MIT Awards Desalination Concept Alternative to Watergrab

Congratulations to Tom Manaugh and Said Majdi for their MIT award for a desalination alternative to the SNWA Watergrab. It's good to see that their concept is very similar to one I have been proposing for years now. Maybe somebody will pay attention now.

In their comments section (on one of the last posts), they suggested that the solar power facility to run the desalination plant be located near Hoover Dam to utilize the Dam's underutilized power lines.

May I suggest a PV solar power facility on Lake Mead. There are two good reasons for doing this: One, the solar facility would shade a part of Lake Mead, thus reducing evaporation losses. And two, no pristine desert valley would have to be bulldozed to accommodate the facility.

The extra costs for building a floating solar facility could be covered by the monies collected from delivering the conserved water.

And some of the power generated could be traded for water from desalination facilities on (or off) the Coast.

SNWA could enter into agreements with Coastal communities whereas; the coastal community would pay for the desalination facility, and SNWA would provide the electrical power to desalinate the ocean water. Consequently; those Coastal communities could deliver water to their customers for far less, and SNWA could trade for more water from the Colorado River for the cost of generating the power to desalinate Coastal water.

Of course, there is one hurdle to cover. The SNWA and the Coastal community would have to pitch in to help desalinate farm runoff waste water for reuse on California farms (who might otherwise lose out in this Colorado River water trade).

...And since the PV solar power facility doesn't have to be solely owned by SNWA, other interested communities (such as Phoenix or Tuscon) could join in to pay for it – and receive a proportional amount of water from the Colorado River.

A Profitable Proto Arcology

Sustainable Photovoltaic Solar Array Operations on Lake Mead

Concept:

Instead of spending billions to get more water, the SNWA should be earning money to get more water. And instead of being the Watergrab super-villain, the SNWA could be the water conservation super-hero.

Here is an opportunity to absorb the energy that would have gone into evaporating water off of Lake Mead – and instead converting it into electricity. Here's an idea that's way better than California's shade balls.

Presently, Southern Nevada gets 300,000 acre feet per year from the Colorado River. And an estimated 900,000 acre feet a year of water evaporate off of Lake Mead! Yes, that's three times what Southern Nevada uses that just drifts away on the winds. If the SNWA could prevent just 1 percent of that evaporation, Southern Nevada could get an extra 9,000 acre feet more per year from the Colorado River – and with return flow credits, that would amount to about 14,000 acre feet per year more. That's about 3 percent more water for Southern Nevada. Not a huge amount of water, but definitely significant.

...What would be huge however; is that the SNWA could do it at no cost (in the long term) to ratepayers. In fact, with solar power arrays, there is money to be earned. Imagine that; more water and lower water bills. Moreover, solar power generation on Lake Mead means that pristine desert valleys don't have to be bulldozed to install solar power. Win – win – win.

Lake Mead covers an area of about 250 square miles. A solar array big enough to cover 1 percent of Lake Mead would be about 2.5 square miles. That's big enough to generate up to 700 MW.

2.5 square miles X 2.788 x 10⁷ square feet/square mile X 10 watts/square foot = 697 MW

And it wouldn't be much more expensive to do. The floating platforms to mount the solar arrays to can be cheaply and sustainably made, with a foam bottom and a solid top for the floor of the platform. Each modular platform array can be tied to its neighbor platform to form a scalable reconfigurable platform network. 

 

And since Lake water will be directly in contact with the platform bottom surfaces, there will be no water/air interface, which means essentially no evaporation under the platforms.

For protection from storms, it would be wise to build wave break platforms surrounding the solar power network. These wave breaks should be capable of eventually generating wave power to help pay for themselves. Moreover, the wave break facilities would shade some more of Lake Mead, thus further reducing evaporative losses.

The wave break platforms could also be made inexpensive, portable, and modular – about the size of a semi trailer. Which means the overall shape and size of the wave brake facility would be determined by spacers between the wave break platforms. Again, scalable and reconfigurable.

Of course; Lake Mead is a National Recreation Area, and the Federal Government might initially be hesitant to build solar facilities on the water. But since every acre of water with solar arrays on it would mean an acre of (usually) Federal land that won't have to be bulldozed for solar arrays, it seems very likely they will come around. Lake Mead is a man-made reservoir. So, floating platforms do not have the environmental impact of land-based solar arrays on natural desert ecosystems. And since this facility's water conservation could result in reduced water transfers from Federal lands (such as the SNWA Watergrab of Central Nevada), solar arrays on lakes could lead to much better environmental results overall.

Phase 1: Photovoltaic Solar Arrays on Lake Mead – Technical Information

The facility would consist of modular platform units that could form a scalable and configurable network of Photovoltaic (PV) solar array platforms, surrounded by modular units of a scalable wave break / wave power generation network. From the air it would look like a distorted checkerboard of platforms and water, inside a circular wall (with an entrance that consists of an opening with an offset wall).

The bottoms of the platforms should be just slightly convex to completely sink into the water at the interface. Since the water will be directly in contact with the platform bottom surface, there will be no water/air interface, and therefore essentially no evaporation under the platform. Consequently, there is a multi-use incentive to make the bottom of the platforms wider than the area where the solar panels are mounted; to reduce evaporation and make the platform more stable. Moreover, since the solar arrays would be installed at an angle near 36 degrees (latitude), some shade from the panels will shade an area larger than the solar array footprint – further reducing evaporative losses.

The platforms would be tied both to the floor of the lake bed and to each other. And because of the encircling wave break, the solar platform network won't have to be as robust.

The wave break barrier could be made modular also. From the top, the wave break modules would appear rectangular. The overall shape of the wave brake facility would be determined by spacers between the wave break platforms. The wave break facility could be perfectly circular, or meander about – like a coastline.

Of course, the wave break barriers would have to be strong enough to absorb the energy of the waves hitting it. Which means the wave break platforms would be more massive than the solar platforms. At water level from the outside, this wave break barrier wall might look imposing (at about 10 feet high) – but it could also serve as a barrier to vandals (and zombie terrorists). To reduce the imposing feel, the wave break facility could be painted white to look more like Lake Mead shoreline from a distance. To give the wave break a recreational function; it could also function as a bicycle, foot, and skate path around the solar facility. At the facility entry, the path could lead radially inward around the opening in the wave break. Inside the wave break, the path could be used as a marina walkway – with slips for boats along the water inside of the path. The path wouldn't drop that 10 feet however. Which means the path would double as a shade for pedestrians on the walkway beneath.

To further the wave break's friendly impression, water slides and dive boards could be installed around the outside edge. Also, charging stations could be located around the perimeter of the wave break facility – available to charge all electric boats with power generated at the facility – for free.

Wave power generation could be achieved at the wave breaks either by having floats that move up and down on guide rods like a bead on a string (or floats on arms) right at the break. When the water hits the break, it would slam the floats much farther up the wall of the break than the height of the wave. And the trough of the wave would drop the float even lower too.

The wave power generation equipment doesn't necessarily have to be installed immediately. But the wave break barriers should be designed so that they can be easily installed later.

And as far as the solar power is concerned; Micro Inverters that function independently for each solar panel would be ideal for the PV solar network. Modularity within modularity means everything is scalable. And bonus; most of this should be off the shelf hardware.

Phase 2: The Next Step - an Island

Once the platform network reaches a certain size, a small crew of people would be needed to stay at the facility to construct, monitor, and maintain things. The crew will need water treatment for both their drinking water and sewage. Drinking water shouldn't be too much of an issue. But sewage treatment on the lake might be. Especially if the goal is to get the sewage to the point that it could be used as fish food. Multiple steps would be necessary. But it shouldn't be impossible, because all we're really trying to do is speed up nature's recycling process. (By the way; it's my opinion that speeding up nature's recycling process is the key to feeding our growing population.)

A conventional sewage treatment facility surrounded by concentric rings of man-made wetlands ought to do most of the work.

A company called Floating Island International has developed what they call BioHaven Floating Islands – which “biomimic natural floating islands to create a “concentrated” wetlands effect.” In other words, they've figured out how to further clean sewage treatment effluent to the point it might end up cleaner than the water in Lake Mead. Think about that; in lined ponds, treated sewage could be turned into microscopic life that could be eaten by larger forms of life, that could eventually feed bait fish, that could be set free near the Island to feed game fish. And the byproduct is Lake Mead water gets cleaned. 

The Island's sewage treatment plant could be located towards the center of the solar platform network – away from sensitive noses. Of course, it would be enclosed. But out there, people wouldn't even see it. They would just appreciate it – in their clean water, productive soil, and fish food.

That “fish food” could be used to entice game fish to hang around the platform network. The edges of the platforms could even be designed to provide fish habitat. Which means the crew could supplement their diets with protein from their own poo-fed fish. This may sound disgusting. But done right; it would be superbly efficient. Eventually, the inhabitants might even want to install a net below the wave break facility with a weave large enough to let small fish in but small enough to hold in fish large enough to catch.

...And that productive soil would be great for greenhouse garden platforms (which would also be useful for shading the Lake). Yes, some of that recycled poo could be used as fertilizer for a garden. Again, this may sound filthy, but it is pretty much identical to what happens in the Environment now – only with a minimized number of steps.

On Lake Mead; one could grow food all year in a greenhouse. It doesn't get that cold in the Winter. Greenhouses could radically limit evaporative losses. And high temperatures in the Summer could be dealt with by pumping cool water from the deep into heat exchangers below the greenhouses.

Water could be pumped up from the deep to cool the floors and air of the floating platforms. This water would pass though heat exchangers – and never come in contact with air, so there would be no evaporation losses. Unless of course, the Islanders choose to release that deep water near the surface to cool the surface water near the Island – thus further reducing evaporation losses on the surface of the lake. (Plus, by being able to regulate the water surface temperatures near the Island, there are more options for controlling algae blooms.)

With a little intelligent valving control, water could be used to both heat and cool living areas. Water could be pumped into the floors, roofs, and walls of the buildings. In the Winter, the water in the roof would be heated by the day sun, and circulated to water storage areas in the walls and floors. And in the Summer, cool water from the deep can be circulated in the floors, walls, and the roofs. This, combined with passive solar heating, would leave little need for heaters or air conditioners – with no evaporation.

In addition, thermal mass aquariums could provide multiple assets. Water could be pumped into aquariums to provide fresh water for bait fish hatcheries. The aquariums could be placed near the passive solar windows to provide thermal mass for living spaces. In the Summer, the aquariums would be in the shade. But as temperatures drop, so does the angle of the sun. In the Winter, the low angle sun would shine directly on the aquariums. Since water has the highest heat capacity of all common solids and liquids, it can take the place of thick earthen walls seen in sustainable earthbound buildings (such as Earthships). And if the water gets too hot for the bait fish, their water can be pumped away to heat the rest of the building – and cool lake water pumped in.

Phase 3: Transformation to a Resort

Once the infrastructure of power, water, sewage, and food production is in place; the Island can be made to feel like an Island Resort.

It is important to consider aesthetics. Many people might see the Solar Island as an eyesore on a National Recreation Area. These people have to be convinced that there is something in it for them. How about an on-water emergency response post? How about a Solar Powered Island Marina? How about techno-fantasy island resort?

People tend to favor places they can go. And with the right image, this Island could become a tourist attraction – kind of like the SNWA's Springs Preserve – only cool.

While it is true that most people would be willing to put up with a huge solar array on Lake Mead – if it meant more water. Why just put up with it? Why not make the place desirable? Why not make it look at little like an actual island? In fact, why not make it a destination – a resort even? But not just any resort. This resort would be for people willing to enjoy what low-impact, sustainable, post-modern livability looks like. Or then again, maybe they'll just want to play volley ball on the beach at the Water Park.

I envision a hidden resort, like some secret island in a James Bond movie. Once you enter through the passage, there is a marina with a boardwalk that leads to a row of buildings that appear to be a combination of Santorini Greece and a fish tank. White! But with lots of passive solar windows – facing South, towards the Marina – which would be on the South side of the Island for that very reason. Businesses located here would be plainly visible to people just coming “ashore.” Through the windows; one could see a restaurant though one window, a convenience store in another, an on-water Ranger Station in another, and a seminar being held in yet another. There may be two or three floors, but each floor is set back, so that every floor can have a patio. And the top roofs are all patios with shades above them (that roll up in the Winter).

A company called Dutch Docklands has already been working on this. They already build homes on the water, and are poised to build islands – complete with sandy beaches and golf courses. Obviously, the golf course in this project would be using artificial turf, but the course would also be covering a section of the Lake to minimize evaporation. So imagine that; a golf course that not only doesn't use water, but actually saves water. 

Fishing could be promoted. And, of course, visitors sewage could be collected for recycling into fish food. But rather than hiding this information, it could be promoted as something to be experienced to inspire hope for the future.

Moreover, the charging stations placed around the perimeter of the Island would remove some of the perceived impediments to electric boats on Lake Mead – thus further cleaning up Lake Mead water.

If the Island population grows, staff facilities (homes) and guest facilities (rooms) could also be installed on the North end of the Island. Another opening in the wave break could be added to accommodate another Marina on the Northwest end of the Island. The passive solar windows facing South on this side of the Island would face a golf course, tennis courts, or other forms of recreational mini-islands – such as a skate park, soccer field, basketball courts, or even another beach. And to the North side of the homes could be another set of greenhouses.

I don't envision this Island to house more than a few dozen residents and guests. Too many people and the sewage treatment facilities would be overwhelmed. But a community the size of small village ought to be able to live somewhat self-sufficiently here – and provide power even if Lake Mead goes dead pool.

From Power Plant to Proto-Arcology

An arcology is Paolo Soleri's concept of cities which embody the fusion of architecture with ecology. As previously mentioned, this Island would not be a city. And this “arcology” concept is not like the closed arcologies mentioned in Paolo Bacigalupi's novel “The Water Knife.” This system is not designed so that its inhabitants can hide away from the rest of the world – like some kind of Elysium. This arcology concept exists help all people, to not harm the environment, to help the local ecosystem, and to sustainably support its inhabitants. Ideally, this could become a good neighbor arcology.

But why?

We've only got one planet, and it's in serious trouble. We are beginning to face the shock and awe of the overwhelming consequences to our Environment from humanity's collective careless actions. We are beginning to realize that we are overdue for the biggest attitude adjustment in human history. We have to learn how to live differently. Many of us have foreseen it. We all need to prepare.

It's time to stop ignoring the externalities. Everything we do needs to be considerate of the fact that we need to be better prepared at being sustainable – so that we can be more sustainable planet-wide – and keep life on Earth healthy. Everything we design needs to be more thoroughly thought out. Every building needs to be a kind of Earthship. Every structure needs to contribute to Life on Earth in as many ways as possible. That means power plants too.

Of course, only one Solar Island means only 9,000 acre feet of water per year gets conserved. It would take as many as 15 Solar Islands to conserve as much water as SNWA pipe dreams of getting from Central Nevada's deserts (during a drought). This Solar Island concept could end up becoming many big projects. But so what! If these Islands are earning money and are a decent place to visit, somebody will want to build more.

I would think that Pahrump (or even Phoenix) would be very interested in a project like this. And if not, there are likely other States – or even private companies who would willingly invest in water and solar power.

And the reason I don't see much resistance is because everyone can benefit. Done right, this could be a way to keep lake elevations up. If participants banked some of the conserved water in the Lake to prepare for droughts, that would mean more water for the Lake. And if there's more water in the lake, there's more shoreline. Everyone wants that. Solar Islands could even be installed to keep Lake Mead levels up high enough for water to run the electric turbines in Hoover Dam.

This development could all happen very fast – much sooner than the expected growth of solar power generation – because the value of the water conserved can be factored into the cost/benefit equation.

I predict a solar-powered arcology rush on lakes on the Colorado River.

The ideas I have published here are all open source. But they're not all my ideas. Check out Seasteading.