You might recall “Aquarius/Let the Sunshine In” as a catchy little tune from the musical Hair, but that’s not what this entry is about…

It turns out that the energy in sunlight is measured at 250 watts/square meter on average across the US, or 3 KWh/square meter/day. See the NREL map below for details.



Now don’t go out and buy solar panels for your roof just yet, not all of that available energy can be directly translated into electricity, the best solar panels are about 15% efficient which means that one might harvest as much as 0.45 KWh/square meter/day into direct current, during day time. Obviously the amount of energy produced is related to location, hours of direct/indirect sunlight, and weather. So just what are these solar panels (photovoltaic cells) anyway?

Photovoltaic (PV) cells are a semi-conductor that absorbs sunlight (photons) into charge carriers (electrons) then directs them to a conductor. Typically, PV cells are grouped into arrays and placed on sheets or panels which in turn are arrayed to generate a desired amount of electricity. Solar panels have been in use for years in space applications, remote sensors, pocket calculators, and increasingly, for individual home power generation (or co-generation.)

There have been some efforts to get to utility scale with PV technology, but the cost remains prohibitive (~$0.20/KWh competing against $0.03-0.07/KWh for other technologies.) Japan and Germany have the most installed PV technology with the largest single installation rated at 12 MW peak production. To put this in perspective, the average fossil fuel plant in the US is rated at 219 MW peak production and the average nuclear plant in the US at 2,000 MW. As costs for PV continue to drop (as they have around 3% per year over the past few years) coupled with fossil fuel cost increases, the point at which PV becomes profitable at scale will likely happen in the next 15 years.

PV power generation does have some distinct advantages including $0 fuel costs, zero-emission power generation, long equipment lifespan, relatively low maintenance costs, and modular application scaling from micro-installations up to small utility size. The disadvantages to solar are in capacity factor, it’s only light so many hours per day and power demands are 24/7. Relatively speaking, it’s expensive to procure and install. And finally, the resulting power is direct current which further degrades efficiency as the power must be “inverted” to use on the grid or in typical AC household power systems. I’ve heard there may be some breakthrough research happening on the production of PV cells that radically change the costs of PV; if this happens, solar may become mainstream faster than any of us would expect.

Google is certainly making a go of it. Recently, the company announced a plan to install solar panels on its buildings (1.6 MW) and that the resulting power would satisfy up to 30% of the company’s energy requirement. Aside from being good for the planet, I presume someone ran the numbers to see this would at least be a slightly positive return on investment.

Ohio State’s 2006 record: 7-0 Next up: Indiana 10/21
Tune: Stray Cat Strut by Stray Cats
Technorati Tags: Energy | Solar | Photovoltaic | Mike Harding Blog

I wrote about this a few months ago in this entry, but it appears that more progress has been made on this subject of science fiction and fantasy. Scientists at Duke University have managed to hide a copper cylinder. It’s still got a ways to go, it’s only 2 dimensional and still casts a shadow, but it looks as though progess is being made. Read this for details.

Ohio State’s 2006 record: 7-0 Next up: Indiana 10/21
Tune: Bohemian Like You by The Dandy Warhols
Technorati Tags: Invisible Cloak | Stealth | Cloaking | Mike Harding Blog

I got an email this morning from my Brother-In-Law with the link to Electoral-vote.com. Last time I looked at this site was on the eve of the 2004 presidential election. When tracking the election there, I thought there was a good chance for regime change based on this amalgamated polling data. (It really is a cool and informative site.) We all know how that turned out – so call me skeptical this time that these polls are any more accurate than the polls cited in 2004. I’m hopeful that we’ll see change (and I don’t mean the red blue change on the map – I mean real change regardless of party) this year where we can get back to core American values of honesty, integrity, fiscal responsibility, charity, and leadership at home and abroad. The past few years have been very costly in a number of dimensions. I do, however, want to go on record as saying I don’t think Democratic control of the Congress is “the fix” – whomever gains control needs to actually do something (and I don’t mean spend time on who their colleagues would like to sleep with.)

Here are a few more related tidbits just because. Post election, let’s revisit to see what degree of accuracy each represents:

• Approval of Congress at All Time Low (16% approve)
• Ohio can break Republican control
• Debate assertion that Bush has a “secret” plan to end Iraq war
• D.C.’s Political Report and Polls (like Electoral Vote)

Finally, November 7th, whatever your political views, get out and vote. It does make a difference. If you don’t vote, you don’t have any right to complain when things go pear shaped.

Ohio State’s 2006 record: 7-0 Next up: Indiana 10/21
Tune: Bar Room Girls by Gillian Welch
Technorati Tags: Election | Polls | Change | Mike Harding Blog

And I’m not talking about the movie of the same title… Do you know how much a cubic meter of dry air weighs at sea level?

About 1kg (1.0007 kg to be exact.) Air also has pressure, at sea level, about 10,194 kg/square meter (14.5 lbs/square inch.) Air also moves, you might have noticed this phenomena called wind. As the Sun heats the atmosphere air will naturally flow (convection) moving from high pressure areas to low pressure areas – it’s effectively a way for the atmosphere to move heat around.

So we’ve got mass and we’ve got movement which means that there must be a way to harness this excess energy flowing around the planet. For many thousands of years humans have used sails to capture the wind and for hundreds of years, sails anchored in place attached to a shaft converting wind energy to mechanical energy. This energy was used in the past to pump water, saw wood, grind things, etc. Today, high efficiency wind turbines are available and being installed for the purpose of converting wind energy into electricity.

Utility scale wind turbines


Each wind turbine has a shaft connected to a gearbox that drives an electrical generator. The turbines also have brakes, yaw and pitch controls, weather stations, and power transmission capability built into them (see diagram below.) Each turbine in a wind farm transmits its power to a shared substation where the electricity is stepped up to the right voltage to enter a supply line for the electricity grid.



The electric production capacity harvested from wind energy has grown from 2.8 gigawatt hours (GWh) in 1992 to 18.8 GWh in 2006 (trailing twelve month calculation.) Wind farms are now sprouting up in many different states across the US with Texas now leading wind production closely followed by California.

Major advantages to wind generated electricity start with fuel cost, $0. Wind farms are also very low impact on the environment in terms of emitted pollution into the atmosphere, ground, and water. In addition, wind farms literally provide another crop for farmers as the actual land usage tends to be small (less than 200 sq meters) for each turbine allowing agriculture to continue even as wind is harvested. Wind farms are also relatively easy to construct and put into service taking an average of 18 months to complete.

The major disadvantages to wind power are predictability of supply, one cannot guarantee that wind will blow when demand for power exists. Also, aesthetics, many people do not like to see ridges peppered with large steel towers with rotating props. And finally, avian impacts. In some wind installations, the death rate for birds, particularly raptors is elevated due to collisions with the props and towers. Each of these issues has solutions and with each new installation, the objections decrease.

Even taking into account the disadvantages, wind still is a vital part of the renewable energy portfolio and continues to grow at a fast pace.

Ohio State’s 2006 record: 7-0 Next up: Indiana 10/21
Tune: Where it’s at by Beck
Technorati Tags: Energy | Wind | Turbine | Mike Harding Blog

If one can believe the polls, we might see some change as a result of this election. 74% of Americans say Congress is “out of touch.” It’s nice to be in the majority every so often…

Ohio State’s 2006 record: 7-0 Next up: Indiana 10/21
Tune: Lawrence (Head of Lettuce) by Naked & Shameless
Technorati Tags: Congress | Elections | Anti-Incumbent | Mike Harding Blog