The Renewable Mix  

WorldChanging today made a point that needs to be repeated pretty often when discussing energy - there is no single substitute to replace fossil fuels - dealing with both depletion and fossil fuel caused global warming requires the creation of a variety of alternatives, which are used much more efficiently than we currently manage.

It's not hard to find people arguing against the greater use of renewable energy sources by making the following kind of argument:

(Renewable Technology X) can't replace our current energy use because of (Insert Well-Known Reason), so it's pointless to pursue its development.

The Well-Known Reasons often boil down to what the industry calls "intermittency" -- the inability of the given energy technology to provide reliable amounts of power. And, constructed as that straw man, it's true: photovoltaics are ineffective at night; wind turbines are non-productive in still air. But as we've said here time and again, nobody is talking about replacing the entire energy infrastructure with a single production source. What will allow renewable energy to succeed is a distributed mix of a variety of sources connected via a smart power grid.

With that said, its time to do another one of my surveys of the Viridian world to see what is in the news lately.

MetaEfficient has a post on growing hydroponic lettuce under red LEDs. The advantage of this is that less energy is wasted than under conventional lights.

Apparently red LEDs are 60% more efficient than fluorescent light when growing vegetables hydroponically.

According to IEEE Spectrum Online: Of all the colors of the rainbow, red is lettuce's favorite. Chlorophyll, the electrochemical engine of photosynthesis, runs on red photons. So if you are growing the vegetable indoors in a factory, why waste energy on colors you don't need?

Using a red LED-based growth process developed by Cosmo Plant Co., in Fukuroi, Japan, instead of a fluorescent lighting based one, cuts a factory's electric bill by 60 percent, the company told Agence France Press.

One commenter notes that lettuce is almost useless as a food crop, so it would be better if this technology was applied to tomatoes, eggplants, zucchini, peppers and the like.

Of course, if you're really into energy efficiency then its probably best to grow your vegetables under real sunlight rather than artificial light - but perhaps in some environments, where energy is plentiful and sunlight scarce -such as Iceland - this is a useful technique.

TreeHugger has a post on water boilers that generate electricity that can be fed back into the grid, which are being promoted by PowerGen in the UK.

The boiler fits under the kitchen counter. It makes a slight humming noise and has an LCD display showing the temperature of the heated water and that its generating 850 watts of electricity. The boiler is based on the Stirling engine, created up by the Scottish inventor Robert Stirling in 1816.

There's a gas burner at the top. It heats up four cylinders, each of which contains nitrogen gas and a piston. The gas expands as it warms up, pushing the pistons down. The pistons are cooled on the central heating water, which passes underneath, so they go up again. The resulting rotation is 1,600 times a minute, turning a generator and producing a constant supply of hot water. It's known as an external combustion engine. The technical name for this particular application is "Micro Combined Heat and Power" or "Micro CHP".

Elsewhere at MetaEfficient, they have a review of a book on constructing "Earth Sheltered Houses". The most energy efficient house is one which doesn't need to be heated or cooled very often, which is the goal of this type of construction.

Earth sheltered houses make use of earth or "berms" for protection against the natural elements.

These homes can be complete underground homes, or homes which are protected by earth on just one side. The major advantage of this style of building is that the house has a constant and comfortable temperature throughout the year, so it is much less expensive to heat and cool. They are also much more resistant to weather and natural disasters.

Of course, if you are putting together an energy efficient house, it would be interesting to see how much energy the house is consuming (or generating) - this gizmo from Sharp does exactly that.

Sharp has introduced (in Japan) a control panel that lets you see in real time, your power consumption, generation from photovoltaics and data on earnings from selling power back to the electricity supplier. We are certain that hygridders can already do this, but Sharp has put it all into one neat little package

WorldChanging has a report on an alternative to methane digesters for processing cattle manure and converting it to energy - a manure powered hydrogen fuel cell. If bullshit can be turned into energy then maybe Canberra and Washington could be the solution to oil depletion ?

It's a bit unclear just how much electricity the fuel cell is producing. The Princeton Union-Eagle, the hometown newspaper for the farm, claims 120Kw/h production, while the Minnesota Department of Agriculture describes the fuel cell as being a "5 kilowatt" device. Either way, it's not big enough to run the whole farm, but is certainly enough to power the residence or office.

It seems likely that the conversion of manure to electricity -- whether by methane digestion or conversion to hydrogen for fuel cells -- will increasingly become a standard part of ranching. And that's not the only way farms and ranches will contribute to the new world of distributed power. Wind turbines can co-exist with other land use quite nicely, and the Great Plains of the American midwest are prime wind-and-farm country. Then there's biodiesel and other biofuels -- not a total replacement for petroleum-based fuels, but a far more renewable (and carbon neutral) augmentation.

TreeHugger has also discovered Australian Papyrus made from banana tree fibre, which I've blogged about previously.

Elsewhere at TreeHugger, they talk about using nature as the guide to improve solar technology.

Graham Fleming from Lawrence Berkeley National Lab, has led the development of a new technology which can see into the heart of photosynthesis; electron transfer. The ability to capture light and then transfer that energy to do work are two main steps in a photovoltaic system. While much of the research focus has traditionally been on light capture, the transfer of the captured energy remains a technological hurdle. Green plants are masters of this trick; the energy they capture is transferred with almost 100% efficiency.

“Nature has designed one of the most exquisitely effective systems for harvesting light, with the steps happening too fast for energy to be wasted as heat. Current solar power systems, however, aren’t following Nature’s model.” - Graham Fleming

Finally, TreeHugger has a cool little piece on sailboats with hydrogen fuel cells that are refueled by the boat itself.

I was delighted to learn that HaveBlue, a Ventura California based company, has created a system which produces propulsion and power for your boat from...water. The clever folks at HaveBlue recognized that if you are going to use an oxygen and hydrogen fuel cell for something, you might as well be floating on the fuel (H2O).

Their technology utilizes multiple renewable resources (sun, wind & motion) to clean and separate the Hydrogen and Oxygen from the sea water. It then uses the hydrogen in a fuel cell for power. While all of these technologies are not brand spanking new, putting it all together on a boat and powering that boat with the hydrogen is an amazing step in applying hydrogen fuel cell technology.

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