Some truth to people who think we can be 100% renewable

I made the same point. You have to consider total energy savings: home, office and commute. Telecommuters are saving time and productivity. They are no saving the planet AFAIK.
I'm not trying to save the planet. really. Just trying to have less impact. With less autos on the road...the reduction of dependence on oil products, pollution, etc. is ok by me.
 
Just saw reference to the Tesla Powerwall 'Storm Watch' Mode on twitter. A user in FL stated their Powerwall recognized a weather event coming and automatically entered into 'Storm Watch'. Great automation idea that the users do not have to think about as the system handles it. Seems like a useful general idea that all these types of systems would/should have.

Here is what the Tesla website says about that.

Storm Watch
When a storm or severe weather is on the horizon, increasing the likelihood of a utility power outage, Powerwall triggers Storm Watch. This mode automatically charges Powerwall to maximum capacity so it can provide backup power.

The Tesla app notifies customers that Powerwall has activated Storm Watch. The mode remains active until the weather event ends, at which time the system returns to its previously selected mode.

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New study done at hourly level for 100% renewable energy by 2050. Lots to digest for those that are interested.

http://energywatchgroup.org/wp-content/uploads/EWG_LUT_100RE_All_Sectors_Global_Report_2019.pdf

Honestly, i didn't read it. Skimming would be a dishonest word as well. While I'm sure the authors believe every word. It seems to me there is too much "and then, such and such is invented, improved, redesigned, made more efficient, etc." Wishing it were so doesn't make it so. A fundamental change of this magnitude doesn't happen by itself. Only a world government could even attempt it (I'm trying to avoid using the term "at the point of a gun" but it's difficult to believe folks would voluntarily change their entire way of doing things without "force" of some kind - for examples, think IRS.)

I'm all for reducing, recycling, reusing, decluttering, efficiency, lowering carbon foot print, etc. etc. I just don't think there is one road map to do it (especially not in 30 years.) I'm absolutely NO expert (talk to ERD50 for that) but I think I know human nature enough to know that this would be like herding cats to accomplish - if it would even work. BUT, YMMV.
 
I noticed Zillow has an option for a solar evaluation number for EACH home. So if you look up a house you can expand and click the URL which will pass all the parms to the sunnumber website:
https://www.sunnumber.com/

Roof assessment: Sun Number measures your roof, calculating the pitch, orientation, and size of each roof plane.
+
Solar radiation: Sun Number calculates the amount of solar radiation for every square meter of your roof.
=
Sun Number: We add in local factors and compute your home’s Sun Number score that will range between 0 – 100.

acU9RqU.jpg
 
I noticed Zillow has an option for a solar evaluation number for EACH home. So if you look up a house you can expand and click the URL which will pass all the parms to the sunnumber website:
https://www.sunnumber.com/

Roof assessment: Sun Number measures your roof, calculating the pitch, orientation, and size of each roof plane.
+
Solar radiation: Sun Number calculates the amount of solar radiation for every square meter of your roof.
=
Sun Number: We add in local factors and compute your home’s Sun Number score that will range between 0 – 100.

acU9RqU.jpg




Interesting, but probably false for mine... I have very little roof that gets sun as I have a LOT of large trees surrounding the house... it gives me a score of 70...
 
Just got back to this -interesting to see perspectives on energy in general. People generally get discouraged when trying to retrofit the 20th century electric grid to where we need to go. It is as you mentioned a physics thing. The current grid is highly vulnerable (squirrels in transformers are a leading cause of outages), never mind weather or intentional attacks on it. Most of us on this board have some memory of the 1970's and the gasoline lines. I'd like to keep my lights on at a minimum and some ability to move in a car.

I understand your skepticism since 90% of the claims I've read usually fail in terms of economics or engineering. Here are a few items just as food for thought for readers of where we are now or are going:

Commuting:
My bad on the post - I had meant to say "net zero energy", not "zero energy" which means electrification of course. There are lots of luxury options like $50K Tesla hooked to power wall battery, but if you're serious about financial breakeven, the current cost structure demands a used electric car like a $12K Nissan Leaf or $16K Toyota Prius. For me, I'd be willing to pay a few thousand more for the ability to keep moving if a major supply disruption occurs, so for us that would mean spreading bets-one gas powered, one electric, just in case.

99% of all vehicle trips are less than 100 miles, according to the federal highway administration.
https://www.fhwa.dot.gov/policyinformation/pubs/pl08021/fig4_5.cfm

Homes:
Since I know many people who live in these homes already I was a bit surprised at the skepticism on this board. A friend built a home in chilly Vermont that uses solar for both heat and light. The heat is done by using solar hot water to heat thermal mass in the basement. They never have cold floors to walk on. They have lived in the house for 5+years, so apparently it works. Another associate lives in a much more elaborate net zero home but I'd call that a "green bling" home ($400K or so to build) which is more of a fashion statement vs. economic, but even that was only 20% higher than local construction of a regular stick built home where we are. That said, they keep warm and the lights on when the rest of town is in blackout mode. That's worth something, and no electric or heating oil bills to pay.

Here's a general article from CNBC:
https://www.cnbc.com/2019/02/14/hom...-future-and-california-is-inching-closer.html

De Young properties, the actual builder featured in the article currently has the following models available. 3532 sq ft, 6br, 4.5 baths big enough for you? Apparently $450K-550K for that model, for those of us trying to downsize there's a 1764 sq ft model for the mid 300Ks. Those are California prices and pretty competitive from what I've seen out there for new development.
https://deyoungproperties.com/floorplans/icon-series/

The major roadblocks to progress are systemic. Centralized power is vulnerable to outages, distributed networks are much more robust. Some more food for thought for those truly interested in a better system:

1. look at DC vs AC appliances - inverters are a weak point and a waster of a small amount of energy. This takes work to do but is useful if you intend to generate solar power-you could eliminate inverters which need replacement every 5-10 years.

2. Storage is still an issue-lead acid batteries are cheap and 100 years old, so no one is advocating them for home use. They need maintenance (water in the cells) so that will eliminate many from trying this. The best options now are still lithium ion with fancy monitoring so people don't burn their homes down.

3. Solar hot water has been a profitable payback for decades. If you're going to do one thing, this is it.

4. Geothermal (i.e. swamp cooler) heat pumps are the next most profitable. You get heat and air conditioning benefits until you hit extreme weather (below zero and above 90), then you need a backup.

To use a real world example, when we moved into our current home in 2005, we cut the electricity bill by 30% by retrofitting lighting, insulation, and harnessing the passive solar potential of the home. It is a passive solar design and we get the inside up to 78 degrees on cold sunny February days just by having a home designed to maximize solar gain. We installed a pool and the pump runs a lot in the summer so we're not suffering by any means.

If we stay in our current home we would retrofit a couple geothermal units. They would supply 80% of our heat and all of our air conditioning, but I'd still want a backup of some sort. We have a wood stove for atmosphere not heating, but would rather replace that with one or two two propane gas fireplaces as a the fanciest way to back up the heat and add another creature comfort. The fireplaces would be about $2000-2500 each.

We have gotten estimates for solar electric systems but have 2 roadblocks currently. One is the electric box will need to be switched out (about $2K expense) and the other is we'd need to use ground mounted systems for another $5-6K additional expense) due to snow loads. And the garage is shaded so the solar vehicle would need ground mounts for 50% of the panels to do it cheapest. That said, over the last 10 years the cost for installing these systems have plummeted from $35K to about $24K before any tax credits etc. So it's getting there even in our case.

Of course the older we get the better the sunbelt looks, so we are looking to move south of here, and long term investment in this house seems not the best option at this point for us.

For those still reading this long boring post (hee hee):
For additional homework, keep an eye on something called software defined electricity (SDE). It is an emerging technology that has the potential to make the flow of electricity digital versus the current analog system. If fully implemented tomorrow, it could reduce the nations electric load by 1/3 as well as radically extend the life of many electrical items. It removes all the analog noise from electric waves in real time and optimizes them. Think of the noise as heat/energy loss and reduced lifespan of electric components.

Note, this is very early technology but my electrical engineer friends say it is not pixie dust and magic, it is possible. It will need decades to roll this out if it is scalable. First uses would be places like large computer server farms for a quick payback. One company leading the charge is 3dfs:

https://3dfs.com/

Hope this helps explain my optimism. The old folks when I was a kid were skeptical about cars, telephones and electricity. I guess it's part of the life stages we are at? I still like to think I'm about 20 in spite of what the mirror tells me :LOL:

An update for those interested in solar progress: We are finally switching over to 100% solar electricity! :dance:

There have been quantum leaps in the quality of systems since we last seriously looked a few years ago. Production efficiencies are now at 18+%, allowing an installation on our garage roof. That eliminates the extra cost of ground mounts or the snow load issues on our main home. When we last considered solar it would have taken about 20% more panels to provide power, so this is a huge plus for us.

Another major improvement since we last looked is the use of panel-level power optimizers to max out production. They monitor energy flow at the panel level and provide the best output for the inverter. Inverters now have a guaranteed 25 year lifespan, as compared to a 5-10 year lifespan when we first looked at them, eliminating the cost of multiple replacements.

The installed cost for a 4.8kW system, everything included before any incentives will be just under $19,500 including switching out the maxed out main electrical panel in the house for a larger one. Current incentives are $1000 for state tax credits, 30% Fed tax credits, and approx. $5000 in SREC paybacks over 10 years under the Massachusetts SMART program. Net cost about $7500. We will finance the rest and the loan will be paid with the cash used to pay our electric bill, which was averaging $1200 a year.

I was amazed we could get this done this year and greatly encourage anyone who has looked before to look again. A lot of the technical hurdles have been eliminated, and the federal incentives are starting to decline after 2019 (next year 26% vs 30%). Good luck!

We are planning on adding a battery system in a 2-3 years. The choices are OK now but everything points to a much better deal in the next few years on storage, so might as well wait.
 
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Thanks for the update. How much kWh does that system provide you with every month?

The recent heat wave really re-affirmed the need to focus on (or plan to upgrade) energy efficiency when we purchase our next house in a few years. We did some easy/cheap retrofit on our current 1980s house (didn’t even have insulation in the attic above 20% of the house when we bought it)
 
... A friend built a home in chilly Vermont that uses solar for both heat and light. The heat is done by using solar hot water to heat thermal mass in the basement. They never have cold floors to walk on. They have lived in the house for 5+years, so apparently it works. Another associate lives in a much more elaborate net zero home but I'd call that a "green bling" home ($400K or so to build) which is more of a fashion statement vs. economic, but even that was only 20% higher than local construction of a regular stick built home where we are. That said, they keep warm and the lights on when the rest of town is in blackout mode...

With enough solar panels and battery storage, anything is possible. The question has always been "how much it costs". I am very interested in learning the details.

...For additional homework, keep an eye on something called software defined electricity (SDE). It is an emerging technology that has the potential to make the flow of electricity digital versus the current analog system. If fully implemented tomorrow, it could reduce the nations electric load by 1/3 as well as radically extend the life of many electrical items. It removes all the analog noise from electric waves in real time and optimizes them. Think of the noise as heat/energy loss and reduced lifespan of electric components.

Note, this is very early technology but my electrical engineer friends say it is not pixie dust and magic, it is possible. It will need decades to roll this out if it is scalable. First uses would be places like large computer server farms for a quick payback. One company leading the charge is 3dfs:

https://3dfs.com/

The company Web site has a lot of hocuspocus mumbojumbo. Fast data sampling, fast processing, but for what and what do they do with the measurement data? It reads like the sale ads of the carburetor that can deliver 100mpg, or fuel magnetizer to polarize the gasoline so it burns hotter.

Many devices already have what is called "power factor correction" built-in. That helps, but does not reduce the electrical load by 1/3!
 
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Thanks for the update. How much kWh does that system provide you with every month?

The recent heat wave really re-affirmed the need to focus on (or plan to upgrade) energy efficiency when we purchase our next house in a few years. We did some easy/cheap retrofit on our current 1980s house (didn’t even have insulation in the attic above 20% of the house when we bought it)

Annual production will be approx. 4900 kWh annually. Monthly is variable of course. We did an LED switch out as well, more low hanging fruit if you have not already tried that, but insulation is a great investment for most older homes.
 
Is there something I'm missing?

Annual production will be approx. 4900 kWh annually. ...

An update for those interested in solar progress: We are finally switching over to 100% solar electricity! :dance: ...We will finance the rest and the loan will be paid with the cash used to pay our electric bill, which was averaging $1200 a year. ...

4900kWh annual and $1200 annual is about $0.25/kWh. In Massachusetts?


And what do you mean by "100% solar electricity" - are you off-grid? Where are the numbers for your storage?

-ERD50
 
For people who are curious about what to expect from a "typical" system, I just found the video of a guy who has a system installed by Tesla. Watching it will provide you with some real-life info.

Basically, he has 5.85 kW peak output from 18 solar panels, coupled with a Powerwall of 14 kWh storage capacity. The cost is $32,426 with $9798 in subsidy to make it $22,698 out of pocket.

The max that his panels could produce in a day was 32 kWh, but his max usage was 50 kWh due to the AC. Commenters are surprised that he uses that much, but it is reasonable. My max daily usage is 100 kWh, but my house is 2x the size, has a large pool, and I live in Phoenix where it is a lot hotter.

Skip to 6:40 where the guy describes the system, then enters into a discussion of how the system works in various days when it is sunny, cloudy, or hot, cold, etc... Of course there are days when his solar panels produce little, and his battery has run out the night before.

PS. This Tesla system does the "ET call home" continuously. If the Internet link is lost, it will shut down!

 
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As some of you know, I installed a DIY solar+storage system with 5.5kW of solar panels and 22 kWh of lithium battery storage. It's an off-grid system, which powers some circuits in the home separately from the grid. It does not feed into the grid at all, because it is not sanctioned to be grid-tied.

I installed a 1.5-ton minisplit heat pump to make use of this solar power. This was done mid June, and I saw some savings right away, but waited until I have a complete month for a good comparison to last year usage. And I just got the electric bill.

For the month ending 7/22/2019, I used 174 kWh on-peak, and 1138 kWh off-peak, for a total of 1312 kWh. Dollar cost: $158.

For the same time last year: 595 kWh on-peak, and 1720 off-peak, for a total of 2315 kWh. Dollar cost: $302.

It should be noted that an accurate comparison is not possible because the on-peak period was defined as 1PM-8PM last year, but changed to 2PM-8PM this year. However, the total kWh consumption is still valid, and shows a 1000 kWh reduction.

The above does not mean that my solar system produced 1000 kWh last month. I have not had it completely instrumented to know exactly, but am sure that I did not get 33 kWh/day. Rather, some of the usage reduction comes from raising the upstairs thermostat to 85F, while using the minisplit to keep the ground flloor at 77F. The 5 rooms upstairs are hot like heck, but they are unused with the children long gone.

PS. On-peak rate is $0.241/kWh, while off-peak rate is $0.073/kWh. Much of the cost savings comes from reduced usage during peak hours. The battery helps extend the system operating hours past 8PM to cover this. In fact, if it is not too hot, the battery was able to power the minisplit till next day. The 22kWh battery has plenty of capacity, but the solar panels do not provide enough juice to fully charge the battery while also running the AC during the day.
 
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Sounds to me if you use that 150/mo avg savings you come out to almost $1800 of savings annually. Of the system cost less than that it paid for itself in the year.

Our electric and gas bill (they are combined) was $99 for June and $150 this past month as we ran the air and fans a lot...it was hot.

2017 we used 6104 kWh
2018 6113 kWh
2019 so far 1100 kWh well below avg.

3000sq ft 2 story subburb of Minneapolis. I think it got down to like -30 this past February and up to 98 lat month. It sure does stay hot upstairs in the summer and cold in the winter. Not sure if that is all 2 stories or if we have insulation problems home bult in 90s.

Zillow gives our home a sun number of 20 out of 100. So essentially solar is not worth the investment since we see only 20% of the available sun others might get
 
As some of you know, I installed a DIY solar+storage system with 5.5kW of solar panels and 22 kWh of lithium battery storage. It's an off-grid system, which powers some circuits in the home separately from the grid. It does not feed into the grid at all, because it is not sanctioned to be grid-tied.

I installed a 1.5-ton minisplit heat pump to make use of this solar power. ...

Us DIY and engineers are waiting for that thread/blog to detail this system!


I was thinking about doing a small version, just for the hobby aspect. A solar panel connected to the freezer in the garage. The mental plan is to use a controller so that when solar power is greater than freezer average draw, I'd switch the freezer to an inverter on the solar, and drop the thermostat on the freezer a couple degrees, so it works to store some energy for over night.

The catch is the economy of scale just makes it silly, other than as hobby/demo purposes. The freezer draw is pretty low on average, but that surge current means I need a hefty inverter, and a hefty battery to handle that surge. Just not worth it for the ~ $10/month bill from the freezer (an old not great efficiency one, but not bad - better to use it than send it to a landfill, I think).


Sounds to me if you use that 150/mo avg savings you come out to almost $1800 of savings annually. ...

But he only saves that much during high A/C use months, not sure what the annual savings would be, but A/C must be used pretty early and late in the year, but some months will be less I'd assume. July must be near peak, AUG probably higher on average?

http://bit.ly/2y5Zw2S <<< short link to youtube

(note, trying a shortlink to avoid taking up so much space in the thread - the auto-display is nice sometimes, but just gets in the way for a small side note). I wish the full display was optional, sometimes good, sometimes too much clutter. Seems the mobile version does not auto display?

-ERD50
 
The dollar cost saving is high only in the 4 summer months, because of the AC usage during the expensive peak hours.

Other times of the year, the kWh usage is less, coupled with a lower rate (peak period and associated rate change with season. My monthly usage can be as low as $98 for 900 kWh in December.

With the total electric bill of $2000/year, how much of that will I save? :) Time will tell.
 
I was thinking about doing a small version, just for the hobby aspect. A solar panel connected to the freezer in the garage. The mental plan is to use a controller so that when solar power is greater than freezer average draw, I'd switch the freezer to an inverter on the solar, and drop the thermostat on the freezer a couple degrees, so it works to store some energy for over night...

You can do one for $600, and it may even run the freezer overnight. No modification to the freezer. And it can run something different than the freezer too.

Used 327W panel: $120
MPPT charge controller: $90
Inverter, pure sine wave, 1kW, brandname: $275
Marine lead-acid battery, 12V: $90
Misc. for DIY auto transfer switch: $20

Total: < $600

PS. NREL data shows production of 400kWh/year with the above panel in Chicago. How many years to pay back?

It might be worthwhile to add another panel or two, move up to a 2kW inverter, then you can also run a window AC in the summer during daylight hours.
 
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I was thinking about doing a small version, just for the hobby aspect. A solar panel connected to the freezer in the garage. The mental plan is to use a controller so that when solar power is greater than freezer average draw, I'd switch the freezer to an inverter on the solar, and drop the thermostat on the freezer a couple degrees, so it works to store some energy for over night.

The catch is the economy of scale just makes it silly, other than as hobby/demo purposes. The freezer draw is pretty low on average, but that surge current means I need a hefty inverter, and a hefty battery to handle that surge. Just not worth it for the ~ $10/month bill from the freezer (an old not great efficiency one, but not bad - better to use it than send it to a landfill, I think).
I've been thinking along similar lines. I even bought a panel and a small controller, I haven't sprung for a battery or inverter yet. The main purpose would be to provide some >small< amount of daily electricity in case of a long term power outage--enough juice to recharge cordless tools and flashlights, maybe run a fan at night. If I buy another panel and another battery, we could run a sump pump or a freezer, maybe. So, if I'm buying the stuff anyway, maybe I should find a day-to-day use for the power and set it up (and get some experience with it). The freezer in the garage might be an appropriate load for this.
 
NW, (and others with solar systems) how do your savings compare to the estimated savings shown when you plug in your location and electric costs on the Sun Number website? I'm curious to see if their estimated annual savings is reasonably accurate.
 
I looked at that Sun Number web site, and I don't know what their number means.

The only thing I can reliably use for planning, evaluating, and benchmarking is the number of kWh production that can be expected at a certain location.

Dollar cost savings depend on the rate plan that people sign up for. Here in Phoenix with SRP (a non-profit government-owned utility), there are 4 different residential price plans for non-solar users. People with a grid-tied sanctioned solar system, which is not what I have, are on a special solar plan.

With the time-of-use plan that I have, my goal is to minimize the power drawn from the grid during the peak hours. Only when there's extra solar power that cannot be used, that it should be carried into the night. Right now, I still use quite a bit of electricity during peak. I will be working to switch more circuits to the solar inverters.

Using more solar power as it is produced is better than storing it in the battery. It reduces the wear and tear on the battery. If the battery runs out at 8PM, that would be optimal cost savings. One kWh used during peak hours is worth 3 kWh during off-peak.
 
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I looked at that Sun Number web site, and I don't know what their number means.

The only thing I can reliably use for planning, evaluating, and benchmarking is the number of kWh production that can be expected at a certain location.

I think that's what this site attempts to do.

Did you put in your address and go to your estimated annual savings amount?

The site said a 24 panel system would save me $839/yr, and if that is accurate it would take roughly 20 years for the system to pay for itself.
 
Did you put in your address and go to your estimated annual savings amount?

I saw some numbers, but on what basis and assumptions do they compute that?

I try to figure out my own saving, using my actual electric rate and my own usage pattern, which would not apply if this were not a DIY system.

Double-checking this Web site can be done by someone with a commercially installed system, not an odd-ball system like mine.
 
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By the way, SRP has its own solar calculator for a grid-tied system. I used it, and it said the payback period is "Never"!

Now, SRP is a non-profit government-owned utility. :)

PS. SRP calculator is pretty slick. It looks at Google satellite map, and figures out how many panels can fit on the roof, and in what orientation.
 
By the way, SRP has its own solar calculator for a grid-tied system. I used it, and it said the payback period is "Never"!

Now, SRP is a non-profit government-owned utility. :)

PS. SRP calculator is pretty slick. It looks at Google satellite map, and figures out how many panels can fit on the roof, and in what orientation.

Any chance you could provide a link?
 
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