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German Solar Park
Solar park in Germany sits next to field of ripening rapeseed (canola). The solar panels are integrated into 6-panel units that sit on piers, each equipped with a tracking system to maximize exposure to the the rising and setting sun, much as sunflowers do. There is space between the piers to grow hay, graze sheep, plant vegetables or even grow grapes.

Drive Further on Sunlight

When teamed with advanced batteries, smart grids and solar electric power, a plug-in hybrid can drive to the moon and back four times. Try that with biofuel.

By EV World

Here's a one-question pop quiz for you.

Given a hectare (2.47 acres) of ground in either North America or Europe (so palm oil and jatropha don't count), which "crop" would yield the furthest driving distance in the same vehicle, making allowances, of course, for different fuel and engine types? Rapeseed (canola), soybean, sugar beets, wheat, corn, miscanthus?

Actually, none of the above. The "crop" that would propel the vehicle the furtherest is sunlight, and by a significant margin.

The annual electricity production from a hectare-sized field of tracking photovoltaic panels like those above would propel a plug-in hybrid 3.25 million kilometers (2 mil miles) compared to 67,000 km (41,000 mi) from corn-derived biogas produced on the same plot of ground. That is 48 times further.

Put another way, the biogas produced from that hectare of ground could propel 3 cars annually, each driving over 13,000 miles. Biodiesel and bioethanols would fare far worse, propelling just two cars a little over 10,000 miles each on an annual basis.

The same field, which can also continue to be used for pasture, cereal or vegetable crops, if single pier solar tracking systems are utilized, could provide 234 vehicles with the same annual driving distance.

In a recent article in Photon International, a respected trade journal for the photovoltaic (solar electric) industry, entitled "Organized Wastefulnes", Christoph Podewils makes a strong case for solar power as the "fuel" of the future, not biofuels. Besides pointing out the threats mono-cropping poses to agriculture -- for example, Germany's rapeseed (canola) crop is being seriously threatened by the pollen beetle, which destroyed upwards of 200,000 hectares in 2006 -- only a fraction of the solar energy falling on the field actually ends up as fuel to propel the vehicle. He calculates that of the 1 million kilowatt hours of solar energy that fall yearly on that hectare of rapeseed in Germany, only 5000kW are used to actually fuel the vehicle.

"That's enough fuel to drive an average diesel truck 22,000 km (13,670 mi.)," he reports.

"A 1 hectare field with a rather humble PV system could produce 520,000 kWh or electricity annually under Germany's rather modest sun conditions. Still, with today's electric cars, that would allow you to travel an incredible 3.25 million km -- that's 147 times farther than with the biodiesel produced by the same-sized field.


Graph courtesy of Photon International

"The basis for these calculations is an average PV (photovoltaic) system efficiency of 15 percent; the system itself would cover less than one-third of the total surface area -- two-thirds of the field would remain untouched, perfect for other agricultural purposes, like sheep herding. By turning the 1.2 million hectares of land used for the production of inefficient energy groups to PV parks, one could produce more than 600 TWh electricity -- that's more electricity than all the power plants in Germany combined can produce in a single year."

Of course, Germany automakers and consumers aren't any more aware of electric vehicle technology than their North American counterparts. Writes Podewils, when he talked to Tomi Engel, the chairman of the German Society for Solar Energy (DSG), Engel began, "'I would stay away from electric cars. In the world of politics, the phrase electric car conjures up images of the TWIKE and the CityEl.'"

"Engel and his colleagues at DSG are following a strategy based on the assumption that electric cars will only become a reality when they meet the demands of the average car driver."

What does excite Engel is the potential of using electric vehicle (pure, hybrid and plug-in versions) batteries as "storage power stations."

Using numbers provide by Japanese battery maker Enax's European representative, Jan-Steffen Lang, the company's new lithium ion battery, which uses aluminum lamination and resembles a "brick of vacuum-packed coffee", can store up to 130 Wh per kg and this is expected to increase to 200 Wh/kg.

"That means 80 of these cells would suffice to power a mid-sized hybrid for 100 km (62 mi). "Furthermore, they're affordable: 'By 2012, they will cost about 200-300Euros per KWh, says Lang.' Similar dimensions are being predicted by Batterien-Montage-Zentrum GmbH in Karlstein in southern Germany.... At these prices, additional costs for 100 km batteries would not be around 15,000 Euros ($19,830), as they are today, but rather 3,200 Euros to 4,800 Euros ($4,230-6,340).

"That makes the Plug-in car not only interesting for purposes of climate protection, but also financial reasons..."

Engel calculates that at 20 Euro cents (26 cents US) per kilowatt and $1.50 per liter fuel, the battery will pay for itself after 70,000-100,000 km (43,000-62,000 mi). To help offset the cost of the battery, he is proposing partnering with electricity companies in Germany with whom the car owner will sign a "fuel" purchase agreement that not only has the utility charging the vehicle battery, but also discharging them when the car is hooked to the grid.

It's what we call here in North America vehicle-to-grid (V2G) capability, and at the moment only AC Propulsion drives offer that ability.

"That would transform every vehicle into a small, storage power system. A half-million vehicles -- about the number in Cologne and Munich -- would store in their 16 kWh batteries as much energy as the largest German pumped (hydro) storage plant, Goldisthal in Thuringia. But that won't be possible without clever infrastructure. The electricity companies will need to be able to maintain the fill levels of every single car battery by computer and radio data transmissions, to ensure that it's full when it's time to drive."

Research is being conducted on this at the Institute of Automotive Engineering at the Technical University in Aachen, Germany.

And this is where PV (and wind power, though less so) comes back into the picture.

"Plug-in cars running on electricity from coal-fired plants will hardly improve environment conditions." Instead, green electricity suppliers -- assuming they can cut the price of their electricity to below the 20 Euro cents threshold -- can become partners in this new sun-fuel economy. Photon International's consultant Michael Rigol is predicting that the cost of solar electric systems will begin to be competitive with grid power in Europe starting around 2010.

"And here's where we come full circle, to PV " writes Podwelis. "For the most part, plug-in hybrids (he mentions specifically the GM Volt) sit motionless in a parking lot when the sun is at its highest and the most electricity is being feed into the grid -- in contrast with electricity usage, the peak power period for traffic is in the morning and evening. So, in the future, the hybrid batteries could absorb the midday peak demand from the PV systems, only to feed them back into the grid during the evening or at night -- or, simply transform that energy into kilometers."

"The only obstacle left is to locate enough surface area to allow for the most effective transformation of solar energy into electricity."

And that brings us back to all those hectares of rapeseed and sugar beets.

Times Article Viewed: 14389
Published: 22-May-2007

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