They setup solar and wind farms at the time to offset the energy required and to my knowledge there's never been any environmental issues with the brine discharge.
They also recycle water here by treating wastewater and pumping it into the ground water where it blends in with water in the aquifer - some of which is later extracted. They pump into the aquifer rather than directly into the water supply because people had an "ick factor" about drinking treated wastewater regardless of how filtered it is.
Most people's views on desalination are based on outdated costs. Current costs for reverse osmosis are $0.0007 per litre, and each litre takes just 3 Wh of electricity, which is less energy than it would take to boil the water for a cup of tea... if you were making your cup of tea in a shot glass.
In the thread on what a future with fusion would like, where energy costs approached zero, one of the questions posed was, "What would the future look like if energy costs trended towards nothing?"
I think desalination is one of those things that would become plausible at scale, and that also would be a transformative change in human's relationship with the planet.
Energy is getting cheaper very rapidly. I think there's room for an order of magnitude drop in prices per kwh on a relatively short timeline of maybe 1 or 2 decades. Basically to well below 1 cent per kwh. Maybe two eventually: ~0.01-0.1 cent per kwh. That won't happen overnight of course but there are multiple paths to potentially very substantial cost reductions still. At those price levels, energy is close to free and we'll indeed be able to address a lot of things with it.
It's not just water. Most of the big issues we have on this planet have an energy component to them either directly or indirectly. Energy is a bottleneck. Making energy very cheap enables a lot of positive changes.
Take agriculture (and by extension, world hunger) for example. Agriculture requires water, light, warmth, and fertilizers. We can make clean water with desalination. We make fertilizers via energy intensive processes to produce ammonia (usually by first creating hydrogen). Light and heat we can create in green houses with yet more energy. With enough energy, you can grow bananas in Iceland and go skiing in Dubai. Neither of those things is science fiction btw. They really grow bananas in Iceland using geothermal energy and there is an indoor skiing hall in Dubai.
There's also synthetic fuel production, transport, heavy industry, etc. All bottle-necked on energy. With synthetic fuels, there's a cross over point where that gets cheaper than drilling up oil and shipping it half way around the globe to refine it into fuel (all of these things take a lot of energy). It's not that far off.
In fact, since the end product (desalinated water) is easy to store in great amounts, desalination could be one of the processes that would run when surplus energy is available.
With current prices for renewable generation and storage, an overcapacity in production of 300-500% seems to be the optimal from a system cost perspective: In such a world, lots of surplus energy would be available at low cost for a flexible consumer such as this.
> In such a world, lots of surplus energy would be available at low cost for a flexible consumer such as this.
That totally happens already. When you look at a windy, sunny day in Germany in the summer, you'll find that renewables are producing so much energy that prices drop into the negative and somebody is being paid to burn it.
I think we'll see this more often with more renewables and it might be a chance to have, not yet highly optimized, processes running that need a lot of energy. Desalination is one of those, so is production of hydrogen.
“ A 2018 United Nations study says there are now almost 16,000 desalination plants operating in 177 countries, producing a volume of freshwater equivalent to almost half the average flow over the Niagara Falls. However, the toxic brine which is usually dumped in the sea, risks contaminating food chains if left untreated.”
Given the volume of the oceans compared to average flow of Niagara Falls, the orders of magnitude difference in volumes makes this an insignificant problem, no?
If you dump the wastewater brine offshore a mile or so there may be local concentrations that are polluting but how does this become problematic in the vast open oceans?
Given the greater currents in the Pacific and Indian oceans I’m sure this could be managed well by dumping out to sea, although I’m sure many plants just pump out near the local beach.
I think that while the ocean is vast, that doesn’t mean it mixes quickly.
If you dump brine, it will stay together as a cloudy salty area for quite a while. No matter where you dump the brine, it will be affecting some ecosystem somewhere.
There are videos of divers moving through different strata of salinities in the ocean, sometimes in caves. It looks as though they’re breaching the water-air layer, but they’re actually coming through a water-water layer of different salt densities.
So dumping in the ocean will still change a local area of ocean to toxic levels of brine concentration.
I’m 100% for desalination, but it’s a tough issue to solve.
As I understand from my old classes the main issue with the brine is just that it's a more concentrated sea water. Can't you just dissolve it again? You have to pump more water sure, is the required amount just that big to get brine to a harmless concentration?
Yep, the brine is only concentrated by a factor of about three, so it very rapidly dilutes near to the discharge point.
Environmental "concerns" like brine discharge are frequently raised without any reference to the quantitative scale of the impact. Desal plant brine discharge is a highly localised environmental impact.
There's an odd bias we have where highly localised environmental impacts are readily accepted when they're visually obvious (a car park eradicates all life in the area of the car park), but when it comes to the open ocean, a localised impact is not accepted.
Would have a hard time believing any announcements from that guy after the Segway: "Steve Jobs, Apple's co-founder, predicted that in future cities would be designed around the device [Segway]"
Surely that isn’t right. My little 12x10 foot greenhouse uses 5kwh on a cold night to stay above freezing using a little 800 watt space heater that cycles off and on.
Edit: nope I checked and that is a correct number.
Wow, I really thought desalination would be something like factor 10 more energy expensive.
Regarding your greenhouse: Does it sit flat on the earth? I'm thinking about lowering the greenhouse at my parents house somewhat into the earth, I think 2 feet would already help with keeping it warmer...
No it just sits on the ground. I went down a whole rabbit hole recently about how to keep a greenhouse warm in winter. Being below ground would probably help somewhat.
I did the math and used a kill a watt to monitor the usage and just doing a little space heater hooked to an Inkbird temperature controller was plenty economical for me. I have cheap electricity where I live though. About 30 cents a night when it is freezing outside. So absolutely worst case scenario would be $9 a month which I can handle for how much joy it gives me to be able to grow plants in the winter.
My thinking is that if you dump brine into the sea you're a putting in a liquid that marine life can swim though and be harmed by. Another problem is just how to get the byproducts of desalination away from the plant.
If the salt were made into a boat, it could be sailed away (moved more easily than on land) and could mix with seawater over a much wider area. Even if it sinks after a short period, it would still be in a rock-like form that would mix with seawater over a longer time period. Similar to how the salt in the sea came from rocks originally?
They setup solar and wind farms at the time to offset the energy required and to my knowledge there's never been any environmental issues with the brine discharge.
They also recycle water here by treating wastewater and pumping it into the ground water where it blends in with water in the aquifer - some of which is later extracted. They pump into the aquifer rather than directly into the water supply because people had an "ick factor" about drinking treated wastewater regardless of how filtered it is.