RECYCLING STUDY

Landfill nation: What makes consumers less likely to recycle?

Consumers are more likely to toss a dented can or a chopped-up piece of paper into the trash than to recycle it, according to a new study in research that examines recycling habits.

Although products that have changed shape are still recyclable, the likelihood of a consumer recycling a product or throwing it in the trash can be determined by the extent to which it has been distorted during the consumption process.

The study looked at how consumers treat products that have gone through physical changes during and after consumption that "distort" the product (but do not affect its recyclability). For example, a piece of paper might get crumpled up or torn into smaller pieces, or an aluminum can might get crushed or dented. And when that happens, people are less likely to recycle.

In one study, participants were asked to evaluate a pair of scissors. Some were asked to cut either one or two sheets of paper into smaller pieces, while other consumers were given a sheet of paper and asked to evaluate the scissors without cutting the paper.

Everyone was then asked to dispose of the paper on the way out (next to the exit were two identical bins, one for trash and one for recycling). Consumers recycled the whole sheet of paper more often than the smaller pieces (regardless of the total amount of paper).

Around the world, more than two billion tons of trash is generated each year, with the United States throwing away more than any other country. Understanding why consumers throw recyclable products into the garbage instead of recycling them could help companies and public policy makers find novel ways to encourage consumers to step up their recycling efforts.

These findings point to important outcomes of the post-consumption process that have been largely ignored and provide initial insight into the psychological processes influencing recycling behavior, the study concluded.

TO CLEAN OR NOT TO CLEAN...THAT IS THE QUESTION

Cleaning Solar Panels Often Not Worth the Cost

Don't hire someone to wash your dirty solar panels. That's the conclusion of a study recently conducted.

Researchers found panels that hadn't been cleaned, or rained on, for 145 days during a summer drought in California, lost only 7.4 percent of their efficiency. 

Overall, for a typical residential solar system of 5 kilowatts, washing panels halfway through the summer would translate into a mere $20 gain in electricity production. For larger commercial rooftop systems, the financial losses are bigger but still rarely enough to warrant the cost of washing the panels. On average, panels lost a little less than 0.05 percent of their overall efficiency per day. The study is focused on smaller systems, for very large installations, economies of scale may mean that washing panels is worth it.

Dust on PV panels does make a difference but it's not a big enough factor in Wisconsin to warrant cleaning. Researchers believe that this is the largest study quantifying losses of electricity output due to dirty solar panels conducted so far. Typically, particulate matter from air pollution, agriculture, construction and traffic accumulates on the panels, as well as pollen and sea salt.

Researchers also found that solar panels mounted at an angle of less than five degrees caused bigger losses in efficiency. That's because dirt slips off panels that are installed at a steeper angle. Here in SE Wisconsin we angle solar arrays at slightly less than 45 degrees.

But solar panels heavily soiled with bird droppings should be cleaned. That's because the droppings essentially block all sunlight and will not be washed away when it rains. Engineers also found that photovoltaic panels were dirty enough to warrant cleaning due to very specific and localized circumstances. For example, being directly next to and downwind of a highway, factory or agricultural field may generate enough dirt to warrant cleaning.

Next steps in the study would be looking more closely at the sites that did warrant cleaning and determine what caused the panels to get so dirty. Finally, researchers could add collectors at specific sites to determine what kind of dirt accumulates on the solar panels; whether special materials could keep dirt from accumulating; and whether special, less costly washing systems would do a better job at removing dirt from the panels.