Grid-tied solar

[dave1949]

Another interesting article on future grid, grid-tied and off-grid perspectives around grid defection (off-grid) and load defection (grid-tied pv + batteries).

Utilities and Renewables Integration and Customer Behavior | The Energy Collective

 

[houstonscott]

Another interesting article on future grid, grid-tied and off-grid perspectives around grid defection (off-grid) and load defection (grid-tied pv + batteries). Utilities and Renewables Integration and Customer Behavior | The Energy Collective

I sure hope the AL batteries are real, cheaply storing enough energy to get through the night (AC or heat) would be a game changer, and utilities will find grid defections way up. HS

 

[dave1949]

I sure hope the AL batteries are real, cheaply storing enough energy to get through the night (AC or heat) would be a game changer, and utilities will find grid defections way up. HS

Yep, when the utilities rural customer base looks like Swiss cheese if 30%-40% of them defect, that would be a game changer. I remember in the 1970's land line phones subscribers paid a surcharge for being outside of town. I guess based on the theory that the phone company had to string miles of wire to pick-up a few customers.

The utilities would be losing their most expensive to own customers maybe? Compared to a multi-story apartment/condo building with a high density of customers, spread-out rural customers require more grid infrastructure to support and the cost of support tends to be higher with tree trimming, pole replacement and such.

In areas where residential solar makes sense, if cost-efficient batteries become available maybe 15-20 years from now a new home build or extensive remodel would incorporate an off-grid system as a standard part of the build package.

 

[buickanddeere]

More insulation and tighter sealing of buildings is cheaper than banks of batteries. heating or cooling a tank of water off peak is cheaper than batteries.

 

[dave1949]

More insulation and tighter sealing of buildings is cheaper than banks of batteries. heating or cooling a tank of water off peak is cheaper than batteries.

You can't plug your toaster into insulation or a tank of water though.

Those types of unqualified statements are energy anachronisms. "Cheaper" isn't just about your monthly utility bills. The real cost depends on the environmental footprint of the batteries and the utility's power sources.

A home with a low energy footprint always begins with insulation and air-tight construction such that air infiltration and air exchange with heat/cool recovery can be controlled. For heating in northern climates incorporating passive solar heat gain and thermal mass to store that energy is another basic starting point.

Incorporating those basic design elements greatly reduces the need for energy and opens the doors to other possibilities. For example, a battery could have a relatively large environmental footprint but needing only a small battery bank may allow that solution to have a smaller footprint than the utility power.

 

[houstonscott]

More insulation and tighter sealing of buildings is cheaper than banks of batteries. heating or cooling a tank of water off peak is cheaper than batteries.

Got to cover all the bases. HS

 

[buickanddeere]

I thought that is what I said. The typical peak loads in a home is heating and cooling. It's cheaper and more reliable to reduce energy demand than it is to install a larger battery bank.
It should be noted that many of these low demand "green" homes with low electrical bills operating on some solar cells and batteries. They happen to use a gas stove, gas water heater, gas clothes dryer and gas furnace. Nary a peep is said CO2 in that application.
Try a home and shop such as mine with an electric stove, electric water heater, electric clothes dryer and electric heat. Solar panels and a bank of batteries is cost prohibitive.

 

[dave1949]

I thought that is what I said. The typical peak loads in a home is heating and cooling. It's cheaper and more reliable to reduce energy demand than it is to install a larger battery bank.
It should be noted that many of these low demand "green" homes with low electrical bills operating on some solar cells and batteries. They happen to use a gas stove, gas water heater, gas clothes dryer and gas furnace. Nary a peep is said CO2 in that application.
Try a home and shop such as mine with an electric stove, electric water heater, electric clothes dryer and electric heat. Solar panels and a bank of batteries is cost prohibitive.

I know the use of gas is common for people who don't have any, or any cost reasonable, grid connection. There really wasn't any affordable alternative and the majority of those people are just interested in having some electricity for lighting, tv, laptop and phone charging, well pump, washer, etc. As the cost of solar pv declines there is less and less need to rely on gas.

We have an electric water heater, electric oven/propane cooktop, electric clothes washer&dryer, two mini-split units and a well pump. We use a little bit of auxiliary electric heat, and run the split units for AC in summer. We used ~45 gallons of propane this winter for radiant floor heat and cooking. Granted, our heating and cooling load is very light compared to a standard built house or a house in the hot south, and we are not raising a family.

Since August of 2012, we have taken a net 3,000 kwh from the grid. Just for round numbers let's say by August of 2015 the net take from the grid will be 3,600 kwh. That's 100 kwh per month average, or 3.4 kwh per day average, that a battery system would have to supply along with more pv capacity to charge the batteries. I realize there are no "average" days or months but that's what the gross numbers are as a starting point.

My very worst-case month was Jan 2014. I took 447 kwh more from the grid than I put in. Most net taking months fall in the 1-200 kwh range. If I were going to increase my solar pv and go off-grid with batteries, I would build a system that would supply basic power for two sunless days and use a generator to supply the rest. On or off-grid, a generator is usually needed for backup.

I'm not saying batteries are going to be useful for everyone, but I think the percentage of grid customers who "could" use them is significant. How many actually "would" is another question.

 

[deezler]

It should be noted that many of these low demand "green" homes with low electrical bills operating on some solar cells and batteries. They happen to use a gas stove, gas water heater, gas clothes dryer and gas furnace. Nary a peep is said CO2 in that application.
Try a home and shop such as mine with an electric stove, electric water heater, electric clothes dryer and electric heat. Solar panels and a bank of batteries is cost prohibitive.

Just about finished building my "forever" home for my family. Being 800 feet off the road and no fan of supporting the natural gas industry, we opted to go electric only. R30 walls, R55 roof, super tight envelope, earth-sheltered, and passive solar, including insulated & exposed concrete floors. So yes, we needed electric washer/dryer, water heater (went with a hybrid heat pump unit), oven/range, etc. And of course, plenty of electric heat - however between the passive solar and one modest woodstove, I hope to basically never use it.

Dave, your situation was and continues to be inspiration for me while I plan and finish my home build. I DEFINITELY plan to attain net zero with a modest bank of PV. No batteries until the **** really hits the fan and I no longer trust the grid.

 

[dave1949]

Just about finished building my "forever" home for my family. Being 800 feet off the road and no fan of supporting the natural gas industry, we opted to go electric only. R30 walls, R55 roof, super tight envelope, earth-sheltered, and passive solar, including insulated & exposed concrete floors. So yes, we needed electric washer/dryer, water heater (went with a hybrid heat pump unit), oven/range, etc. And of course, plenty of electric heat - however between the passive solar and one modest woodstove, I hope to basically never use it.

Dave, your situation was and continues to be inspiration for me while I plan and finish my home build. I DEFINITELY plan to attain net zero with a modest bank of PV. No batteries until the **** really hits the fan and I no longer trust the grid.

Nice house. I'm glad I inspired you. You have all the design elements in place for a low energy footprint. I hope you post some project pics.

A couple things I would do differently here after learning from experience:
1) AC. We lived okay without it for 7 years but threw in the towel last summer. Too much interior heat build-up in long spells of hot weather and too much humidity causing condensation on cool surfaces on and near the earth bermed north wall of the house.

2) I should have put in an air handler system with a heat recovery unit and make-up air.

3) I have never solved the problem of overnight condensation on the south windows in cold winter weather. Our winter indoor humidity level is nice, but those windows are the coldest thing in the room after sundown and drop below the dew point overnight. I prepared for it with slate window sills to avoid rot, but I'm not sure how to prevent it by simple low-energy means. I think it could be greatly reduced by moving warm air across the windows.

Regular heating systems with baseboards, radiators or forced air vents supply a curtain of rising warm air from being installed below a window typically. Putting your warmest air on your coldest surface is a recipe for rapid heat loss and that always bugged me, but I think there is a method to the madness after all.

Another possibility is insulated exterior roll-up shutters--known as rolladens. Rolladen Shutters Those would work also for sun control and cut some of radiant heating from the large windows in summer. You still get radiant heat from the windows even when they are in shade. All the houses in Germany have rolladens and we learned to really love them. They do a lot of nice things--storm protection, privacy, noise reduction, insulation, shade--and I wish I had installed them here.

Insulated drapes are useful but not a cure for the condensation because they don't seal enough air flow.

 

[ultrarunner]

I've wondered if we are setting ourselves up with grid tie...

The power company has already said it we be changing the price schedule to drop the higher tiers and replace the loss with higher baseline charges for simply being connected.

Water is already doing this... after 3 years of a steady drumbeat to conserve the utility is said conversation is affecting the bottom line so 33% across the board increase to make up for 25% less water use...

 

[ultrarunner]

Floor to ceiling wool drapes can make a difference... in the old days drapes had a wooden valance over the track to insulate and I only still see these in old homes..

 

[dave1949]

Floor to ceiling wool drapes can make a difference... in the old days drapes had a wooden valance over the track to insulate and I only still see these in old homes..

I remember those valences. They would help to trap rising warm air.

Yes, the power companies are raising basic service charges. Ours have gone up $2 per month in the last year. What choice do they have really? As more of the load defects their revenue declines. They raise charges and scare away more revenue. They are not in a good place to be with regular residential or light commercial customers in some areas.

 

[Kyle_in_Tex]

Ouch, while those Roladens are nice, you could double your pv for $12,000 for 12 windows' worth. Very nice storm protection though. Would be good for a person working night shift to darken the room in the daytime.

 

[ultrarunner]

Rolladen are almost standard in many parts of Europe for many reasons... security, insulation, protections from weather extremes... some of my friends would put them down every night... if there was ever a fire it sure would take a long time for the smoke to show... then again most homes there are concrete and concrete block construction.

I don't have any on my home since I have real wood shutters that latch from the inside... I do have double pane windows and all the new construction is triple pane now... even if only on the North side...

 

[dave1949]

Ouch, while those Roladens are nice, you could double your pv for $12,000 for 12 windows' worth. Very nice storm protection though. Would be good for a person working night shift to darken the room in the daytime.

Ya, that's one reason I don't have them. :laughing:

They are danged cool though. Until they are released to go all the way closed there is a small gap between each strip that lets in a soft light or a little fresh air if the window is open. In most German homes the rolladen housing is set into/flush with the exterior wall above the window. You don't see the housing box sticking out above the window.

The windows in German homes swing in like barn doors or tilt in from the top depending on how you set the latching lever when opening the window. They have doors that work the same way, plus the doors and windows have a more positive locking seal. The multiple latch bolts travel on a cam surface such that latching the door or window pulls it tight against the jam seal. They close against a lip all the way around the frame including the door threshold.

 

[Redneck in training]

I don't think you realize how fast this technology has changed, all your issues are talking points from 10 years past. I used $17 for a reason. The latest technology doesn't even use water to frack. HS

The drilling is the expensive part. Low flow formation require many usually horizontal holes and that is lot of drilling that has to be repeated as the well gets depleted.

 

[houstonscott]

The drilling is the expensive part. Low flow formation require many usually horizontal holes and that is lot of drilling that has to be repeated as the well gets depleted.

I know it works, I'm very close to a person who invested $500k over 10 years ago, those wells pay 50k a month today. HS

 

[Redneck in training]

I know it works, I'm very close to a person who invested $500k over 10 years ago, those wells pay 50k a month today. HS

THere are exception to everything. Typical fracked well in low permeability formation has short life. Most new sources are in difficult locations (expensive to exploit). Fracking was originally used to "rejuvenate" old depleted wells (I worked on such project more than 25 years ago). Only after the oil/gas cost increased it was used to exploit formations which would otherwise had very slow flow.

 

[buickanddeere]

Around here now that Net Metering has been abolished even though NM is still promoted on the hydro One web site. Have a look at the power bill and find the typical load from 9:00AM to 3:00PM during the daytime peak rate. Purchase enough grid tie inverter capacity and enough solar panels to cut your use of utility power to zero during the mid day peak rate.
It is windy here so it can be practical to install a small wind turbine to power the inverter outside of the six hours of prime sun.