Footprints for Sustainables

[Thelema]

Did you know that a solar panel needs 30 years of functioning at optimal performance before it pays for itself?

Or that electric cars comparatively actually use more CO2, because the amount of coal [usually] used to generate the electric kJ produces more CO2 than a similar amount of petroleum?

Or that experiments using mass-bio fuels with maize find that the net CO2 output is 20% worse than the oil-fuel scenario?-due to still poorly understood mechanisms whereby plants exude CO2.

Or that wind farms will never be profitable, because the expense in erecting and maintaining them will NEVER outweigh their output?

In short, there are many side-steps to the problem, but in terms of the bigger picture, there are still no better energy technologies than oil-based fuels- even from a long term prospective- that reduce the overall burden on the environment, when one considers cost of construction and maintenence.

[Torsten]

Most of what you have written is very poorly informed - at best outdated and at worst misleading.

Did you know that a solar panel needs 30 years of functioning at optimal performance before it pays for itself?

This is bullshit. A solar array will only take about 8 years to pay for itself at current electricity prices. The battery storage required may add another 5 years to this if you are looking at the full set up. This is an improvement from about 10-15 years ago when it was 20 years for a system to pay for itself.

The new sliver technology will bring the price of the panels down so that the solar component of a system will only take 4-5 years to pay for itself. ie, in the next 2-3 years it will be possible to have full domestic systems that will pay for themselves in under 10 years. These figures are supported by the CSIRO and plenty of practical experience both scientific and of my friends. I have looked into this a lot as we intend to run our property on solar [have done it before, but at a smaller scale].

Or that electric cars comparatively actually use more CO2, because the amount of coal [usually] used to generate the electric kJ produces more CO2 than a similar amount of petroleum?

This is misleading. The idea about e-vehicles is that they charge up on offpeak power. Off peak power is essentially free as it is not possible for generators to slow down their turbines enough between peaks and troughs. It takes about 48 hours to stop a turbine, so the most they can do is slow it down about 30%. That 70% of power is being generated regardless of whether it is needed or not - and it isn't. Charging your car at night would simply make use of the power that is wasted and hence it is actually not adding ANY CO2.

Or that experiments using mass-bio fuels with maize find that the net CO2 output is 20% worse than the oil-fuel scenario?-due to still poorly understood mechanisms whereby plants exude CO2.

HUH? Plants and oxidations can never produce more than 100% of the carbon absorbed by the plant. So, at worst a biofuel can be carbon neutral. That is of course as long as the machinery used in production and transport is also run on biofuels. And that is the problem at the moment. We use petrodiesel tractors to harvest the biodiesel fuel, which means some 40% of the fuel produced is already negated by it's production. Add to this the fertilisers and you have a totally ineffficient system. Corn and wheat will not be the ethanol answer for the future. Sugar cane will be the primary crop in the tropics and switchgrass in the temperate zones.

Or that wind farms will never be profitable, because the expense in erecting and maintaining them will NEVER outweigh their output?

I think you meant to say this the other way round, because the way you said it actually supports wind energy.

Anyway, whoever said this would have to be quoting statistics from over 25 years ago. Wind power has been profitable in many parts of europe and the USA for many years. Companies have been building wind farms without subsidies as profitable businesses for many years now. Lots of venture capitalists are entering the market because they see big money in wind.

In short, there are many side-steps to the problem, but in terms of the bigger picture, there are still no better energy technologies than oil-based fuels- even from a long term prospective- that reduce the overall burden on the environment, when one considers cost of construction and maintenence.

In short, this is the biggest piece of tripe I have read about alternative energies for years [except Howard's regular idiocy]. Use some updates figures and educate yourself about the technologies before passing such judgement please.

[Torsten]

Did you know that a solar panel needs 30 years of functioning at optimal performance before it pays for itself?

Solar panels cost retail about $8 per watt capacity.

I don't know how to calculate 'optimal performance' figures as they do not apply to any calculations I have done before. For my region the calculation is maximum out put for an average of 8 hours per day.

This means a 1W panel produces an average of 8W per day.

Over a period of 30 years this would be 88kW.

At 20cents per kW [incl GST] this would mean equivalent grid power would cost $17.60, ie more than twice as much as solar and hence a panel would be paid off after about 13 years.

However these figures are skewed and specific for australia. Australian power is extremely cheap because of our coal reserves. Once the true cost of coal [ie carbon trading] is added to this, the cost of our electricity will go up dramatically. Even the power generators themselves agree that a 15% [over 5-10 years] hike based on a carbon subsidy is a good move, so chances are the hike will be greater.

You would also need to take into consideration the increase in the price of electricity over the next 30 [ie 15] years. While deregulation has given us a few eyars of low bills, we have seen that in other countries this has led to a degeneration of the grid which was generally followed by a hike in prices.

Either way, we will not be enjoying 18 cents per kW for much longer. And with every increase over the next 15 years the solar panel pay off time is reduced.

Also, you can't just look at the pure dollar for dollar amounts. To 'pay for itself' one should also take into consideration the massive reduction in pollution, the independence from a less and less reliable powergrid, and the wasted power that is generated to keep our power on standby.

What I have calculated above is for home solar set ups only as this is what I am most interested in and know more about. I admit solar still isn't a great financial alternative yet for homes, but this is quite different from commercial production.

Commercial producers buy solar panels at less than $3 per watt, ie less than half of retail. So when a factory wants to supply it's own power they can have a solar generator nearby that delivers them power at $3/Wh indefinitely. That means the panel has paid for itself in under 10 years. Considering that industry consumes 40% of all power and 60-70% of all daytime/peak power this would be a massive saving for generators and the business.

Solar is so attractive as a commercial power source because it is a desirable base generator, ie it produces the most power when it is most needed. This can dramatically reduce the need for slow reacting base generators such as turbines.

Solar is also still in it's infancy. The technologies are being revolutionised right now, instantly cutting the cost of panels by 50%. Then once these go into mass production in china they are expected to drop another 50-70%. ie, in 10 years time we will likely be buying unbreakable solar panels at a mere $2/Wh in retail, which will bring the time to pay off a panel down to under 4 years.

Now, faced with the option of having your set up paid off in just 4 years and never having to pay another power bill, it won't take people long to comprehend the advantages.

obviously solar poower isn't for everyone or everywhere, but in australia I think the majority of homes can be run on rooftop solar system for no more than 10 years of powerbills in the very near future.

The future is very sunny indeed.

[reshroomED]

Solar panels cost retail about $8 per watt capacity.

I don't know how to calculate 'optimal performance' figures as they do not apply to any calculations I have done before. For my region the calculation is maximum out put for an average of 8 hours per day.

This means a 1W panel produces an average of 8W per day.

Over a period of 30 years this would be 88kW.

At 20cents per kW [incl GST] this would mean equivalent grid power would cost $17.60, ie more than twice as much as solar and hence a panel would be paid off after about 13 years.

The 'optimal-performance' part of the figures is the wattage rating of the panel, and relates to anyone who uses such. In real terms you'll get closer to 3W/day (per 1W panel in eight hrs daylight). And it isn't quite as simple as that, but close enough for what we're speaking of).

 

However these figures are skewed and specific for australia. Australian power is extremely cheap because of our coal reserves. Once the true cost of coal [ie carbon trading] is added to this, the cost of our electricity will go up dramatically. Even the power generators themselves agree that a 15% [over 5-10 years] hike based on a carbon subsidy is a good move, so chances are the hike will be greater.

You would also need to take into consideration the increase in the price of electricity over the next 30 [ie 15] years. While deregulation has given us a few eyars of low bills, we have seen that in other countries this has led to a degeneration of the grid which was generally followed by a hike in prices.

Either way, we will not be enjoying 18 cents per kW for much longer. And with every increase over the next 15 years the solar panel pay off time is reduced.

Also, you can't just look at the pure dollar for dollar amounts. To 'pay for itself' one should also take into consideration the massive reduction in pollution, the independence from a less and less reliable powergrid, and the wasted power that is generated to keep our power on standby.

What I have calculated above is for home solar set ups only as this is what I am most interested in and know more about. I admit solar still isn't a great financial alternative yet for homes, but this is quite different from commercial production.

$/KW is simple, you'll save money.

BUT, the energy required to create a solar panel and battery bank is far greater than the average panel will produce in it's work-life, so you're not helping the planet at all.

ed

[Torsten]

The 'optimal-performance' part of the figures is the wattage rating of the panel, and relates to anyone who uses such. In real terms you'll get closer to 3W/day (per 1W panel in eight hrs daylight). And it isn't quite as simple as that, but close enough for what we're speaking of).

yeah, I suck at maths. Although, with sun tracking this number increases. Also, the 3W is based on the older 11% efficient cells.

In the process of recalculating this I did find a few other bits and pieces of interest. For example, that manufacturers give 25 years warranty on panels. This means that the expected life is well in excess of the 30 years generally cited. By calculating the benefits over 40 or 50 years we would nearly halve the costs again.

BUT, the energy required to create a solar panel and battery bank is far greater than the average panel will produce in it's work-life, so you're not helping the planet at all.

OK, I had heard this before and dismissed it. Now it intrigues me, so I did a bit of research.

Keep in mind that the following is about panels from the late 90s. We have increased efficiency of production and of the panel itself quite dramatically since then.

"The total energy requirement to produce a PV panel is 1,060 kWh/m2. In Sydney the useable panel output will be 153 kWh/m2/year [0.42 kWh/m2/day], giving an energy payback time (EPBT) for the panel of 6.9 years. After mounting in an open field or on a roof the EPBT will be 11.5 or 8.3 years respectively."

http://www.ecotopia.com/apollo2/pvepbtoz.htm

So, under 7 years for the panel alone. This would have been for 14% [theoretical] efficiency panels, so subtract 2.3 years for the new ~20% panels, which leaves 4.6 years. The silicon acccounts for about 60% of this, with the other 40% being mostly for the aluminium frame. This frame is no longer needed with the new sliver cells. The amount of energy required for sliver cells will also be only a fraction of the crystalline wafers. ie, the new sliver panels will have no frame [-30%] and maybe a third of the silicon cost [-40%], which means the new panels will be a mere 30% of embodied energy compared to the 90's models. That brings the EPBT down to just 1.5 years.

This is for the panels only though. Very little has happened in the way of domestic electricity storage and I am hoping for some important breakthroughs in that field. At the moment the panels represent about 60% of both cost and embodied energy, which leaves 40% for the rest of the system. By far the largest chunk of tihs would be the batteries. So, you're looking at another 5 years EPBT for the batteries.

So, even if there are no advances in either panels or batteries, the total EPBT is under 15 years, which is the number cited by many researchers on both sides of the discussion. I could not find a single decent research reference that suggested a panel would not pay for itself in it's lifetime.

The advance into sliver technology is a done deal, so within the next few years this will drop to well under 10 years [even without battery advances].

[foolsbreath]

This is misleading. The idea about e-vehicles is that they charge up on offpeak power. Off peak power is essentially free as it is not possible for generators to slow down their turbines enough between peaks and troughs. It takes about 48 hours to stop a turbine, so the most they can do is slow it down about 30%. That 70% of power is being generated regardless of whether it is needed or not - and it isn't. Charging your car at night would simply make use of the power that is wasted and hence it is actually not adding ANY CO2.

As a side note, this is also why the move to fluorescent lighting is thought to be a red herring, as most lighting is used at night and with present power consumption we are not using the base load (that 70%), changing light sources will have absolutely no effect on power consumption until a way to significantly reduce the base load is found. All we are doing is fattening the light producers pockets and increasing the mercury finding its way into land fills

Before i found this out, I changed about half my lights to compact fluoro's and have had the same number of incandescent and CF' bulbs fail to date!

[Anodyne]

There was a doco on SBS last week about alternative energy sources in which one of the guys claimed that some major breakthrough had be made in the solar storage problem by a US company & would be available within a few years. No hints though, which was a bit annoying.

As a side note, this is also why the move to fluorescent lighting is thought to be a red herring, as most lighting is used at night and with present power consumption we are not using the base load (that 70%), changing light sources will have absolutely no effect on power consumption until a way to significantly reduce the base load is found.

There are still advantages - fluorescents have much longer lives & seem to survive where incandescents pop (power fluctuations, faulty wiring or whatever). Also, if you're running your house on solar power/generator/whatever, that reduction can be very important.

[Torsten]

There was a doco on SBS last week about alternative energy sources in which one of the guys claimed that some major breakthrough had be made in the solar storage problem by a US company & would be available within a few years. No hints though, which was a bit annoying.

As they were using solar thermal energy I would think they use a way of storing the heat in a heat sink, rather than storing the electricity.

[Guest Øskorei]

Apologies for butting in and referring back to the earlier parts of this thread, but....

Did you know that a solar panel needs 30 years of functioning at optimal performance before it pays for itself?

To quote the first response to the opening thread... This is Bullshit. If a typical family is paying $200 per quarter (being conservative), or $800 per year for their electricity bills, then by reasoning of simple calculation, that's $24,000.00. Actually, if I have just calculated my spreadsheet correctly using a 2% per year CPI increase, the figure is $32,454.46 over 30 years.

With current technology, there is no way that a solar system, combined with stand alone solar water, would take 30 years to pay itself off.

There were NSW government rebates available a while ago, and although the applicants exceeded the available funds, with the shift towards alternative energy, we will soon see public money being invested back into the 'emission issue' as a political draw-card, so this will no doubt roll out in the next few years with greater funding, so whatever the cost to private consumers willing to convert their homes, we can expect to knock off another 30% that the government will pick up.

As for the 'electric car', the almighty oil conglomerates are firmly in the pockets of Washington decision makers - lets face it, this is where the world's decisions are made - and I feel that while there are billions to be made from oil, the lack of funding for electric vehicle R&D will suffer.

However, in Australia there are at least two hybrid cars on the market, a toyota and a honda. At a local technology 'museum'about two years ago there was another on display, that being the Holden E-Commodore, however I am yet to see or hear about it's release. Which is a shame, as the Holden label is an Australian icon amongst those people who have some sort of patriotic lean towards the car-maker, and might have been successful if released. Anyone heard about the E-Commodore project lately ? Be interested to know if it's still on the cards.

Anyway, back to the point at hand (Hmmm, the ANZAC 'spirit' is misleading my input to the discussion ) All corrections/clarifications welcome, but isn't the big draw-card with the Hybrids is that the cells/batteries are charged while the vehicle is in motion, using the engine as one big alternator ? With automatic switching between petrol & electric as reserved energy stock requires ?

A pure electric vehicle is ideal, of course if charged by solar powered energy, but the hybrid vehicle is here NOW, so the step up to greater public acceptance might be just around the corner, if the oil/car/political trilogy of corruption allows the R & D to continue. If hybrids save only 30% of petrol burning energy, then it's still a step forward.

[Torsten]

The problem with hydrib vehicles is that the are specifically designed not to be plugged in. For some reason this was seen as a marketing pitch. It would make a lot more sense to have hybrids with larger batteries which can also make use of off-peak power. At the very least your morning trip to work could be done on waste electricity. Your trip home could then be petrol supported, but at a much higher efficiency.

[Greeny]

Personally as a mechanic Im againast hybrid transport. Yes agreed it is more efficient but damn im gonna have to learn a whole bunch more components. Its hard enough keeping up with todays truck components yet alone the addition of hybrid ones. Personally switching to alternative fuels like PROPER Biodiesel (none of that fryer crap) and ethanol/methanol is to me the answer. When you think of the fact that the modifications required for biodiesel aren't that extreme and agreed the mods for ethanol are a bit more excessive but still achievable it makes more sense to make the switch. High compression is the key with ethanol and that can be easily obtained with a supercharger or turbocharger. I bet all my fellow hoons would agree with that. To modify an existing petrol burning engine to ethanol requires some cylinder boring and a ring change. Im sure with mass production of current and older model car kits this would be easily affordable.

Think about it in the eyes of farmers they need a helping hand and I beliece alternative fuel crops are the answer. Switchgrass is easy to grow and would be well suited to australian conditions as far as I know.

Down with Hybrid!

[Guest Øskorei]

A Mechanic with a hoon-Vehicle avatar ? Nooooo, say it isn't so What is that smoking bastard, Greeny - an old 1970's Holden Statesman with a supercharger?

DOn't know what your age is (please share in this topic for clarity) but Trade-Qualified Mechanics, if they want to stay in the industry, have had to learn about the new technologies all the time. For the past 15-20 years, there's been a massive shift in auto technology. Not so long ago, Mechanics were faced with the impossible task of understanding fuel injection over barrel carbs. Auto-Electricians had to wrap their head around the newer wiring technology, which included self-diagnostics on the part of the patient (ie the vehicle) as opposed to an old-school wiring loom.

A shift towards hybrid vehicles won't push you out of the game, it'll just mean you'll have to understand the concept and learn how to fix it ! I'll bet a year's wage that you're working on cars right now that are miles apart from the sample avatar.

Unlike houses, cars are upgraded all the time, so retro-fit isn't really a point to argue about.

I envy you, Greeny, for you're on the cutting edge of technology, and will learn more about the new stuff (as it rolls out) than most others.

[reshroomED]

yeah, I suck at maths. Although, with sun tracking this number increases. Also, the 3W is based on the older 11% efficient cells.

In the process of recalculating this I did find a few other bits and pieces of interest. For example, that manufacturers give 25 years warranty on panels. This means that the expected life is well in excess of the 30 years generally cited. By calculating the benefits over 40 or 50 years we would nearly halve the costs again.

Nah, not your maths at fault but shonky advertising.

I (used to) do a lot of remote-area solo camping plus lived in a shack in the bush in SW Tassie a few years far from town power etc. As such, solar power has always been of interest to me personally, and working as an electrical/electronics professional in remote areas has shown me some of the practical side of things.

The wattage rating of pe cells can be misleading, most only reaching their rated output on top of a mountain on the equator on a sunny day.

Then there's actual hours of cloud-free sunlight (most systems are designed around the six hour mark from memory)

Then you have losses due to voltage regulation/inversion (if you plan to run 240VAC devices).

Then there's loss in storage (batteries).

Then there's speed of recharging your batteries.

So, in the real world, your average 80W BP panel will only actually supply around 20W usable at 240VAC.

And really you need to look at current, not watts (Watts = Volts x Amps) and make sure that your panels will provide more than you use.

I've got a 60litre 12vdc fridge in the back of my car, that pulls around 2A (approx 24W at 13vdc) and cycles on approx 30% of the time on a hot day. I'd love to have it on solar, but would need better than an 100W panel, and probably closer to 200W to run the fridge solely without charging from the car alternator. And thats with 200Ah of batteries (and would only work in the sunny states).

 

OK, I had heard this before and dismissed it. Now it intrigues me, so I did a bit of research.

Keep in mind that the following is about panels from the late 90s. We have increased efficiency of production and of the panel itself quite dramatically since then.

"The total energy requirement to produce a PV panel is 1,060 kWh/m2. In Sydney the useable panel output will be 153 kWh/m2/year [0.42 kWh/m2/day], giving an energy payback time (EPBT) for the panel of 6.9 years. After mounting in an open field or on a roof the EPBT will be 11.5 or 8.3 years respectively."

http://www.ecotopia.com/apollo2/pvepbtoz.htm

So, under 7 years for the panel alone. This would have been for 14% [theoretical] efficiency panels, so subtract 2.3 years for the new ~20% panels, which leaves 4.6 years. The silicon acccounts for about 60% of this, with the other 40% being mostly for the aluminium frame. This frame is no longer needed with the new sliver cells. The amount of energy required for sliver cells will also be only a fraction of the crystalline wafers. ie, the new sliver panels will have no frame [-30%] and maybe a third of the silicon cost [-40%], which means the new panels will be a mere 30% of embodied energy compared to the 90's models. That brings the EPBT down to just 1.5 years.

From the reasons given above, these estimates are inaccurate.

I've seen arguments for and against, both backed with extensive data, but personally believe them inefficient environmentally (this opinion was formed after discussing this exact question with BP Engineers while contracted to BP). Each study has different criteria as to what is actually involved energy expenditure wise in construction. Really a bit hard to quantify precisely.

Reading up on the sliver cell, seems this may change things when available. Looks very promising

 

This is for the panels only though. Very little has happened in the way of domestic electricity storage and I am hoping for some important breakthroughs in that field. At the moment the panels represent about 60% of both cost and embodied energy, which leaves 40% for the rest of the system. By far the largest chunk of tihs would be the batteries. So, you're looking at another 5 years EPBT for the batteries.

Batteries are another area where it isn't as simple as it appears, and I wouldn't be holding my breath re breakthroughs in this field (hardly any improvements over the last 30yrs and no interesting research that I'm aware of).

Discharging batteries more than about 30% impacts their lifespan, so you'll really need about threetimes the storage capacity that you wish to use.

ed

[Torsten]

well, we're definitely going solar in the next couple of years and the plan is to basically copy a system my friend has that pretty much reflects the data I provided above [no, not the first set ]. he's been running it for 5 years, so the data is pretty solid. he's got some fancy batteris, which we may give a miss, which brings the cost of the system down to about 50K. we'll probably start with just lighting though as we don't want to buy the majority of our panels until sliver cells are in production.

re 240V, this is not a desirable voltage if you are not covering large distances. all our lighting will definitely be 12V. I mean, we already have lots of 12V lighting and it would be silly to step up to 240 just to bring it back down to 12.

Batteries is not so big an issue for us as 50% of our consumption in summer is aircon. So, we are initially just looking at offsetting that - which is mostly while the sun shines.

[reshroomED]

well, we're definitely going solar in the next couple of years and the plan is to basically copy a system my friend has that pretty much reflects the data I provided above [no, not the first set ]. he's been running it for 5 years, so the data is pretty solid. he's got some fancy batteris, which we may give a miss, which brings the cost of the system down to about 50K. we'll probably start with just lighting though as we don't want to buy the majority of our panels until sliver cells are in production.

re 240V, this is not a desirable voltage if you are not covering large distances. all our lighting will definitely be 12V. I mean, we already have lots of 12V lighting and it would be silly to step up to 240 just to bring it back down to 12.

This is one of the biggest issues (using 12vdc appliances, lighting etc).

If you're willing to do this, you've already saved a ton of juice. And if you've seen such a system operating you can be sure it suits you.

The common usage of 12vdc down-lights these days, plus the recent improvements in light output for LED's (and more to come in the near future I'd imagine) make lighting very viable.

In Tassie I'd run the genset about every three days with a 600Ah battery bank. Now I've got a little Honda that does about six hours on two litres of fuel, so would probably need it once per week or less.

If you're going solar in a big way then a large genset is a must too.

 

Batteries is not so big an issue for us as 50% of our consumption in summer is aircon. So, we are initially just looking at offsetting that - which is mostly while the sun shines.

This is where battery choice is critical as the panels won't keep up.

But for $50K I'd assume that you'd meet your needs adequately.

What part of that pricing is labour?

ed

[Torsten]

If you're going solar in a big way then a large genset is a must too.

we will need a big one for the workshop anyway. welders etc are too much of a drain on such a system [not even sure if it is possible]. so we'll probably have to run the generator an hour or two a day anyway [on homegrown and homemade biodiesel] which will help with the batteries.

What part of that pricing is labour?

nil. a lot of it will be planned into the new house design [eg wiring, roof panels] and I have a basic understanding of a few things like setting up battery banks and wiring etc. For the rest [and advice and supervision] I intend to get the sparky who set up my mate's place cos he already knows what he is doing. I know trades people hate it, but I'd rather pay more and get them to teach me everything they are doing than to just let them do it. After all, if the economy does collapse I'll need to be able to fix things myself anyway