Green-Washed! - Solar Laptop Chargers

(11/19/2008) - As an “open-source” brand, the Green Movement has opened itself up to all kinds of green-washing.  Companies become “green” overnight without doing any of the things normally associated with the term – using less energy and less resources, buying solar panels, improving recycling rates etc.

Consumer products can be green-washed as well, though the definition of what is and isn’t a green-washed product can vary.  In the Green-Washed? series, The Finite World will evaluate and (when practical) review products to evaluate how environmentally friendly they actually are.

Solar Laptop Chargers

Solar laptop chargers are small, portable arrays of photovoltaic cells, and vary in terms of size, power, and build.  The Voltaic Generator and the Notepower  are laptop bags with built in photovoltaic panels.  Rated at 17 watts and costing $599 ($35/W), the Voltaic Generator is more costly than the Notepower, which comes in two versions: 15W for $219 ($15/W) or 22W for $299 ($14/W). 

Brunton Sunrolls roll out and are lighter, but don’t produce as much electricity.  The 4.5W Sunroll costs $295 ($66/W), the 9W for $480.60 ($53/W), and the 14W for $655.20 ($47/W).  Apple Juicz offers more powerful fold-out PV panels, running from $500 for 18W ($28/W) to $1000 for 55W ($18/W) of electricity producing power.

How good are these chargers?  Are they worth the purchase?  How much energy do they save?  Lets run through a sample scenario, designed to maximize the hypothetical use of the laptop charger:

Jody lives in LA, where it is sunny about 90% of the time.  She has an unshaded south-facing window where she can always charge her laptop, and only uses her laptop at night, allowing it to charge during the day. 

According to Mr. Electricity, laptops use anywhere from 15-45W of electricity.  Lets say our hypothetical laptop uses 30W on average, and that Jody uses her laptop for three hours every night (about how long my fully-charged laptop batteries tends to last).  That’s 90Wh (or 0.09kWh) per day. 

Lets assume Jody bought a 22W Notepower, economically the most efficient charger at $14 per watt.  If Jody bought her laptop’s electricity directly from the grid, it would cost her $0.12 per kilowatt hour, or $0.0108 per day.  So what’s the payback time for Jody’s $299 charger?  At least 76 years. 

Most users won’t be this lucky.  A solar panel’s power rating is the maximum amount of power generated when exposed to direct sunlight.  If there’s a cloud in the way, power generation is going to be decreased substantially, and most areas come with more clouds than L.A.

Finite Considerations

If costs were the only consideration, I’d be advocating for coal power and strip mines.  Just because solar chargers cost more doesn’t necessarily mean they are poor purchases.  Its hard to say, exactly, what the energy costs and environmental impact was to produce these solar chargers.  Some, like the Voltaic Generator, are made in part from recycled materials. 

I couldn’t find a study estimating the return on energy invested of these solar chargers.  The closest report I found was an energy-payback study done for large PV arrays. According to this 2006 report, the energy payback for commercial PV installations in Southern Europe is 1-2 years.  Larger systems such as these currently run about $3 or 4 per watt. 

The Verdict

The primary utility of these devices is to charge your laptop or electronic device when you’re unable to find a wall socket.  If you make frequent trips to locals off the grid with your computer in tow, a solar charger might be something to consider.  However, there are much better options for home use. 

There are plenty of more efficient ways to spend your money.  If a solar charger would have blown your budget, check to see if your local utility company offers special renewable energy plans.  Portland General Electric customers in Oregon, for example, can sign up to have their electricity come from renewable sources for a small surcharge.  The more people who sign up, the more incentive PGE has to buy from renewable energy sources. 

If you have a bit more money to spend, consider putting the money for your own solar charger or solar water heater.  There are also lots of new companies that rent solar panels directly to homeowners.  For a deposit and a flat monthly fee, these companies will you solar panels for your home.  Though costs vary between company and size of system, all claim to offer prices equal to or lower than the grid electricity you’d be offsetting.  They also pay for instillation and maintence - big potential costs if you're installing your own system.  Even if a rented panel ended up being a more expensive than gird power, these units are a much better deal than portable solar chargers.

I wouldn’t go so far as to say the makers of portable solar chargers would be lying if they told you their solar charger is “green.”  They aren’t, however, the best option for making an impact.

If you want a solar charger, fine.  But lets look at these products for what they truly are: devices to charge your laptop or electronic device while you’re unable or unwilling to find a wall socket.  They are not workable solutions to the energy crisis, and there are much more efficient ways to spend your money.  

Though they serve an ostensibly green purpose – gathering solar energy – solar powered laptop chargers are a luxury and a poor choice for spending your money if you want to have a positive impact.