Are We Green Yet?

Last weekend I washed down our thin-film photovoltaic array for the second time this summer. It's a matter of climbing an aluminum step ladder and squirting water at the blue black material stuck to the sheet metal roof between the standing seams. Muddy water slowly becomes clear and the film emerges to convert solar energy to electricity through its amorphous silicon cells at full efficiency once more.

Summer is dry and dusty in Upper Ojai. Last year the situation was exacerbated because our driveway had not been sealed and we were building the pool. Our suspicion is that we lost a great deal of PV efficiency through the months of June through September with the film caked in a layer of dirt. On October 12 last year it began raining and continued, on and off, for five days. Five or six inches of rain later, the PV was clean for the winter.

This summer we knew better. Topher Blunt Of Ojai Solar Electric who installed our PV (and the Shucco solar thermal panels for the hot water tank) now has a lucrative side-line in cleaning the solar arrays that he builds. He has the contract for washing down the 235 kW array at Santa Barbara City College he installed last year. Like selling razors at a loss to make money on replacement blades, his business model may subtly change to reflect this new service component. I suggested to someone at a dinner party, whose job it was to find 'Green' careers for ex-cons, that cleaning PV arrays might be a viable option. In any case, newly conscious of this maintenance aspect I did the first cleaning in July.

The PV effect was discovered in 1954, when scientists at Bell Telephone found that silicon created an electric charge when exposed to sunlight. Up until the I980's solar cells were being used primarily to power space satellites and smaller items like calculators and watches, although they had some agricultural and 'back-woods' applications since they could be used to re-charge 12V battery packs for lighting and small appliances.

However, there was enough buzz in the architectural community about their potential residential application that in 1981 I designed a single family house dubbed 'Ole Soleil' in a design studio at UCLA the model for which had a roof covered in a blue foil to indicate a PV material. A year later in Japan, again under the auspices of UCLA, I was attaching black wing-like elements to model robo-houses that were designed under the influence of the emerging solar power construct, samurai costumes and Gundam mecha (or robot) anime.

During the 80's and 90's solar power continued to exist in high-tech military and space applications, in small consumer electronics and kitsch items like lawn ornaments as well as on the Alternative Technology frontier where it was seen to have a potential political role in, quite literally, bringing power to the people.

By the late 1990's the architectural potential of the technology was finally realized with the first BIPV (Building Integrated PV) installation on the south and west facing curtain walls between the 37th and 43rd floors of a skyscraper in Times Square. By 2001, Home Depot was selling residential PV kits in its California stores.

But early in this century it became apparent that thin-film rather than flat-plate technology represented the way forward. Lorrie was flipping through the pages of Architectural Record in the summer of 2008 when she saw an advertisement for Uni-Solar thin-film solar adhered to a standing seam metal roof. Although the slab had already been poured for our Ojai house, and the roof specified as corrugated steel (with the expectation of installing flat-plate PV panels above it), we revised the specs and went with standing seam and in the spring of 2009 the solar fruit-leather was rolled out between the seams.

We have Stanford Ovshinsky (and his marketing team) to thank. Born in Akron, Ohio the son of a Lithuanian scrap metal dealer, he founded ECD (Energy Conversion Devices) in 1960; our thin-film PV's are manufactured (right here in the good old USA, in Greenville, Michigan) by Uni-Solar, a subsidiary. His pioneering work in the field of amorphous and disordered materials has become the enabling technology in thin-film photovoltaics.

Ironically, Suntech, one of the largest solar photovoltaics providers in the world has bet its future on old fashioned, flat-plate silicon and Wuxi, the city of 5 million that has grown up around its plants in China, now faces the prospect of becoming China's Detroit.

We narrowly avoided avoided the fate of using first generation technology at a moment in time when third generation PV using nanoparticle expertise and zinc oxide (sunblock!) is being developed at The University of Pennsylvania (Sierra, The Magazine of the Sierra Club, September/October, 2010). Green technology is a moving target. (One of the allures of passive-solar is that, give or take a heat exchanger or two, it's a timeless strategy.)

Our house is a product of its time. The Green zeitgeist of the mid-aughts mandated PV, radiant heating and geo-thermal HVAC. We adopted thin-film solar (just-in-time). We avoided the active radiant heating boondoggle (more on that another time) and decided that geo-thermal didn't really make sense if you could offset your straight-up air-source HVAC with PV generated power.

We also reached back into the the 1970's and 80's and to our education at UCLA where passive solar was king and expertly taught under Murray Milne and Baruch Givoni. Givoni's classic text,  Man, Climate, and Architecture, John Wiley & Sons, Hoboken, NJ, 1976 was, at that time, considered the most authoritative volume in the field of building climatology - at a time when green was a color, inexperience ..... and nothing more. For a while we toyed with the idea of a Trombe wall the ne plus ultra of passive solar.

A Trombe wall is a sun-facing wall patented in 1881 by its inventor, Edward Morse, and popularized in 1964 by French engineer FĂ©lix Trombe and architect Jacques Michel. It is a massive wall separated from the outdoors by glazing and an air space, which absorbs solar energy and releases it selectively towards the interior at night (Wikipedia) It works on the green-house (meaning, back in the day, a glass structure for horticulture!) principle whereby solar radiation passes through glass but is then trapped as infra-red radiation to which the glass is opaque.

We elected, in the end, to rely on the concrete slab to absorb heat on winter days and radiate it on winter nights for our passive radiant heating. The glazing is shaded such that no sun enters the house past April and only reappears in October.

Are we green yet? I've been around long enough to find the question exasperating. What I have done for the last thirty years is apply appropriate technology to the system requirements of human habitation. Our national reliance on dirty fuel for the majority of our electricity demands that we find ways to reduce usage (Passive strategies) and maximize on-site generation opportunities (Active solar - sun and wind); diminishing water supplies require a program of rainfall capture, grey water irrigation (or no irrigation) and reduced usage; waste management is covered by reduce, re-use and recycle of which reduce is the most powerful and potentially transformative dictum.

Was the green solution to stay in our 90 year old house in Santa Monica Canyon? Perhaps, but having built a net-zero-energy, recyclable-steel framed 100 year house ( based on our fire resistant strategies) it seems to me that we may have earnt the right to offset a little of that green angst that now infects us all.