Archive for November, 2009

US Diplomacy: Science Envoys to Muslim World

Sunday, November 29th, 2009

Three prominent US scientists were recently named by Secretary Clinton as special envoys to assess potential for assessing potential for scientific partnerships with Muslim-majority countries, according to an article in the November 13, 2009 Science (subscription needed).

Ahmed Zewail
picture credit Ahmed H. Zewail, Nobel Prize winner in chemistry at Cal Tech, whose early degrees come from Egypt’s Alexandria University, plans to travel to the Middle East next month.

Elias Zerhouni
picture credit Elias Zerhouni, radiologist, former direction of the National Institutes of Health. Zerhouni graduated from Algiers Medical School.

Bruce Alberts
picture credit Bruce Alberts, former president of the US National Academy of Sciences and current editor-in-chief of Science. As NAS president, Alberts helped create and co-chaired InterAcademy Council.

Obama in June promised to establish at least three “centers of excellence” in the Middle East, North Africa, and Muslim-majority regions in Africa. There are 57 Muslim-majority countries.

Even more encouraging, the State Department has a goal of increasing science capacity in the department and at embassies, providing science and technology capable diplomats around the world.

Read more here.

GHG reductions from intermittents in actual use

Saturday, November 28th, 2009

November 8, 2009, at 5:50 AM, on a Sunday, Spain’s windmills supplied 53% of its electricity, and over half between 3 and 8:30 AM. OK, not the biggest demand portion of the week, but certainly an indication of Spanish trust in wind to reduce greenhouse gas emissions. Wind produced 11% of Spain’s electricity in 2008, and this year is expected to provide even more. According to an article in MIT’s Technology Review, “If Spain meets its goal of generating 30 percent of its electricity needs from renewable power by 2010, with half of that amount coming from wind power, it will reduce carbon dioxide emissions by 77 million tons”.

How much actual emissions reductions results when intermittent sources of electricity, solar and wind, use fossil fuel backup? The operating assumption has been that if wind supplies 10% of the power, greenhouse gas emissions from natural gas decline 10%.

An analysis in Environ. Sci. Technology, Air Emissions Due To Wind And Solar Power, examines this assumption.

Utilities match demand with supply. Demand varies during the day with work hours, temperature, etc. Power plants are turned on and off, ramped up and down, to accommodate shifting demand. Using intermittents complicates things, as now utilities must also follow sun or wind, sometimes quickly. Note: this study assumes natural gas backup, but some utilities use hydro as backup, and others use coal.

If a generator produces 2 tons of CO2 per MWh, averaging 10% solar plus wind over the year has been expected to cut emissions by 0.2 ton. If the reduction is only 0.1 ton, this is only 50% of expected reductions.

The use of solar and wind with natural gas backup was found to achieve 76-79% of expected GHG reductions, and 20-45% of expected NOx reductions at best (day time only, obviously for the solar). In some instances, NOx production of intermittent plus natural gas backup exceeded that of natural gas alone, because the natural gas was more often run at less than optimal power levels. The poor results for NOx indicate that relying on wind to help meet clean air requirements may be unsuccessful.

Running natural gas generators at suboptimal levels increases maintenance costs as well.

natural gas generator
This natural gas generator is used to provide peak power, rather than to run all the time. The report examines the effect of backing up intermittents on both efficient and peak natural gas generators.

How complicated is it to integrate intermittents into the grid?

A report from North American Electric Reliability Corporation (NERC), Accommodating High Levels of Variable Generation (pdf), discusses this issue at some length. One problem is that wind declines during heat waves, down to 5 – 10% of nameplate capacity during a recent California heat wave (compared to capacity factors averaging over 30% in the US).

While error in forecasting demand is normally 3% and unlikely to be more than 10%, wind forecast could readily be 20%, or as much as 100%. Experience in Texas shows that wind output can decline dramatically in 1 – 2 hours.

Because wind is stronger during hours of low demand, the use of wind requires a more rapid ramping of non-wind sources. In one example, without wind, conventional sources need to ramp from a low of 9,600 MW to a high of 14,100 MW, or 4,500 MW. Wind lowers nighttime use of conventional sources to 7,000 MW. To increase to 13,600 MW (plus some wind power) requires 6,600 MW ramping capability.

While solar power is greater when wind tends to be low, under some weather conditions, photovoltaics (solar panels) can change output by ± 70% in 2 – 10 minutes, several times each day.

Future analysis, or technology change, may alter these results. For now, wind and solar perhaps should be credited with only 75-80% of expected greenhouse gas reductions based on capacity factor.

Glacier Man

Friday, November 13th, 2009

Chewang Norphel ran away at age 10 to attend secondary school 250 miles away. He paid for lessons by cooking and cleaning. He then studied at the university in Lucknow, and brought his knowledge home, to build roads, culverts, bridges, and schools. Subsistence farmers had no money, but volunteered their labor. Materials were still a challenge, but creativity solved problems where money could not: canals were built without cement, instead using roots from planted weeds to plug gaps.

Over time, needs changed. Ladakhi farmers in the trans-Himalayan region of India, 2.5 miles high, depend on glacier melt. So do more than one in six people worldwide, more than one billion people. In Ladakh, rainfall is only 2 inches per year, comparable to the Saharas. Melting glaciers once provided substantial water.

According to the October 30, 2009 Science (subscription needed),

global warming has hit this region particularly hard. The tree line has risen more than 150 meters during Norphel’s lifetime, and glaciers have retreated by as much as 10 kilometers.

Nearby glaciers were gone, and more distant glaciers did not supply meltwater until May or June. So Norphel found a way to build artificial glaciers, channeling winter water flow into stone embankments that allow it to spread and trickle into a depression, and freeze. His glacier melted from late March to late April, after which natural glaciers provide meltwater. The crops watered by the artificial glacier feed 4 villages, 1,500 people.

“Before the artificial glacier, we really struggled to get any barley,” says Tashi Tundop, a 76-year-old farmer from Stakmo village. “But now we can grow many crops, even potatoes, which need to be planted earlier in the spring, but sell for much more money. I get three times more income than I used to.”

glacier man
This Christian Science Monitor article has a video.

Norphel has built glaciers for other areas, though not every site has the necessary altitude, water flow, and surface area temperature. An early rain in 2006 devastated one glacier. Help with analysis, design, and money are all needed.

Norphel’s brilliant method to help this region adapt to climate change may not survive continuing climate change. Winter snowfall is down, and September rain, which ruins harvests, has increased. But for now, glacier man has made a large difference in the lives of the local people.

Information from October 30, 2009 Science (subscription needed).