Tuesday, February 5, 2013

Living in a Solar Powered Home

After the first question, “How much does solar cost?”, the second question people often ask is,  “What's it like living in a solar powered home?” For anyone considering (or just curious about) a solar powered home, here are some of our experiences living in a home powered by the sun.

First, a bit of background info. Our system is a grid-tie solar photovoltaic (PV) system mounted on the roof of our one story home. Grid-tie means the electric utility and our solar system provide power to our home. The PV system converts sunlight into electricity which we use in conjunction with the normal utility to power our home. We've had the solar system for 3+ years, and it provides roughly 1/3 of our yearly energy consumption. At times, when we produce more than we use, our retail electric provider (REP) buys back the excess energy. Our average electric bill is under $100. During a utility power outage, the solar PV system is shut down. This prevents the flow of electricity back to the grid (from the solar system), protecting equipment and utility workers.

Having a grid-tie solar system does not require any major lifestyle changes, although you do become more aware of your overall energy consumption. Peak production for the solar PV system is midday. To take advantage of this, it's advantageous to run pool pumps, washing machines, etc. during this time period. This is not required, but does reduce the amount you “sell back” to your REP and also reduces demand on the utility grid.  Another great tool for monitoring overall energy consumption (if you are in the north Texas Oncor service area , and have a smart meter) is to register your electric meter at smartmetertexas.com. With a smart meter, energy consumption can be easily tracked. And, with a solar system, it's always fun to look and see “zero” consumption during many midday hours!

Maintenance on the PV system does not require a great deal of effort, but if you periodically clean the solar panels, they will produce more energy. We use window washing equipment (mop, squeegee, extension pole/handle) to keep the panels clean. On a single story home this is not a problem, because we clean the panels from the ground. However, this can be potentially dangerous on multi-story homes, so alternative methods may be necessary. Occasionally here in north Texas, snow removal is also necessary to achieve maximum production. Other maintenance items are to make sure the underside of the panels are free from leaf clutter, visual inspection for nesting, loose wiring, etc. and to check the attic periodically for leaks. Occasional trimming of trees/shrubs may also be needed to prevent shading on the solar panels.

It's also important to monitor (if you have a monitoring/data collection with your system) daily/weekly/monthly energy production. Periodically checking this data can highlight inconsistencies or an issue with the system. Many system monitoring services also provide email trouble reports/alerts for malfunctioning equipment. A minor problem recently occurred on our system. We were alerted (via email) to the problem, which eventually required warranty replacement for the malfunctioning equipment.

Protecting your investment from peril is also necessary. Inform your insurance company of the added value of your solar system, and adjust your homeowners policy to cover replacement in the event of a hailstorm, other weather event, or even theft/vandalism. For example, last year, we had hail damage on the roof covering of our home. There was no damage to the solar panels, but the claim covered removing/replacing the solar PV system so the roof could all be replaced.

So, living in a solar home does require some extra effort. But the long term satisfaction of knowing we produce (at least a portion) our own power, outweighs the required effort. If you are thinking about installing solar, I hope these experiences help in your decision making process. Go solar!

Plano Solar Energy Advocate (RL)

7 comments:

  1. I too, live in a solar powered home, but I generate over 100 percent of my power, of which 14% goes to recharge a Nissan Leaf EV car. My average monthly consumption is about 1650 MWH. I have 54 panels, installed on 4 arrays, three of which are ground mounted. The only roof mount array I have is installed on a tractor barn roof (composition shingle). I have diligently tracked production, and notice absolutely no difference after washing down an array. (My installer, Mountaintop Solar of Boerne Texas tells me some of his other customers have similar experiences.) My panels use Enphase microinverters. Panels and inverters are easier to maintain on a ground mount array than on a roof. I highly recommend ground mounts. The only drawback to solar in Texas is our lousy PUC and its failure to enforce legislation already passed by the legislature to promote solar.

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    1. Very nice system! You are a "shining example" of near/net-zero. I assume you are still grid-tie; does your utility pay you back for excess generation? I agree, ground mount is preferable if you have the space, and ground mount arrays will keep module temperatures significantly lower, which will help production. I also agree that module soiling and cleaning would be very difficult to quantify in the field, but under STC (standard test conditions in the lab), soiling has been quantified, and is a factor. The derate factor (loss) for soiling varies, but is normally chosen as 0.95, or 5% loss), in system design calculations. Luckily, this year with the abundant spring rain, I have not cleaned my panels at all! I also agree the PUC of Texas has some catching up to do with solar, but keep advocating the benefits and hopefully they will get the message!

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    2. Our home and site is in Burnet County, near Kingsland, TX. We are served by Pedernales Electric Co-op (PEC). PEC netmeters us, and we trade one-for-one until I generate more in a billing cycle than I use. Then they re-imburse me only 3 cents per kwh, which is less than one half of wholesale. They don't even roll forward credits, month to month, as many utilities do. Thus, they really don't encourage solar in a meaningful way, even though they pay lip-service to renewables on their website. Hopefully this will change. By not rolling forward credits, no one in their right mind would install as system as large as mine, because during spring months I over-generate, and barely keep up in the summer. If your utility is kinder, be thankful!

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  2. I made a mistake on the previous comment. Avg consumption is about 1650 kwh, not mwh. (that WOULD be high! I have a slight disagreement with the author of the above post. I disagree that one should run pool pumps and washing machines at midday! Just like any grid tie customer, with or without solar, always shift arbitrary loads to off-peak hours - even night. By doing so you will help reduce peak load on the grid, a community service, and you will help your utility company (at night) use up some of that abundant west Texas wind, which peaks around midnight. You will net out the same, either way. When time-of-day metering comes (and it will) you REALLY don't want to run your pool pumps and washer/dryers at midday. Always shift arbitrary loads to off peak times, where practical.

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    1. No worries on the typo! For reference, my avg net consumption (adding solar generation and subtracting solar sold back) is less than 900 kWh/month. I also understand your statements about not running loads during midday, and for most this should be the preferred behavior. But, if you have on-site generation, you have some flexibility with this. I qualify my choice to run pool pumps (and occasionally washing machine) midday, because I am often generating excess power during midday, even in the summer, I don't generally run my AC during midday hours (mostly run at night), So, I choose to use the excess midday power (generated on site) to run my pool pump. So, no net on-peak grid power needed! I recently installed a variable speed pool pump which has further reduced my consumption and would highly recommend the upgrade to anyone who has a pool!

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  4. Nice post. Solar Energy is truly the main source of energy on earth and we are just using 0.001 percent of it, it should be used in order to prevent non-renewable sources of energy. Also solar energy is the most important form of energy it can be diverse in various forms.

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