Off Grid Solar

Replies to This Discussion

Permalink Reply by Randy Chatterjee on September 20, 2011 at 8:13am

A couple questions.  

Why will the Smart Meter program complicate or render impossible the grid-tied option?  Wasn't that part of the program itself, to encourage distributed generation?  Of course a grid tie would also necessitate (by current code or practice) cutting power from your panels when the grid goes down, quite insane IMHO.

Are you parallel-wiring your house to keep the solar power separate from the grid power, or how else are you finessing the relationship between the two systems?

How much battery capacity do you figure you will need?

Solar Panels are dropping in price to now $1.50 to $2.50 per watt.  Has that drop helped to make you decision, which still is not an economic one here by any means?

I am rewiring my home (currently in gut renovation) for solar on the house and workshop roofs, and am leaving the panel area accessible enough to adapt to parallel circuitry, if necessary.  I am also planning on using a future electric car's battery for my backup/nighttime power in order to minimize, or obviate, grid flow.

Good on you, and please share your progress.

 

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Permalink Reply by Paul Pilon on September 21, 2011 at 1:34pm

Hi Randy,

 

I just don't want a "Smart Meter" on my home.  I consider wifi and microwave transmissions a form of pollution and I'll have no part of it.  If they come in a bi-directional unit then a grid-tied system is viable.  Unfortunately I've also come to the conclusion that grid-tied would be the same as me putting an oil rig on my property and selling the crude to Chevron to offset the gas I burn with my car.  So if I want to be ramp down my oil dependancy then I'm also going to have to go the same route with regards to electricity.  Otherwise I'd just be adding to the problem IMO.

The hydro will be cancelled and disconnected from my breaker panel.  What electricity I use will have to be generated by the solar array with a propane generator as a backup.  We have a natural gas fireplace so I'll remove the electric water tank and replace it with a natural gas hot water on demand unit that doesn't use any electricity (some do).  There are natural gas generators but they make more noise and are not built for continuous starts/stops.  Wind will also be looked at but I'll have to install an anemometer and trend the wind data 6 months to a year to see if it's feasible.  I think it will be.

I'm not sure how much battery I can get by with so that the generator doesn't run at all except under extremely lengthy low light conditions.  I don't care about lights or even cooking so long as I can keep my fridge and freezer going.  Those are the two priorities so you have to consider how much power those two use on a daily basis and then multiply that by how many days you're willing to go before you shut them down.  That could be a lot of battery.  I'm going with two 245 amp/hour batteries but I'll likely need to double that as soon as I can.  They are big, heavy lift truck batteries.   

The panels I'm using are made here in Burnaby by a company called Day4.  They are supposed to handle shading better than others.  I like that they're local.

 

 

 

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Permalink Reply by Paul Pilon on September 22, 2011 at 10:41am

Sorry, that'll be two banks of four 245 amp/hour batteries at 12V which is almost $2k per bank.  At some pont I'll be adding a wood burning stove and hopefully removing the NG fireplace.

 

The generator is going to cost me nearly $5k.  The solar equipment alone will be $25k $4k of which is the installation.  The hot water on demand will run another $4 installed.   On top of that I've been quoted upwards of $13k for a solar hot water system, hence the decision to go with the NG hot water system for now. 

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Permalink Reply by Paul Pilon on December 22, 2011 at 11:07am

The solar system is in place but hasn't been comissioned so we haven't disconnected from Hydro yet.  Parts that had to be ordered but were on "back order" and some logistics with regards to scheduling tradesmen with my schedule were impediments but even without the solar system we've managed to reduce our winter consumption of electricity considerably.  Last year this time we were using 40 kW/day and now we're down to 12kW/day with the addition of LED lighting, NG clothes dryer, and the hot water on demand unit.  We've also turned off the electric heating in all the rooms but the bedroom, which we keep at a nominal temperature.  Next we'll change to stove to a gas unit.

Obviously the gas bill is going to climb but I don't have figures to compare cost and consumption yet. 

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Permalink Reply by Rob Baxter on December 27, 2011 at 10:11pm

I have emailed Paul about this project but I thought I should post my comments here as well for other people who might come across this discussion.

First, I want to point out that 13k for a solar hot water system for a single family residence is very high.  Most homes should be able to do it for $9,000 - even less if you only have 2-3 people.  Plus there are incentives of $1,700 right now that would reduce that price further.

Taking a building that is currently grid-connected off-grid is not a good decision for most people.  Instead I would recommend making the building "net-zero."   This means that it would produce all the power that it needs but still be grid connected.  This is far better from an economical, energy and environmental perspective.

Let me explain why.   In this part of the world we get about 4 times as much daily sun energy in the best month (summer) than in the worst month (winter).  We also tend to use more energy in the winter than the summer.  If you want to go off-grid you would have to design a system that supplies you with enough energy for the worst month.   That means that the system has to be at least 4 times as big as it needs to be for the summer months.  So during the summer months your solar energy system is producing energy that is being wasted.  And all the energy and resources that went into making the panels is wasted.

If the energy system is grid-connected and you want to be net-zero you only have to design it for the annual average daily sun energy (because you can always get extra from the grid).  So it only has to be half the size.  And the extra energy that is produced in the summer is not wasted - it is put on to the grid and used by other buildings.  Because you are adding to the grid you are reducing the need for new large dam projects (like site C), run of river projects and importing dirty coal electricity from Alberta.

If a building needs to switch some of its appliances to natural gas or use generators in order to go "off-grid" that also creates problems.  The electricity grid in BC is relatively clean (about 85-90% is not from fossil fuels).  So by switching to natural gas green house gas emissions are greatly increased.  Also, although natural gas burns relatively clean there are still some particulates that cause local pollution and can lead to health issues for the building occupants.

I would encourage people to look at creating "fossil-fuel-free" buildings.  This could be done by making the buildings and loads efficient, using heat-pumps for space heating, using solar hot water, and then off-setting at least 10-15% of the electricity with solar photovoltaics (to match BC Hydro's GHG mix).

And it is important that you get good reliable advice about renewable energy systems before spending the money.

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Permalink Reply by Paul Pilon on December 28, 2011 at 10:36am

Hi Rob,

Thanks for the input.  All good points and I'm sure most people wouldn't consider an off-grid system.  The only reason I"m doing it instead of a net-zero/grid-tied system is to avoid the smart meter.  Had there been a hardwired unit I might have swallowed it but since that wasn't offered here in BC then it's just not an option I'm willing to participate in.   

As for increasing my GHG emmisions then you can thank BC Hydro for that but we'll be evolving the system to use as little NG and propane as possible but for now the house has to be liveable.  We'll be using a solar cooker when possible for example.  Solar hot water will likely be added to create a hybrid system in the new year as well as a small wind turnbine or two.  A wood burning stove and a sterling engine will find it's way in there somewhere too.

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Permalink Reply by Paul Pilon on January 2, 2012 at 12:09pm

Here's what the house looks like with nine 235W Day4 panels:

 

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Permalink Reply by Paul Pilon on September 28, 2012 at 12:48pm

So we've been running hydro free for some time now after adding 3 panels to the front of the house that faces east. Those panels start to charge the batteries early in the day.

During the summer we've been using our electric stove top to make rice or boil water for coffee/tea, never needing to run the generator to fill up the battery bank. I'll even distilled 30 litres of water during the day and I've yet to drain the bank to the point that the generator will start up automatically. I've tried running the clothes washer and dryer, dishwasher, and vacuum all at the same time with the computer runnning but it's not enough of a load. I run it for maintenance purposes and once every two weeks to give the bank a whopping big charge.

Now with winter coming I'm installing a gas range but I'm going to keep an induction stove top to use when possible. That and the Sun Oven we purchased, which I highly recommend, and we'll keep our gas consumption down as much as possible.

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Permalink Reply by Randy Chatterjee on October 5, 2012 at 11:48pm

Paul,
Do I understand correctly that you have 12 panels now, and all in the range of 235W max output? What total daily energy "harvests" are you currently bringing in?

For a couple weeks now I have had 8 Day4s of similar wattage connected from a south aspect garage roof. I pull in an average of 5 kWhs per day from all 8, reduced a bit due to some shading from an overhead power line onto two modules . The "best placed" panel has brought in 1.00 kWh in one day, but the average is closer to 625 Wh per module per day, a rated-power-to-energy multiplier of only 2.6 for the period of the equinox and in very sunny weather.

We in Canada are not by any means in an optimal location for PV, but it feels good to get currently half of our power from our own roof. We are still grid-tied, which I don't love, but we were not interested in spending more on batteries at this time. This may be a goal some day, and could help justify an otherwise suspect purchase of an electric car, which could serve dual purpose as both (nighttime) transportation and battery backup. However, as noted by Rob Baxter above, grid-tying has significant ecological benefits.

I, too, have additional roof space I could dedicate to more PV when the time comes, but a Solar Hydronic tie-in to our gas-fueled hydronic radiant floor system is next. This would make the biggest immediate impact on our GHG/carbon footprint, and likely provide quicker payback (if that were really the only reason to do it).

Module prices continue to drop, and soon we may see pricing below $1 per rated watt. I paid about $1.25-$1.50/w. More importantly, EROEI for the Day4 modules is still at least 2-3 years, so I am far from being able to brag about being more carbon neutral.

All in good time.
Randy

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Permalink Reply by Paul Pilon on October 15, 2012 at 10:27am

Hi Randy,

Yes we have 12 panels, three are 245W facing east for morning sunlight.

With an off-grid installation you don't get per panel info. I can tell what each of the strings of panel are doing for a given period by checking the charge controller for each set. On nice days it's not uncommon for me to produce 90 plus volts DC and 60 or 70 amps, all day. Now with the dingy weather we drained the batteries for the first time to the point that the generator came on and topped them up which took about two hours which I think is about 10 litres of propane. I've got to figure out settings for it to run more often but for less time as losses increase as heat builds up in the batteries and the generator. Yesterday when it rained all day we made maybe 2kWh. lol The max I recall was just under 15 kWh.

That's great that you took the plunge as it's a significant investment.

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Permalink Reply by Paul Pilon on December 30, 2012 at 5:17pm

Since november and december have been particularly dismal in regards to sunlight, the PV system has produced as little as 0.2 kWh and as high as 2.0 kWh. As a consequence our production has not kept up with our usage (about 3 kW/day) and we've been running the generator every Monday, Wednesday, and Friday for 2 to 3 hours in the afternoon. We're still on the original 400L propane tank but it's going to be filled soon so that should carry us through to the point where we won't need the generator. Not as good as I'd hoped but it is what it is.

The only other way to reduce our consumption would be to replace the fridge and freezer, but unless I find units that use a decent amount less I'm not sure there'd be any point. We don't use the dishwasher anymore and everything is plugged into power bars and turned off until needed. The clothes washer and dryer get used when the generator is running.

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Permalink Reply by Randy Chatterjee on December 30, 2012 at 7:20pm

The attached photo of my 8 modules' kWh production for November and December is also available here. Yes, it's been bad, very bad, actually since mid October...the last time we saw much in the way of sun. The grey line in the image below is the estimated output, and I did much worse, as little as 130 watt hours in a day. At 49 degrees north, it's basically a dark time of the year in a very dark area.

I expect to see just 17 kWh of energy this month (December) from a setup delivering 1500 peak watts. Doing the math, one way to look at this is that December will have delivered the energy of about 12 hours of peak summer sun, or between 2 and 4 days of average summer production. Call it roughly 1/10th of the summer capacity. And the fact is, by looking at the Science World and every other solar installation in this area, all did equally poorly. Installation is not the issue. It's the location, and its..our...weather.
If you want a wake up call, check out the energy return from ANY installation in Phoenix here. Sorry about that.

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