The future of grid tied / interactive systems

Photowhit · March 2015

It appears that the Power companies are pushing back on Grid tied "net metering". Having to pay retail for a commodity they regularly pay less than half for... and having extra billing and service issues....

Might the future be systems that can produce all the electric for most of the solar day through an Inverter directly with a small Lithium or Capacitor reserve for the starting loads and some system to smooth out delivery basically a small "off grid" type system with very minimal(but highly productive) reserve, running from the grid during 50-70% of sunny days, but during lower use times...

Of course then the Power companies will want a minimum daily service...

verdigo · March 2015

My utility just installs a meter and whatever I produce kwh for kwh is subtracted from the next bill. I think its fair as my original intent was to build a grid backup system.

The inverter's ability to sell production above charged batteries is just gravy.

Photowhit · March 2015

verdigo wrote: »

My utility just installs a meter and whatever I produce kwh for kwh is subtracted from the next bill. I think its fair as my original intent was to build a grid backup system.

The inverter's ability to sell production above charged batteries is just gravy.

You, thinking it's fair is nice, but the utility may not think it's fair. Imagine you had a car lot and had to sell cars for exactly what you paid for them...

Power companies, all over, are increasing 'line fees' or 'availability fees' or splitting off the service fee and the per Kwh charge. This helps them compensate for the fact that the net metering law requires them to pay the same for the electric the buy from you as the electric they sell to you.

verdigo · March 2015

Photowhit wrote: »

You, thinking it's fair is nice, but the utility may not think it's fair. Imagine you had a car lot and had to sell cars for exactly what you paid for them...

Power companies, all over, are increasing 'line fees' or 'availability fees' or splitting off the service fee and the per Kwh charge. This helps them compensate for the fact that the net metering law requires them to pay the same for the electric the buy from you as the electric they sell to you.

The power companies are not being good sheep for Uncle Shepard I guess.

sub3marathonman · April 2015

Here in Central Florida, Lakeland Electric is perfectly happy, and has entered into a contract, to buy PV electricity from a company for $0.13/kwh, yet they're attempting to thwart individuals from having PV interconnected solar and purchasing that electricity from them for $0.10/kwh (including a $0.05/kw fuel charge credit) by forcing them into a "Residential Service Demand" rate high enough such that the demand charges will usually offset the solar credit the customer gets from selling that $0.10/kwh electricity to them.

But yes, they worry because they are guaranteed a profit not only on the electricity, but on the grid infrastructure required, such that less grid infrastructure means less profit too, so they can't have that.

verdigo · May 2015

My PoCo (Kentucky Utilities) ultimately gets it's power from TVA, which is government owned. The government doesn't require it's self to abide by the same rules as it requires private/public PoCo s to adhere to. Its kwh for kwh as far as credit goes and production over consumption does not accumulate past the next billing cycle.

DanKegel · May 2015

Photowhit wrote: »

Might the future be systems that can produce all the electric for most of the solar day through an Inverter directly with a small Lithium or Capacitor reserve...

Yup. Germany, parts of Australia, and now Hawaii and Arizona are all tiptoeing down the path of exposing customers to prices that carry information about the utility's real costs. It's not pleasant - losing high feed in tariffs and net metering makes solar less attractive - but it sets up incentives for adding storage.

There are many companies gearing up to offer storage, and Tesla's announcement gives them all a boost by validating the category. By this time next year, we'll probably start seeing a few actual grid-tied solar + storage installations that make economic sense (at least with the federal tax credit).

Photowhit · May 2015

My idea in posting this was to get people to think about a system that was a hybrid of a different sort with a very minimal battery, but lithium based battery that would allow for the high surge to start motors and the like during the day. So a system might run 'Off grid' during most days, with out the high expense for large storage, never intending to back feed the grid. The system would have to be over sized, but not tremendously... I can see a 3/4 year projected off grid days, allowing for higher draws in the Summer time for A/C.... just thinking outloud...

inetdog · May 2015

Photowhit wrote: »

My idea in posting this was to get people to think about a system that was a hybrid of a different sort with a very minimal battery, but lithium based battery that would allow for the high surge to start motors and the like during the day. So a system might run 'Off grid' during most days, with out the high expense for large storage, never intending to back feed the grid. The system would have to be over sized, but not tremendously... I can see a 3/4 year projected off grid days, allowing for higher draws in the Summer time for A/C.... just thinking outloud...

A slightly different approach from the Tesla Storage Wall, but benefiting from similar strides in battery technology.

JustinA · April 2016

One of the two electric companies I have access to charges $27 a month just to have the electric connection, regardless of whether you're using solar or not.

solar_dave · April 2016

Here is a good article about the utilities and the possibility of grid defection.

http://www.greentechmedia.com/articles/read/grid-defection-isnt-a-reason-to-fight-distributed-energy

BB. · April 2016

In California, they just pass laws (decades ago) to make leaving the grid (and Co-generation) illegal, unless you pay a bunch of money first.

Therefore, no folks illegally leave the grid.

...But they do disconnect your power if you don't pay your bill. And I have disconnected when doing electrical work. "Forget" to reconnect? (Downside is city can red tag a home with no utility power, and just having solar panels on your roof can be a violation if no permits/GT Solar exemption is filed with utility).

People who run the game, want your money.

-Bill

DanS26 · April 2016

JustinA said:

One of the two electric companies I have access to charges $27 a month just to have the electric connection, regardless of whether you're using solar or not.

Don't feel like the Lone Ranger.......my POCO charges $37.50 per month connection fee......where will it stop?

BB. · April 2016

I can hand wave that about 1/4 of an electric bill is fuel charges.

Roughly, about 3/4 of the charges are for infrastructure to supply 20-30kwatts at anytime and without limits.

So, I could "justify" a $100 standard electric bill as $75 fixed costs and $25 variable based on usage.

Presently (lasted I looked), in California, commercial power is around 50% (reservation) fixed cost, and 50% is based on usage. The fixed cost is based on 15 minute peak usage in the last 1 year period. Peak is either direction, load or generation.

And reservation charge also takes power factor into account. Lots of motors with bad PF, Bill is 1/PF larger (typically bad PF is 0.7 to 0.8). Good pf>0.95

-Bill

MarkC · April 2016

BB. said:

And reservation charge also takes power factor into account. Lots of motors with bad PF, Bill is 1/PF larger (typically bad PF is 0.7 to 0.8). Good pf>0.95

-Bill

Bill - in CA do the PUCs actually measure individual's PF? Most all articles of PF state that only large industrial users pay based on PF - but those articles are probably out of date! Makes me wonder how long our co-ops here in TX will give such generous rate structures to grid-tied energy producers. As you know, I'm working on another 3000 watts for my solar shed - beginning to wonder if a 10 year payout is really going to happen.

mike95490 · April 2016

The smart meters can log and report PF

BB. · April 2016

As far as I know (and that is not very far)--Reservation and Power Factor charges are for commercial users--And not every one will have a PF measurement/bill.

However, as Mike says, the new electronic utility meters are certainly capable of reporting many different factors back to the utility.

-Bill

littleharbor2 · April 2016

mike95490 said:

The smart meters can log and report PF

Big brother is watching.

MarkC · April 2016

I'm going to ask my co-op point blank if/can they monitor PF - and if so what do they do with the data.

bill von novak · April 2016

inetdog said:

A slightly different approach from the Tesla Storage Wall, but benefiting from similar strides in battery technology.

One interesting approach I heard was in reducing service sizes, from 200 amps down to 100 or 50 amps. In large homes this often isn't enough to power everything, so the balance comes from a shallow battery with a hybrid inverter. Solar then charges the battery as in a standard hybrid inverter.

This answers many of the issues utilities have - since they are required to supply less peak power the load on their infrastructure declines, as does the requirement to build out more capacity as population increases. It also allows users to offset power usage more directly since solar goes to recharge the battery first, and gets fed back second.

The future of grid tied / interactive systems

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