The Power Of Salt For Renewable Energy

According to this Plant Engineering article, potential for a new form of renewable energy lies where salt water and fresh water meet. A team of mechanical engineers at MIT are currently studying this process.

Plant Engineering

Where the river meets the sea, there is the potential to harness a significant amount of renewable energy, according to a team of mechanical engineers at MIT.

The researchers evaluated an emerging method of power generation called pressure retarded osmosis (PRO), in which two streams of different salinity are mixed to produce energy. In principle, a PRO system would take in river water and seawater on either side of a semi-permeable membrane. Through osmosis, water from the less-salty stream would cross the membrane to a pre-pressurized saltier side, creating a flow that can be sent through a turbine to recover power.

The MIT team has now developed a model to evaluate the performance and optimal dimensions of large PRO systems. In general, the researchers found that the larger a system's membrane, the more power can be produced - but only up to a point. Interestingly, 95 percent of a system's maximum power output can be generated using only half or less of the maximum membrane area.

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Just Not Buying It: Purchase of 'Green' Products Slows Down

Today, about a quarter of Americans purchase products based on their green reputation, but this number is declining. This EHS Today article discusses the projected future for consumers and green product consumption. 

EHS Today

A new study finds that “green” certification and brand reputation are playing a larger role for

Further, when making a product selection, about 30 percent of American consumers select products based on a company’s “green” reputation, and 25 percent look to see if the product has been certified by a leading certification organization.

The study also pointed out that while overall interests in green and sustainable issues are gaining ground, many green purchases and behaviors – including selecting green cleaning products and personal care and food products, and energy and water conservation – either are stagnant or in decline.
consumers when choosing products. The Shelton Group, a marketing and communications firm focusing on the sustainability and energy sector, conducted the study and found that 70 percent of consumers want “greener” products and corporate commitments to sustainability.

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