Could We Dredge the Netherlands Without Fossil Fuels? | Hacker News Reader

Could We Dredge the Netherlands Without Fossil Fuels?

lowtechmagazine.com

54 pointshelb13 comments

The horse powered dredge boats are interesting to compare to today's technology. They don't specifically give dimensions, but considering the space it takes one horse to walk, plus some extra space for dredging and boat functions, it is easy to place 750 watts of solar panels in the same space.

You could make solar powered dredge boats which would be functionally equivalent to the horse boats. You'd only dredge when the sun shines, but you also wouldn't have to stop and change horses every hour and maintain dozens of horses per boat.

You would get a good 4-5 months of dredging 4 hours/day, and you'd get to take December and January off! (or operate a fraction of an hour a day).

You'd need about 20 thousand of the boats to keep up with current demand, so that might be a traffic congestion problem during the summer months.

Interesting ideas! Might want to take into account the customarily rainy weather in the Netherlands. The graph here shows roughly 50% of the time conditions are rainy, so your estimates might be somewhat over-estimating. Luckily there are other opportunities for green energy in the Netherlands, like wind power for example.

It's an interesting article, but a better title would be "How the Netherlands were dredged without fossil fuels".

The article makes note of how wind power was used pre-electricification at several points (windmills, specialized sailboats) so they're not oblivious to that obvious answer.

Since it can be periodic and during daytime surely electric dredgers with umbilicals could do some of the heavy pumping based off a wind and solar powered grid. Would be interesting to see the dredging power requirements vs local renewable resources.

Anywhere you'd really need to dredge, you can run power lines and dredge on tethered power electrically.

I think it's interesting from the standpoint of understanding human capacity and thinking differently about how we allocate our time and effort though. I'm not sure that typing 24/7 is the ideal way to build a life.

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

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.

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?

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.

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-...

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.

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.

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.

Wind power and a long extension cord....

Just put a big battery on a boat. If it gets good utilization and can charge inexpensively, it should pay for itself in fuel savings.

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