Monday, April 30, 2012

Wind Farms Linked to Local Climate Change [Climate]


Wind Farms Linked to Local Climate ChangeWind power, one the oldest and most established forms of alternative energy, might not be as green as we thought. A new study in the US has linked wind farms to local temperature rises of over 0.7°C—enough to change local weather and climate.

The study, published in Nature Climate Change, analyzed temperature changes around large wind farms in Texas, over the period from 2003 to 2011. The researchers found that temperatures around the farms increased by 0.72°C per decade. Writing in the journal, the researchers explain:

"We attribute this warming primarily to wind farms... These changes, if spatially large enough, may have noticeable impacts on local to regional weather and climate."

The heating, it's suggested, is a result of the energy created in the farms, as well as the movement and turbulence generated by turbine rotors. Interestingly, most of the heating occurs at night: it's speculated that, while the earth usually cools after the sun sets in turn bringing down the air temperature, the turbulence that the turbines produce keeps the ground around them warm for longer.

There's no denying that it's a small-scale study, but with the wind power industry big and growing—it produced 238 gigawatts of power last year, up by 21 percent over the previous year—it's a concerning finding. Perhaps most worrying is the fact that future wind farms are set to be bigger than those that have come before, which the researchers say would exacerbate the effects. The scientists plan to widen the scope of their research to assess other farms in the future. [Nature Climate Change]

Image by rasmithuk under Creative Commons license


Sunday, April 1, 2012

DIY Mini Aquaponic Vegetable and Fish Farm [Weekend Project]


DIY Mini Aquaponic Vegetable and Fish FarmAquaponics is the combination of hydroponic gardening and aquaculture (fish farming) in an integrated system that uses fish waste to fertilize the vegetables. Commercial aquaponic systems can be both massive and expensive but a simple backyard system can be put together for around two hundred bucks, less if you're good at scrounging materials.

Instructables user Engineering for Change provides a basic plan that can utilize a variety of pipes and water barrels. To construct the setup in the photo above you'll need 15-20ft of 4-in diameter PVC or ADS pipe, 4 pipe elbows, 4 pipe T connectors, 15-20ft of pex or aquarium tubing, two 50-gallon drums,burlap, scrap wood, and a water and air pump. You'll also need a power drill and a way to cut 1-in holes and 3-in holes. The system should take around two hours to assemble.

Full step-by-step instructions and photos can be found at the source link below, but you're basically drilling many holes in the PVC pipe to allow access to plants, assembling the pipes, adding cheap plastic cups with the bottoms perforated as mini-planters, and assemble the tubing to pump water from one barrel to the four vertical pipes.

You'd buy small trout or tilapia minnows for the 50-gallon barrels and use burlap or peat moss to give plants a surface to latch onto. The water from the fish tanks would pump out the fish waste on the the plants which would benefit from the fish waste fertilizer. Other than the source of electricity for the air/water pumps this system requires little else in the way of inputs. It's probably not practical for everyone, but if you're a gardener with a touch of mad genius you may want to give it a try. I know I will one day.

Build a vertical aquaponic veggie-fish farm | Instructables