Solar PV Excess - a blessing ? « Alternative Technology Assn Forums

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Solar PV Excess - a blessing ?

(34 posts) (16 voices)

Started 7 years ago by scipe
Latest reply from Benny

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scipe
Member

Rather than pay $400 - $500 per year for the 'privilege' of being connected to
the grid to allow yourself to be fleeced at 6c/kWh for your clean, green,
electricity, What about using all excess in onsite food production?

With better systems becoming available peeps may only be staying with grid
to export excess? Many may go off grid once reliability is proven, use for
Heating, ventilation, UV light, etc to augment/support growing of vegetables.

Hothouse or Food Wall, whatever, keep the low tech approach using batteries
for 24/7 if required. (Use up all those marginal batteries - failure would
not be major issue).

Stick it to the man, and get a feed at the same time.

?

Posted Thursday 21 May 2015 @ 12:55:16 am from IP #
David
Member

This does not make a whole lot of sense.

Good off-grid is very reliable indeed, what stops most people going off-grid or serious hybrid is the upfront cost of doing so. Having said that, I'm almost off-grid most of the time, but it's still cheaper to have the grid rather than use a generator for short fall power.

Posted Thursday 21 May 2015 @ 8:52:08 am from IP #
Johnnojack
Member

David is it time to have a heart to heart with a neighbor and use a extension cord from his house for your generator. You might pay 1/2 or 1/3 of his service charge plus metered power you use, win win.

Posted Thursday 21 May 2015 @ 9:19:20 am from IP #
David
Member

Johnnojack said:
You might pay 1/2 or 1/3 of his service charge plus metered power you use, win win.

No, not going to work for me. I have 3 phase, they don't. We run our office from the back of our house as well.

When we get to the farm that's fully off-grid from day one, but that's a whole different story. Anyway I do have generator in fact I have 4 of them of different sizes ranging from a baby 1KVA to reasonable sized one at 145KVA, and no that's not a mistake.

I design and install off-grid and hybrid systems. It one of my favourite types of work. Our home system is currently 8.2kW's PV AC-coupled, Selectronics 7.5kW battery inverter, 1000AH battery bank, etc.

It's, more I give them power when there's a long blackout. However the fact is the grid is cheaper ATM than running a generator. Even with the service/quarterly connection charges, generator service can cost more than the annual connection charges, not to mention one has to buy it in the first place, which is often forgotten about. Lets say a generator costs $5500 delivered, that's roughly 12 years of service charges at todays charges, without even starting it. Then you still have to service it, replace the starter battery in that time at least once, pay for fuel, replace air/oil filters, etc.

One may not like the grid but it does or can have a useful place, it's just taking the distributors a while to wake up. Tesla's battery has scared the crap out them, and there starting to wake up to the fact they had better play in the sand pit with the rest of use or things could go very poorly for them.

We export excess power when we don't use or need it.

Posted Thursday 21 May 2015 @ 11:49:20 am from IP #
Morbo
Member

maybe they just change the regulations, so people cannot have hybrids.
I recently sent an email to the VIC premier reg what Labor is going to do about the SFITs in VIC, no reply 3 days in.
Maybe send it again, with request for a "read" note.

Posted Friday 22 May 2015 @ 12:09:32 am from IP #
Johnnojack
Member

Ok then, sounds like you have it sorted pretty well already. Why I asked the question is, I was talking to someone a few days ago and their neighbour has a small standalone house system and could go off grid if he had a generator for those solar challenged weeks. Do you think in that case he could get away with an extension cord to the neighbour? Said neighbour might prefer it to having a generator running next door too. Would the best way to set it up be running a battery charger on the offgrid battery bank? What size is a $5500 genny? Diesel?

Posted Friday 22 May 2015 @ 6:57:05 am from IP #
Morbo
Member

what if you need just 1-2 kWh a day to get you through? Then running a camping generator 1 hr a day will just be enough to bump up the batteries? Still better then neighbours aircon 24/7

Posted Friday 22 May 2015 @ 10:50:55 am from IP #
David
Member

Morbo said:
maybe they just change the regulations, so people cannot have hybrids.

Some, Vic distributors make it extremely difficult or almost impossible to have hybrid system. But there are ways to have a system so to speak "off-grid" and distributors have no say in the matter.

Morbo said:
I recently sent an email to the VIC premier reg what Labor is going to do about the SFITs in VIC, no reply 3 days in.

Don't be surprised if it takes weeks to get response, that's typical for most pollies when they're in power. When in opposition they normally respond fairly quickly but of course can do very little apart from make some sort of promise that are totally forgotten when they do get into power typically.

The old SFIT finishes 31-12-2016 and goes the same FIT that is currently offered to those that install Solar ATM.

Posted Friday 22 May 2015 @ 12:13:19 pm from IP #
scipe
Member

gizmag.com 7 Jul 2015

Philips .. develops "light recipes"..

develop ... sustainable food virtually anywhere....enable local food
production on a global scale...using practically no land or water."
'energy efficient'

Philips Greenpower LED lighting is used".

Might make sense.

Posted Wednesday 8 Jul 2015 @ 11:18:22 am from IP #
sun2steam
Member

This ia already in use: in illegal marijuana farms!

Posted Wednesday 8 Jul 2015 @ 11:13:42 pm from IP #
Morbo
Member

and in Taiwan. They figured out, what frequency the plants responded best to and optimised LEDs.

Posted Friday 10 Jul 2015 @ 10:19:58 am from IP #
scipe
Member

gizmag.com/aerofarm july 9 2015

Aerofarms to open worlds largest INDOOR vertical farm"

New Jersey .. cutting edge growing technology .. in converted .. factory
(Oz has mountains of 'ruined' factories) to grow high quality and healthy
produce ALL YEAR ROUND."

serve local markets .. minimise farm-to-fork journey .. benefit environment
and the produce itself" ... LED lighting for photosynthesis...targeted to
maximize efficiency and MINIMIZE ENERGY CONSUMPTION. ... faster growing
cycles and more biomass"

elimination of pesticides (!) , increased product shelf-life, reduced
contamination risks"

75 times more productive per sq foot than traditional farming..
and uses over 95% LESS WATER... estimates capacity to grow 910,000 kgs of
leafy greens and herbs every year."

"scalable" *

Could make a whole lot of sense.

Posted Thursday 16 Jul 2015 @ 1:07:15 am from IP #
Morbo
Member

how about getting rid of that concrete in the backyard

Posted Thursday 16 Jul 2015 @ 5:09:51 am from IP #
Beaverlee
Member

Food production operates direct from the sun when PV panels are generating their heart out. I have yet to find a use for my excess power, so I may as well get 6c a kwH for it. And like the previous comments stated, even if the supply charge is equal to a gennie, its a lot more convenient, and I've already paid for the connection in the first place !

Posted Wednesday 22 Jul 2015 @ 7:49:46 am from IP #
sun2steam
Member

Probably the best use of excess solar energy is to use it to heat or cool the house using a reverse cycle air conditioner.

Even pre-cooling or pre-heating makes sense as there is thermal mass in a house and if you keep it warm during the day it will stay warm into the night. Or in summer you can cool the house while you are away during the day and you will not need to cool it once the sun goes down.

This can be automated. At the moment I am working to develop such a controller.

Posted Wednesday 22 Jul 2015 @ 12:38:08 pm from IP #
Morbo
Member

controller could work on the difference in temperature. Maybe could drive a fan first as well, in winter, when its warmer, get outside air in. Fan needs less energy and this would help, if there is not much sun, but warm ambient air.

Posted Thursday 23 Jul 2015 @ 12:03:13 am from IP #
Bushwalker
Member

Would you need a controller at all?

Just set the AC to Auto heat/cool, set the temperatures and switch it over to the PV as you leave the house in the morning. If you need heat/cool after the sun goes down, switch it back to mains. I guess you could automate the switch...

Posted Thursday 23 Jul 2015 @ 2:29:56 am from IP #
sun2steam
Member

Without some kind of controller the AC might be running when the sun is not shining.

Posted Thursday 23 Jul 2015 @ 5:45:40 am from IP #
Bushwalker
Member

That's the switch you throw when you head out the door to work. No way grid power will be powering the AC unless you reverse the switch.

If you want to make a controller out of it, all you need is a clock timer and a relay.

Posted Thursday 23 Jul 2015 @ 12:51:57 pm from IP #
807gt
Member

Excess solar pv power? Don't sell it to your electricity retailer for 6 cents per kwh ,push it into your hot water tank with a solar power diverter .I bought my kit from Mk2pvrouter.co.uk . I almost don't sell any power to my retailer and hardly ever buy off peak power. Very happy .(I am an electrician ) !

Posted Friday 24 Mar 2017 @ 8:56:21 am from IP #
EcoLocation
Member

The property we're planning to build on came with a shed so we put up a second hand 5kW solar system while we build, just to boil the kettle pretty much as we build. The advice I received when I rang a friendly solar company was to connect to the grid, there is the idea of contributing to the greening of the state.

It seems a bit strange to be collecting sunlight to power light to grow plants, could just put a green house up. Having said that I have bought a roll of red and blue hydro LED lights. Apparently stevia grows well hydroponically and costs a mint, pun intended. Also thought of putting a dehydrator full of fruit on to use up some of the power but again, could build LO-FI solar one and put it outside.

Posted Friday 24 Mar 2017 @ 10:42:50 am from IP #
Cissa
Member

Excess solar energy in my house for the cooler times coming will be utilized with 200 watt mini blow heaters and 60 watt towel rails in bedrooms and laundry(for old dog) with timers. So small, if it's cloudy not much energy to pay for.Working on overhead fans with thermostat in atrium for pushing heat to ground level when the sun shines.All extra in house warmth for the winter and great use of back to the grid 6c fit.Will add to heat mass, circulate air for growing winter salad greensand as an afterthought prolong the brewing season!

Posted Friday 24 Mar 2017 @ 9:47:42 pm from IP #
Benny
Member

I think thats a great plan Cissa. When my 40c Fit runs out and I upgrade from 1.5kW to 5kW PV I intend to do the same in winter. Although I have small rev cycle AC units - only 500W max input on heating so I plan to run the AC on those sunny but cold days and offset having to run it at night.

Posted Saturday 25 Mar 2017 @ 1:55:35 am from IP #
Bushwalker
Member

Given the ongoing and upcoming grid problems in SA and other states, definitely worth having some off-grid PV.

Batteries are becoming more mainstream and as demand and tech improves the cost will continue to fall. Bring it on. We still have a good FIT, but later might even add some off-grid PV for backup when the grid faults, and routine power draws like the HWS and lighting.

Posted Saturday 25 Mar 2017 @ 3:42:38 am from IP #
megamont
Member

The AEMO report into the system black acknowledged that there is now a need to source additional security from new technologies – such as storage and demand response, along with large-scale solar, wind farms, and household solar and storage – rather than relying on traditional coal and gas plants.

“As the generation mix continues to change across the NEM, it is no longer appropriate to rely solely on synchronous generators to provide essential non-energy system services (such as voltage control, frequency control, inertia, and system strength),” the report says.

“Instead, additional means of procuring these services must be considered, from non-synchronous generators (where it is technically feasible), or from network or non-network services (such as demand response and synchronous condensers). “

One of the big lessons of the event and subsequent reports is the need for a grid that is “smarter” and responds quicker to unforeseen events, and also for AEMO to better understand the performance characteristics of the plant at its disposal.

Posted Tuesday 28 Mar 2017 @ 5:23:44 am from IP #
oysters
Member

I read somewhere that there is a rule change in regulations that has just started, whereby if you have more than 5kw you can't connect to the grid (in any state) unless there is an exemption. The main issue with this is if your solar is more than 5kw, or, you have 5kw solar plus AC batteries with some inverters thus you can physically export more than 5kw at a time to the grid.

Does anyone know much about this?

Apparently if you have DC batteries and the right inverter set up then its not an issue. I would have assumed a modern smart inverter could also be set so that it can only export up to 5kw even if more is available.

I was also reading the other day that it seems like battery costs are set to plummet. With the new Powerwall 2 (and the previous one pushing prices down in the market), Powerwall 2 is now financially viable in all states of Aus (ie savings exceeds upfront cost, years to payback varies depending on circumstances of course). In a couple of years after I remortgage I'm going to install as many panels as I can (grid tied), and then a little later get batteries. I'll probably stay grid tied in the circumstances, as no doubt I'll be exporting to the grid (being my own little green power plant). I can't wait!

Posted Tuesday 28 Mar 2017 @ 11:15:03 am from IP #
Morbo
Member

just get as many panels as you need for yourself and then the minimum batteries to pull you through. There are no AC batteries.

Posted Wednesday 29 Mar 2017 @ 11:16:32 pm from IP #
Lance
Key Master

There actually are AC batteries, the enphase units for example are modular units that only have an AC connection, they have a regular DC battery with bidirectional inverter/charger, so they act for all intents and purposes as an AC battery. While technically the battery inside the box is DC, to the customer it is an AC battery, and that's how they are promoted.

Posted Thursday 30 Mar 2017 @ 5:54:33 am from IP #
rockabye
Member

Just returned from a Sonnen 'AC' battery system workshop in Launceston this afternoon. Almost plug and play. Typicall install 1 hour apparently.

They claim to be the first on the market with their system built in Germany and lithium battery made by Sony Japan. 10,000 cycle warranty which works out to be around 60,000kWh for their 6kWh model.

Posted Thursday 30 Mar 2017 @ 10:08:01 am from IP #
Cissa
Member

Tesla AC powerwall withdrawn from Australian market???

Posted Thursday 30 Mar 2017 @ 8:44:49 pm from IP #

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