Tag Archives: solar-energy

Record photovoltaic efficiency

Encouraging advances is solar power technology from the US DoE’s National Renewable Energy Laboratory:

Scientists at the U.S. Department of Energy’s National Renewable Energy Laboratory (NREL) have set a world record in solar cell efficiency with a photovoltaic device that converts 40.8 percent of the light that hits it into electricity. This is the highest confirmed efficiency of any photovoltaic device to date.


The 40.8 percent efficiency was measured under concentrated light of 326 suns. One sun is about the amount of light that typically hits Earth on a sunny day.

Mmm. I wonder what the efficiency will be under normal conditions (once it’s mass produced)? Still, it’s pretty impressive as a proof of concept:

…the new design uses compositions of gallium indium phosphide and gallium indium arsenide to split the solar spectrum into three equal parts that are absorbed by each of the cell’s three junctions for higher potential efficiencies.

Beautiful. Kudos to humanity’s glorious electrical engineers!

[story here via ElectricalEngineer.com and KurzweilAI.net][image from Alex // Berlin on flickr]

Back of the envelope: is solar power feasible?

solar_panelsDr Buzzo has some interesting back of the envelope calculations concerning localised solar power generation. This kind of localised, renewable energy generation, is something that Greenpeace are pretty hot on:

Day by day the sun supplies 15,000 times the amount of the daily energy-demand of the total global population. In less than 30 minutes the sun sends more energy to our planet than is consumed in a whole year.

This certainly looks promising. Dr Buzzo looks at it from the other direction, by taking available data on the amount of solar energy available, the efficiency of solar panels etc, and looking at how much energy could be generated in his native Connecticut:

Reasonably speaking I

Where to put the carbon…

Aside from nuclear power, one of the most enticing possibilities for solving problems of energy security, peak gas, and global warming is carbon sequestration.

windfarmBy burning cheap and widely available coal but storing the resultant carbon dioxide rather than venting it into the atmosphere means you (theoretically) have a cheap and low-carbon energy source.

The main issue is finding a place to stick all that carbon dioxide. Dave Goldberg of the Lamont-Doherty Earth Observatory claims there is a vast area off the east west coast of Oregon under the Juan de Fuga Fuca tectonic plate which addresses many of the safety issues of carbon sequestration:

“We have insurance upon insurance upon insurance,” he said.

First, the center of the proposed location is about 100 miles off the coast, obviously far away from human settlement. Second, the impermeable sediment cap on the permeable basalt reservoir is hundreds of feet thick, creating an effective seal for the compressed CO2. Third, when CO2 mixes with water inside the basalt, over time it turns into a variety of carbonates, which are, essentially, chalk. Fourth, if there were an unforeseen leak, in deep water, CO2 forms into icy hydrates in the water, preventing it from floating up to the surface.

As to the UK: what about using the recently emptied North Sea oil wells as a carbon sink?

It is becoming clear that if we are to create a genuinely zero-carbon (or even low-carbon) economy we are going to have to embrace nuclear power and carbon sequestration, as suggested in Plan D of David David J. C. Mackay’s excellent (but unfinished) free ebook Substainable Energy – Without the Hot Air. The evidence is mounting that wind power, solar thermal, and photovoltaics don’t work well enough.

[story from Wired][image from Scott Ableman on flickr]