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.