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Producing energy like plants: cleantech breakthrough?

Tony Chan | August 5, 2008 | 0 Comments

It’s been a long time since I’ve written about advances in clean energy regeneration, but it is always an area of interest and I follow it on my spared time or whenever I can, simply because it is so much like the telecoms industry circa 1997.

What caught my eye this week and prompted to do this rant is reports that scientists have found the ‘nirvana’ of energy.

The reports describes a system discovered by MIT professor Daniel Nocera and Matthew Kanan, a postdoctoral fellow in the professor’s lab, which was inspired by the way plants produce energy through photosynthesis. The new system uses a process called, electrolysis, which splits the molecules of water into oxygen and hydrogen in a [I'm guessing here because professor Nocera is a professor of Chemistry] chemical reaction set up by catalysts.

According to the technical description, MIT has developed a catalyst consisting of cobalt metal, phosphate and an electrode, which when placed in water and run electricity through it, produces oxygen gas, thus separating the oxygen molecule out. Another catalyst, such as platinum, is used to produce hydrogen gas. In this way, the system “duplicates the water splitting reaction that occurs during photosynthesis – which is how plants store energy from the sun.

The now single molecule gases are combined in a full cell to create carbon-free electricity.

Graphics – Patrick Gillooly, MIT

The professor believes the system opens the door for the widespread deployment of solar power, because it offers users a way to store solar power for use during the night, when sunlight isn’t exactly available.

The main benefit of the system is that ‘you can do it in a glass of water, at atmospheric pressures, in room temperature.’ It is also easy to manufacture and uses ‘earth-abundant’ materials. Existing electrolysis systems, with a cool named, electrolyzers, are confined to industrial use and no suited for home applications, according to MIT’s report.

As described by the professor, the system operates with a conventional solar power system such as photovoltaic cells on the roof. During the day, the house uses the sun’s energy directly for electricity. Any excess energy is siphoned off to the electrolysis system for splitting water into its two molecular parts, which also stores the now-separated oxygen and hydrogen molecules in, for lack of a better term, containers.

At the end of the day, when the sun sets, the system then kicks in and then oxygen and hydrogen molecules are sent to a fuel cell, which reassembles the water molecule to produce electricity.

The discovery has been hailed as the nirvana [more or less the holy grail of Eastern philosophy] of clean energy.

CALL ME A SKEPTIC:
As disclaimer: I’m no expert in solar energy, or chemistry. The system as described by the reports, just doesn’t make much sense to me. Yes, the ability to split water easily and cheaply certainly sounds like a major breakthrough, but its application in storing energy from the sun just doesn’t add up.

For starters, why go through the process of splitting molecules and then recombining them in a fuel cell when you can take the excess electricity from your solar power system and store it directly to the fuel cell, or batteries for that matter, which is what many home systems do today. The only advantage I can think of is space, because batteries and fuel cells alike take up a lot room.

Now, as far as I know, any time you use energy to produce electricity, there’s an inherent inefficiency in that the amount of energy you use will always be less than the energy from the electricity you produce. In other words, any process in between will also use up some of the original energy you put into it. So unless the new electrolysis system can produce a net energy gain (which would really make it a mind-blowing invention), then it will also produced less energy is put into it, making it less efficient then simply storing the energy directly from the sun in batteries or fuel cells. Alas, none of the reports I read reveal the efficiency of the electrolysis system.

Another issue that the system doesn’t address, and which is the core problem with solar power systems today, is the inefficiency and high costs of solar panels, which is probably the main deterrent for adoption today.

And while the proposed system is supposed to be cheap – at least to produce according to the reports – it still requires fuel cells, which are expensive.

So forgive me for taking the reports with a grain of salt, but it just reminds me of all those press releases that I read, and have tried to forget, about breakthrough technologies back in the late 90s. Then again, just look at WAP, its inside all the phones.

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