Solar, Wind Renewable Energy

[Koolau]

Just touching on some issues from the past several posts:

I assume that transferring hydrogen via pipe line will be at relatively high pressure - not liquid. At atmospheric pressure, it would take an awfully big pipe or a very long time to send hydrogen gas that far.

Regarding "weighing" the hydrogen, it is known that ideal gasses (and hydrogen gas - which is really H2 - is close enough to ideal for gummint w*rk) occupy 24.45 liters per molecular weight (so about 2 grams of H2 expands to 24.45 liters at normal room temp and atmospheric pressure.) If you compress the H2 to 100 atmospheres, then 24.45 liters of the compressed H2 will weigh about 200 gms. SO, in short, you don't actually weigh it - you determine the volume and convert to weight if you know the pressure and temp. YMMV

 

[mpeirce]

There's talk of blending some hydrogen into the nat gas lines to the homes. Not 100% carbon free, but they say it helps in the interim.

Adding hydrogen into existing pipes can cause problems by embrittling the metal pipes. Retrofitting existing pipes is expense. The more hydrogen gas you mix in, the faster the problem happens.

And if you are burning it, it’s not really pollution free since burning it in air produces NOx emissions. In fact, it produces more NOx than natural gas.

 

[NW-Bound]

... in short, you don't actually weigh it - you determine the volume and convert to weight if you know the pressure and temp. YMMV

The earlier poster asked a rhetorical question, I believe, when he read that the BarMar hydrogen pipeline will carry 2 million tonnes/year of hydrogen.

We have been buying gasoline, natural gas, propane, ethanol, and other fuels by volume, not by weight. It will be the same with compressed hydrogen.

By the way, as a classroom experiment, you can put hydrogen in a balloon and weigh it. The weight will be negative due to the lift, because hydrogen is lighter than air. Then, you can figure out the weight of hydrogen if you know the weight of air, but this is of course not a direct measurement.

Adding hydrogen into existing pipes can cause problems by embrittling the metal pipes. Retrofitting existing pipes is expense. The more hydrogen gas you mix in, the faster the problem happens.

And if you are burning it, it’s not really pollution free since burning it in air produces NOx emissions. In fact, it produces more NOx than natural gas.

The problem with NOx is discussed in this article: https://www.cleanegroup.org/hydrogen-hype-in-the-air/.

 

[NW-Bound]

France and Spain are also discussing a submarine cable to bring electricity across the Bay of Biscay (on the Atlantic side), in addition to the BarMar hydrogen pipeline on the Mediterranean side.

Going over land across the Pyrenees is too tough, they say.

 

[explanade]

France and Spain are also discussing a submarine cable to bring electricity across the Bay of Biscay (on the Atlantic side), in addition to the BarMar hydrogen pipeline on the Mediterranean side.

Going over land across the Pyrenees is too tough, they say.

Europe looked at putting solar farms in North Africa -- supposedly just a portion of the surface area of the Sahara can produce enough to meet global demand.

But there are obstacles like transmission lines across the ocean. There are also concerns about political stability of the nations with which they'd partner for these projects.

So some North African nations have talked about converting to hydrogen and shipping to all kinds of overseas clients, not just European ones.

So maybe this talk about shipping hydrogen has to do with working around having to build long transmission lines.

 

[Koolau]

Europe looked at putting solar farms in North Africa -- supposedly just a portion of the surface area of the Sahara can produce enough to meet global demand.

But there are obstacles like transmission lines across the ocean. There are also concerns about political stability of the nations with which they'd partner for these projects.

So some North African nations have talked about converting to hydrogen and shipping to all kinds of overseas clients, not just European ones.

So maybe this talk about shipping hydrogen has to do with working around having to build long transmission lines.

Yeah, these days, burying anything under sea could be problematic. Recent events have shown the vulnerability of such transmission. I'm surprised there hasn't been a follow-on event.

Geopolitical issues may doom any attempt to generate electricity in one place and then transmit it to another place for use.

 

[ncbill]

I looked some more at the above EG4 DC/AC mini-split, and it does not do the fancy things that I described earlier that are theoretically possible.

What happens is that if the panels are capable of more power than what the mini-split needs, the excess potential power that can be harvested goes to waste. There's no battery to dump the excess power to, nor this unit is allowed to dump into the grid.

So, you don't want to use too many panels on this. It would be like buying a pickup with a big V8, just to pull a trailer once in a while.

Still, the advantage is for people who do not have a grid-tied system, nor a stand-alone system with a battery storage. Instead of a conventional mini-split running off the grid, they can use this along with some panels, and the panels will help reduce the electric bill. If the unit does not cost too much more than a conventional mini-split, it is viable.

What happens if there's an electric outage, and the mini-split reverts to running totally on the panels, and the panels do not put out enough juice? Or you lose power in the late afternoon, when the sun angle is low and the panel output is weak?

In the case above, I would hope that the machine is programmed to reduce its speed, and manages to run on the reduced solar power. This means that you would still have some cooling during a blackout in the summer, just not to the level that you normally get.

Of course when the sun is down or at night, you don't have any AC without the grid. You would need a battery.

PS. My 18,000-BTU variable-speed minisplit power draw varies from 200W to 1500W, depending on the indoor/outdoor temperatures and the thermostat setting.

Plus one can often source used solar panels cheap, e.g 250-300W for ~$60 each.

Stringing a few of those dedicated just to the mini-split is less complex & less expensive than connecting the panels to a charge controller/inverter/battery bank.

 

[NW-Bound]

Plus one can often source used solar panels cheap, e.g 250-300W for ~$60 each.

Stringing a few of those dedicated just to the mini-split is less complex & less expensive than connecting the panels to a charge controller/inverter/battery bank.

Very true with inexpensive used solar panels.

As often mentioned, if I had a bigger lot, it would not be hard for me to go off-grid.

I have a big lot with my high-country boondocks home. And more, I also have a sun-lit south-facing hill slope that's just perfect for more panels than I care to put up. However, that's not my full-time dwelling, else I would have done it already.

But then, up there the challenge will be to generate enough electricity in the winter to survive against the sub-zero temperature (F not C).

It's easier to be off-grid where it's hot rather than cold.

 

[Alan]

Adding hydrogen into existing pipes can cause problems by embrittling the metal pipes. Retrofitting existing pipes is expense. The more hydrogen gas you mix in, the faster the problem happens.

And if you are burning it, it’s not really pollution free since burning it in air produces NOx emissions. In fact, it produces more NOx than natural gas.

They have been running trials this last few years in the UK using existing pipes to feed hydrogen and have concluded that they can be used. They have also been running trials feeding hydrogen into hundreds of homes at various concentrations and in the coming years plan on feeding 20% hydrogen into the gas supply in different regions.

If all goes to plan the switchover to 100% hydrogen will be complete in the next 20 years but will progress in stages. There are some demo houses not far from us where all the gas appliances have converted to hydrogen.

Of course all plans are subject to change, plus I’m not qualified to argue the science, just reporting what is happening.

https://www.britishgas.co.uk/the-source/greener-living/hydrogen-boilers.html

But although the timescales and exact details are still be ironed out, any switch to hydrogen is likely to happen in three main stages.

Stage 1
New boilers will be built to a new ‘hydrogen-ready’ standard, which means they’ll work with natural gas but can also be easily modified to run on 100% hydrogen. According to some industry estimates, these boilers should be available from 2023-2025.

Stage 2
A 20% hydrogen blend will be introduced into the gas supply. Most boilers will be able to use this as normal – including all new British Gas boilers. The rollout of 20% hydrogen isn’t expected to begin until 2028 at the very earliest.

Stage 3
When the gas supply switches to 100% hydrogen, every new boiler sold in the UK will simply be a hydrogen boiler. This is the ultimate goal, but it probably won’t happen until the mid-2040s.

 

[NW-Bound]

It's about time the US gets into the hydrogen game too.

The following article talks about signs that the Permian Basin is being tapped out.

https://finance.yahoo.com/news/oil-wells-creeping-texas-cities-140014722.html

 

[Koolau]

It's about time the US gets into the hydrogen game too.

The following article talks about signs that the Permian Basin is being tapped out.

https://finance.yahoo.com/news/oil-wells-creeping-texas-cities-140014722.html

I know very little about oil production, but my understanding is that some older fields have been rejuvenated by fracking.

Clearly, we are running out of the cheapest oil and it's only gonna get more expensive. But, that doesn't mean we are running out of available oil any time soon. Oil is very well understood and producing it is well understood. Hydrogen is still a bit mysterious and likely economically inefficient by comparison to oil. By no means am I against hydrogen but it's not a slam dunk fuel from what I understand. Storing renewables seems a more worthy goal than "committing" to hydrogen - but what do I know??

 

[NW-Bound]

I know very little about oil production, but my understanding is that some older fields have been rejuvenated by fracking.

Clearly, we are running out of the cheapest oil and it's only gonna get more expensive. But, that doesn't mean we are running out of available oil any time soon. Oil is very well understood and producing it is well understood. Hydrogen is still a bit mysterious and likely economically inefficient by comparison to oil. By no means am I against hydrogen but it's not a slam dunk fuel from what I understand. Storing renewables seems a more worthy goal than "committing" to hydrogen - but what do I know??

Sadly, fracking was what brought the Permian Basin to life.

As the article says, after 10 years of drilling/fracking like mad, it is being tapped out.

 

[ERD50]

... By no means am I against hydrogen but it's not a slam dunk fuel from what I understand. Storing renewables seems a more worthy goal than "committing" to hydrogen - but what do I know??

Hydrogen isn't available as a 'fuel', what is available is bound up, mostly in water.

But it could be a way to store renewables. Convert water to H and O, later burn the H. But there are a lot of losses, and H is hard to store. But it still might be the best alternative in some cases.

-ERD50

 

[ncbill]

It would be easier to handle if we added C to that H and ended up with methane instead of hydrogen.

 

[NW-Bound]

It would be easier to handle if we added C to that H and ended up with methane instead of hydrogen.

I know. And everyone knows.

The problem is C is a dirty letter. No C allowed.

 

[Koolau]

I know. And everyone knows.

The problem is C is a dirty letter. No C allowed.

C is not going away for a long time. Dirty or not.

 

[ls99]

When Si based units take over the world, and C based beings are extinct, wil hydrocarbons still be needed?

 

[JoeWras]

When Si based units take over the world, and C based beings are extinct, wil hydrocarbons still be needed?

Nope. Saw Star Trek, and they had the answer. Hydrocarbons just get in the way.

 

[NW-Bound]

I dunno. We have been digging up all the hydrocarbon to burn, and I am afraid we will run out sooner than people think.

All that C that's in the atmosphere, how do we get it back? It's 0.04% of the air, so not easy to recapture, then bind with H again.

Maybe the guy who figures this out will rule the world, not the guy who invents a new battery better than the lithium cell.

 

[explanade]

Saw headline, Japan to require all new home builds after 2025 to have solar.

 

[Time2]

Weights and measurements were the actual research, and a whole lot of work was done on it.

Here is an update of an older Galvanometer that uses light and a series of mirrors to expand a small rotation of a D'Arsonval movement to create high sensitivity.

You can skip to 9 minutes for the meter workings, but her development of the story is worth listening to.

 

[Time2]

Hydrogen isn't available as a 'fuel', what is available is bound up, mostly in water.

But it could be a way to store renewables. Convert water to H and O, later burn the H. But there are a lot of losses, and H is hard to store. But it still might be the best alternative in some cases.

-ERD50

30 years ago, I said we need a bacteria that eats one of our waste products and releases hydrogen. We still need it.

 

[NW-Bound]

^^^ Just be sure the bacteria will not escape and eat us.

 

[ncbill]

30 years ago, I said we need a bacteria that eats one of our waste products and releases hydrogen. We still need it.

Biogas reactors in China have bacteria that eat human & animal waste, releasing methane for cooking & heating.

Along with nastier corrosive stuff like hydrogen sulfide which needed scrubbers to remove.

 

[JoeWras]

Speaking of biomass... I'm trying to grow lettuce this winter, in a greenhouse. I was looking at simple greenhouse heaters, just enough to take the edge off since lettuce can handle some cold.

What I found was a lot of people put their compost pile next to their greenhouse, run a pipe through it, and have a simple pump and fan that runs on solar to extract the heat.

I'm considering it, but it is a lot of work for just a tiny bit of heat, plus, I'd have to move my pile.

I could see how this would be hard to scale up to be useful at all. Still something to think about.