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Energy usage audit (and improvement)

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  • #469010
    dianne
    Participant

    Airgead post=313257 wrote: Generally you would need to swap inverters if you went from grid connected to standalone. You can apparently get some inverters that will do both. They are very common in places like India where the grid supply is not reliable so they have grid connect with a small battery backup. I don’t know whether any of those type are licensed for use in Australia. There are some safety issues that may prevent them from being used. Normally a battery backed system can not be tied to the grid for safety reasons.

    Cheers

    Dave

    Thanks for that :tup: was thinking along the lines of having a grid system until it starts to go on the blink and then switching to the stand alone system. So thanks for that.

    #469011
    Airgead
    Member

    RuddyCrazy post=313313 wrote: This is getting off topic but that thread I did before and the mention of the selectronic SP range inverters can be grid tie OR standalone.

    Yes. I do remember you mentioning them. You would need to check with you local supply authority before installing though. The rules are ever so slightly different in the various states. Nice product though. One unit that can do everything. Not sure of cost though. May be significantly more expensive that a straight grid connect inverter.

    Cheers

    Dave

    #469012
    Airgead
    Member

    slowlynow post=313308 wrote:

    If we all go ‘self sufficient’ in a world with diminishing resources it is in fact, hugely inefficient! Power grids are efficient, factory farming is efficient. Maybe not ethical, but resource savvy.

    This may not be what people want to hear, but I think it comes back to this blue planet’s biggest dilemma, too many people. Without technology and the most efficient way of doing things, there is no way we can possible survive in the long term!

    (Going ever so slightly off topic here)

    Indeed. Living simply doesn’t necessarily mean living alone…

    Its much easier for a whole group to live simply than an individual as resources and expertise can be shared. Going it alone means you need to produce everything yourself.

    Cheers

    Dave

    #469013
    DB346
    Member

    Airgead post=313345 wrote:

    If we all go ‘self sufficient’ in a world with diminishing resources it is in fact, hugely inefficient! Power grids are efficient, factory farming is efficient. Maybe not ethical, but resource savvy.

    This may not be what people want to hear, but I think it comes back to this blue planet’s biggest dilemma, too many people. Without technology and the most efficient way of doing things, there is no way we can possible survive in the long term!

    (Going ever so slightly off topic here)

    Indeed. Living simply doesn’t necessarily mean living alone…

    Its much easier for a whole group to live simply than an individual as resources and expertise can be shared. Going it alone means you need to produce everything yourself.

    Cheers

    Dave

    Further to above, I have to disagree with Slowly Now, our pre-existing Power Grids are extremely inefficient with only approximately 27% (according to a relative who works in one) of the power produced at the station, actually reaching the power using customer by the time it leaves the station and travels the grid, there is a constant residual loss the entire way. Me thinks in this instance 73% wastage is inefficient.

    Trying to confirm the power stations wastage rate on the WWW, but not having much luck.

    #469014
    Airgead
    Member

    DB346 post=313544 wrote:

    Further to above, I have to disagree with Slowly Now, our pre-existing Power Grids are extremely inefficient with only approximately 27% (according to a relative who works in one) of the power produced at the station, actually reaching the power using customer by the time it leaves the station and travels the grid, there is a constant residual loss the entire way. Me thinks in this instance 73% wastage is inefficient.

    Trying to confirm the power stations wastage rate on the WWW, but not having much luck.

    That’s sort of true… Typically the transmission losses are on the order of 30%. Another 30% is lost in thermal losses at the power station. Total losses are around 60% of the total thermal energy in coal (conversion efficiency of 70%… solar is closer to 15%…). The actual losses in transmission are only 30% though so 70% of the energy produced at the power station makes it to the consumer.

    Rooftop solar is produced close to load so the transmission losses are much lower. A grid with local production can be up to 90% efficient. Even with transmission losses its still far more efficient to grid connect.

    Peak loads can be 300% of steady load so you would need 3x the generating capacity to cover that. A 10% or even 30% loss is far less than that.

    Cheers

    Dave

    #469015
    DB346
    Member

    Hey Airgead,

    Where did you get those figures? Can you point me in the right direction to the website?

    I may have misinterpreted what my relative told me, but I am sure he said only 27% got to the customer.

    #469016
    slowlynow
    Member

    So you agree and disagree Airgead 🙂

    Sorry to drag this off course before. I am one of the ones who is trying to be one many living within society, who are living more simply! Trying to be a positive influence through actions, ie grid connect solar!

    Not trying to bring this down!

    #469017
    Airgead
    Member

    DB346 post=313550 wrote: Hey Airgead,

    Where did you get those figures? Can you point me in the right direction to the website?

    I may have misinterpreted what my relative told me, but I am sure he said only 27% got to the customer.

    Last year I was working for a major high/medium voltage switchgear manufacturer. If it was on the news my source would be described as “internal company documents obtained by us…”

    You can find some of this stuff buried in technical reports from the generation and transmission companies but its written in pure engineer and is a bit hard to follow.

    Cheers

    Dave

    Edit – Here’s a link from the ABS – http://www.abs.gov.au/ausstats/abs@.nsf/0/1DD46A713657BA33CA256E000075736B?OpenDocument its a bit dated (2002) but still relevant. Its all raw numbers not percentages and only covers transmission losses not generating efficiency. Their figures say 13 losses which is lower than mine but mine were newer and may reflect the higher loads on the grid which can make losses worse.

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