- Chelsea Green Publishing - http://www.chelseagreen.com/blogs -

If you build it green, will they come? And will it be too cheap to meter?

BW’s Green Business reports that venture capital investments in “cleantech” is booming [1]. Despite an overall drop in VC funding in U.S. businesses between the first and second quarters of 2008, investment in cleantech companies was up 41 percent from the first to the second quarter, from $683.5 million in Q1 to $961.7 million in Q2.

There’s been some shifting of priorities lately. The amount of money being invested in biofuel opportunities dropped 44 percent from Q1 to Q2. Meanwhile, “Energy/Electricity Generation” is a strong investor priority, capturing 52 percent of the total for the quarter, followed by energy efficiency.

Which of all these brave new investments will bear fruit? Which will result in technologies that are truly useful and make a difference? Which will result in products that earn their investors mega-profits? Will there be much overlap—as in, will the profits arise from products that are truly useful and make a difference? Stay tuned!

Meanwhile, on the basic science front, MIT has announced a “breakthrough” that could make solar power more useful [2]. (Hat tip to Juan Cole [3].)

In a revolutionary leap that could transform solar power from a marginal, boutique alternative into a mainstream energy source, MIT researchers have overcome a major barrier to large-scale solar power: storing energy for use when the sun doesn’t shine.

Until now, solar power has been a daytime-only energy source, because storing extra solar energy for later use is prohibitively expensive and grossly inefficient. With today’s announcement, MIT researchers have hit upon a simple, inexpensive, highly efficient process for storing solar energy.

Requiring nothing but abundant, non-toxic natural materials, this discovery could unlock the most potent, carbon-free energy source of all: the sun. “This is the nirvana of what we’ve been talking about for years,” said MIT’s Daniel Nocera, the Henry Dreyfus Professor of Energy at MIT and senior author of a paper describing the work in the July 31 issue of Science. “Solar power has always been a limited, far-off solution. Now we can seriously think about solar power as unlimited and soon.”

Inspired by the photosynthesis performed by plants, Nocera and Matthew Kanan, a postdoctoral fellow in Nocera’s lab, have developed an unprecedented process that will allow the sun’s energy to be used to split water into hydrogen and oxygen gases. Later, the oxygen and hydrogen may be recombined inside a fuel cell, creating carbon-free electricity to power your house or your electric car, day or night.

The key component in Nocera and Kanan’s new process is a new catalyst that produces oxygen gas from water; another catalyst produces valuable hydrogen gas. The new catalyst consists of cobalt metal, phosphate and an electrode, placed in water. When electricity — whether from a photovoltaic cell, a wind turbine or any other source — runs through the electrode, the cobalt and phosphate form a thin film on the electrode, and oxygen gas is produced.

Combined with another catalyst, such as platinum, that can produce hydrogen gas from water, the system can duplicate the water splitting reaction that occurs during photosynthesis.

The new catalyst works at room temperature, in neutral pH water, and it’s easy to set up, Nocera said. “That’s why I know this is going to work. It’s so easy to implement,” he said.


A few comments… First of all, the MIT press release isn’t quite right when it says that storing extra solar energy for use after sunset is “prohibitively expensive and grossly inefficient.” That’s pretty much true for solar energy systems that are small scale and/or are based on photovoltaics (the panels that directly convert sunlight into electricity). But it’s not true for concentrating solar power systems [4] that indirectly generate electricity by using sunlight to create heat, which then turns water to steam, which then powers a turbine generator. Such systems exist and are more efficient than photovoltaics, and, depending on the details of the systems, are capable of continuing to generate electricity even after sunset. (For example, if the concentrated sunlight heats up a heat-transfer substance to thousands of degrees, the residual heat can keep the water boiling and the turbines turning for hours after dark.) What’s cool and hopeful about the MIT deal is that it makes stored solar power more affordable for the small scale—assuming the technology pans out of the lab.

Also, were you like my good friend and coworker Jesse, wondering, “how is this different from good old fashioned electrolysis?” I emailed some of my college friends who wasted their academic years studying physics and chemistry* (and homebrewing beer), and put the question to them. The response:

Good old fashioned electrolysis takes place in a highly corrosive environment. The normal catalysts are salts that cause all sorts of problems. Because salt is a great catalyst in ion exchange it requires special metals to avoid these problems. Specifically on the anode where oxygen is produced, if you use a cheap metal, you will quickly oxidize the electrode, causing failure of your system. In order to prevent this, you need to use an inert metal, most typically platinum. If they are able to use a catalyst that enables you to avoid salt, and eliminate the need for platinum as an anode, you probably will see a big cost savings. This is the main drawback of current hydrogen fuel cells. It costs too much to produce them due to the need to use platinum as an anode. So, even if the process is the same efficiency as current electrolysis methods, it may make it much more affordable by avoiding the need to use increasingly expensive precious metals. The key that I hear in the video, is that they use “earth abundant materials” to produce their reaction. If it is also more energy efficient, that would make a big difference as well. So, while the process appears to be the same, the materials appear to be different, and presumably more affordable and efficient.

Thanks, Al!

* You think I’m being sarcastic, but not so fast… What did Perry do with his PhD in biochemistry? He became a lawyer!

[Graphic [5] courtesy of lumaxart [6].]