Monday, December 19, 2011

Solar power: a fringe electric source no more

Solar power, which was once laughed off as a fringe electricity source for true believers who lived far off the grid, is running rampant through renewable energy discussions.

Used to be, it was horrendously expensive—appropriate for satellites and mountain cabins that needed little more than lighting.

It was only in the 1970s that solar photovolaic cells dropped in price from $100 a watt to $20 a watt.

That still meant that an average Hawai`i home using 500 kilowatt-hours monthly needed more than $80,000 in $20/watt panels ($20,000/kW) alone. Here’s how we came to that: 500kW/30days/5hours/.8efficiency x 1000 (to convert kW to watts) x $20. With installation, costs were approaching the century mark.

By 2005, panels were down to $3-$4 a watt. And in 2009, First Solar announced it could manufacture photovoltaic cells at less than $1 a watt. And if you buy enough of them, the retail price for quality panels today is about $1.25.

You can get the very cheapest panels in bulk even now at $1, and the consulting firm Ernst & Young predicts retail prices generally at $1 within two years. New science is promising even better results.

And the prices are still falling.

This means extreme disruption in the solar business. Deciding when to buy and install is like trying to catch a falling knife. It might be way cheaper next month. Do you buy now or wait...and if the latter for how long?

More than one solar firm has gotten into trouble with a business plan based on building $3/watt panels, when global prices suddenly drop to $1.50.

“Research and development spending is high and this is driving the development of different photovoltaic technologies to lower cost points and higher efficiencies. In the foreseeable future, photovoltaic electricity will become cheaper than grid electricity in an increasing number of markets, creating further demand,” said Ernst & Young in this report.

Not long ago, the biggest chunk of your solar installation cost was the panels. The racks, wiring and inverters (to change panel DC power to grid AC) were the smaller portion. Now, that has been turned upside down. An installer recently told me that with $1.25/Watt panels, he was putting in large systems at about $3/Watt complete. (Home systems, being smaller, have higher per-watt installation costs—maybe their total is around $5/Watt—and it could be more depending on site issues.)

Let’s say you put 2 kilowatts of solar on your roof for $10,000, take state and federal tax credits totaling 65 percent, your cost is $3,500. You’re producing 240 or so kilowatt-hours a month at 5 hours of useful sunshine a day and 80 percent efficiency (including passing clouds, wire losses and such—the dirty truth is that you never achieve useful AC electricity anywhere near your system’s rated capacity.)

At $.35 per kilowatt-hour, you’d pay the utility $84 for that power. That pays back the $3,500 in less than four years. If you produce more than you need, utilities in Hawai`i through various programs will buy the power for roughly $.20 per kilowatt-hour. The payback is longer if you’re selling power rather than displacing your own usage. If you do a good job of shifting load to sunlight hours, you save more money.

It’s still challenging to make a case for going entirely off-grid—since battery prices have not yet taken the same dive that photovoltaic panels have taken. But there may be specialized situations—remote locations, significant daytime loads and so forth—in which the economics work out.

But one of the interesting features of the current situation is that with high oil prices, utilities in many cases are buying solar power from developers at slightly cheaper than their cost of diesel-fired power. The Kaua`i Island Utility Cooperative is setting up a subsidiary to produce its own power, and company CEO David Bissell figures he can make it for significantly less than oil-fired power.

And that, as Ernst & Young suggested above, can do something about Hawai`i’s outsize power bills—even if oil prices remain stable at current levels.

© Jan TenBruggencate 2011

Tuesday, December 13, 2011

Japan tsunami debris field approaches Hawai`i

The Japanese tsunami of March 11, 2011, dumped millions of tons of debris into the ocean, setting it adrift on the surface of the North Pacific—and some will be in Hawai`i soon.

(Image: Computer model of the Japan tsunami debris field on Dec. 13, 2011. Credit: IPRC/SOEST, University of Hawai`i.)

Some of that material should get to the Hawaiian Islands via a fairly direct southern route, while some will sweep across the northern Pacific, down the West Coast, and back to Hawai'i.

The first pulse of that stuff should arrive in the Hawaiian archipelago from the west this winter, and a second major pulse could arrive on the trades from the northeast in three or four years, according to Nikolai Maximenko, oceanographer with the University of Hawai`i's International Pacific Research Center.

The federal government's best guess for when it hits our beaches in the main islands is 2014 to 2015, said Carey Morishige, Pacific Islands Regional Coordinator of NOAA's Marine Debris Program.

And with respect to radioactivity from Japan's nuclear powerplant disasters, the residual radiation might be detectable with extremely sensitive laboratory equipment, but should be no health hazard to anyone in the Hawaiian Islands, said radiochemist Henrieta Dulaiova, of the University of Hawai`i's Department of Geology and Geophysics.

They spoke Dec. 10, 2011, at a Kaua`i conference sponsored by the Surfrider Foundation.

An estimated 20-25 million tons of debris was estimated by the Japanese government to have been created when the tsunami hit Japan's shores. Of that, Maximenko said, a third to a quarter was pulled into the ocean. And a lot of that material likely sank. More has dispersed widely, and it's likely that a large amount of what's left will be trapped in the massive Eastern Pacific gyre known as the Great Garbage Patch.

A 15-year progression of how the debris is likely to move can be found here.

You can see it catching the fringes of the Main Hawaiian Islands, and settling in the Garbage Patch.

Maximenko said the first of the remaining debris could be arriving at the western end of the Hawaiian archipelago any day now. A Russian sail training ship spotted debris 250 miles from Midway Atoll in September. The material spotted included lumber, household appliances like refrigerators and televisions, washbasins, boots and other stuff. They even picked up an empty Japanese fishing boat, drifting amid the debris.

Maximenko said the debris should move inexorably down the chain, first Kure and Midway, then the nearer islands of the Papahanaumokuakea refuge, and then Kaua`i.

“From the times of arrival and composition, we hope to learn much,” Maximenko said. His model for how the debris may be moving can be found here.

A number of frequently asked questions are answered at this NOAA marine debris site. Basic information about marine debris is here.

Surfrider and the NOAA marine debris program will be monitoring the coastlines and setting up programs to deal with the arrival of Japan tsunami debris. RaisingIslands invites folks with information on the subject to add to the comment selection on this post.

© Jan TenBruggencate 2011

Wednesday, December 7, 2011

Hawaiian volcano science: why Kilauea sits on Mauna Loa, but is a sister of Mauna Kea

A pair of important new papers on Hawaiian volcanoes shed light on several intriguing geology questions, including why the islands haven't formed in a single line.

Study of the chemical composition of lavas suggests that there are two parallel lines of Island volcanics, which researchers call the Loa trend and the Kea trend. They get their names from their biggest mountains, Mauna Loa being of one line and Mauna Kea the other.

(Image: Much of the work discussed in these papers involves study of the chemistry of lavas. Here, the robot arm on the JASON2 submarine, operating 10,000 feet below sea level, collects a lava sample from Mauna Loa. Credit: University of Hawai`i.)

One paper in June in the journal Nature Geoscience, was written by Maxim Ballmer and Garrett Ito of the University of Hawai`i School of Ocean and Earth Sciences and Technology, Jeroen van Hunen of Durham University in the UK and Paul Tackley of the Swiss Institute of Geophysics in Zurich. It is entitled, “Spatial and temporal variability in Hawaiian hotspot volcanism inducted by small-scale convection.”

The other paper, published in Nature Geoscience in November, is by Dominique Weis, Mark Jellinek and James Scoates of the University of British Columbia, Michael Garcia of the University of Hawai`i's Department of Geology and Geophysicsand Michael Rhodes of the University of Massachusetts. It is entitled “Role of the deep mantle in generating the compositional asymmetry of the Hawaiian mantle plume.” You can find the University of Hawai`i's press release on this paper here.

The traditional theory about how the Hawaiian archipelago was formed involves a molten “hot spot” which pushes magma up from the Earth's mantle, popping periodically through the ocean floor as the Pacific tectonic plate grinds slowly to the northwest.

But there are problems with that theory, including the parallel lines of volcanoes, as well as what's called the rejuvenated stage or secondary volcanism—which involves why features like Diamond Head and Punchbowl develop a couple of million years after most of the islands' mass has been erupted.

Ballmer and his associates proposed a new model, in which asymmetric melting in the mantle, uneven heat transfer, and a washboard model of the underside of the Earth's crust help explain what's seen on the surface.

It suggests that the rising plume of magma divides in two, feeding the Loa line and the Kea line separately, which explains why Loa lavas tend to be chemically different from Kea lavas. In part that's because the magma feeding the Kea side is hotter, they say.

“Lavas with these distinct characteristics have erupted in parallel along the Kea and Loa trends for at least 5 million years,” writes the Weis team. They argue that the differences in the composition of the lavas may be because the different sides of the magma plume are remelting different kinds of rock as they rise toward the surface.

The Kea line includes Kilauea, Mauna Kea, Kohala, Haleakala, West Maui and both sides of Moloka`i. The longer Loa line includes Lo`ihi, Hualalai, Kaho`olawe, Lana`i, Ko`olau, West Ka`ena and Kaua`i.

Mauna Loa is so darn big that while its caldera is on the Loa line, its slopes extend all the way to the Kea line, which is why Kea-fed Kilauea appears to lie on the slope of Mauna Loa.

Issue two: Why isn't the Hawaiian archipelago one long continuous ridge rather than a series of islands separated by deep channels? Perhaps because of the washboard effect on the bottom of the crust. The volcanoes are able to pour out large amounts of lava where the crust is thin, but not where it's thick.

Issue three: Ballmer and his associates argue that secondary volcanism is associated with a melting zone under older islands that drags nearly 200 miles downstream of the main hot spot activity. That explains why small eruptions at cinder cones like Diamond Head occurred a few hundred thousand years ago, far from the main activity at that time at Hawai`i Island.

A side note: A few decades ago, one of the fun questions for volcano freaks who chase eruptions was this: Is it technically possible for Mauna Loa and Kilauea to erupt at the same time. The theory then was that each was fed by the same plume, so maybe only one could erupt at a time.

But in 1984, Mauna Loa erupted during a Kilauea eruption, setting the question to rest. Now there's a good theory on why that's possible. One is a Loa and one is a Kea.

© Jan TenBruggencate 2011