Harvesting Energy at Night: Solar Cell Keeps Working Long After Sun Sets

[sun rise]

I know there are a lot of "get a horse" people when it comes to new technology. This is especially notable when it comes to non-fossil fuel sources of energy. Personally I've never gone wrong by betting on technology improving over time. This is one example of a potential breakthrough. I've highlighted the key sentence in the story. We'll see if it can be commercialized and made cost-effective but I'd bet it can with some R&D.

Harvesting Energy at Night: Solar Cell Keeps Working Long After Sun Sets

Harvesting energy from the temperature difference between photovoltaic cell, surrounding air leads to a viable, renewable source of electricity at night.

About 750 million people in the world do not have access to electricity at night. Solar cells provide power during the day, but saving energy for later use requires substantial battery storage.

In Applied Physics Letters, by AIP Publishing, researchers from Stanford University constructed a photovoltaic cell that harvests energy from the environment during the day and night, avoiding the need for batteries altogether. The device makes use of the heat leaking from Earth back into space – energy that is on the same order of magnitude as incoming solar radiation.

 

[exchemist]

I know there are a lot of "get a horse" people when it comes to new technology. This is especially notable when it comes to non-fossil fuel sources of energy. Personally I've never gone wrong by betting on technology improving over time. This is one example of a potential breakthrough. I've highlighted the key sentence in the story. We'll see if it can be commercialized and made cost-effective but I'd bet it can with some R&D.

Harvesting Energy at Night: Solar Cell Keeps Working Long After Sun Sets

Harvesting energy from the temperature difference between photovoltaic cell, surrounding air leads to a viable, renewable source of electricity at night.

About 750 million people in the world do not have access to electricity at night. Solar cells provide power during the day, but saving energy for later use requires substantial battery storage.

In Applied Physics Letters, by AIP Publishing, researchers from Stanford University constructed a photovoltaic cell that harvests energy from the environment during the day and night, avoiding the need for batteries altogether. The device makes use of the heat leaking from Earth back into space – energy that is on the same order of magnitude as incoming solar radiation.

Something wrong here.
I quote:
"Using electricity at night for lighting requires a few watts of power. The current device generates 50 milliwatts per square meter, which means lighting would require about 20 square meters of photovoltaic area".
These numbers imply that 20m² of solar cells only give you a miserable 1W of night time power. You can't light even a single room with that.

 

[Heyo]

I know there are a lot of "get a horse" people when it comes to new technology. This is especially notable when it comes to non-fossil fuel sources of energy. Personally I've never gone wrong by betting on technology improving over time. This is one example of a potential breakthrough. I've highlighted the key sentence in the story. We'll see if it can be commercialized and made cost-effective but I'd bet it can with some R&D.

Harvesting Energy at Night: Solar Cell Keeps Working Long After Sun Sets

Harvesting energy from the temperature difference between photovoltaic cell, surrounding air leads to a viable, renewable source of electricity at night.

About 750 million people in the world do not have access to electricity at night. Solar cells provide power during the day, but saving energy for later use requires substantial battery storage.

In Applied Physics Letters, by AIP Publishing, researchers from Stanford University constructed a photovoltaic cell that harvests energy from the environment during the day and night, avoiding the need for batteries altogether. The device makes use of the heat leaking from Earth back into space – energy that is on the same order of magnitude as incoming solar radiation.

Also known as a Peltier Element. Ancient stuff.

 

[icehorse]

Batteries themselves are not sustainable. For example, Lithium is rare, toxic and hard to dispose of. We need to promote and research non-battery alternatives for storing power:

- "two pond" hydro storage systems
- compressed gas
- flywheels
- massive "coo-coo clock" storage systems

And others.

 

[Twilight Hue]

Something wrong here.
I quote:
"Using electricity at night for lighting requires a few watts of power. The current device generates 50 milliwatts per square meter, which means lighting would require about 20 square meters of photovoltaic area".
These numbers imply that 20m² of solar cells only give you a miserable 1W of night time power. You can't light even a single room with that.

It's a start I suppose.

 

[Twilight Hue]

Batteries themselves are not sustainable. For example, Lithium is rare, toxic and hard to dispose of. We need to promote and research non-battery alternatives for storing power:

- "two pond" hydro storage systems
- compressed gas
- flywheels
- massive "coo-coo clock" storage systems

And others.

Green proponents rarely talk about lithium mining. Cobalt mining as well.

I think non battery alternatives are a good direction.

I like bio diesel atm.

 

[exchemist]

Batteries themselves are not sustainable. For example, Lithium is rare, toxic and hard to dispose of. We need to promote and research non-battery alternatives for storing power:

- "two pond" hydro storage systems
- compressed gas
- flywheels
- massive "coo-coo clock" storage systems

And others.

Lithium itself is not that rare (though high grade deposits may be), nor is it very toxic, but you are quite right that Li batteries have toxic components, mainly due to their associated heavy metal content (Pb, Ni, Co,Cu etc).

Potential Environmental and Human Health Impacts of Rechargeable Lithium Batteries in Electronic Waste

 

[sun rise]

Something wrong here.
I quote:
"Using electricity at night for lighting requires a few watts of power. The current device generates 50 milliwatts per square meter, which means lighting would require about 20 square meters of photovoltaic area".
These numbers imply that 20m² of solar cells only give you a miserable 1W of night time power. You can't light even a single room with that.

3W LED is equivalent to a 25W incandescent. For people who have no nighttime light, this can be significant.

But the big point is that it's a lab experiment. The article itself talked about engineering improvements based on the great potential. I'm mindful of solar cell efficiency improvements:

 

[sun rise]

Batteries themselves are not sustainable. For example, Lithium is rare, toxic and hard to dispose of. We need to promote and research non-battery alternatives for storing power:

- "two pond" hydro storage systems
- compressed gas
- flywheels
- massive "coo-coo clock" storage systems

And others.

The use of non-lithium batteries is still in its infancy. Non-lithium battery chemistries to grow in importance for stationary energy storage sector – report

 

[exchemist]

3W LED is equivalent to a 25W incandescent. For people who have no nighttime light, this can be significant.

But the big point is that it's a lab experiment. The article itself talked about engineering improvements based on the great potential. I'm mindful of solar cell efficiency improvements:

The thermocouple, which is what this seems to use, has been around for more than a century. I see a fundamental problem in the small magnitude of the temperature difference they are trying to exploit, whereas a solar cell takes in energy in the form of a radiation distribution corresponding to the surface temperature of the sun. But no doubt we shall see if this gets anywhere.

 

[icehorse]

The use of non-lithium batteries is still in its infancy. Non-lithium battery chemistries to grow in importance for stationary energy storage sector – report

Thanks for this. I didn't get any sense of the long term ecological sustainability of any of these alternatives..