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Is Biodegradable Always Environment-Friendly?

Bioplastic sounds like a welcome eco-alternative to the many plastic products we use daily. But the reality isn't so simple.

Plastic nightmare
Plastic nightmare
Esther Widmann

MUNICH — Everyone these days is talking about plastic waste that, instead of being recycled, is floating in the world's seas. In many hip salad bars, for example, food is now available to take away in bowls made of bioplastics. Problem solved, right?

Wrong. There are bioplastics made from renewable raw materials, for example corn starch, and there are bioplastics that are biodegradable. This isn't the same thing. Not all plastics made from renewable raw materials, sometimes also known as "bio-based plastics," are biodegradable. And conversely, not all biodegradable plastics are made from renewable raw materials. Whether or not a plastic product is biodegradable depend not on the raw material, but on the chemical structure of the plastic.

It might sound rather complicated, but it's somehow logical: Because biodegradable plastic decomposes easily, it's not suitable for uses in which the plastic should be as durable as possible, for example water bottles. Researchers at ETH Zurich recently developed a bioplastic called polyethylene furanoate (PEF) that can be used in the same way as polyethylene terephthalate (PET) for water bottles. PEF consists of renewable raw materials and is, therefore, a step forward. It's recyclable or can be incinerated in a process that's CO2-neutral. But it's not biodegradable.

In fact, even "biodegradable" is not always biodegradable. For many of these plastics, it only works under certain conditions. For instance, the EN 13432 standard in use in Europe defines a material as "compostable" if, after 12 weeks in an industrial composting plant in which a certain temperature, humidity and oxygen levels are guaranteed, 90% of the material disintegrates into parts smaller than two millimeters. In other words, this won't necessarily happen in your home-made compost in your garden.

So far, there's no evidence that bioplastics degrade in seawater.

That's why many waste management companies in Germany — the ones in Munich and Berlin, for example — are not at all enthusiastic about the use of bioplastic bags in organic waste bins. In most cities, organic waste is composted for three months only. This is enough to produce fertile humus, but not enough to decompose these bioplastic bags. For this reason, the companies tediously have to sort the bags out. Instead, they recommend you wrap the organic waste in newspaper. The paper absorbs part of the liquid and is good for compost anyway because it loosens it up.

As for the plastic in the oceans, bioplastics wouldn't make much of a difference. The scientific arm of the German parliament has studied the question and wrote in a report that, so far, there's no evidence that bioplastics degrade in seawater. It must, therefore, be assumed that just like other plastics, they only decompose into ever smaller particles and become microplastics, but don't actually disintegrate. And even if the production of degradable plastics were to increase, it would "hardly contribute to reducing the amount of waste from the oceans," the report reads.

It gets worse. Germany's Federal Environment Agency takes a very critical view even of plastics made from renewable raw materials. Why? Well, because, ironically, the production of bioplastics from corn, potatoes or sugar cane still requires crude oil, for example for the production of fertilizer and as fuel for tractors.

The cultivation itself doesn't tend to be organic either, given the use of pesticides, not to mention the usual — at first invisible — side effects, such as too much nitrate in the groundwater. Genetically modified organisms are also often used. And the fact that corn or potatoes are basically used to process food into plastic is also questionable in itself. Bioplastics from forestry and agricultural waste such as sawdust or orange peels are better. In many cases, however, consumers will hardly be able to tell what the plastic they're using is made of.

The more often you use something, the less important it becomes which material it's made of.

Bioplastics are also more and more often used to make toys. Of course, wooden toys are preferable but some things simply can't be made with wood. And if children put bioplastic toys in their mouths, it certainly is less harmful than if they did it with cheap products made from crude oil, isn't it? Well, not necessarily.

Bioplastic toys are indeed a trend. Lego, for example, no longer wants to use crude oil for its bricks, but sustainable, renewable raw materials instead, which always looks good on the packaging. But even if the raw materials are produced sustainably, in order to make bioplastics resistant and flexible, the same chemical additives are required as for traditional plastics made from crude oil. And nobody has yet researched how dangerous these additives are.

Still, this doesn't mean you can't do anything right. There is, at least, one rule of thumb you can follow: The more often you use something, the less important it becomes which material it's made of. Plastic toys, even from the "wrong" kind of plastic, can be passed on among friends.

When shopping in the supermarket, you shouldn't take a new bag because in almost every household, there's the famous "bag with the bags inside" from which you can help yourself. You probably also have a cotton shopping bag lying somewhere. Always have such a bag folded up with you in case you go shopping spontaneously. Prepared in this way, you won't need a bag from the supermarket, at least not in the foreseeable future. And with a little preparation the previous evening, you won't even need any disposable crockery from the salad bar.

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Green

In Argentina, A Visit To World's Highest Solar Energy Park

With loans and solar panels from China, the massive solar park has been opened a year and is already powering the surrounding areas. Now the Chinese supplier is pushing for an expansion.

960,000 solar panels have been installed at the Cauchari park

Silvia Naishtat

CAUCHARI — Driving across the border with Chile into the northwest Argentine department of Susques, you may spot what looks like a black mass in the distance. Arriving at a 4,000-meter altitude in the municipality of Cauchari, what comes into view instead is an assembly of 960,000 solar panels. It is the world's highest photovoltaic (PV) park, which is also the second biggest solar energy facility in Latin America, after Mexico's Aguascalientes plant.

Spread over 800 hectares in an arid landscape, the Cauchari park has been operating for a year, and has so far turned sunshine into 315 megawatts of electricity, enough to power the local provincial capital of Jujuy through the national grid.


It has also generated some $50 million for the province, which Governor Gerardo Morales has allocated to building 239 schools.

Abundant sunshine, low temperatures

The physicist Martín Albornoz says Cauchari, which means "link to the sun," is exposed to the best solar radiation anywhere. The area has 260 days of sunshine, with no smog and relatively low temperatures, which helps keep the panels in optimal conditions.

Its construction began with a loan of more than $331 million from China's Eximbank, which allowed the purchase of panels made in Shanghai. They arrived in Buenos Aires in 2,500 containers and were later trucked a considerable distance to the site in Cauchari . This was a titanic project that required 1,200 builders and 10-ton cranes, but will save some 780,000 tons of CO2 emissions a year.

It is now run by 60 technicians. Its panels, with a 25-year guarantee, follow the sun's path and are cleaned twice a year. The plant is expected to have a service life of 40 years. Its choice of location was based on power lines traced in the 1990s to export power to Chile, now fed by the park.

Chinese engineers working in an office at the Cauchari park

Xinhua/ZUMA

Chinese want to expand

The plant belongs to the public-sector firm Jemse (Jujuy Energía y Minería), created in 2011 by the province's then governor Eduardo Fellner. Jemse's president, Felipe Albornoz, says that once Chinese credits are repaid in 20 years, Cauchari will earn the province $600 million.

The Argentine Energy ministry must now decide on the park's proposed expansion. The Chinese would pay in $200 million, which will help install 400,000 additional panels and generate enough power for the entire province of Jujuy.

The park's CEO, Guillermo Hoerth, observes that state policies are key to turning Jujuy into a green province. "We must change the production model. The world is rapidly cutting fossil fuel emissions. This is a great opportunity," Hoerth says.

The province's energy chief, Mario Pizarro, says in turn that Susques and three other provincial districts are already self-sufficient with clean energy, and three other districts would soon follow.

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