9

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 ...


6

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 ...


6

(Draft answer till I get around to find some figures) There's a few ways I see to go about this: Running a Haber Bosch process or similiar with a non-fossile source for energy and H2, or finding other N sources. There's principally two routes, N fixing plants in crop rotation + organic fertilizer and reusing N-rich wastes and wastewater. The key difference ...


6

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

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

The glib answer is to use less energy. The best way of doing that is fixing the fabric of the house - massively increasing insulation, massively decreasing air permeability (and as a result fitting a ventilation system). There is no technical-wizardry answer. The simplest solution is best (but unfortunately outrageously expensive).


4

The favored anode catalyst in a hydrogen fuel cell is platinum(1) or another platinum-group element (e.g. palladium). The catalyst is required in small quantities for an individual fuel cell but of course this demand scales up linearly with the number of fuel cells you want to produce. There is ongoing research into development of alternative anode ...


4

There are three forms of heat transfer: conduction, convection, and radiation. Physically, there is no such thing as "direct electrical heating". The most "direct" way to convert electricity into heat is by running a current through a resistance. The resistance will heat up. This heat can be used to heat water or another carrier for a domestic convection ...


3

The issue is really with sustainability rather than scarcity, and it is also linked to ecological issues. An article in the Berkley University web site gives some background information. In order to maintain their farms through long droughts the farmers want more rivers dammed. Damming a river means flooding an ecologically rich valley. There might be ...


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.


3

THelper did the heavy lifting, but I did some additional digging and found some more info. The official UN closing press release from the climate action summit includes this paragraph: 65 countries and major sub-national economies such as California committed to cut greenhouse gas emissions to net zero by 2050, while 70 countries announced ...


2

"Obviously, it would be most ecologic to leave the coal where it is. But since this does not happen..." Actually, there are some who would like to buy the coal in the ground and leave it there as part of an environmentalist strategy, as explained in the 2014 paper "Buy Coal! A Case for Supply-Side Environmental Policy" by Bård Harstad. ...


2

Almost all of the well-known mitigation tools yield fast benefits. PV's payback is around a year. Onshore wind around 3 months, offshore wind around 9 months. The payback time on each of these three depends on the weather regime where it's located. Biomass when done well less has a payback of less than a year. Most energy efficiency measures take less than ...


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 ...


2

I have trouble finding that list as well. I know that in the past 19 countries already pledged to be carbon neutral by 2050 (see https://www.carbon-neutrality.global/members/). I did also find this UN Climate Action Summit summary page where it says: Five new countries (Austria, Chile, Italy, Japan, Timor-Leste) joined the Carbon Neutrality Coalition ...


2

National Grid supplies the energy for the UK, and also manages the high voltage power transmission system. Each year, they prepare a Future Energy Scenarios report looking at energy needs across the UK and the different alternatives for how those needs can be met. The most recent FES was published in July 2018, and is the source for the figures and quotes ...


2

Why do most car manufacturers prefer electric batteries over hydrogen fuel cells? Because it's cheaper today, easy to pack the batteries under the floor, won't decrease the range much and won't have as fast acceleration. Apart from internal combustion engine cars burning hydrogen (which is very silly!), there is no pure hydrogen car today. All cars that are ...


1

There are a number of issues with hydrogen as an energy source. Firstly, there is a lack of infrastructure for hydrogen. The same can be said for battery charging, but slowly the number of battery charging stations is increasing. Nothing comparable has yet been done for hydrogen. Sourcing hydrogen is another problem. The main ideas for sourcing hydrogen is ...


1

The proton.energy website is very optimistic, maybe a bit too much. I see a number of (potential) problems: The technology uses "hydrocarbon reservoirs" which is a different word for existing oil and gas fields, so that makes the resulting fuel non-renewable. The exact process is not clear to me, but the paper they link to talks about water being ...


1

For a college project, I'm looking to learn about direct electrical and biomass heating as a means of decarbonization of our college campus? Where can I learn about these? Searching for direct electrical heating seems to focus on subsea pipelines. Where can I learn more about them? Direct electrical heating probably refers to electric resistance heating. It'...


1

My question is, what good ways are there store/sink coal? Just sinking large quantities of coal in the oceans is probably be a bad idea, and can have disastrous side effects. So what is known in this direction? You are correct, buying coal and trying to sink it into oceans is a bad idea. Your other idea, to leave coal in the ground as nature created it, ...


1

Note: the plants need nitrogen (for protein synthesis), not necessarily ammonia. Ammonia however is only one source of nitrogen. So I'm using the general term nitrogen below: In practice this has already been done through various methods: no-till: crop leftovers (e.g. stalks and husks from maize) are left on the field. Plowing is minimized or abandoned ...


1

I wanted to comment but since i can't... Are you talking about the energy generation to produce fertilizer ? Then of course you can go non-fossil sources...you can use the sun the wind the water i think that if it is a closed environment you can even use the methane you generate to generate your own power But what you should ask yourself is do you really ...


1

What are the most promising alternatives, in terms of the economics and scalability, to decarbonise steel production? Both for the reduction of iron oxide to iron, and for the iron-to-steel process? I'll answer the first: Direct reduction of iron oxide to iron using hydrogen. There are several features that make this a promising alternative: Firstly, ...


1

Magnesium Oxide based cements are interesting. Here are the downsides when compared to portland cement: They cure extremely fast so transporting pre-mixed cement doesn't work out. Here are all of the upsides when compared to portland cement: They are produced at a lower temperature and release less CO2 during the process than when compared to portland ...


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