German solar experiment draws tourists as it shades sheep

Sheep graze under the largest solar energy experiment in Europe. At the Pellworm Islanders' request the 64 panels that this summer began producing 300 kilowatts for the local spa are raised high enough off the ground to let a few of Pellworm's 6,000 sheep dine in the shade.

They are undisturbed by AEG Telefunken engineers who check their maintenance-free solar apparatus only rarely. And they pay no attention whatsoever to the weekly comings and goings of the Geesthacht Research Center's J. Brugmann, who tends the more finicky experimental windmills across a fence.

The 1,200 residents of Pellworm, too, take the contraptions in stride. They would even like to get a solar heating system in addition to the present direct solar energy converter.

According to Deputy Mayor and tour guide leader Manfred F. H. Delfs, the islanders approve of the experiments and find them to be a tourist attraction.

He rattles off all sorts of information: Pellworm is 1 of the 3 or 4 sunniest places in West Germany. This generator the size of two soccer fields is financed partly by AEG Telefunken, partly by government research funds, and partly by the

The Pellworm unit, which converts light directly into electricity (without any intermediate stage of heat), can pick up some energy on cloudy days or even moonlit nights.

It therefore stores adequate power in its 6,000-ampere battery to run the spa's kitchen, restaurant, lighting, baths, swimming pools, and sauna all summer even if five consecutive dark days keep the photovoltaic output temporarily below consumption.

The 2,000 summer vacationers who come to reinvigorate themselves in West Germany's windiest as well as sunniest spot seem to approve of the experiment, too. They flock to this bucolic, dike-rimmed island on a ferry that at low tide seems to dig its way through a silty channel in a sea of mud.

Once here, they round off their swimming, bird watching, cycling, weaving, dike walking, and mudflat trekking by scrutinizing the solar panels and one-, two-, and three-blade windmills.

Mr. Delfs includes both energy sources in his tours. And in the past year Mr. Brugmann has given away 6,000 brochures about his three working and six defunct wind rotors - and that only to the especially curious who manage to accost him in the half minute it takes him to get from the car door to his various meters.

''In summer I'm a tourist guidebook,'' he says ruefully, as he pulls out yet another brochure from a box in his car to give to yet another inquiring couple.

Can one purchase these 10-kilowatt-class windmills for individual use? ask the latest newcomers, Joachim Bahrdt and Marianne Schubert, persevering. ''We ask because we're architects.''

They have just been in neighboring Denmark looking at the ubiquitous modern windmills there, and they can't really understand why it is almost impossible to get official permission to install private household windmills in West Germany.

Nor can Mr. Brugmann understand it. He clearly thinks the Danes have the right idea (as well as good windmills, since the only 1 of his 9 that he never has any trouble with is the serially produced Danish one that stands here as a test control).

He does recommend to the architects, however, the use of windpower to convert salt water into fresh water at their summer place in the Canary Islands. The Geesthacht Center finally succeeded this past spring in getting just such a wind-powered desalinator to produce certified pure water on Pellworm's satellite island of Hallig Suderoog.

There engineers have managed to get the kinks out of the prototypes sufficiently to tolerate the sudden fierce gusts of wind that so readily disable most of their models.

The solar panels over the fence have their own success as well in supplying the Pellworm spa with electricity. On the basis of this success Telefunken, in a race with Japanese and American firms, is aiming for bulk manufacture of its silicon modules this year. It hopes that by the year 2000 West Germany can acquire a 6 billion mark ($2.6 billion) share in the 2 percent of primary energy then expected to come from renewable sources.

So far the major hindrance to commercial solar cells has been cost. The key element of silicon - which releases electrons on absorbing light - is cheap and abundantly available in sand. But its reworking into the most efficient form of monocrystals is exorbitant. This made no difference in solar cells' initial use in powering spaceships in the 1960s.

Here on earth, however, the mid-1970s cost of 19 DM per kilowatt and even the 1983 cost of 2 DM is simply not competitive with today's 17-pfennig cost of oil- and gas-generated electricity.

Telefunken's answer is to produce the less expensive (even if at present only 10 percent efficient) silicon polycrystals - the form used on Pellworm. With this the firm anticipates getting costs down to 30 pfennigs per kilowatt within this decade.