Energy Matters Forums

[solowanderer]

(should mention I'm in Yarraville about 3k from Melbourne CBD)

[zzsstt]

The question is, if I'm using a wvo (biomass) powered generator to only charge my phone at night, should I be alowed to feed in the excess?
In this situation, "Can I connect a generator to a grid connect"?

If you are not connected to the grid, there is no way you can feed power in, so the question is not relevant.

If you are connected to the grid, then as far as I know engine powered generator are not acceptable for grid feeding. Even running wvo they are not "green", simply less "red". My own feeling (and I'm not a big believer in climate change, I'm just trying to be "more sensible") is that biodiesel or wvo are a fine alternative to fossil fuels for situations where mobility is required - which makes them ideal for running cars and tractors etc. Biodiesel or wvo are "sustainable" in that they can be regenerated on an annual time frame, but they still add CO2 to the atmosphere and they are very inefficient as they require a vast amount of energy to be expended in their production. Where there is a requirement to power a vehicle to carry heavy loads or travel great distances, such inefficiencies are outweighed by the advantages. However for static power generation, even though using wvo is "recycling" it is an inefficient form of power generation and a sub-optimum form of recycling;

To generate 1kwh of electricity, a PV system produces zero CO2 (for the sake of argument let's assume the energy that was used to manufacture the system was also PV derived).

To generate 1kwh of electricity, a coal fired system generates 1kg CO2 (I'm told this is about the average in Australia).

Now, how much CO2 does a biodiesel generated kwh generate? Biodiesel is very interesting, as it is open to all sorts of hype and interpretations. However the direct burning of biodiesel will produce much the same CO2 as the direct burning of diesel, so in terms of direct CO2 the biodiesel powered generator is no better than a diesel powered one. In indirect terms however, wvo is obviously gaining an extra use from a product that would otherwise require disposal, which is a good thing.

In overall terms, wvo is therefore far more green than diesel, obviously. But I would suggest that the optimum use for wvo is still for transportation purposes rather than for static power generation, where there are far more efficient ways of generating power. As a result, I would guess that wvo driven generators would be unlikely to become subject to FITs.

[470rigby]

In indirect terms however, wvo is obviously gaining an extra use from a product that would otherwise require disposal, which is a good thing

Actually, waste cooking oils (and fats) are reprocessed and re-used for cooking, soap making etc. In this case it is obviously being sourced for less than its value to the reprocessor.

[zzsstt]

Actually, waste cooking oils (and fats) are reprocessed and re-used for cooking, soap making etc. In this case it is obviously being sourced for less than its value to the reprocessor.

It may be that in this particular case such reprocessing does not or cannot happen. Many such recycling schemes are limited to the larger towns and/or the larger users, where it is economically feasible to collect and reprocess. However in smaller towns it is simply not worthwhile, as the transport costs (both in $ and in CO2) outweigh any advantages. One major uninterruptable power supply maker has a recycling program for old UPS batteries, but every time we replace a battery we fill in the forms and have never yet had one collected - it's simply too far to warrant the cost I guess!

Interestingly this is where local recycling on a smaller scale can work very nicely for some products. We use coffee grounds (local cafes have plenty) as mulch and in the compost, which works very nicely. Waste vegetable oil can be used directly in (some) diesel engines, which is probably a better option for a local cafe in a remote area than to attempt to persuade a recycler to cart the relatively small amounts involved. The question is finding the best overall use for a product!

[redfrog75]

Great chat guys!!! Wish I'd come across this sooner......
You probable don't care, but in SA where I am from, we can only be paid for PV instalations currentlt, but we have legislation about to go before parliment, that would allow the rebate to be paid on anything that produces electrcity back into the grid. Makes sense to me, unless, of course, said politicans have friends in the solar business.....(now this wouldn't happen in Australia would it )
I too have been looking for inverters that can take both wind and solar, and I too have been saying just what has been said, ie, the inverter doesn't know the sun is shining, or the wind is blowing, or the river is flowing, it has no idea, so why not have an inverter that can take all of those, or maybe more correctly, if the wind people would make their machines have the same V as the solar, or hydro etc, wouldn't that be sweet.

My old man is a farmer, and whilst I'm not a farmer, we both live in places that would easily support both wind and solar. But my Dad will only go ahead if I can find him an inverter that will take 2 or 3kw solar, and 1-3kw wind, otherwise he won't do. Fair enough I rekon.
So the hunt goes on..........

[zzsstt]

I can see the superficial attraction in the thought of having a multi-input type inverter, but I'm not sure about the reality (nevermind the legalities for a moment!).

If there is enough wind to make a wind power system genuinely worthwhile, then it will be producing power for most of the time. If there isn't enough wind, then a turbine is an expensive piece of sculpture and PV is a better option.

So is the suggestion to have (say) a 10kw inverter and a 10kw turbine, with PV panels that are only used when the wind isn't blowing? Or a 10kw inverter with 10kw of PV that works through the day, with a 10kw turbine that is disconnected during the day and used only at night? Or a 10kw inverter with a 5kw turbine and 5kw of PV?

The total input of the inverter must not be more than it's rated input, so if the PV + turbine at full output are more than that, then DC power must be dumped. For both wind and PV, the inverter is the cheap bit of the system, so paying a high price for either a turbine or PV panels that are dumping power seems an expensive way of producing electricity........

There are only two situations I can see where a combined approach makes sense. The first is for off-grid installations where the need for constant power outweighs the cost, and the second is if the local climate is such that the wind blows 12 hours every night, and the sun shines on each (windless) day, such that the two sources of power can feed the inverter at near maximum levels 24/7.

I guess it still comes back to the efficacy of wind power. If there is enough wind to make it worthwhile it's a better option than solar, but if there isn't then it doesn't make sense either alone or in combination.....

[Joey]

Wind and Solar are dynamically too different to combine as a single unit , Inverter manufacturers aren't stupid, if it was possible and viable it would be produced but in reality it's only a good idea to people that have no practical experience with PV or Wind Power., It's a bit like saying Ford and Holden should be making a dual fuel engine that takes Diesel and Petrol because a few people think it's a good idea.
Even a 1KW Wind turbine would be massively intrusive in a residential area , let alone a 5 KW monolith on a tower 15 meters in the air. , It simply will never happen and never be a realistic option in a residential location.

While legislation may pass to allow other forms of generation , there simply isn't anything other than PV available that's worthwhile having in suburbia

I have to admit I am always amazed how many think it is their "right" to be able sell electricity to the grid , It's not a right it's a privilege , being paid for excess energy produced no matter what method was never intended to be a money making exercise , it simply exists so that the excess power we make in excess of what we need isn't wasted , thankfully energy providers are willing to buy this off us.
If people feel so strongly that what they are making is worth something , use it for your purposes or find someone else that will purchase it off you for what you think it's worth and be sure to let me know how you go with that.

[Jehu]

I don't think anyone here wants to put up a 10kW turbine in their backyard. That idea is absolutely stupid. When most people (well the ones I've talked to anyway) say they want a wind turbine it's one of them 1-200W ones, you know, the ones the size of a satellite dish. And also the idea behind having a smaller one is to a, give the system a boost when the PV array isn't producing at full capacity and b, during the night.

Also over the last few days these blimmin winds have blown down heaps of trees knocking out power to over 9000 homes around where I live, including me. It's for times like these that I want a system like I described earlier.

[Joey]

I don't think anyone here wants to put up a 10kW turbine in their backyard. That idea is absolutely stupid. When most people (well the ones I've talked to anyway) say they want a wind turbine it's one of them 1-200W ones, you know, the ones the size of a satellite dish. And also the idea behind having a smaller one is to a, give the system a boost when the PV array isn't producing at full capacity and b, during the night.

Also over the last few days these blimmin winds have blown down heaps of trees knocking out power to over 9000 homes around where I live, including me. It's for times like these that I want a system like I described earlier.

No one is stopping you having a your own little wind turbine , if you think it's worth it go for it , it might charge some batteries and provide backup lighting in a blackout , it's just not your energy providers obligation to pay you to do it , regardless if they were it would be useless and disconnected during a blackout anyway if it was grid connected.

As has already been discussed in detail there is a full back solution , it's a costs a lot of money but it is also 100% legal ., As much as wish you could do things the grid is not open to experimentation or peoples idea's it is very regulated for good reason.

[Jehu]

I was just clarifiying for everyone as zzsstt keeps on talking about wind systems that are rediculosly huge for a residential property.

I understand the issue of regulation. Some people can do some stupidly shoddy jobs of things if they do it themselves which can be rather dangerous for everyone.