How solar panels are making waves

How solar panels are making waves
Ultimately, integrating DSTATCOMs would mean a smarter grid, reducing headaches for electrical utilities and increasing the integration of renewable energies, Prof Ghosh says. Credit: David TREBOSC

If you think of electrical current flowing like water from the grid to your home, you can start to imagine the waves your rooftop solar panels create when they try feeding current in the opposite direction.

Now multiply that by 180,000, the number of West Australian homes operating rooftop , and it's clear our has never been more complicated.

And with complication, comes expense.

Current policy sees ordinary homes hooked up to just one of three electrical phases supplied by the , which is perfectly sufficient for powering the average home.

Problems arise, however, when supply from exceeds demand, reversing the flow of in that single phase for that single house, while the power in the other phases are still flowing downstream.

An expensive way past the problem is to connect every home to all three phases, according to Curtin University Department of Electrical and Computer Engineering Professor Arindam Ghosh.

Since the peaks and troughs of each cycling phase are slightly offset, supplying three phases smooths the into a more regular supply, he says.

As well as being expensive this solution would be wasteful as it would mean supplying extra wires to customers who don't really require them.

Fix-all for power woes

A more economical solution, Prof Ghosh says, is to use Distribution Static Compensators (DSTATCOMs).

"They're a device that can shape your power supply, a power-quality enhancement device," Prof Ghosh says.

DSTATCOMs could be a fix-all for regulating the quality of Perth's : the devices balance supplied current between all three phases, reducing surges, boosting sags, and ironing out instability and flicker.

"They can also act as energy storage," Prof Ghosh says.

"They can store excess energy in batteries, you could then use this energy to shave off the evening peak energy use."

DSTATCOMs work by taking the single-phase reverse-flowing current your solar panels feed into the grid, then rapidly redirecting that current into whichever of the three phases need it most, balancing supply according to demand.

Prof Ghosh and his team have been developing efficient ways to connect and control DSTATCOMs so the devices will work with existing power transformers.

"Eventually we'll see large uptake of solar, but right now higher penetration will be difficult unless we see policy change," he says.

Ultimately, integrating DSTATCOMs would mean a smarter grid, reducing headaches for electrical utilities and increasing the integration of renewable energies, Prof Ghosh says.


Explore further

Could solar eclipses disrupt electricity in Germany?

More information: Farhad Shahnia et al. Circulating the reverse flowing surplus power generated by single-phase DERs among the three phases of the distribution lines, International Journal of Electrical Power & Energy Systems (2016). DOI: 10.1016/j.ijepes.2015.09.021
Provided by Science Network WA

This article first appeared on ScienceNetwork Western Australia a science news website based at Scitech.

Citation: How solar panels are making waves (2015, November 25) retrieved 19 July 2019 from https://phys.org/news/2015-11-solar-panels.html
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Nov 25, 2015
You need the three-phase connection anyways for electric vehicle or storage battery chargers.

An electric car basically uses a similiar amount of electricity per day as the house itself, and you don't want to spend the whole 24 hours charging it, so you need more supply capacity than the single phase can practically offer. Same thing if you want to buy cheap power from the grid to store it for later.

You also need about 2x more supply capacity when you start heating on electricity instead of gas. Even in Perth it gets cold for a month.

Nov 25, 2015
"You need the three-phase connection anyways for electric vehicle or storage battery chargers. "
-------------------------------------------------

No,you won"t. My service is single-phase.

And you won't need gas, oil, oil filters and changes, air filters, and the cleanup of dirty and smelly oil when you are done.

Nov 27, 2015

No,you won"t. My service is single-phase.


And you don't own an electric car, and you use gas for heat and hot water.

At 380 Wh per mile, a 40 mile daily commute consumes 15.2 kWh a day, 450 kWh a month. A typical Californian home consumes about 550 kWh a month so the electric car represents a doubling of electricity consumption.

All told, the average Californian home consumes between 16, - 17,000 kWh energy a year, or 1,380 kWh a month, and if all that was converted to renewable sources such as wind and solar power, plus the 450 kWh for the electric car, the average power demand per household would increase 3.3x

So while your single phase supply might be enough now, it won't be tomorrow.

Of course, they can increase the supply in the single phase to some extent, but you have to remember that a doubling of supply current results in quadrupling of transmission loss.

Nov 27, 2015
And you won't need gas, oil, oil filters and changes, air filters, and the cleanup of dirty and smelly oil when you are done.


Yep. You only need a $12,000 battery swap when the car is over 8-10 years old, which more than covers the cost of regular maintenance a regular car goes through in a year.

That is, unless you plan to scrap the car at half-way through its normal lifecycle and lose the resale value.

Nov 28, 2015
@eikka All told, the average Californian home consumes between 16, - 17,000 kWh energy a year, or 1,380 kWh a month, and if all that was converted to renewable sources such as wind and solar power, plus the 450 kWh for the electric car, the average power demand per household would increase 3.3x [
Wrong. Average power demand remains constant and unchanged

Nov 28, 2015
Eikka thinks I will double the use of electricity with my electric car, but I will be generating my own power with PV and storing it in a battery system. Saving that $50/week we spend on gasoline will help a lot.

But the real reason I want to be independent is natural disaster and power outage. We live in earthquake country, and I want to have power, water, heat, light and transportation if things go down.

That "battery swap" Eikka says we will need is going to add storage capacity to homes, as the old car batteries are used for home power storage. The newer replacements will offer greater range, anyway.

Nov 28, 2015
Gkam if you plan to use your solar panels to charge your EV that means that you plan to keep your car home during the daylight hours. Good luck with that. Or did you mean that you plan to supply power to the grid during daylight hours thinking that this offsets your charging usage when all of the other EV cars are plugged in?

When energy storage, via battery, H2 or fuel, becomes cost effective from both a CO2 and a financial prospective then your plan will be viable. Until then, renewables will only play a secondary role in our energy balance.

You might not believe this but I love the idea that the sun, in theory, could supply all of our energy needs but, there is no way it can do so now with today's existing technologies without driving 90% of the worlds population into starvation and poverty.

Nov 28, 2015
wouldn't it be simpler to develop and make energy efficient DC to DC converters then we can replace all transformers with DC to DC converters to step up and down the voltages and thus we can dump ac and go for 100% dc for the whole of the electric grid?
Admittedly, the initial expense of such a change-over will be very high not least because it would mean all our appliances would have to be adapted to work on ac. but I think his would have several long-term advantages that would make it pay for itself in the very long run including solving the problem discussed in this link but also it should, in theory, reduce transmission losses over long distances. Such a changeover doesn't require replacing all the cables themselves because any cable that can handle ac can handle dc of about the same voltage just fine.

Nov 28, 2015
... to be adapted to work on ac..

misprint: that should have been "...to be adapted to work on dc"

Nov 28, 2015
166, I plan to pay in advance, by pumping power into the grid when it is most important and costly, and taking power for charging at night, when supplies are cheapest, and I can get it for nine cents/kWh. I am being a good citizen.

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