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9

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 worms sustainability", you refer to PhotoVoltaic panels, and not solar concentrators (mirrors and lens), which are silly cheap and sustainable. A large ...


6

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 calculations. A wind turbine with 3MW power, rotor diameter of 100 meters rotating at a hub hight of 100 meters may allow growing plants with a height up to 25 meters (~ ...


5

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 of ~44GWh a year. Your assumed figure of 1GWh is only 2.3% of its rated capacity. No-one would bother financing/building a turbine on that site if they could ...


4

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 peak oil; but it doesn't help anyone to continue with a pretense that it's a problem. That's because we can't afford to burn the fossil fuel reserves we do ...


4

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, and burn the rest of the plant for heating. Problem is you will likely get enough waste heat from the power plant to provide most of the rest of your ...


3

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, market wastes and similar stuff is certainly better, for the reason you describe in your last paragraph: Kitchen wastes are typically 70-80% moisture. ...


3

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 gasoline and corn ethanol over time based on the historical crude oil and ethanol plant resource mixes and future projections. From: Boland. S. and Unnasch. S. (...


3

US airlines alone use about 18 billion gallons/430 million barrels of fuel a year (worldwide? Link is not clear on exactly what they include), which at 6.9 lbs/gallon is about 124 billion pounds or 56Tg. From your link above, "Salicornia produced an average annual crop of 1.7 kilograms per square meter of total biomass and 0.2 kilogram per square meter of ...


2

This is an incomplete answer, as I can't go into the ecological value of a patch of desert. But as always you need to take a look at the inputs and outputs of a process. First, you need a lot of infrastructure in the desert: Tanks and greenhouses for the plants pipes to pump the seawaer there roads and other infrastructure processing equipment for the ...


2

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. According to the U.S. Energy Information Administration: Natural gas occurs deep beneath the earth's surface. Natural gas consists mainly of methane, a ...


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 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 diameter rotor needs to be more than 500m away from the next one, probably around twice that. This article: https://www.sciencedaily.com/releases/2011/01/...


1

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 aviation. "Are Advanced Biofuels for Airplanes Ready for Takeoff?" (Scientific American, May 2017) This excellent SA piece discusses the industry forces behind ...


1

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 producing any type of product from biomass has an influence on: GHG emissions (the method and amount of energy required for harvesting and processing) use of ...


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