Midcoast Green Collaborative Forum

July 13, 2008

Sustainability Post #26 — Questions before photovoltaics

Filed under: Conversation, Information — Tags: , , — Topher @ 3:06 pm

Here are some questions to ask yourself before making the decision to install photovoltaic (PV) panels.

1. Am I sure I don’t have a micro-hydro resource?

If you have a stream which runs all year long, and it drops more then ten feet over your property, you should investigate putting in a micro-hydro generation system rather than PV.  It will save you a lot of money.

2. Am I sure I don’t have a wind resource?

Although not as cheap as hydro, wind is certainly cheaper than PV. You will need a reasonably reliable source of wind, and a tower tall enough to get about 30 feet above obstructions.

3. Have I taken advantage of all solar heat opportunities?

Solar hot water systems can heat much of your domestic hot water needs, and some of your heating needs, in most parts of the U.S.  Solar hot air is another option for heating the house.  Both are about 6 times as efficient as PV and cheaper.

4. Have I reduced my electrical use to the absolute minimum?

Solar photovoltaic panels are not environmental friendly to produce, don’t but any more of them than you absolutely have to to offset your electrical usage.   Replace all lights with CFLs or LEDs.  Improve the efficiency of your appliances or buy new high efficiency ones.  Get your family into the energy saving mindset.  Post the electric bill on the fridge, and reward those who help lower it.   Consider a heat pump to replace electric baseboard heat.

5. Is the place I plan to put them optimal?

If your prospective location is partially shaded, consider looking for another location.  Does your neighbor have a better spot; consider working a deal.  Can you sacrifice a tree or two to improve the solar exposure?

6. Does my state ave a net metering law, or a feed in tariff?

If you are going to connect to the power grid, you should be fairly compensated for the power you produce, otherwise the financial aspects are much less favorable.

7. What are the current tax incentives?

Be careful, some state offer rebates but only fund them for a limited number of applicants.  If you miss out, you get nothing.  The tax situation changes all the time, check on it often.

8. Does the power go out for extended periods of time (especially in the winter)?

Consider having some battery backup, even in a grid tied system.  Put vital systems on a separate circuit connected to the battery backup.

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5 Comments »

  1. What resources are you using for wind power calculations? I’ve done a bit of research recently and it looked like the payback period for commercially available windmill kits (small roof mounted and tower mounted) was +30 years or so.

    Comment by pale_chartreuse — July 16, 2008 @ 2:37 am

  2. Given the numerous variables involved, the recommendation is purposefully vague. If you have wind, it is worth investigating it over PV solar.

    For informational resources, I would recommend Paul Gipe’s book, and Solar Living institute. I wouldn’t recommend roof mounting almost any wind turbine.

    Concerning payback, if fuel were to follow the inflation rate it has over the last five years, in thirty years it will be $400 per gallon. How many gallons does that wind turbine have to offset at that rate? The truth is no one knows what energy prices are going to do, so payback is a poor way to look at these things.

    Comment by Topher — July 16, 2008 @ 7:52 pm

  3. Well, I’m usually not building for myself. I am constantly looking for tools to promote sustainability to my co-workers and clients.

    This is also known as the “No, you really don’t want to waste your money on the latest, sexy, recycled flooring/countertop/shiny thing, and then go around bragging about how green you are. You want to seal and insulate and green your power source first. Then you can look smug when the fuel bill comes in.” This argument is still astonishingly difficult to make, especially when the Value Engineering dudes start slashing the (capital, not operational) project budget.

    Comment by pale_chartreuse — July 16, 2008 @ 9:44 pm

  4. The only thing I can suggest for that situation is to convince the client that what matters is TOTAL monthly budget (you would think it wouldn’t be too hard a sell). That way any change in capital expense that results in a net increase in monthly budget, will look bad.

    Comment by Topher — July 17, 2008 @ 1:51 pm

  5. http://digital.designnewengland.com/designnewengland/20080708/?folio=60

    This is the article I was using to run numbers on wind power.

    On how to change people’s behavior: there is frequently a problem in the construction industry that the company that pays to construct the building are not going to own, maintain, or use the building long term. The developer may just flip the building to a new owner, lease the space and eventual fuel bills to others, or may be part of a large organization where capital budgets never have any real contact with operational budgets.

    (This is similar to your example of the mobile home problem. In that case the person who lives in the home may or may not be the owner. The owner of the land, who also provides the utility hook-ups, has no interest in the energy efficiency of the individual units and the actual owner/user may not have the funding or property rights to make improvements. Long term planning gets short changed all around.

    http://ca.youtube.com/watch?v=lAISHayc30I
    This is a link to a YouTube series of instructional videos for repairs and energy upgrades for mobile homes. I thought you might find it interesting.)

    That is why the best clients for a sustainability pitch are institutions like hospitals or colleges. These are clients that know that they will need to live with their decisions long term. You just need to show them some kind of metric on which to base their judgement. Developers and construction managers are a much tougher nut to crack, but I keep trying.

    Comment by pale_chartreuse — July 19, 2008 @ 10:08 am


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