Residential Payback for Off-Grid Solar Q1 2023 (grid connected)

[philatio]

Here, utilities talk about the "Duck's back curve", power demand peaking in the evening. It is a lie.
Power demand actually peaks mid afternoon. PV peaks at noon (oriented West could peak early afternoon.)
Total of all demand minus PV is what yields the duck's back curve. (You could subtract any once source from all load and make a different curve.)

This was very interesting. I had to google it.

To me, this can easily be remedied if they did as many of us do. Add storage.

This seems like many other scenarios where legacy systems/business are trying/fighting against the inevitable.

If the internet is to be believed (ya ya I know), it took approximately 23 yrs for the automobile to replace the horse and buggy.

I agree with your stance @Hedges ... why should the electricity infrastructure be updated when the can shift the burden to those trying to be responsible.

Like water off a duck's back. Pun intended. This studied was model over a decade ago. Why are they sitting on their laurels.

 

[wattmatters]

Power demand actually peaks mid afternoon.

Grid demand or total demand? Different things.

Either way, here peak demand is still in the early evening. Removal of behind the meter supply just accentuates the peak. I guess different mixes of commercial, residential and industrial consumption in different regions affect the time of peak demand.

So far, time of use rates have not been imposed on consumers,

Well that's not helping. Price signals are needed to shift consumption behaviour, along with education and energy standards. My peak tariff is more than triple the feed in credit. 4:1 and higher ratios are pretty common here. Self consumption of solar PV is hence rewarded as is load shifting to cheap hours of the day.

A simple pager that receives a probability figure broadcast to all could knock a percentage of A/C offline or a while, thereby adjusting A/C power draw to utilize no more than available PV. Much cheaper to switch a 24V control signal than to build grid-scale or distributed batteries to store the same power.

Most larger aircon systems here have DRED control capability (it's a requirement they have it) but it's not something the grid operators have imposed or use.

I actually want to one day rig up my own DRED controller using Home Assistant automations (I have a buddy who has done this). It can set the aircon to operate at 0%, 50%, 75% or 100% of normal power. I want to be able to automatically knock it back to operate at lower power levels at night, especially during our peak tariff period once our solar PV is no longer able to cover it. Indeed if it can manage to operate at lower power levels most of the time I may even consider moving that circuit over to operate from the off-grid system. But our home's thermal properties need to be better than they currently are.

Given the abundance of PV, what we want is for consumers to pre-cool their houses when surplus PV is available, storing that energy in the thermal "battery" that is their house.

Using the home as a thermal battery is a good idea. It does however require a home with good thermal properties (hence the energy standards). Our home is less than stellar on this front. Bit by bit I am improving it but it will never be good enough to make this concept work. It just leaks too much heat - a function of its 50 year old design and build.

 

[wattmatters]

To me, this can easily be remedied if they did as many of us do. Add storage.

Yes, however the problem is residential battery storage systems (not DIY stuff like what we do) are very expensive and hard to financially justify, especially so while ever a region has 1:1 net metering.

Even when net metering is asymmetrical the tariff differentials may still not be high enough to make a battery worth while.

In Australia we need a commercially installed home battery system to cost no more than ~US$250/kWh for it to have a hope of being barely financially worthwhile. That's actually pretty hard to achieve with DIY (legally), and impossible for normal commercial battery installations. e.g. a Tesla Powerwall here is triple the price it needs to be to make financial sense.

 

[philatio]

Yes, however the problem is residential battery storage systems (not DIY stuff like what we do) are very expensive and hard to financially justify, especially so while ever a region has 1:1 net metering.

Even when net metering is asymmetrical the tariff differentials may still not be high enough to make a battery worth while.

In Australia we need a commercially installed home battery system to cost no more than ~US$250/kWh for it to have a hope of being barely financially worthwhile. That's actually pretty hard to achieve with DIY (legally), and impossible for normal commercial battery installations. e.g. a Tesla Powerwall here is triple the price it needs to be to make financial sense.

I am not talking consumer level storage. I am referring to grid level storage as is being done in your neck of the woods:

Tesla Megapack selected for big new 300 MWh energy storage project to help renewable energy in Australia

This seems a step in the right direction.

 

[wattmatters]

I am not talking consumer level storage. I am referring to grid level storage as is being done in your neck of the woods:

Oh OK. Yes grid level is going to be cheaper per kWh and be used far more efficiently and effectively from an overall grid perspective - such systems benefit everyone.

Grid level storage is really an interesting space to watch here. We just had this happen, where a grid battery project has outbid the pumped hydro options for a minimum 50MW 8-hour storage facility:

Eight hour big battery trumps pumped hydro in NSW long duration storage tender

First big battery with eight hours storage beats pumped hydro projects to win Australia’s first long duration storage tender.

reneweconomy.com.au

It is interesting because up to now it's been assumed batteries would struggle to be competitive with pumped hydro for grid storage beyond 2-4 hours of supply.

Here the state govt is tendering for storage as the state transitions away from coal power. One of our largest coal power plants ended operation just the other day. The state's largest coal power station will cease operating in 2025 (and is likely to become a site for a big battery). The state govt are looking to add 600MW of long duration storage between now and 2025.

I still think we'll get a mix of battery and pumped hydro, as having some technical redundancy for energy storage is prudent, and they can complement each other as well as provide some geographical diversity with supply.

 

[philatio]

Oh OK. Yes grid level is going to be cheaper per kWh and be used far more efficiently and effectively from an overall grid perspective - such systems benefit everyone.

Grid level storage is really an interesting space to watch here. We just had this happen, where a grid battery project has outbid the pumped hydro options for a minimum 50MW 8-hour storage facility:

Eight hour big battery trumps pumped hydro in NSW long duration storage tender

First big battery with eight hours storage beats pumped hydro projects to win Australia’s first long duration storage tender.

reneweconomy.com.au

It is interesting because up to now it's been assumed batteries would struggle to be competitive with pumped hydro for grid storage beyond 2-4 hours of supply.

Here the state govt is tendering for storage as the state transitions away from coal power. One of our largest coal power plants ended operation just the other day. The state's largest coal power station will cease operating in 2025 (and is likely to become a site for a big battery). The state govt are looking to add 600MW of long duration storage between now and 2025.

I still think we'll get a mix of battery and pumped hydro, as having some technical redundancy for energy storage is prudent, and they can complement each other as well as provide some geographical diversity with supply.

Good luck getting anything like that done hear it Texas.

They recently passed incentives on to natural gas companies because it wasn't far that the federal government only gave incentives for renewables.

Texas is a big oil and gas state. Politicians have to keep their campaign coffers full.

Just my jaded, cynical point of view.

 

[philatio]

Oh OK. Yes grid level is going to be cheaper per kWh and be used far more efficiently and effectively from an overall grid perspective - such systems benefit everyone.

Grid level storage is really an interesting space to watch here. We just had this happen, where a grid battery project has outbid the pumped hydro options for a minimum 50MW 8-hour storage facility:

Eight hour big battery trumps pumped hydro in NSW long duration storage tender

First big battery with eight hours storage beats pumped hydro projects to win Australia’s first long duration storage tender.

reneweconomy.com.au

It is interesting because up to now it's been assumed batteries would struggle to be competitive with pumped hydro for grid storage beyond 2-4 hours of supply.

Here the state govt is tendering for storage as the state transitions away from coal power. One of our largest coal power plants ended operation just the other day. The state's largest coal power station will cease operating in 2025 (and is likely to become a site for a big battery). The state govt are looking to add 600MW of long duration storage between now and 2025.

I still think we'll get a mix of battery and pumped hydro, as having some technical redundancy for energy storage is prudent, and they can complement each other as well as provide some geographical diversity with supply.

Good luck getting anything like that done here in Texas.

They recently passed incentives on to natural gas companies to build more plants because it wasn't fair that the federal government only gave incentives for renewables.

Texas is a big oil and gas state. Politicians have to keep their campaign coffers full.

Just my jaded, cynical point of view.

 

[wattmatters]

Good luck getting anything like that done hear it Texas.

Texas has some similarities with Australia. Similar population and a large land mass (although Australia is 11 times larger) and Australia too is fossil heavy with powerful lobby interests, and is the largest exporter of LNG in the world and the second largest exporter of coal in the world.

 

[Hedges]

Counterbalance to other places banning natural gas?
Natural gas burns clean, meets the need of heating and electric generation when other sources can't keep up.

And certain programs need the helium.

 

[wattmatters]

Natural gas burns clean, meets the need of heating and electric generation when other sources can't keep up.

Per unit of energy it results in fewer CO2 emissions than burning coal however it's still a significant source of emissions and we should be minimising its use where ever it is possible to replace it with low carbon sources of energy (e.g. solar PV/thermal, hydro, wind, nuclear).

Being a finite resource it makes much more sense to restrict gas use to industrial processes for which there is little alternative.

 

[sunshine_eggo]

Per unit of energy it results in fewer CO2 emissions than burning coal however it's still a significant source of emissions and we should be minimising its use where ever it is possible to replace it with low carbon sources of energy (e.g. solar PV/thermal, hydro, wind, nuclear).

Being a finite resource it makes much more sense to restrict gas use to industrial processes for which there is little alternative.

The single biggest, fastest and cheapest option to reduce CO2 emissions is to convert all coal plants to natural gas. Period.

 

[Hedges]

Natural gas usage should be maximized, to the extent it is a byproduct of oil production, getting vented or flared off.

At least for oil and gas leases (extraction of resources belonging to the government), we should ban the waste of either component. If it isn't cost effective to built pipeline or compress and carry in tanks, leave in the ground for now.

I agree renewables should be used instead of fossil fuel to the extent possible. Which means curtailment of PV/wind should be avoided. I think PG&E prefers to discourage rooftop PV (no profit in it for them), instead buying electricity from natural gas fired peaker plants which can be resold for a profit.

 

[wattmatters]

The single biggest, fastest and cheapest option to reduce CO2 emissions is to convert all coal plants to natural gas. Period.

Perhaps but here the big grid energy future supply auctions are all being easily won by solar PV and wind, with battery firming. Gas here is the most expensive generation source of electrical energy we have - it's the fuel of last resort.

 

[Hedges]

The single biggest, fastest and cheapest option to reduce CO2 emissions is to convert all coal plants to natural gas. Period.

And then use the coal in Australia to make hydrogen, which is sold to Japan?

 

[wattmatters]

And then use the coal in Australia to make hydrogen, which is sold to Japan?

Ugh. lol

Presently gas is used for that.

Green Hydrogen (e.g. water electrolysis using low carbon energy) has a loooong way to go to be a sound economic alternative. If it ever makes sense, I suspect powering long haul/bulk transport is its niche.

For global steel production we'll be using coking coal for a long time. Some pilot plants are testing use of hydrogen (assuming one day it can be economically rational) for steel production but scaling up is a massive challenge.

 

[Hedges]

Ugh. lol

Presently gas is used for that.

"Earlier this year, Japan and Australia opened a joint project in the state of Victoria to turn a type of coal called lignite, or brown coal, into hydrogen. The hydrogen is then liquified to minus 253C, then piped into a specially built ship which carries it to Japan."

Climate change: Is ‘blue hydrogen’ Japan’s answer to coal?

The Fukushima disaster turned Japan away from nuclear. A new energy source may help it quit coal.

www.bbc.com

6 December 2021

 

[wattmatters]

I doubt it will go ahead at scale even though Japanese govt has committed another couple of billion dollars for it and they have sent a small trial shipment. I think the benefit of this is more about demonstrating the ability to ship H2.

Japanese-funded $500m project to extract hydrogen from Victorian coal is at risk, sources say

Exclusive: funding requests, uncertain responsibilities and a failure to secure long-term contracts has critics asking if the fossil fuel-based venture is still a good deal

www.theguardian.com

It's an insanely dumb use of the dirtiest coal we have. Lignite can't be transported/exported because it's such a big fire risk. Either use it on site or leave it in the ground. It's behind some of some of the worst coal pit fires which often burn uncontrolled for years.