Solar Energy Use, Availability and Harnessing Questions

Bill,

A search on the net reveals a wealth of information and statistics on this topic, try searching for solar irradiance, solar power, energy efficiency, nrel, sustainable power, ata.org.au, homepower magazine etc. and you will overloaded with information. The trick is to put it into some form of perspective. For example, according to one publication, "an area of 1% of the Sahara could provide all the worlds' energy needs from solar thermal power stations". But what does that mean? You could try coming from the other direction. The average house (in Australia) uses about 20kWh of electricity per day. If you wanted to generate that amount of electricity you would need (depending on where you live) somewhere around 40-70sqm (square metres) of PV panels. Call it 64 for convenience. That's an area 4m x 4m (12feet x 12feet). That would easily fit on your house. But we haven't considered heating and cooking (often by gas) which could use twice as much energy so lets triple the area to about 200sqm. Now domestic consumption is about 30% total energy consumption so lets triple it again to around 600sqm. Now we have to find an area of about 25m x 25m (100feet x 100feet). If those PV's were installed on existing roofs (houses, factories, malls, bus shelter, etc) you could probably account for half to two thirds of the requirements and then you would have to find additional land for the rest. Of course this a very simplistic example, it doesn't consider solar heating which is much more efficient, it doesn't consider substituting fuels used for transport, energy efficiency and energy reduction (which make a huge difference) etc. etc. But you get the idea. The simple messages are that we can make a big difference by doing the things we do more efficiently and, more importantly, doing things differently. If a thing's not worth doing, it's not worth doing well.

Cheers
MOC

Of course 64sqm is 8m x8m (26feet x 26feet) but the comments remains valid.

One of the other problems would be the production of those solar cells. Not even considering the pollution, the energy required to produce X solar cells is approximately equal to the energy produced by those solar cells during the first two years of their life (this according to a seemingly-knowledgeable solar panel salesman I met at an energy fair this past summer). And this was supposedly THE efficient solar cell process (although for 'standard' semiconductor-based silicon solar cells, not any new potentials...). Creating the solar cells to offset 1/3 of the annual energy usage would require an investment of approximate 1/3 of the annual energy usage for two years (or, assuming facilities can be found and the tradeoff between facilities and energy usage is 'lossless' or reciprocal) 2/3 of the annual energy usage for a year. This doesn't begin to touch on the gallons of water used, the pollution created, etc... The other external costs of solar cell production... I'm not sure photovoltaics are the answer, even if they might be PART of an answer...

To: William Angel

Regarding your request for information on solar energy resources, I did a quick study for Alberta -- it is not hard to do. Every year we receive 300 times more solar energy on Alberta's land surface than we extract in all our coal, oil, tar sands, and natural gas reserves (and 50% of our natural gas is exported to America). I will communicate directly with you on this subject away from the CBSM list. If anyone wants more information on this subject they could send me an e-message.

Sincerely,
+Gordon Howell (=====Go OILERS Go=====)

D. Gordon Howell, P.Eng. BScEE (Alberta, 1975)
President, Howell-Mayhew Engineering, Inc.
Emerald Award (2002)
15006 - 103 Avenue Edmonton,
Alberta, Canada T5P 0N8
Phone : +1 780 484 0476 GMT-7 (Mountain Time)
E-mail : [email protected]

Do we question that in many places it takes a barrel of oil to get 3 barrels out of the ground? We need to apply the same standards to all f our resources instead of "picking on" renewables......

Thanks & Adios,
CJD
Carol Dollard

I agree completely... But I'm also very wary of technological 'magic bullets'. There is no free lunch in energy and thermodynamics, and I'm not convinced that covering the world in solar cells at the moment is the answer. I'm slightly more enthusiastic about wind power, wave power, tidal power... But they all have environmental impacts that tend to be externalized - not taken into account - and they all have the potential of doing harm as well as good. I do believe that solar energy is a viable alternative energy source. I'm not convinced it is the only answer or only alternative, and may not be the best (I would say the same about nuclear energy for some of the same reasons). The manufacturing process (and I'm certainly not an expert but have some knowledge of it) uses toxic materials as well as great amounts of energy (hence the two year energy/energy payoff period). The energy 'payoff' period is not bad with an expected lifetime of 20-30 years, but we haven't included the environmental destruction involved yet... I'm just tossing in a word of caution - technological fixes are often a means of taking a problem in one place and moving the problem to another location not as easily seen (we create much more food with petrochemicals than we ever did without, however, global warming, pollution, great wealth inequity and attendant hunger, and - potentially - a lack of investigation into more environmentally friendly alternatives are only some of the problems possibly related to that change in agricultural technique). All the solar cells in the world can't save as much energy as not using it.;-) I'm not an advocate of 'life in the cold and dark' either, but don't believe we can jump quickly on any 'fix' (unless the fix actually decreases our consumption rather than just moving our consumption around to a new location) without a more complete analysis than I've seen. It could be the 'out of the frying pan, into the fire' analogy again, and this one (think about the infrastructure created and wealth invested just to build the plants for these solar cells...) could be another monster that, despite good intentions, devours us. And, concerning the oil... We'd have to increase our oil consumption to create the solar cells. If we obtained the energy (with the assumption of no other investment or other environmental degradation) without increasing our consumption - by cutting back 'normal' energy usage in order to create solar cells - I'd be more supportive, off the top of my head. Now I'm just urging caution... However, there are 'other' solar technologies (passive solar heating of water, for example, and, potentially, some environmentally friendly photovoltaic films in development, or algae-based energy capture...) that are more 'ready for prime time'. Along with local food consumption, less travel with less energy use, decreasing our usage, etc... There are a great many ways that can act to 'save the earth' without any harmful side-effects whatsoever. Despite the sacrifice, we'd be better off implementing as many of them as we can at the moment and encouraging better research and analysis of future (near future, not the 'hydrogen future' falacy) alternatives. Anyway, far more than I meant to say, and it probably doesn't really express my thoughts and opinions (I'm not anti-solar, just very skeptical), but it's a retort!

;-> Peace - and conservation!
Pete

You have a sack of grain. You eat the sack of grain. The grain is all gone. You starve. You have a sack of grain. You plant some of the grain. You eat the rest. You harvest several sacks of grain. You plant some of the grain. You eat the rest. And so on... You have a bucket of oil...

Cheers
MOC