Debate switching to solar power

[kb58]

Yet another variable. Some power suppliers credit you for the power you make for the same amount that they charge everyone else. This is unsustainable as a business model (who's paying to maintain the grid)? For this reason, more and more (and likely, eventually all) suppliers will switch to giving you a very small fractional credit for the power you make, so give up any delusions of making big bucks selling power back to the grid. The point is, sizing the system to make the most economic sense isn't trivial, and usually ends up being smaller than what people want - which of course installers are all to happy to screw you over on.

One more thing is that you'll likely find is that your utility's pricing tier structure over a 24-hr period is will be nearly impossible to determine. Next to national secrets, power company's charges are a very frustrating and opaque thing, which is very likely on purpose.

 

[davidcarmichael]

Yet another variable. Some power suppliers credit you for the power you make for the same amount that they charge everyone else. This is unsustainable as a business model (who's paying to maintain the grid)? For this reason, more and more (and likely, eventually all) suppliers will switch to giving you a very small fractional credit for the power you make, so give up any delusions of making big bucks selling power back to the grid. The point is, sizing the system to make the most economic sense isn't trivial, and usually ends up being smaller than what people want - which of course installers are all to happy to screw you over on.

One more thing is that you'll likely find is that your utility's pricing tier structure over a 24-hr period is will be nearly impossible to determine. Next to national secrets, power company's charges are a very frustrating and opaque thing, which is very likely on purpose.

Actually they are moving to a basic monthly charge to pay for the grid in this area and leaving the net metering alone.
I think this is a better idea as everyone needs the grid whether they use a little or a lot of power. Might be tough on low income folks but I think they have price breaks in some cases.

 

[Janderso]

Are you going to stay on grid or are you thinking of going totally off grid? I believe the on-grid option is cheaper, the off- grid system requires a sizeable investment in batteries+ charge controllers and inverters plus more pv panels
Mark
ps my brother in Phoenix is contemplating an off grid system- the irony is that even though he's got plenty of sun the high outdoor temperatures require lots of air conditioning which eats up a lot of the system capacity

Boy, you would want a home that is built with the best high tech insulation known to man.
I didn't know, going off grid, was an option.

 

[mickri]

Back in the 80's there was a lot of hype about solar home heating with more options being floated than you could throw a stick at. I was doing RE appraisals at the time and looked into becoming an expert in the valuation of solar homes. Everybody was waiting for a study that was being done by a university in New Mexico. The study included a typical for the time building with typical insulation. Next was a very well built, well insulated building. Then there were well built, well insulated buildings each with a different type of solar heating. The end result was that 90% of the energy saving came from the well built, well insulated building and none of the different solar heating options added more than 10% energy savings.

Well built well insulated buildings are very tight. They don't breath and trap moisture inside the home. They have to have positive ventilation built into the home. This was unknown to me and when I remodeled my house at the time I did not provide ventilation for the home to breath. My super insulated tight home literally rained inside the house. I had to punch holes in the roof for vents and create small gaps at the top of the cathedral ceilings to create airflow. It was a mess. Live and learn as the saying goes.

 

[davidcarmichael]

Boy, you would want a home that is built with the best high tech insulation known to man.
I didn't know, going off grid, was an option.

It's not really an option unless you have no option.

The cost of batteries to store all of the solar, wind and maybe water energy you collect, so you can have electric power 24x7 is prohibitive and the control systems very complex. Added to this the fact that all (non-exotic) batteries have a limited lifetime, plus all of the insulation you would need, and you are talking about a lot of cash. Storing solar heat is less of a problem but even that requires a huge amount of well insulated storage.

 

[davidcarmichael]

Back in the 80's there was a lot of hype about solar home heating with more options being floated than you could throw a stick at. I was doing RE appraisals at the time and looked into becoming an expert in the valuation of solar homes. Everybody was waiting for a study that was being done by a university in New Mexico. The study included a typical for the time building with typical insulation. Next was a very well built, well insulated building. Then there were well built, well insulated buildings each with a different type of solar heating. The end result was that 90% of the energy saving came from the well built, well insulated building and none of the different solar heating options added more than 10% energy savings.

Well built well insulated buildings are very tight. They don't breath and trap moisture inside the home. They have to have positive ventilation built into the home. This was unknown to me and when I remodeled my house at the time I did not provide ventilation for the home to breath. My super insulated tight home literally rained inside the house. I had to punch holes in the roof for vents and create small gaps at the top of the cathedral ceilings to create airflow. It was a mess. Live and learn as the saying goes.

Have a look at this guy. He says all homes in the south are built wrong and backs it up with sound reasoning.

 

[mikey]

My home is 3,000 SF. All walls are insulated, as is the attic. I have a new Architect 80 roof with ridege vents, 2 large solar fans and have 4 Mitsubishi split system air conditioners, two of which run most of the day.

I had a solar water heater installed. This is an electric 80 gal heater that is powered during the day by 4 solar panels and off the house supply at night.

I have 29 Panasonic 330 HIT panels to supply the house, along with 2 Tesla Powerwalls. On sunny days, which is most days in Hawaii, my home is almost 100% supplied with this system. My home was 99% powered by this system in June and July.

My previous electric bill was over $300/month. It is now less than $27.00/month and $25 of that is the mandatory charge to stay hooked up to the grid so actual cost for grid supply now averages less than $2.00 per month. My system has been in place for about a year now and I like it. I also got a 30% Federal and State rebate so the cost was not too bad. I would say that whether or not a PV system is worth the cost depends on a large number of variables but for me, it was a good investment.

 

[markba633csi]

I have told my brother to take the number of panels he's been planning on using and double or even quadruple it- not sure if he believes me yet
but I keep trying

 

[Boswell]

When we built our home we built it with 12" think walls. Just build two standard 2x4 walls spaced 3.5" apart and then filled it all with fiberglass batt insulation. No east or west facing windows and large overhangs on the south side. I/R barriers on the East and West facing walls along with the roof. I agree with others that Insulation is the most cost effective way to save energy cost. different climates require different techniques though.

 

[Aaron_W]

On the site I recommended above, some of them are electrical engineers who've installed their own systems. They did a TON of monitoring and computations, finding that solar is a real mixed bag as far is being a net positive. There's cost of the equipment, installation cost (if not done yourself), daily exposure, equipment reliability, degradation over time, electrical pricing tiers, time of use (TOU) policies, etc.

Their strong advice is a bit surprising: consider simply using less power instead of installing solar. This is extremely telling, having people who "been there done that" came to the conclusion it may not be worthwhile.

During the evaluation for switching from generator to solar at the station I worked at, one of the things that was done, was having an electrical engineer evaluate the current lighting, appliances, HVAC etc. More efficient appliances means less power required. The cost of new appliances in some cases can be more than offset by the savings from reducing the amount of power generation required.

In that particular case, since the station was already on a generator, efficiency was pretty high, but one area we hadn't expected to change was due to the batteries. Our estimates for the solar field was based on the size of the current generator. The generator was oversized to handle the starting load of the HVAC. They were able to significantly downsize the solar field from our estimate, because the battery system was able to absorb the brief power spike caused when the HVAC started.