Solar-angetriebene Entsalzungsanlagen

Vor Kurzem haben wir hier über das ZDF Interview mit Annalena Baerbock „Was nun Frau Baerbock“ berichtet. Dort ging es um die konfusen Antworten von Baerbock zum Thema Fliegen. Immerhin scheint es nun Klarheit zu geben, die Grüne Kanzlerkandidatin möchte bei einem Wahlsieg Inlandsflüge abschaffen. Strengenommen sogar Kurzstreckenflüge und das sind per Definition alle Flüge unter 1.500 Km. Die Baerbock Aussage, dass jeder in den Urlaub fliegen kann wie er möchte, ist offenbar falsch. Wer dann z. B. in Frankfurt oder München als den größten deutschen Hubs vom Ausland her landet, darf entweder per Zug oder Auto weiterreisen, wenn er in eine andere deutsche Stadt möchte. Mal sehen, wie das ankommt. Die Tagesschau berichtete.

Das Portal Reisetopia hat die Emissionen von verschiedenen Flugstrecken analysiert und spätestens, wenn man sich das Ergebnis ansieht wird klar, wieviel Symbolik hinter dem Baerbock Vorschlag steckt, man könnte auch sagen welcher Populismus. Dazu passt ein Kommentar von Axel Bojanowski in der WELT mit dem Titel

Für Arme sind die Klimaschutz-Kosten bedrohlicher als der Klimawandel“.

Er behandelt unter anderen das Thema, dass sozial schwächere besonders hart an den Klimarechnungen zu tragen haben werden, die gerade aufgemacht werden. Es geht aber auch darum, wie andere durchaus berechtigte soziale Fragen komplett aus dem Fokus geraten sind, weil die Klimaaktivisten den besten Zugang zu den Medien haben und die Medien ihrerseits kaum noch über Themen außerhalb des Klimas so berichten wie über das Klima, Corona mal außer vor. Der Artikel befindet sich hinter einer Bezahlschranke.

+++

Nochmal ein Bonbon zum Thema potentieller Grüner Finanzminister Habeck, die ZEIT hatte entsprechende Spekulationen angestellt. In zwei Minuten per Video präsentiert Habeck sein Wissen über Banken und Eigenkapitalausstattungen von Banken oder soll man besser sagen sein Nichtwissen? Kleiner Hinweis, der Mann mit dem Habeck diskutiert ist nicht der Moderator sondern ein Gast aus dem Publikum, der eine Frage stellen durfte. Der ist am Ende konsterniert, weil er sehr unbefriedigte Antworten von Habeck bekommt, ihm im Gegenteil den Sachverhalt erklären muss. Auch der verzweifelte Blick zu Annalena Baerbock („Vielleicht kann Annalena ja was dazu sagen?“) ist bezeichnend. Die aber ist nach eigenen Worten Völkerrechtlerin und hat selber Probleme mit Mathematik. Auf ihrer Webseite wurde stolz von 7 Mitarbeitern gesprochen, 5 in Berlin, 2 in Potsdam, 1 in Frankfurt/oder. Die Zahl wurde mittlerweile in 8 berichtigt.

+++

„Ich habe Angst, dass noch mehr Menschen ertrinken im Mittelmeer wegen der Klimakrise“. Mit dieser Botschaft blockierte ein 53 jähriger Mann in Augsburg in Namen von Extinction Rebellion (XR) eine Kreuzung in Augsburg. Ob der Mann sich schon einmal die Beweggründe von Menschen angesehen hat, die die Flucht über das Mittelmeer antreten? Weiterlesen bei der Augsburger Zeitung.

+++

Mit einem knappen Sieg für die Errichtung von Windkraftanlagen in einem Wald bei Elbersberg in der Nähe von München ging ein Bürgerentscheid aus. Die Legende von der großen Mehrheit der Bevölkerung, die die Windkraft trägt, kann jedenfalls nicht aufrechterhalten werden. Die SZ berichtete.

Vielleicht kannten diejenigen, die für den Ausbau von Windkraft in einem Wald gestimmt haben auch einfach den Artikel (Windkraft im Wald – mehr Schaden als Nutzen) aus Spektrum der Wissenschaft aus dem Jahr 2015 nicht?! An den genannten Fakten hat sich seitdem nichts geändert. Hört auf die Wissenschaft gilt halt nicht immer.

+++

Steven Koonin am 24.4.2021 in der New York Post:

Obama administration scientist says climate ‘emergency’ is based on fallacy

„The Science,” we’re told, is settled. How many times have you heard it? 

Humans have broken the earth’s climate. Temperatures are rising, sea level is surging, ice is disappearing, and heat waves, storms, droughts, floods, and wildfires are an ever-worsening scourge on the world. Greenhouse gas emissions are causing all of this. And unless they’re eliminated promptly by radical changes to society and its energy systems, “The Science” says Earth is doomed. 

Yes, it’s true that the globe is warming, and that humans are exerting a warming influence upon it. But beyond that — to paraphrase the classic movie “The Princess Bride” — “I do not think ‘The Science’ says what you think it says.” 

For example, both research literature and government reports state clearly that heat waves in the US are now no more common than they were in 1900, and that the warmest temperatures in the US have not risen in the past fifty years. When I tell people this, most are incredulous. Some gasp. And some get downright hostile. 

Weiterlesen in der New York Post

+++

University of California – Santa Barbara:

Researchers say cultivated seaweed can soak up excess nutrients plaguing human health and marine life

It’s easy to think that more nutrients—the stuff life needs to grow and thrive—would foster more vibrant ecosystems. Yet nutrient pollution has in fact wrought havoc on marine systems, contributing to harmful algae blooms, worse water quality and oxygen-poor dead zones.

A team of researchers from UC Santa Barbara has proposed a novel strategy for reducing large amounts of nutrients—specifically nitrogen and phosphorous—after they have already been released into the environment. In a study appearing in the journal Marine Policy, the authors contend that seaweed’s incredible ability to draw nutrients from the water could provide an efficient and cost-effective solution. Looking at the U.S. Gulf of Mexico, the team identified over 63,000 square kilometers suitable for seaweed aquaculture.

„A key goal of conservation ecology is to understand and maintain the natural balance of ecosystems, because human activity tends to tip things out of balance,“ said co-author Darcy Bradley, co-director of the Ocean and Fisheries Program at the university’s Environmental Markets Lab. Activities on land, like industrial-scale farming, send lots of nutrients into waterways where they accumulate and flow into the ocean in greater quantities than they naturally would.

Opportunistic algae and microbes take advantage of the glut of nutrients, which fuel massive blooms. This growth can have all kinds of consequences, from producing biotoxins to smothering habitats in virtual monocultures. And while these algae produce oxygen when they’re alive, they die so suddenly and in such volume that their rapid decomposition consumes all the available oxygen in the water, transforming huge swaths of the ocean into so-called „dead zones.“

Cultivated seaweed could draw down available nutrients, the authors claim, limiting the resources for unchecked growth of nuisance algae and microbes. Seaweeds also produce oxygen, which could alleviate the development of hypoxic dead zones.

The authors analyzed data from the U.S. Gulf of Mexico, which they say exemplifies the challenges associated with nutrient pollution. More than 800 watersheds across 32 states deliver nutrients to the Gulf, which has led to a growing low-oxygen dead zone. In 2019, this dead zone stretched just over 18,000 square kilometers, slightly smaller than the area of New Jersey.

Using open-source oceanographic and human-use data, the team identified areas of the gulf suitable for seaweed cultivation. They found roughly 9% of the United States‘ exclusive economic zone in the gulf could support seaweed aquaculture, particularly off the west coast of Florida.

„Cultivating seaweed in less than 1% of the U.S. Gulf of Mexico could potentially reach the country’s pollution reduction goals that, for decades, have been difficult to achieve,“ said lead author Phoebe Racine, a Ph.D. candidate at UCSB’s Bren School of Environmental Science & Management.

„Dealing with nutrient pollution is difficult and expensive,“ Bradley added. The U.S. alone spends more than $27 billion every year on wastewater treatment.

Many regions employ water quality trading programs to manage this issue. In these cap-and-trade systems regulators set a limit on the amount of a pollutant that can be released, and then entities trade credits in a market. Water quality trading programs exist all over the U.S., though they are often small, bespoke and can be ephemeral. That said, they show a lot of promise and, according to Racine, have bipartisan support.

Seaweed aquaculture would fit nicely within these initiatives. „Depending on farming costs and efficiency, seaweed aquaculture could be financed by water quality trading markets for anywhere between $2 and $70 per kilogram of nitrogen removed,“ Racine said, „which is within range of observed credit prices in existing markets.“

What’s more, the researchers note that demand is rising for seaweed in food and industry sectors. Potential products include biofuel, fertilizer and food, depending on the water quality, Racine said. This means that, unlike many remediation strategies, seaweed aquaculture could pay for itself or even generate revenue.

And the time seems ripe for the authors‘ proposal. „The U.S. has traditionally had a lot of barriers to getting aquaculture in the ocean,“ Bradley explained. „But there is mounting political support in the form of drafted bills and a signed executive order that could catalyze the expansion of the U.S. aquaculture industry.“

This study is the first of several to come out of the Seaweed Working Group, an interdisciplinary group of researchers looking to understand and chart the potential of seaweed aquaculture’s benefits to society. They are currently investigating a range of other ecosystem services that seaweed cultivation could provide, such as benefits to surrounding fisheries and carbon capture. The researchers are also working on a paper that explores nitrogen and phosphorous removal at the national level with fine-scale scale analysis modeling nutrient removal from native seaweeds off the coast of Florida.

As long as humans continue adding nutrients to the environment, nature will find ways to use them. By deliberately cultivating seaweeds, we can grow algae that we know are benign, helpful, or even potentially useful, rather than the opportunistic algae that currently draw upon these excess nutrients.

Paper: Phoebe Racine et al, A case for seaweed aquaculture inclusion in U.S. nutrient pollution management, Marine Policy (2021). DOI: 10.1016/j.marpol.2021.104506

+++

Aalto University am 27.4.2021:

Friendly bacteria at center stage: Treating wastewater with less energy and lower emissions

Bacteria that eat nitrogen and organic matter are part of processes that can be developed for treating wastewater with less energy and emissions.

More than half of the energy required for wastewater treatment is used to supply oxygen to the biological reactor. The bacteria need oxygen to function. However, treatment plant operators do not know exactly where in the basin the oxygen is needed. That’s why they have to add more oxygen to the water than the bacteria actually need.

„At the moment, only 20% of the oxygen ends up in the bacteria, while the remaining 80% goes to waste,“ says Anna Mikola, Professor of Practice for Municipal Waste Treatment.

She is leading a project that has just begun to develop a small underwater vessel for taking measurements. Using this tool, researchers will in the future be able to collect information on the amount of oxygen at different locations in the basin. With the measuring instruments currently available, measuring oxygen concentrations would be expensive and would require a large number of instruments.

The development of the underwater robot is still under way. Mikola estimates that it will be ready for testing in a real sewage treatment plant in about a year from now.

Laughing gas is no cause for merriment at a sewage treatment plant

When bacteria remove nitrogen from sewage, the end result should be pure nitrogen gas. But this is not always the case. Sometimes the bacteria’s normal functioning is disturbed and they instead produce nitrous oxide, also known as laughing gas.

„Under certain abnormal conditions, as much as one fifth of the nitrogen can be released into the atmosphere as laughing gas instead of nitrogen,“ says Mikola.

Laughing gas is 300 times more harmful to the Earth than the familiar carbon dioxide.

Mikola reports that, through close cooperation within the international research group, they have gradually started to understand the processes associated with the formation of laughing gas. The addition of excessive amounts of oxygen into the sewage is, indeed, one thing that increases laughing gas emissions. But it is not the only cause.

Researchers have noticed that laughing gas starts to form when one group of bacteria disappears entirely from the sewage due to toxic emissions.

„The bacteria work together, and if one group is lost, laughing gas starts to form.“

Some substance in the sewage entering the treatment plant causes this poisoning. The researchers do not yet know, however, what this substance or combination of substances is. And once the laughing gas starts to form, it is not easy to get the process back on track. The disturbance may continue for three to four months.

The formation of laughing gas also easily goes undetected if no direct measurements are made of nitrous oxide emissions. At the Viikinmäki sewage treatment plant, measurements of laughing gas emissions have been carried out for over a decade already.

„It is a big improvement that we can detect the situation and help the process get back on track within just two to three weeks.“

+++

American Institute of Physics:

Solar-powered desalination unit shows great promise

Despite the vast amount of water on Earth, most of it is nonpotable seawater. Freshwater accounts for only about 2.5% of the total, so much of the world experiences serious water shortages.

In AIP Advances, scientists in China report the development of a highly efficient desalination device powered by solar energy. The device consists of a titanium-containing layer, TiNO, or titanium nitride oxide, capable of absorbing solar energy. The TiNO is deposited on a special type of paper and foam that allows the solar absorber to float on seawater.

When sunlight strikes the titanium layer, it heats rapidly and vaporizes the water. By placing the unit in a transparent container with a sloped quartz roof, the water vapor can be condensed and collected, producing a copious amount of freshwater.

„In the solar energy field, TiNO is a common commercial solar absorbing coating, widely used in solar hot water systems and in photovoltaic units,“ author Chao Chang said. „It has a high solar absorption rate and a low thermal emittance and can effectively convert solar energy into thermal energy.“

The investigators developed a method for depositing a layer of TiNO using a technique known as magnetron sputtering. They used a special type of highly porous paper known as airlaid paper that acts as a wicking material to supply water from the seawater reservoir. Airlaid paper is made from wood fibers and is commonly used in disposable diapers.

The evaporation unit included three parts: the TiNO layer on top, a thermal insulator, and the airlaid paper on the bottom. The insulation layer is polyethylene foam, which has many air-filled pores that trap heat and allow the multi-layer unit to float on top of a reservoir of seawater, minimizing heat loss to the surroundings.

„The porous airlaid paper used as the substrate for the TiNO solar absorber can be reused and recycled more than 30 times,“ said Chang.

Salt precipitation on the TiNO surface could interfere with efficiency, but the investigators found even after a long time, no salt layer formed on the surface. They suggest the porous nature of the paper wicks away any salt that might form on the surface, returning it to the seawater reservoir.

The salinity of ordinary seawater is over 75,000 milligrams of salt per liter. Ordinary drinking water has a salinity of about 200 milligrams per liter. The desalination unit was able to decrease the seawater salinity to less than 2 milligrams per liter.

The combination of low cost, high efficiency, and lack of fouling for this desalination technology shows it has the potential to help solve the world’s freshwater shortage.

Paper: „Porous TiNO solar-driven interfacial evaporator for high-efficiency seawater desalination“ AIP Advances, aip.scitation.org/doi/10.1063/5.0047390

+++

Oxford Brookes University:

Vertical turbines could be the future for wind farms

The now-familiar sight of traditional propeller wind turbines could be replaced in the future with wind farms containing more compact and efficient vertical turbines. New research from Oxford Brookes University has found that the vertical turbine design is far more efficient than traditional turbines in large scale wind farms, and when set in pairs the vertical turbines increase each other’s performance by up to 15%.

A research team from the School of Engineering, Computing and Mathematics (ECM) at Oxford Brookes led by Professor Iakovos Tzanakis conducted an in-depth study using more than 11,500 hours of computer simulation to show that wind farms can perform more efficiently by substituting the traditional propeller type Horizontal Axis Wind Turbines (HAWTs), for compact Vertical Axis Wind Turbines (VAWTs).

Vertical turbines are more efficient than traditional windmill turbines

The research demonstrates for the first time at a realistic scale, the potential of large scale VAWTs to outcompete current HAWT wind farm turbines.

VAWTs spin around an axis vertical to the ground, and they exhibit the opposite behaviour of the well-known propeller design (HAWTs). The research found that VAWTs increase each other’s performance when arranged in grid formations. Positioning wind turbines to maximise outputs is critical to the design of wind farms.

Professor Tzanakis comments „This study evidences that the future of wind farms should be vertical. Vertical axis wind farm turbines can be designed to be much closer together, increasing their efficiency and ultimately lowering the prices of electricity. In the long run, VAWTs can help accelerate the green transition of our energy systems, so that more clean and sustainable energy comes from renewable sources.“

With the UK’s wind energy capacity expected to almost double by 2030, the findings are a stepping stone towards designing more efficient wind farms, understanding large scale wind energy harvesting techniques and ultimately improving the renewable energy technology to more quickly replace fossil fuels as sources of energy.

Cost effective way to meet wind power targets

According to the Global Wind Report 2021, the world needs to be installing wind power three times faster over the next decade, in order to meet net zero targets and avoid the worst impacts of climate change.

Lead author of the report and Bachelor of Engineering graduate Joachim Toftegaard Hansen commented: „Modern wind farms are one of the most efficient ways to generate green energy, however, they have one major flaw: as the wind approaches the front row of turbines, turbulence will be generated downstream. The turbulence is detrimental to the performance of the subsequent rows.

„In other words, the front row will convert about half the kinetic energy of the wind into electricity, whereas for the back row, that number is down to 25-30%. Each turbine costs more than £2 million/MW. As an engineer, it naturally occurred to me that there must be a more cost-effective way.“

The study is the first to comprehensively analyse many aspects of wind turbine performance, with regards to array angle, direction of rotation, turbine spacing, and number of rotors. It is also the first research to investigate whether the performance improvements hold true for three VAWT turbines set in a series.

Dr. Mahak co-author of the article and Senior Lecturer in ECM comments: „The importance of using computational methods in understanding flow physics can’t be underestimated. These types of design and enhancement studies are a fraction of the cost compared to the huge experimental test facilities. This is particularly important at the initial design phase and is extremely useful for the industries trying to achieve maximum design efficiency and power output.“

Paper: Joachim Toftegaard Hansen et al, Numerical modelling and optimization of vertical axis wind turbine pairs: A scale up approach, Renewable Energy (2021). DOI: 10.1016/j.renene.2021.03.001