Stories tagged solar energy

Aug
20
2014

Hot spot: This solar farm in the Mojave Desert in California is igniting birds in flight at an alarming rate. Mirrors on the ground reflect super-hot light to the towers to be converted into electricity.
Hot spot: This solar farm in the Mojave Desert in California is igniting birds in flight at an alarming rate. Mirrors on the ground reflect super-hot light to the towers to be converted into electricity.Courtesy Craig Dietrich - Flickr
A huge solar energy farm in the Mojave Desert seems to be having one serious side effect: passing birds in flight are bursting into flames.

What's going on is that 300,000 mirrors on the ground are directing sunlight to huge towers that convert that energy into electricity. Bugs are attracted to the bright light from the mirrors drawing hungry birds to get into the path of the reflected light. And that concentrated light energy is causing the birds to catch fire, sometimes at a rate of one every two minutes. The flaming birds have been noticed since the plant powered up in February and its estimated that the total bird kill this year could top out at 28,000. Researchers estimated that one bird they found dead had been roasted by light beams that were nearly 1,000 degrees F.

Plans for building a second plant are on hold while investigators study the situation at the current site. What do you think? Is the potential of killing many birds a worthwhile cost for increased clean, "green" electricity?

Sun power: A new online mapping system tells you how strong the solar energy is where you live in Minnesota.
Sun power: A new online mapping system tells you how strong the solar energy is where you live in Minnesota.Courtesy Pujanak
Have you wondered how strong the sunshine is that falls near your home for solar power purposes? A team of University of Minnesota graduate students has mapped the solar suitability for locations all across the state. You can search it like a Google map and find out the power of the sunshine where you live.

Sep
20
2011

There’s been some buzz about the relationship between clouds and climate recently, prompting Andrew Revkin of the New York Times’ Dot Earth blog to get his panties in a twist about the “…over-interpretation of a couple of [scientific] papers…”

What gives? I wanted to know too, so I’ve done a bit – ok, a lot – of research and this is what I can tell you: The heart of the discussion is not whether there is a cloud-climate connection (that’s clear), but rather over what that relationship behaves like. There are at least three possible theories, but before we get to those, let’s review some important background concepts.

Gimme the Basics First

Cloud Formation

First, scientists think of air as units of volume called air masses. Each air mass is identified by its temperature and moisture content. Clouds are basically wet air masses that form when rising air masses expand and cool, causing the moisture in the air to condense. You can see the process in action yourself just by exhaling outside on a cool morning. The Center for Multiscale Modeling of Atmospheric Processes has a webpage to answer your other questions about clouds.

Earth’s Energy Budget
Earth's energy budget: Incoming solar energy is either absorbed (orange) or reflected (yellow).  Outgoing energy is radiated (red).  The arrows show the direction and magnitude of movement where thick arrows signify bigger movements.
Earth's energy budget: Incoming solar energy is either absorbed (orange) or reflected (yellow). Outgoing energy is radiated (red). The arrows show the direction and magnitude of movement where thick arrows signify bigger movements.Courtesy NASA

Energy from the Sun is essential for life on Earth. Let’s pretend the Earth has an “energy budget” where solar energy is like money, absorption is like a deposit, reflection is like a transfer, and radiation is like a withdrawal. It’s not a perfect analogy, but it’ll work for starters: Most of the incoming solar energy (money) is absorbed by (deposited into) the ocean and earth surface, but some is absorbed or reflected (transferred) by the atmosphere and clouds. Most of the outgoing energy is radiated (withdrawn) to space from the atmosphere and clouds. The figure to the right illustrates this process.

The Greenhouse Effect

Thanks to the greenhouse effect, our planet is warm enough to live on. The greenhouse effect occurs within the earth’s energy budget when some of the heat radiating (withdrawing… remember our budget analogy from above?) from the ocean and earth surface is reflected (transferred) back to Earth by greenhouse gases in the atmosphere. Greenhouse gases include carbon dioxide, methane, and water vapor. This National Geographic interactive website entertains the concept.

Climate Change

Climate change is occurring largely because humans are adding more greenhouse gases to the atmosphere. More greenhouse gases in the atmosphere means more heat reflected back to earth and warmer temperatures. Warmer temperatures might sound pretty good to your right now (especially if you live in Minnesota and could see your breath this morning as you walked to school or work), but it’s not. Why? Check out NASA’s really great website on the effects of climate change.

Alright, already. What’s the climate-cloud relationship?

From what I can tell, there are three possible theories about the climate-cloud relationship:

  • Clouds actively drive climate change. This is a linear process where clouds reflect too much heat back to Earth, which increases the average global temperature and causes climate change.
  • Clouds passively blunt climate change. This is a cyclical process where more climate change includes increasing average global temperature, which increases average global evaporation, which creates more clouds. More clouds absorb more heat, keeping the average global temperature from rising even faster and lessening climate change. This slows down (note: it does not stop) the rate of climate change.
  • Clouds passively amplify climate change. This is a cyclical process where more climate change includes increasing the average global temperature, which increases average global evaporation, which creates more clouds. More clouds reflect more heat back to Earth, which raises the average global temperatures and worsens climate change. This speeds up the rate of climate change.
  • So which is it? Probably NOT Theory #1. Maybe Theory #2… or maybe it’s Theory #3? Scientists aren’t quite sure yet, so neither am I, but the evidence is stacking against Theory #1 leaving two possible options. The next big question seems to be surrounding the size of the effects of Theory #2 and Theory #3.

    Using what you just read about cloud formation, the earth’s energy budget, greenhouse gases, and climate change (Woah. You just learned a lot!), what do you think? What’s the climate-cloud relationship?

    If you want, you can read more about what scientists are saying about the climate-cloud relationship here:

Why hasn't someone thought of this earlier? The Cincinnati Zoo has installed solar cells over about 800 spaces of its 1,000-car parking lot. The cells will generate enough electricity for about 20 percent of the zoo's power needs. And zoo visitors will return to cooler cars at the end of their visit.

Old-fashioned.  Now out of date?: Solar cells have been around for decades, but with low-efficiency and high manufacturing costs, they have yet to be adapted into our everyday life.  Could new interdisciplinary research by the University of Minnesota make solar power more efficient and affordable?
Old-fashioned. Now out of date?: Solar cells have been around for decades, but with low-efficiency and high manufacturing costs, they have yet to be adapted into our everyday life. Could new interdisciplinary research by the University of Minnesota make solar power more efficient and affordable?Courtesy Andrej Salov

This month University of Minnesota researchers have developed a technique to better capture solar energy using 'quantum dots,' a type of nanoparticle. Researcher William Tisdale said, while

“This work is a necessary but not sufficient step for building very high-efficiency solar cells. It provides a motivation for researchers to work on quantum dots and solar cells based on quantum dots.”

The technology could improve solar energy efficiency from 30 to 66 percent! That's incredible. Furthermore, the improvements may also cut manufacturing costs (and carbon footprints) by removing the need for high temperature processing. The ramifications for nanotechnology and clean energy abound.

Last May, the Bureau of Land Management halted new projects for developing solar energy on public land, out of concern for the impact these might have on the environment. But on July 3, they lifted the ban in response to public concern over rising energy costs.

Apr
03
2008

Here comes the Sun: Scientists announce new breakthroughs in solar energy technology. Photo by S4N7Y from Flickr.com
Here comes the Sun: Scientists announce new breakthroughs in solar energy technology. Photo by S4N7Y from Flickr.com

A company in Massachusetts has developed a process for producing solar power cells using inkjet printers. This could drastically reduce the cost of producing the cells, and increase the number of ways they are used.

Meanwhile in Atlanta, Lonnie Johnson – the man who invented the Super Soaker squirt gun – is working on a solar-powered electrical generator that would be twice as efficient as current models.

Feb
24
2008

Grand Challenges for Engineering in the 21st Century

Want to know what to do with your life. A diverse committee of experts from around the world, at the request of the U.S. National Science Foundation, identified 14 challenges that, if met, would improve how we live.

Here is their list in no particular order. You can learn more about each challenge by clicking on it.

You can vote for which is most important

The committee decided not to rank the challenges. NAE is offering the public an opportunity to vote on which one they think is most important and to provide comments at the Engineering Challenges website

It’s a little early, but Popular Science has issued their list of the top innovations of 2007. Their grand prize winner are nanosolar powersheets, thin flexible films that use nanotechnology to harness solar energy -- and allowing me to tag this post as both "nanotechnology" and "energy." The health innovations section allows me to use the "health" tag, and a new toilet that uses 40% less fresh water allows me to tag this as "water." It's a win-win-win!