5 ms·

Simplest to use biofuels or hydrogen cells for this sort of thing?

Arbalest 8y ago
Biofuels has always been and should only be considered as a bridging solution. Crops use a bunch of elements that we really don't need for energy transfer but really do need for nutritious food. Phosphorous most significant among them, but plenty of other soil minerals too. Put them in an engine and poof, they're in the air not being good for much.
- jagger27 8y ago
  What about algae-based solutions? I'm curious where the phosphorus and mineral losses come into play. Is it not totally feasible to repurpose the waste products of fuel production back into fertilizers?
  - Arbalest 8y ago
    I have my doubts as to whether it would be cost effective enough to filter out everything but the long chain hydrocarbon molecules (in the case of biodiesel), though ethanol based fuels might be better as they already have to be fairly well purified. Really depends on the individual chemistry I guess. Hopefully the waste isn't too contaminated.
Robotbeat 8y ago
Large waterborne vessels is a good application of hydrogen fuel cells, IMHO. Already large LNG-powered vessels are becoming common, from LNG tankers themselves to LNG-fueled cargo ships and even cruiseliners. Liquefied hydrogen would require similar refrigeration and insulation technology. In fact, here are two LNG-fueled dredging vessels: https://www.vanoord.com/news/2018-van-oord-adds-two-new-lng-vessels-dredging-fleet https://www.vanoord.com/news/2018-van-oord-adds-two-new-lng-... Natural gas can be made by combining electrically-produced hydrogen and CO2 (which CAN be pulled from the atmosphere). But I do think LH2 is more likely to be the main energy source if we go to synthesized fuels.
- evgen 8y ago
  LH2 is an very energy-efficient fuel that is otherwise the worst possible liquid fuel choice you could make. It requires cryogenic cooling, causes embrittlement in materials it comes into contact with, has a very poor volumetric energy density, and has almost no existing infrastructure in place. Even if you lost 50% of your energy in conversion to synthetic methane or propane you would be better off using a synthetic version of a fuel we already know how to handle well.
jillesvangurp 8y ago
A better option could be synthetic fuels produced using solar/wind from air and water. Some gas plants are already being converted to burn Hydrogen Peroxide instead, which can be produced from sea water using wind power. Of course a lot of that stuff might be obsoleted by improvements in batteries and other ways of storing energy. Then there are a few projects that are attempting to convert co2 back into fuels using solar energy. Even producing diesel this way could become feasible. Of course scaling production up is going to take time. A lot of this will ultimately be cost driven, the current fuel burn rate makes operating these vessels enormously expensive. Short term the cheapest option is simply to continue to burn huge amounts of oil. That's not going to get cheaper or better over time and will create incentives for people to become more creative. The same is true in the aviation industry BTW. Fuel is the driving cost factor there. Anyone that can figure out how to slash that cost is going to get a lot of business. Right now solar and wind are enjoying exponential growth and price drops. Using that cheap energy to produce fuel might become feasible very soon and cost effective soon after.

Biofuels has always been and should only be considered as a bridging solution. Crops use a bunch of elements that we really don't need for energy transfer but really do need for nutritious food. Phosphorous most significant among them, but plenty of other soil minerals too. Put them in an engine and poof, they're in the air not being good for much.

jagger27 8y ago
What about algae-based solutions? I'm curious where the phosphorus and mineral losses come into play. Is it not totally feasible to repurpose the waste products of fuel production back into fertilizers?
- Arbalest 8y ago
  I have my doubts as to whether it would be cost effective enough to filter out everything but the long chain hydrocarbon molecules (in the case of biodiesel), though ethanol based fuels might be better as they already have to be fairly well purified. Really depends on the individual chemistry I guess. Hopefully the waste isn't too contaminated.

Robotbeat 8y ago

Large waterborne vessels is a good application of hydrogen fuel cells, IMHO. Already large LNG-powered vessels are becoming common, from LNG tankers themselves to LNG-fueled cargo ships and even cruiseliners. Liquefied hydrogen would require similar refrigeration and insulation technology. In fact, here are two LNG-fueled dredging vessels: https://www.vanoord.com/news/2018-van-oord-adds-two-new-lng-vessels-dredging-fleet https://www.vanoord.com/news/2018-van-oord-adds-two-new-lng-... Natural gas can be made by combining electrically-produced hydrogen and CO2 (which CAN be pulled from the atmosphere). But I do think LH2 is more likely to be the main energy source if we go to synthesized fuels.

evgen 8y ago
LH2 is an very energy-efficient fuel that is otherwise the worst possible liquid fuel choice you could make. It requires cryogenic cooling, causes embrittlement in materials it comes into contact with, has a very poor volumetric energy density, and has almost no existing infrastructure in place. Even if you lost 50% of your energy in conversion to synthetic methane or propane you would be better off using a synthetic version of a fuel we already know how to handle well.

jillesvangurp 8y ago

A better option could be synthetic fuels produced using solar/wind from air and water. Some gas plants are already being converted to burn Hydrogen Peroxide instead, which can be produced from sea water using wind power. Of course a lot of that stuff might be obsoleted by improvements in batteries and other ways of storing energy. Then there are a few projects that are attempting to convert co2 back into fuels using solar energy. Even producing diesel this way could become feasible. Of course scaling production up is going to take time. A lot of this will ultimately be cost driven, the current fuel burn rate makes operating these vessels enormously expensive. Short term the cheapest option is simply to continue to burn huge amounts of oil. That's not going to get cheaper or better over time and will create incentives for people to become more creative. The same is true in the aviation industry BTW. Fuel is the driving cost factor there. Anyone that can figure out how to slash that cost is going to get a lot of business. Right now solar and wind are enjoying exponential growth and price drops. Using that cheap energy to produce fuel might become feasible very soon and cost effective soon after.