South Africans Revolutionize Concentrated Solar Power With Mini Heliostats

Taffykay writes: Concentrated Solar Power (CSP) offers significant benefits, but it's often prohibitively expensive. Paul Gauché from Stellenbosch University in South Africa hopes to change that with Helio 100, a series of 'plonkable' miniature heliostats that require no installation or concrete, and offer solar energy that's cheaper than diesel. The Guardian reports: "Helio100 is a pilot project with over 100 heliostats of 2.2 sq meters each, generating 150 Kilowatts (kW) of power in total – enough to power about 10 households. According to Gauché, the array is already cheaper than using diesel, the go-to fuel for most companies and businesses during regular power outages in the country.

Comments

ain't no sunshine when she's gone

[turkeydance]

and i know, i know , i know....

Last sentence makes me squirm with anticip-

[ClickOnThis]

...

So, what is Google's RE?

Re:Last sentence makes me squirm with anticip-

[ClickOnThis]

If only there were some amazing internet search technology where you could cut and paste Google's RE and get an accurate answer.

Yeah...maybe Google could even offer it. Oh, wait.

And now the penny drops: it's a broken reference to Google's RE<C.

Thanks for the improvement.

Another deflationary pressure on oil prices.

[Maxo-Texas]

Imagine if these cut diesel fuel usage in africa by 30% over the next 5 years.

Re:Another deflationary pressure on oil prices.

[Darinbob]

In some places, more diesel is used for electricity than is used for vehicles.

No details

[Michael Woodhams]

TFA is lacking in details about how this works, but if you follow the link you get to a Guardian article which is lacking in details, but links to the projects website which excessively uses gratuitous Javascript and is lacking in details.

They talk about "plonkability" - that the mirror structures can just be plonked on the ground and will 'just work'. This suggests to me that somewhere in their system is some intelligence or calibration which is able to notice where each mirror is relative to the target and adapt its pointing accordingly. Their photos show the target tower having two rectangular surfaces pointed towards the mirrors. I suspect the plane white surface is there to aid mirror pointing calibration in some way, but I don't know.

Re:No details

[Michael Woodhams]

You'd use differential GPS. Wikipedia says this has accuracy of 10cm in the best case. Whether that is good enough for this application I'm not sure. Given that affordability is a big part of their goal, if they were taking this approach they'd not attach a GPS to each mirror, but rather have two receivers that they used for a callibration stage and then wouldn't be needed again unless something shifted. You'd need to know orientation as well as location for the mirrors.

I doubt this is what they're doing, but who knows.

Bullshit

[ChrisMaple]

100 units of 2.2 sq meter each has a total solar input of 220 kW peak, roughly. They're claiming 150 kW. That's 68% efficiency, which nobody has achieved.

Re:Bullshit

[tlhIngan]

That's 68% efficiency, which nobody has achieved.

These are heliostats, not PV panels. Heliostats work by heating a salt to high temperatures then using the heat to power a turbine in a traditional heat engine. The latter tends to be highly efficient (over 90%), while the former is around 75% efficient or more.

It is as the article says - it's converted to heat then heat is used to generate electricity, something a lot of power plants do (including nuclear, coal, natural gas, and others).

If it was PV panels, you're correct, since the best PVs are only getting around 20%. But if you don't mind the extra space for the equipment, solar thermal is the way to go.

Re:Bullshit

[superposed]

Heliostats work by heating a salt to high temperatures then using the heat to power a turbine in a traditional heat engine. The latter tends to be highly efficient (over 90%), while the former is around 75% efficient or more.

I think you're trying to say that mirrors can heat salt with >75% efficiency and heat engines tend to be >90% efficient. The first claim seems vaguely plausible, but the second claim is certainly false. Typical single-cycle power plants have efficiencies around 35%, and combined cycle plants (combustion turbine plus heat-recovery steam generator) have efficiencies up to about 50%.

With a heat engine operating at normal terrestrial temperatures (say 300 K on the cold side and 1000 K on the hot side), the maximum possible efficiency is 70%. To achieve 90% efficiency, the high temperature side would have to be at least 3000 K (half as hot as the sun). I doubt this system is that hot.

Re:"Smokers"

[Socguy]

While what you talk about does happen, it's not a problem because of the relatively rare nature of the incidents. Skyscrapers in cities kill orders of magnitude more birds than power towers.

Frankly, the birds would be far better off if we switched to CSP exclusively due to the wholesale destruction of habitat caused by fossil fuel development.

Re:"Smokers"

[Anonymous Coward]

Bird deaths caused by wind and solar are minimal compared to the bird deaths caused by traditional fossil fueled infrastructure. Much like the wind turbine issue, it is much ado about nothing. It is just more visible and makes a better news story than the slow poisonings or secondary displacement deaths caused by other power sources, but in scale is far less damaging.

Re:"Smokers"

[JoeMerchant]

Nature of bird injury mostly depends on how the bird is exposed - full on strike, or did he just get "winged?"

Maybe with large migratory populations, the carnage will continue for a long time. The elevated track people mover in Miami didn't run for a year or so after the tracks were built - pigeons thought the tracks were just the greatest place ever made to hang out, nest, etc. The first months of operation (of the very quiet electric cars) were a nasty pigeon bloodbath, feathers and guts everywhere. After a few months, the remaining pigeons caught on, there's hardly ever one run over anymore. I don't think any special mitigations (tiny cow-catchers, warning lights, sounds) were put in place, just Darwin in action.

Re:Wow, such BS

[Tokolosh]

The South Africans have mismanaged their power supply system to the extent that they now have to operate open-cycle emergency/peaking sets on diesel, continuously. This is very expensive, as you say, and is contributing to the downward economic spiral. Hence the grasping at straws.