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November 7, 5:22 PMSF Environmental Policy ExaminerThomas Fuller

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Malcolm Drake, frequent commenter (and voice of reason) here, has often posted on his experiences with solar power. He lives in southern Oregon (my two years in Portland were not blessed overly much by sun, but the southern part of the state is quite different.

As part of what I really want to do with this space is to point out productive pathways to the future, I asked Malcolm to share his experience with solar power.

The world seems to be moving slowly, but inexorably, towards renewable energy sources. Many new energy sources hold promise-some more than others. But it’s too early to tell, really, because government subsidies, tax breaks, information, and misinformation all influence people’s choices and future options. Solar is, however, the world’s fastest growing energy technology: http://en.wikipedia.org/wiki/Photovoltaics

My favorite form of renewable energy is actually hydroelectric, for its benefit/cost ratio, lack of emissions, reliability, and the fact that it works 24/7. I particularly favor microhydro (small), as it generally does not require big dams and reservoirs. Unfortunately, regulations on microhydro can be quite onerous.

Photovoltaic, aka PV or solar electric, has some big advantages over almost any other energy scheme: PV panels have no moving parts whatsoever, no labor costs, ore costs, shipping costs, safety plans, etc. The only moving part in most PV systems is a tiny cooling fan in the inverter (the electronic unit that converts PV’s DC power to AC and synchronize the PV’s AC voltage and frequency with that of the grid, in order to sell power back to the power company, thus utilizing “the grid” as a de facto battery.)

The main ingredient in PV panels is Silicon (Si). Since Si is the second most common element in Earth’s crust, we’ll never run out of it.

Silicon “cells” are very thinly coated with “doped semiconductors”. Sunlight sends photons smacking into this coated Silicon, knocking loose electrons, resulting in a flow of (electric) current.

Currently, PV is expensive, but the guarantee is 25 years on panels, and 10-15 years on inverters. Here are some reasons people invest in it: 1) your home is too remote to economically hook up to the grid, 2) you want help lower the PV’s cost by stimulating PV production 3) you want to save on your electric bill, or even eliminate it entirely. (Currently, this is only feasible if you take advantage of state, federal, and/or municipal grants and tax credits. 4) You can sell power during peak afternoon hours, then buy it back at nighttime, off-peak hours, thereby economically charging the batteries on your electric vehicle. 5) You want to be a good role model.

Naysayers like to point out that PV power cannot be “stored. Well, it’s sort of true. The issue is that PV, like many other power sources, is not a stand alone energy source. It only works when the sun’s out. Although solar, at this point, cannot replace fossil fuels, it can certainly reduce our dependence on them. It’s one part of an energy system, which, in the short run, will likely include many renewable energy sources, as well as the good old fossil fuel standbys we’re all familiar with.

There are three basic types of power production: Base load, dispatchable, and intermittent. Base load power plants are large, and include coal, nuclear, natural gas, oil, and biomass plants. They run continuously, 24/7, but cannot handle large changes in demand for power, which occur from moment to moment.

Large hydroelectric plants can do that, and are thus baseload and dispatchable .

Solar and wind are intermittent power producers, for obvious reasons, and each depends on some of these other sources, especially hydroelectric, to utilize the grid as a de facto battery.

It is possible to store power from PV, wind, or other intermittent energy sources, in order to make it independent of the grid. Small PV (and wind) systems, especially where the grid is not available, generally use batteries to store power generated when there is sun or wind. Batteries, unfortunately, are expensive, need care and feeding, have to be replaced every so often. They also cause “efficiency losses”, perhaps 10-20% of any power stored in them.

A much less common PV (and other) energy storage scheme involves pumping water, during periods of excess power generation, to a higher elevation, giving the water “potential energy”. This water is later used to spin one or more turbines, thus allowing power use when it’s needed, instead of only when the sun shines (this turns PV, wind, etc into a dispatchable power source!)

I’ve been a renewable energy aficionado for 32 years, but only recently has it been economically feasible for me to get into PV. I investigated setting up a PV system in 2002, at which time it would have cost $11 per watt, for materials only. In 2003, thanks to the Energy Trust of Oregon, and Oregon state tax credits, I was able to buy a 3000 watt system for $7800 ($2.60/watt), including labor, permits, everything.

On October 21, 2009 I signed a contract for another 3000-watt system. The cost of materials only for this system is $17,177.50, or $5.73 per watt. That’s a drop of almost 50% since 2002; PV costs are clearly coming down fast!

The total cost of this system, including labor is $20,177.50. After grants and tax credits, it works out to only $2264.10, or 75 cents per watt. The electricity produced here in Oregon, at $0.075 per Kwh will be just under $400 per year, so my “payback period” is a bit over 5 ½ years. I’m also told that my system adds $5780 to my home’s value.  If you have a business here, even larger tax credits and grants are available.

Residents of other states likely have higher cost per Kwh, so their payback time may be much shorter. Look for federal and state energy agencies for details; at present, the Feds offer 30% of the PV system’s cost as a tax credit, while all states have different programs.

PV requires a sunny location. Many homes have one; almost all large commercial/industrial buildings do, on their roofs. And on the flat roofs typical of these buildings, no roof penetrations are necessary, so no leak worries.

Added bonus: since PV systems, like other “dispersed power sources”, provide power near where it is used, it eliminates the need to build larger transmission lines. Thus, it actually tends to improve the overall quality (accurate voltage and frequency) of power on the grid itself.