“tells us all we need to know — the future is inevitably wind, solar, and geothermal.

MIT sounds like they’ve missed the boat. Everything anyone needs to know is already known, eh? Or did I miss something?

1. It would be very helpful to define a rigid standard metric, or perhaps a small number of metrics, that would allow clear intercomprison of the different technology options. Perhaps establish a standard energy demand scenario, and determine what fraction of demand each technology could meet on its own, and what fraction would require additional investment in other technologies (transmission and storage) to meet.

2. Some analysis of the “learning curves” for solar systems – are we still on track with the projections of a few years ago for price vs volume?

Wow. Thanks for the observations on developing world power and 110/220 VAC. I think though that as PV approaches $1/Watt it will be able to complement the microgrids you’ve seen.

Your question is well put; I would broaden it to: “How can we best exploit private (usually rooftop) intermittent PV?” Less expensive grid tie-in is one answer, batteries (including UPS) and storing hot (and chilled) water add value too.

Commercial users with a steady demand for DC power (computers, POS terminals, lighting) could use all their rooftop PV, and supplement it with the grid and/or CHP.

Rectifiers with voltage stepdown (power supplies) are quite inexpensive.

Looki8ng at the rectifiers/inverters needed for HVDC shows that the losses at each end are about the same, but 1/2 per cent. Note that the same technology is used both for the rectification and the inversion.

I strongly suspect the cost of low voltage inversion will go down.

Low voltage DC and batteries are good technology for places even further from the grid, but those places are disappearing.

I can see great value for standardizing low voltage DC “stuff”. But even if we paid the trillions and trillions of dollars it would take to change the world’s grids to high voltage DC we would still have the expense of stepping it down to lower voltage DC for our cell phones.

I think the really critical question is “How can we bring down the expense of hooking small privately owned arrays to the grid?”.

Thanks for thinking broadly about pros and cons of a DC standard, and what the topology would look like. I believe it addresses Joe’s request squarely:

“What questions would you like answered of MIT’s Future of Solar Energy Study?”

The point is to make solar cost effective. A DC standard removes some complexity and waste from the system. Yes, our 110/220 VAC system with central power plants and a grid has served well for 100 years, and CSP (Joe’s solar thermal baseload) fits right in with that model.

But now we produce billions of DC devices annually, each with its own custom power supply: cell phones, music players, computers, printers and other peripherals, TVs, cameras, LED lighting, and more. DC devices are the fastest growing, highest value-added electricity users. PV is a fast growing DC source (with fuel cells and thermionic knocking on the door), and the DC -> AC -> DC conversion impedes penetration.

You have helped think through a DC standard for us first-worlders. But it would add huge value to the 2 billion energy poor people who have no access to a grid.

In “Hot, Flat, and Crowded”, Tom Friedman asks of every promising energy technology, “Does it scale?” PV, with a DC standard connecting directly to electronics, batteries, and LED lights scales all the way down to the poorest, struggling to get just their first watts.

Just a thought.

What is the likelilhood of implementation and and efficacy of large scale deployments of Co2 scrubbers like the prototype discussed in this article?

We really need more sophisticated software for sites like this.

That said, Mark’s initial problem was the cost of inverters to get from the DC produced by a set of residential panels in order to integrate them with the grid.

My points would be that:

1) it would be very, very much too expensive to convert the existing local consumption grid to DC,

2) if we were to use more inverters the price would likely be closer to $1k than $3k, and

3) even if we switched the grid to DC we would still have to have voltage controllers to match specific sets of panels to the grid. There’s some cost there as well.

Remember that a cloud can drift over your panels, dropping them below grid level. Simple panel controllers simply disconnect the panels from the system when panel voltage is less than system voltage (otherwise you get backflow). More sophisticated controllers trade amps for volts and convert voltage to system levels so that power is not wasted.

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Low voltage DC standards? Absolutely! One power brick per house/office. Lots of us would retrofit a small wattage DC system. Building into new construction would cost little.

BTW, I recently purchased a “netbook” for travel. Wonderful little puppy (Asus PCee). When turned off the power brick pulls ZERO watts. Every piece of electronic gear should adopt this design.

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Solar roofing – when (and I don’t even say “if” any longer) thin film drops to well below $1 per watt we can stick it on roofs and not worry about adjusting angles. We’ll probably see houses of the future designed with significant portions of their roofs oriented south and pitched for optimal “summer AC” or “winter heat pump” depending on the climate.

And we could install automatic hot water wash downs for snow if it makes economic sense.

Harnessing the particular strengths of this institution, [Deutch] says, the report will be “MIT speaking in a way only MIT can — with an interdisciplinary focus, addressing in depth an area of energy.” The report will have “a breadth of focus that encompasses technology, economics and policy, and looks at how these need to work together.”

Two basic questions:

What characteristics of deployment would generate positive feedback, internationally and nationally, for increasingly ambitious climate/energy policy?

What government action is required to initialize deployment trajectories with such characteristics?

Too many platitudes are bandied about in conjunction with these questions,
in the clean development & clean tech context. They deserve a solid interdisciplinary in-depth investigation.

Hopefully the MIT study will at least seek to provide a thorough review. The questions seem pretty important to the future of solar energy.

strait -> straight. It looked wrong when I typed it, but I wasn’t “thinking straight”.