets, battery capacity must increase to hold four times more energy per unit mass Currently available batteries have poor specific energy compared to jet fuel: Jet fuel: 11.9 kWh/kg Diesel: 13.3 Gasoline: 12.9 Lithium metal batteries (e.g. LiPo): ...


2

Another option that could be explored (and indeed is, to a limited extent) is the increased use of airships. Being neutrally buoyant, they need much less energy per trip, and the propulsion could be provided by solar power (they also have a large area on top of the envelope to hold solar cells). The downside, of course, is the need for large amounts of ...


2

If you are going to use wood gas to run a generator, don't bother removing the CO. Burn it. https://www.youtube.com/watch?v=X3KipK49v7g is a vid on making a woodgas powered truck. That said: Consider getting a manual transfer switch, and a gas or diesel powered generator. While the power may have been off for 10 days this time, I found in our (shorter) ...


2

This master's thesis by Dahiru Rufai Ahmed at the university of Oulu provides a comprehensive background into the removal of CO2 from wood gas. On pages 36-37 it mentions the water-gas shift (WGS) reaction as a method of adjusting the hydrogen/carbon monoxide mixture or removing CO entirely to get pure H2. "The WGS reaction is an exothermic reaction (∆Hr ...


1

The answer is: Unknown. So try it. We need more data points. One of the mechanisms that would have a net benefit even if biochar doesn't work at all: Process ag waste for energy. Suppose you have a unit the size of a standard 53 foot seacan that you can load bales of straw/cornstocks, wood chips into, and then this is turned into a mix of energy, ...


1

Trees follow the logistics curve for growth. More complicated, the number of trees descreases as they get larger. E.g. after a forest fire, lodgepole pine sprout at about 10 per square foot. In 10 years there is about 1 per square yard. At 30 years it's one per 6 foot square. The fastest mass growth rate is when a given area is mostly at the 1" diameter ...


Only top voted, non community-wiki answers of a minimum length are eligible