Home › Blog › Page 1481

by craigshieldsPosted on Posted in Photovoltaics

Efficiency of Solar PV and Wind PowerA young lady from a faraway land writes: My name is Alexandra, and I am a pupil at Herschel Girls School in Cape Town. I am doing a Science investigation and I am researching wind and solar energy, and which one is more efficient.

What an excellent question. And how lucky you are to go to such a wonderful school (pictured here) in such a beautiful part of the world (see below).

To get to the point:  You probably mean: How much electricity does the device produce as compared to the total energy incident upon it? In that case, (more…)

Tagged with: , , , , , ,

by craigshieldsPosted on Posted in Renewables - Politics

Environmental Bills in the U.S. CongressIf you have a few extra minutes and you don’t mind being sickened, here’s a report from the League of Conservation Voters that consists of only two parts.  It:

• Lists the 35 most important bills related to environmental issues that were introduced onto the U.S. Congress in 2012, and

• Follows with a large table that displays each senator’s and representative’s vote on the matter.

Here’s a particularly disgusting excerpt: (more…)

Tagged with: , ,

by craigshieldsPosted on Posted in Wind Energy

More on High-Altitude WindI’ve been in touch with the fellow in Italy I mentioned earlier on my piece about high-altitude wind power, in which I expressed concern that the levelized cost of energy for his concept (KiteGen) wouldn’t be competitive with other energy resources.  I had forgotten Italy’s passion for small wind (defined as anything under 60 KW) and their willingness to put their Euros where their mouths are.

He writes:  (more…)

Tagged with: , , ,

by craigshieldsPosted on Posted in Wind Energy

Efficiency in Wind TurbinesQuestion:  In physics, the Betz Limit is the top theoretic percentage of kinetic energy that can be extracted from a moving fluid, e.g., wind.  It’s based on the fact that, if you took it all, i.e., stopped the wind dead, the oncoming wind behind it would run into what you had just stopped.  In other words, you don’t want to design a device in which the wind can’t get out of its own way.  So, having said all this, what is the Betz Limit (i.e., this theoretical top percentage)?  (more…)

Tagged with: , , ,

by craigshieldsPosted on Posted in Fossil Fuels

Chevron Will Not Clean Up Ecuador Anytime SoonOver the past few years, I’ve written several articles calling out Chevron’s nauseating behavior in defiling the rain forests and people of Ecuador. In many such posts, I’ve speculated that they’d still be fighting against the world justice system long after I’ve left this planet, if such is required to nullify the multi-billion-dollar judgments that the international courts have imposed–and consistently upheld on appeal.  (Pictured: Ecuador’s President Rafael Correa)  (more…)

Tagged with: , , , , ,

by craigshieldsPosted on Posted in Wind Energy

HAWP - High-Altitude Wind PowerWe don’t hear as much about high-altitude wind as we did a few years ago, though the subject has not completely disappeared.  There is no doubt that the wind resources a thousand feet or so above the Earth’s surface are far superior to those we experience down here, and this can be quite attractive given that the power generated by a moving fluid is proportional to the cube of its velocity.  Doubling the velocity means octupling the power.  But it’s equally clear that harvesting that resource requires specialized/expensive solutions. (more…)

Tagged with: , , , ,

by craigshieldsPosted on Posted in Efficiency

Protecting the Environment with Fleet Management SystemsManaging a fleet of vehicles is already a daunting task with all the requirements necessary to make it work. However, another thing that fleet management companies consider when they outfit their vehicles with the latest technology is how they can actually help lower the carbon footprint of their fleet. The environment is a hot-button topic and everyone is doing their bit to make the world a better place for future generations. This is why, apart from taking care of the driver’s safety and the security of the products or items they are carrying, fleet managers are also looking at fuel efficiency and lesser smoke emission. (more…)

Tagged with: , ,

by craigshieldsPosted on Posted in Renewables - Science

In Most Circles, the Concepts of Clean Energy and Sustainability Are Only Somewhat InterestingA friend in England and I were just talking about how easy it is to miss subtle cues in dealing with others, and thus irritate the people around us.

I noted where I frequently screw up with people in general, which is this:  I wrongly believe folks generally want to discuss the many different dimensions of sustainability.  To me, this is the only thing that matters, but most people don’t see it that way, and lose interest in it quickly.  (more…)

Tagged with: , ,

by craigshieldsPosted on Posted in Renewables - Business

Even When CleanTech Ideas Are Asinine, It’s Sometimes Hard to be BluntI think we’ve all been in the position of being asked for an opinion on something we think is terrible, but hesitating to answer the question truthfully.  Here’s one every man fears: “Does this dress make me look fat?”

In clean energy, I find myself in this position all the time.  Sometimes it’s more awkward than others, like this discussion with a friend:

Friend Asks:  Hi, Craig.  Do you mind providing your opinion on this?

(more…)

Tagged with: , , , ,

by craigshieldsPosted on Posted in Sustainability

Aeroponics, Fabulous Solution for Sustainable Gardening, Could Be Even BetterI ran into a fellow the other day who distributes the “Tower Garden,” a device that uses the principle of aeroponics to enable consumers, restaurateurs, and even grocery stores to grow vegetables quickly, effortlessly, and with far less carbon footprint than traditional methods.  The food that most of us Americans find in our grocery stores was grown with chemical fertilizer and pesticides (that are getting more intense each year as our soils are further depleted and our farming techniques get more aggressive), then trucked an average of 1200 miles to reach us.  Aeroponics replaces all that, making it very easy for anyone to grow vast amounts of organic produce in any sunny spot around his house, or, as shown here, indoors. (more…)

Tagged with: , , , ,