10 votes
Accepted

What is the most environmentally-friendly fuel source (e.g. wood, coal, oils, alcohols) for campfire cooking?

Solar thermal Given your limited criteria, solar thermal is in fact the ideal solution. I assume you say that "[solar] heating is so inefficient and the materials for solar panels introduce a can of ...
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  • 360
6 votes

Are trees more productive than wind turbines?

Wind turbines do not turn the ground between them into desert. There is still farming and growth of various plants (even trees) possible. It should not be excluded in those comparisons and ...
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  • 929
5 votes

Are we running out of fuel?

No, we're not running out of fuel. Peak oil never made sense as a problem, and still doesn't. I know that's an inconvenient truth for anyone who'd vested a lot of time and effort into the question of ...
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  • 14.6k
5 votes

Why do some people say that biofuels are renewable energy source if producing biofuels requires nitrogen fertilizers?

They're called renewable because it's possible to do them in a renewable manner. Specifically, the energy in them comes from the sun, in a fairly short time span (i.e. years, rather than millennia or ...
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  • 14.6k
5 votes

Are trees more productive than wind turbines?

A tree farm of that size in a temperate climate would only produce ~1.7GWh/y (net). You are overestimating the productive value of trees by a factor of ~15. A 5MW wind turbine can produce a maximum ...
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  • 2,734
4 votes

Carbon emissions from Ethanol car fuel

There are a ton of different factors to take into consideration here. Lets make sure we keep net GHGe and tailpipe GHGe separate here. Net GHGe Net GHGe: Since 2015, satellite observation as well as ...
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3 votes
Accepted

Is using vegetable oil for electricity generation more efficient than burning whole plants?

Burning more of the plant makes better use of the plant, but requires a much larger setup to be efficient. I suspect that at the scale of us mere mortals, your best bet is to extract and burn the oil,...
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3 votes

Will natural gas or propane generators also run off of methane?

Natural gas is just really, really old biogas The terms "natural gas" and "biogas" both describe a mix of gaseous hydrocarbons primarily composed of methane; the different names depend on the origin. ...
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  • 11.2k
2 votes

How can I separate carbon monoxide from wood gas?

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: ...
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2 votes

How can I separate carbon monoxide from wood gas?

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) ...
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2 votes

Sustainability of waste incineration vs biofuel/biogas?

I can only answer regarding the actual plant. If food wastes need to be trucked all around Sweden when the incinerator is down the road, the picture may be different. Biogasification of food wastes, ...
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  • 2,816
2 votes

Sources for the carbon impact of US corn ethanol?

Source 1: This 2014 research report from a company called Life Cycle Associates contains a nice table and graph showing the volume weighted carbon intensities (g CO2 e/MJ) of U.S. petroleum ...
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  • 13.9k
2 votes

Are trees more productive than wind turbines?

The question assumes a false dichotomy: Trees or turbines. The actual turbine footprint is small, leaving most of the land available for other purposes. 250,000 m2 is roughly 500m x 500m A 100m ...
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1 vote

Does bio jet fuel have a positive energy balance?

I looked into this question a bit today and it seems that the industry is not yet mature enough to determine a narrow, consistent range for the energy in to energy out (EIEO) ratio of biofuels for ...
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  • 11.2k
1 vote

What would be the most sustainable biomass source for (100%) ethanol production?

There isn't one general sustainability metric that can easily be calculated or derived to compare the various options, so this question is rather difficult to answer. The choice of feedstock for ...
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  • 13.9k

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