In October 2005, SunPower, a subsidiary of Cypress Semiconductor, announced a new photovoltaic cell that approaches double the efficiency of the current generation of photovoltaics – up to 30% efficient at converting sunlight to electricity. This is a huge leap forward – but it’s still not enough. "Not enough" in the sense that, for solar to truly make a difference, it’s going to need to achieve 50% or greater efficiency. That’s just my opinion, certainly - but it’s based on the popularity – and shortcomings – of the photovoltaics most widely used now.

A short while ago, I excerpted an image from the (utterly fabulous) WorldWind program, which is a satellite view of my mom’s house. Nearly thirty years ago, my parents put in place a solar water heating system, and several years ago, they invested in a solar electric system. The image is a bit too large to insert here – so simply click on the following link to go to the page: Mom’s house - just to the right of the crosshairs. You can see the solar electric panels – the set of two and four large panels extending away from the crosshairs. The solar water heating system is just ‘above’ those.

Now, it’s not a large house – but neither is it a terribly small house. But as you can see, the entire backside of the roof of the home is occupied by the solar arrays. It’s a dandy system of course – the meter runs backward during the day, and her power bill is rarely more than a few dollars each month. Unfortunately there are many natural gas appliances in the home – auxiliary water heater, clothes dryer, stove, and household heating – all of which cost, regardless of how much is earned by feeding electricity back to the utility.

But the shortcoming of it is pretty clear. It is quite costly – somewhat mitigated by state incentives, tax breaks, and the like – and again, the huge area that has to be committed to the array means a lot of reinforcement and customizing of the installation is required for it to be safe and long-lasting.

Theoretically, using the SunPower modules, rather than six arrays, only three would be required. That’s a significant benefit – but it really is still not enough. we need to get to where a single homeowner – of nearly any size home – could self-install their own ‘array’ – amounting to one panel about four feet wide by six feet long. even better, built into the roof when the home is built. to get there means panels that are about 70-80% efficient – that’s a guess, but i’d bet i’m not far off the mark.

But think about that in the larger scheme of things. if that installation were down in the $2000 to $4000 range – it’d be a no-brainer to have one installed on every house that gets any appreciable sun. It would eliminate the need for a large number of our *existing* power plants. most of the utility power output is needed to supply homes and industry during the peak hours of the day. With millions of homes pumping energy back into the grid during the day, servicing peak intervals wouldn’t require all those plants – which otherwise go idle at night.

Regrettably, I’m not a photovoltaic researcher. So I have to wait with everyone else for the breakthroughs necessary to get there.

Tags: photovoltaic cell, solar power, sun energy, sunpower photovoltaic cell, wind energy