Residential wind/solar installations?

[Happy]

Wait a few years and they'll have developed a commercial solar PV cell that runs at at least twice the current efficiency. Existing solar PV only uses the red wavelength of light whereas they are developing cells that generate electricity from all the visible wavelengths which will obviously improve efficiency.

This is only beginning.

I also read somewhere that every single brick and roof tile can be made to collect solar energy.
I saw report that window glass is able to harness solar power, we have many more developments coming.

Water tanks a while ago were not legal in residential area in NSW, unless I got it wrong and look now you cannot build a house without one.

 

[treefrog]

This is only beginning.

I also read somewhere that every single brick and roof tile can be made to collect solar energy.
I saw report that window glass is able to harness solar power, we have many more developments coming.

turn it up happy, if you want solar from roof tiles or bricks buy the black ones(dark colour)
if you want solar from glass face the window north

me/ I've been building passive solar houses for over 20 years and it is possible to build a 200m2 house in canberra at only 5% additional cost with "old fashioned" passive solar tricks so that no cooling is required in summer and precious little heating in winter is required (that was a single wood fire)

 

[Happy]

turn it up happy, if you want solar from roof tiles or bricks buy the black ones(dark colour)
if you want solar from glass face the window north

Passive solar is probably the cheapest solar system we can have right now.

But bricks, tiles and glass I mentioned were all used to produce electricity.

 

[wildkactus]

happy,
the technology you refer to is BIPV (Building integrated photovoltaics) interesting stuff and is in use now in a few buildings in japan.
but it will really take off i think once nanotechnology is perfected, which will allow more pvcells on to smaller and varied surfaces.

there is also a glass that has a film of transperant PV cells applied to it, that can be used in windows.

I think some of this technology was invented in OZ @ UQ, but could be wrong.

 

[Smurf1976]

Smurf I think we are talking about two different things here.

and regarding Hot water systems:

- Which is most efficient between rooftop Solar HWS or Quantum heat pump system?

- Can we direct the cold air from the quantum heat pump to some kind of refrigeration or air-con use... is there enough 'chill' to be useful ?
-dukey

There's nothing "wrong" with putting some panels on the roof if that's what you want to do.

But if your aim is to reduce CO2 emissions and you only have x $ to spend (either capital or annual cost) then there are a lot more effective ways to spend it that will save far more CO2 than solar panels on the roof. Simply buying green power from the utility being a lot cheaper and ultimately cleaner than DIY generation at home using solar.

As I said, there's nothing "wrong" with any of this. But if the aim is to cut CO2 then panels on the roof aren't the best way of doing it. Obviously there are some other benefits as you point out.

As for the hot water, it depends on location, whether you have cheap gas available and your hot water usage pattern. Also it depends on whether you want to save $ as first priority or if first priority is energy efficiency.

Solar with gas boost wins for energy efficiency under most circumstances. No real dispute about that one.

But if gas boosting isn't an option then it comes down to climate. If lots of sun then solar with electric boost will generally win. If it's a cooler climate (eg Vic, Tas) then the Quantum leaves any commercially available electric boosted solar water heater for dead.

Northern Australia expect to save 75 - 80% with solar. Vic / Tas it's realistically 50% at best.

Quantum expect to save 70 - 75% anywhere in Australia unless you live in the mountains.

Personally, I'd go for the Quantum for sure if frost is an issue. The solar units do have some answers for that, but they involve either loss of efficiency (heating the panels at night) or require ongoing maintenance (glycol based systems).

The Quantum and similar systems are a "drop in" self contained replacement for a conventional electric water heater. No panels anywhere and just the same maintenance as an electric tank - new anode every 5 years and perhaps a relief valve.

All that said, if you're going to be using electric boost or a Quantum unit then if you have gas available that's nearly as efficient as is (without solar). Not quite but it's a small difference and still a lot cleaner than a non-solar electric unit. Also cheap to buy, low maintenance etc too but not as cheap to run as any solar system.

So overall lots of choice here.

Outright worst choice (in terms of energy efficiency) - conventional electric

Best - solar with gas boost

In the middle and roughly the same (depending on climate) - solar with electric boost, Quantum and similar, conventional gas water heater.

If you just want cheap to run and fairly cheap to buy then I'd go for the Quantum or something similar. Only about $900 more than a conventional electric tank after the rebates and it requires no additional plumbing or wiring if the unit being replaced is outside.

As for cooling, yes you could use the Quantum in this way but it's not normally done in domestic situations. Just requires some ducting - not really profitable to pay for it usually but you could DIY quite cheaply if you're good with that sort of thing.

As for running costs, you'll need to know your local gas and electricity rates to work it out in $ but use the following consumption figures for a typical household. All figures are annual. The last figure in brackets is the approximate efficiency from fuel in ground to hot water at tap including all losses except in the hot water pipes after it leaves the heater.

Electric continuous (small tank) 5800 kWh (22%)
Electric off-peak extended hours 6300 kWh (24%)
Electric off-peak short hours (night only) 6800 kWh (23%)
Gas storage = 30,600 MJ (natural gas) / 612 Kg (LPG) (55%)
Gas instantaneous = 22,500 MJ (natural gas) / 450 Kg (LPG) (74%)

Electric boost solar (warm climate) = 1575 kWh (94%)
Electric boost solar (cool climate) = 3150 kWh (47%)
Electric heat pump (Quantum etc) = 1890 kWh (79%)
Gas boosted solar (warm climate) = 7090 MJ (142 Kg - LPG) (236%)
Gas boosted solar (cool climate) = 14175 MJ (284 Kg - LPG) (118%)

All the above are of course approximations for typical household usage. If you have 5 minute showers then it will be less. If you have 20 minutes showers, a spa and wash in hot water with 6 people living in the house then obviously your consumption will be higher.

Use your local gas, electricity and LPG rates and multiply the rate by the consumption to work out the cost.

 

[treefrog]

you lot that are rooting for PV and more advanced high tech solar power in residences really are dreamin' - off in cloud cuckoo land.

just received a formal quote from origin in the post - re the systems I was referring to earlier

an awful lot like the share market actually - hype and spin.
both 1w systems they quoted on will only deliver 4kwh per day (not the sales numbers of 6-7 they originally advised

working on 22c/kwh (as that is what will come off my bill if I go ahead) the total quote for a choice of either of two PV systems offered: price is the same for each - $13495 installed.
Now lets disregard the 8g the govt will contribute as that is my money anyway (taxes) and work the numbers on the basis that there is no free lunch and the system must be paid for - then someone has to provide all the loot at say 8%pa = $1079.60 in interest alone EVERY year until it needs to be replaced in total in 20 yrs - or $2.95/every calenday day. and that disregards ongoings of operation, maintenance, insurance etc
now the system is going to provide 4kwh every day (ave) and trim my elect consumption at a saving of 22c/unit = 0.88c/day or less than 1/3 return on the interest only (88/295 = 29.8% return) - helll that is just like the share market - buy for 2.95 and next time you check your shares are 88c
and that is paid forever as the original money is gone forever

as I said earlier - only the govt could get away with a promo like that

Is that really the best we can do with solar PV after what 20yrs of development.

And now we got new high tech solar bricks - they should be cost efficent after what, another 50years??

 

[treefrog]

There's nothing "wrong" with putting some panels on the roof if that's what you want to do.

But if your aim is to reduce CO2 emissions .

Electric continuous (small tank) 5800 kWh (22%)
Electric off-peak extended hours 6300 kWh (24%)
Electric off-peak short hours (night only) 6800 kWh (23%)
Gas storage = 30,600 MJ (natural gas) / 612 Kg (LPG) (55%)
Gas instantaneous = 22,500 MJ (natural gas) / 450 Kg (LPG) (74%)

Electric boost solar (warm climate) = 1575 kWh (94%)
Electric boost solar (cool climate) = 3150 kWh (47%)
Electric heat pump (Quantum etc) = 1890 kWh (79%)
Gas boosted solar (warm climate) = 7090 MJ (142 Kg - LPG) (236%)
Gas boosted solar (cool climate) = 14175 MJ (284 Kg - LPG) (118%)

very good stuff smurfy, but don't think there will be a lot of decissions made just on the basis of total energy efficency as much as anyone would like to decide on that basis. Capital + running costs (your advice there on how to calculate is great) + ongoings and replacement all need to be factored in and that is bundle more work - energy co's should be doing this anyway - total comparisons I mean - anyone know of any that do??

 

[Dukey]

G'day all ... Just to clarify how the payments for grid connected solar systems in Qld will work - here is the explanation from the Qld govt website ... most interesting bits I've marked blue. http://www.dme.qld.gov.au/Energy/solar_feed_in_tariff.cfm

How much will consumers be paid? (from Qld dept mines & energy website)

Customers participating in the scheme will be paid 44 cents per kilowatt hour (kWh) for surplus electricity fed into the grid””around three times the current general domestic use tariff of 15.45c/kWh (inc GST).

The rate of 44c/kWh is the same as the solar feed-in tariff paid to customers in South Australia. It is currently the most generous feed-in tariff paid in Australia.

The average consumer operating a 1 kilowatt (kW) solar system could save up to 25 per cent on their electricity bill by using electricity generated by the PV system and from payments received from the Solar Bonus Scheme.

The amount of electricity a customer returns to the grid will depend on how much energy is being consumed while the solar panels are generating power. Customers may be able to maximise their solar bonus by improving the energy efficiency of their home to export more electricity to the grid. This could be achieved by reducing standby power consumption, shifting tasks to the evening and minimising the use of air-conditioners.

Who is eligible to receive the bonus?
To be eligible to receive the solar bonus, customers must:

• consume no more than 100 megawatt hours (MWh) of electricity a year (the average household uses 10 MWh a year)
• purchase and install a new solar power (photovoltaic) system (not solar hot water system) or operate an existing system that is connected to the Queensland electricity grid
• generate surplus electricity that is fed into the Queensland electricity grid
• ensure they have an agreement in place with their electricity distributor (Ergon Energy or Energex) to have adequate metering installed.

How will customers receive the solar bonus?

The solar bonus of 44c/kWh will be paid for electricity fed into the grid at times when the solar system generates more electricity than the household or business is using at any instant.

The customer's quarterly solar bonus payment for this excess electricity will be deducted from their total grid-connected electricity consumption charge on their electricity bill.

The customer's grid-connected electricity consumption will also be lower (than without a solar system) as a result of the household or business consuming a portion of its electricity directly from the solar system.

If the solar bonus payments are greater than the total grid-connected electricity consumption charges over a 12-month period, the customer is entitled to have this balance refunded, rather than maintaining an ongoing credit with the retailer.

When can consumers start claiming the solar bonus?

It is anticipated that the solar bonus (feed-in tariff) will be available from electricity retailers by mid-2008.

For customers participating in scheme, the solar bonus of 44 cents will be offered until 2028, but is to be reviewed after 10 years or when 8 megawatts of solar systems are installed (equal to 8,000 systems of 1 kW capacity), whichever occurs first.

So - while it's still not enough to make it economic for most people - at least you would be getting payed/credited at the higher tariff whenever your systems produces more elec. than your household is using. (this for example might happen during sunny weekdays when everyone is at work or school and the 'house load' elec. is minimal). ... this is no doubt better than the case as I had assumed it to be... net metering averaged over the billing period - which would generally result in zero payments/credits for excess elec. production.

Just how much difference this payment scheme makes is difficult to quantify... need detailed individual household elec. usage data throughout the day....


Oh ... and thanks Smurf for your detailed figures / answers provided previously.