# Solar Freakin' Railways **URL:** \ **Category:** Miscellaneous and Personal Stuff I Must Share\ **Created:** [March 21, 2023, 8:16pm UTC](https://boards.straightdope.com/t/solar-freakin-railways/981462 "2023-03-21T20:16:57Z")\ **Posts on this page:** 20\ **Page:** 2
**Author:** ![Tim\_T-Bonham.net](https://avatars.discourse-cdn.com/v4/letter/t/46a35a/32.png) [@Tim\_T-Bonham.net](https://boards.straightdope.com/u/Tim_T-Bonham.net)\ **Post date:** [March 22, 2023, 4:21am UTC](https://boards.straightdope.com/t/solar-freakin-railways/981462/21 "2023-03-22T04:21:52Z")
> [@Sam\_Stone](#): > > Fundamental question: Is there any evidence that we are real-estate constrained for solar power? Why is this even a thing? There is plenty of otherwise-unusable land in North America where you could put solar facilities. The obvious ‘unused real-estate’ for these is rooftops, all over the country. Especially because the power generated can be used right there in the building, without the transmission lost from sending it for miles or hundreds of miles through the grid. All over the place there are schools, factories, park buildings, etc. with flat roofs and wide-open space around them. Those are even more suitable than most homes for solar panels. (The solar panels on my roof produce 44% of the power used in my house; there could have been more if I was willing to cut down the trees in my yard. Most commercial buildings don’t have to worry about that.) ---
**Author:** ![Sam\_Stone](https://avatars.discourse-cdn.com/v4/letter/s/ecccb3/32.png) [@Sam\_Stone](https://boards.straightdope.com/u/Sam_Stone)\ **Post date:** [March 22, 2023, 4:22am UTC](https://boards.straightdope.com/t/solar-freakin-railways/981462/22 "2023-03-22T04:22:27Z")
> [@davidm](#): > > I’m extremely skeptical that it would be enough to power the train, I’m skeptical that you could get enough energy to light and heat the railroad car the cells are on. Average solar irradience in the U.S. is about 4.5 kWh per day per square meter. Solar panels are about 20% efficient, so that’s about .9 kWh per day per square meter. In reality less because they are often in the wrong direction, not inclined, and dirty. A stndard shipping container with a walkway could hold about 20 sq. m of panels. So, maybe 18 kWh per day. less up north, a little more down south. It would take almost four days to charge a Tesla Model 3. ---
**Author:** ![Gatopescado](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/gatopescado/32/5711_2.png) [@Gatopescado](https://boards.straightdope.com/u/Gatopescado)\ **Post date:** [March 22, 2023, 6:49am UTC](https://boards.straightdope.com/t/solar-freakin-railways/981462/23 "2023-03-22T06:49:31Z")
This would be a shitty idea in India. ---
**Author:** ![kenobi\_65](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/kenobi_65/32/13178_2.png) [@kenobi\_65](https://boards.straightdope.com/u/kenobi_65)\ **Post date:** [March 22, 2023, 7:03am UTC](https://boards.straightdope.com/t/solar-freakin-railways/981462/24 "2023-03-22T07:03:41Z")
> [@davidm](#): > > I’m extremely skeptical that it would be enough to power the train, so you’d still need to supply some of the electricity in traditional ways such as overhead wires or through the rails. This appears to be an article on said train – it’s a very small, two-carriage tourist passenger train, which runs on a very short (~3 kilometer) route. The article claims that, on a sunny day, the solar panels are able to charge the train’s batteries sufficiently to make 4 or 5 trips. Rooftop solar panels alone aren’t going to be nearly enough to power a larger train (i.e., a longer passenger train, or a freight train) for any significant distance, at the kinds of speeds that diesel or traditional electric trains can achieve. > **[The world’s first solar-powered train in Australia | 2022 Bridgestone World...](https://www.bridgestone.com/bwsc/stories/article/2019/06/17-2.html)** > > Under the BWSC theme ‘Dream bigger. Go farther,’ Bridgestone supports challengers in achieving their dreams. Let us introduce a solar-powered project that improves both mobility and environmental sustainability. #BWSC22 ---
**Author:** ![Robot\_Arm](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/robot_arm/32/18280_2.png) [@Robot\_Arm](https://boards.straightdope.com/u/Robot_Arm)\ **Post date:** [March 22, 2023, 2:32pm UTC](https://boards.straightdope.com/t/solar-freakin-railways/981462/25 "2023-03-22T14:32:46Z")
> [@kenobi\_65](#): > > Rooftop solar panels alone aren’t going to be nearly enough to power a larger train (i.e., a longer passenger train, or a freight train) for any significant distance, at the kinds of speeds that diesel or traditional electric trains can achieve. If you made the train twice as big, it would require twice as much energy, but it would have twice as many solar panels. So the size of the train cancels out. Farther and faster are the limitations. ---
**Author:** ![Sam\_Stone](https://avatars.discourse-cdn.com/v4/letter/s/ecccb3/32.png) [@Sam\_Stone](https://boards.straightdope.com/u/Sam_Stone)\ **Post date:** [March 22, 2023, 4:45pm UTC](https://boards.straightdope.com/t/solar-freakin-railways/981462/26 "2023-03-22T16:45:36Z")
> [@kenobi\_65](#): > > This appears to be an article on said train – it’s a very small, two-carriage tourist passenger train, which runs on a very short (~3 kilometer) route. The article claims that, on a sunny day, the solar panels are able to charge the train’s batteries sufficiently to make 4 or 5 trips. Yeah, that’s not a great example of solar power working for trains. First, the solar panels appear to be mostly on the building that houses the train, as well as the train itself. There are a LOT of solar panels in play. And for all that, you can drive the train 8-10 miles on a full day of sunlight, and it’s a tiny, two-car train. Also, this is in Australia, which is way better than almost all of North America for solar power. If anything, that demo train shows how weak solar power really is, and how much of it you need to do anything in the real world. ---
**Author:** ![running\_coach](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/running_coach/32/15836_2.png) [@running\_coach](https://boards.straightdope.com/u/running_coach)\ **Post date:** [March 22, 2023, 4:54pm UTC](https://boards.straightdope.com/t/solar-freakin-railways/981462/27 "2023-03-22T16:54:37Z")
> [@Sam\_Stone](#): > > If anything, that demo train shows how weak solar power really is, and how much of it you need to do anything in the real world. - There are plenty of rooftops and parking lots that could house panels. [![](https://img.youtube.com/vi/IZEaYjo4ZJU/maxresdefault.jpg "VFX Artist Reveals how Many Solar Panels are Needed to Power the ENTIRE World") ](https://www.youtube.com/watch?v=IZEaYjo4ZJU) ---
**Author:** ![Sam\_Stone](https://avatars.discourse-cdn.com/v4/letter/s/ecccb3/32.png) [@Sam\_Stone](https://boards.straightdope.com/u/Sam_Stone)\ **Post date:** [March 22, 2023, 5:19pm UTC](https://boards.straightdope.com/t/solar-freakin-railways/981462/28 "2023-03-22T17:19:51Z")
Yeah, there are. But we are also maxxing out on solar power. All you have to do is look at the price of energy when the sun is shining to see that. Until we can store solar energy at grid scale, we don’t need a lot more solar. That’s the other thing the ‘solar freaking railway’ people don’t get. See this chart of energy in Alberta yesterday: > The sun was shinging brightly, and solar was producing 78% of its capacity. That’s as good as I have ever seen it. But look at the pool price, which is a good reflection of supply vs demand. The energy we are generating is worth $60 MWh. But pur average energy cost is now about $200/MWh, and our morning and evening peaks (where solar is almost nonexistant here) run up to $800/MWh. It won’t take much more solar before we drive the daytime price of energy to zero. That’s already happened in some places in Europe. Sometimes they produce so much solar in Germany they have to pay their grid partners to absorb the excess. After that, more solar is just a waste of money. But it’s also a poor investment now, because solar power replaces imported energy we can buy for cheap during the day, while doing absolutely nothing about the major shortages we run into in deep winter and at night, which is where we are incurring our major energy costs. I have been saying for years that solar power without storage can only provide at best about 20% of pur energy. Solar capacity factor (the percentage of capacity you actually realize) in North America ranges from about 19% to 23%. That means when you see someone talk about the cost of ‘solar capacity’ you should multiply the cost by four or five. This as opposed to coal or gas, which can run at over 90% of capacity forever. We need to figure out energy for cloudy days, winter, and nights, not how to get more energy when the sun is shining. That’s not currently our problem. If we could develop grid-scale storage that mattered, solar could do a lot more. But we don’t have grid scale storage of anything more than trivial capacity, so solar is maxxing out. ---
**Author:** ![running\_coach](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/running_coach/32/15836_2.png) [@running\_coach](https://boards.straightdope.com/u/running_coach)\ **Post date:** [March 22, 2023, 5:50pm UTC](https://boards.straightdope.com/t/solar-freakin-railways/981462/29 "2023-03-22T17:50:42Z")
> [@Sam\_Stone](#): > > Yeah, there are. But we are also maxxing out on solar power. - Something preventing us from building more? ---
**Author:** ![Sam\_Stone](https://avatars.discourse-cdn.com/v4/letter/s/ecccb3/32.png) [@Sam\_Stone](https://boards.straightdope.com/u/Sam_Stone)\ **Post date:** [March 22, 2023, 6:43pm UTC](https://boards.straightdope.com/t/solar-freakin-railways/981462/30 "2023-03-22T18:43:33Z")
> [@running\_coach](#): > > Something preventing us from building more? No, you can build as much as you want. But at some point, you get more energy during the day than you need, and making more solar is a waste of time and money. You can see that in the pool price, which is the price that grid participants pay for imported energy or get from exporting it. When solar is down here, our pool price can go as high as $1,000/MWh. That’s a sign that we are very short of power during those times. On a sunny day, the pool price can drop down to $50 or lower. If you were getting $50/MWh for exporting solar energy or replacing imported energy with solar, and $200-$800/MWh for energy when the sun isn’t shining, would your conclusion be that we should spend finite resources on more solar energy? What if the pool price when the sun is shining is zero, indicating there is no more demand for energy under those conditions, would you think building more solar is a good idea? I hope not. ---
**Author:** ![Chronos](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/chronos/32/134_2.png) [@Chronos](https://boards.straightdope.com/u/Chronos)\ **Post date:** [March 22, 2023, 10:52pm UTC](https://boards.straightdope.com/t/solar-freakin-railways/981462/31 "2023-03-22T22:52:37Z")
> [@Robot\_Arm](#): > > If you made the train twice as big, it would require twice as much energy, but it would have twice as many solar panels. So the size of the train cancels out. I’m not sure about that… Train energy use isn’t actually proportional to the length of the train. That’s why trains are so long to begin with, because it’s more efficient that way. I still don’t think it’s likely to be enough to make panels on the train significant, though. > [@Sam\_Stone](#): > > It won’t take much more solar before we drive the daytime price of energy to zero. That’s already happened in some places in Europe. If we can get to that point, though, that’s huge, because daytime is when most of the energy demand is. Is it a total solution? No. But it’s one heck of a partial solution. ---
**Author:** ![silenus](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/silenus/32/166_2.png) [@silenus](https://boards.straightdope.com/u/silenus)\ **Post date:** [March 22, 2023, 11:02pm UTC](https://boards.straightdope.com/t/solar-freakin-railways/981462/32 "2023-03-22T23:02:14Z")
Right now, somewhere, Robert Heinlein is laughing his ass off. ---
**Author:** ![Chronos](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/chronos/32/134_2.png) [@Chronos](https://boards.straightdope.com/u/Chronos)\ **Post date:** [March 22, 2023, 11:51pm UTC](https://boards.straightdope.com/t/solar-freakin-railways/981462/33 "2023-03-22T23:51:29Z")
Keep 'em rolling! ---
**Author:** ![running\_coach](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/running_coach/32/15836_2.png) [@running\_coach](https://boards.straightdope.com/u/running_coach)\ **Post date:** [March 23, 2023, 4:07am UTC](https://boards.straightdope.com/t/solar-freakin-railways/981462/34 "2023-03-23T04:07:58Z")
> [@silenus](#): > > Right now, somewhere, Robert Heinlein is laughing his ass off. - > [@Chronos](#): > > Keep 'em rolling! - I want a tumblebug. ---
**Author:** ![Elmer\_J.Fudd](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/elmer_j.fudd/32/1211_2.png) [@Elmer\_J.Fudd](https://boards.straightdope.com/u/Elmer_J.Fudd)\ **Post date:** [March 23, 2023, 5:45pm UTC](https://boards.straightdope.com/t/solar-freakin-railways/981462/35 "2023-03-23T17:45:29Z")
There are ways of getting solar power to last the night; like using it to pump water to a reservoir at the top of a mountain during the day and draining it through hydro turbines at night. ---
**Author:** ![enipla](https://avatars.discourse-cdn.com/v4/letter/e/54ee81/32.png) [@enipla](https://boards.straightdope.com/u/enipla)\ **Post date:** [March 23, 2023, 6:23pm UTC](https://boards.straightdope.com/t/solar-freakin-railways/981462/36 "2023-03-23T18:23:17Z")
I have a friend that works with such a system. She’s on the water commission or something. They pump water up during off peak hours, and then run it through turbines when demand is high. ---
**Author:** ![bump](https://avatars.discourse-cdn.com/v4/letter/b/7c8e57/32.png) [@bump](https://boards.straightdope.com/u/bump)\ **Post date:** [March 23, 2023, 6:53pm UTC](https://boards.straightdope.com/t/solar-freakin-railways/981462/37 "2023-03-23T18:53:49Z")
And you could put “floatovoltaics” on the reservoir itself to generate even more power… [Solar Panels Floating in Reservoirs? We’ll Drink to That | WIRED](https://www.wired.com/story/solar-panels-floating-in-reservoirs-well-drink-to-that/) ---
**Author:** ![Pardel-Lux](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/pardel-lux/32/20182_2.png) [@Pardel-Lux](https://boards.straightdope.com/u/Pardel-Lux)\ **Post date:** [May 7, 2023, 8:38am UTC](https://boards.straightdope.com/t/solar-freakin-railways/981462/38 "2023-05-07T08:38:34Z")
Putting solar panels on artificial water reservoirs is looking like a good idea, according to this [ars technica article](https://arstechnica.com/science/2023/03/floating-solar-panels-could-provide-over-a-third-of-global-electricity/). Some data to back up an idea that was already floating around. ---
**Author:** ![silenus](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/silenus/32/166_2.png) [@silenus](https://boards.straightdope.com/u/silenus)\ **Post date:** [May 7, 2023, 2:03pm UTC](https://boards.straightdope.com/t/solar-freakin-railways/981462/39 "2023-05-07T14:03:47Z")
I saw what you did there. Well done. ---
**Author:** ![Shalmanese](https://avatars.discourse-cdn.com/v4/letter/s/45deac/32.png) [@Shalmanese](https://boards.straightdope.com/u/Shalmanese)\ **Post date:** [May 7, 2023, 3:37pm UTC](https://boards.straightdope.com/t/solar-freakin-railways/981462/40 "2023-05-07T15:37:42Z")
> [@Elmer\_J.Fudd](#): > > There are ways of getting solar power to last the night; like using it to pump water to a reservoir at the top of a mountain during the day and draining it through hydro turbines at night. Every good pumped hydro site has already been built on decades ago. It’s the most efficient grid storage solution but it’s also been maxed out. [Previous page](https://boards.straightdope.com/t/solar-freakin-railways/981462.md?page=1) [Next page](https://boards.straightdope.com/t/solar-freakin-railways/981462.md?page=3)