eli5: Why do we not run heavily on solar energy as a society or at least in sunny places?
In: 8
it is the inertia of infrastructure where if you have spent $1000’s on a power system that is meant to last 30 years, it is hard to say lets toss the whole system away and go solar.
It takes about 10 years to pay the costs back on solar vs normal power costs these days but that is down from 15 years ago in 2020 but the whole pay every thing now while the price is dropping gives so 2nd thoughts. Delayed gratification is big on price delays uptake.
Since we assigned ZERO cost to health, environment, and climate damage, fossil fuels look a lot cheaper than the alternatives.
Now renewables and storage are coming along nicely, all cost trends say they will dominate the markets in a few years. Nuclear is losing the cost competition, fossil causes climate change.
solar was extremely expensive up until like 2010. its cheap now but we use a LOT of energy so its only single digits percentage of our overall energy mix. its growing like 20 or 30% a year though now.
while the options for clean energy are numerous and viabile, the question is what do we do with the rest of the energy industry? Let’s take the electric companies for example. Do we just disolve them? Fire everyone working there and wish them the best? You could say that we could train them for the new jobs, but many of those workerst are past their 40s, maybe even 50s. From a business point of view, it would be better to train a new guy instead. So replacing an industry would harm the society in a way.
I’m sure there is a proper way to do it safely for everyone involved, especially the common people, but that’s one of the main arguments why they’d never do something that drastic. That, and also, which company owner or industry bigshot is willing to give up on their currently succesful business in exchange for a possibly succesful new one?
Modern power grids depend on more than just energy availability. Here is one example. There is at least one more that is equally, if not more, complex.
I’ll be talking about frequency stability and [inertia.](https://www.nrel.gov/news/program/2020/inertia-and-the-power-grid-a-guide-without-the-spin.html)
Modern power grids are designed kind of like a [bucket of water.](https://energycentral.com/c/um/back-basics-simple-analogy-visualize-evolution-modern-grid) When the energy going into the bucket and the energy coming out of the bucket are balanced, the water level is stagnant (this is good.) The larger the bucket you have, the longer it takes for the water level to change when there is a disturbance (like when the garden hose filling the bucket cuts off or if some dirt plugs one of the holes that’s draining water.)
Power grids are designed to operate in a very narrow band of frequencies (I cango into why but that’s a whole topic in itself.) The frequency of a power grid is literally the speed that all synchronous machines will move at. When the frequency of a grid decreases, it’s because all the synchronous machines are slowing down, because the energy consumers are taking energy out of the bucket faster than it can be replaced by the generators. This “amount of available energy in spinning synchronous machines” is called “[inertia](https://en.wikipedia.org/wiki/Inertial_response)” and is exactly the same idea as a baseball having inertia when you throw it. Large conventional generators (natural gas, coal, nuclear, hydroelectric) are synchronous machines and have a large amount of mass for the amount of energy they produce, meaning they have a high inertia per unit of power. This means that having lots of these generators gives you a larger bucket to handle discrepancies between energy producers and consumers. If a generator forces offline for whatever reason and you have a large bucket, you’re less likely to violate those narrow frequency bands compared to if you had a small bucket.
So now we come to wind and solar (specifically photovoltaics, or solar panels.) Solar units have zero inertia, because there are no moving parts. They operate on solid state electronics, so they contribute nothing to the bucket size. Similarly, wind units are very light, so they *can* provide some inertia to the system, but are usually connected in such a way that they can generate a bit more energy by not being synchronous (if you’re curious to look further, [here](https://www.site.uottawa.ca/~rhabash/ELG4126WindGenerators.pdf) is a good non-eli5 explanation)
There are types of solar power generators that are synchronous, but they’re way less efficient and way more expensive, specifically solar thermal generators. They use a conventional turbine, but instead of getting their heat from burning a fuel, they get it from using mirrors to concentrate sunlight, usually to a central tower.
Power grids were built around this idea of high inertia, so while it is possible to mitigate concerns of low inertia generators (such as [synchronous condensers](https://en.wikipedia.org/wiki/Synchronous_condenser), which are basically generators without an energy source,) they’re expensive and are currently used in very limited scenarios.
There is also an idea of what’s called “synthetic inertia” or “virtual inertia” that wind and solar units can provide, but that is another pretty complicated topic that isn’t without its own caveats.
The other topic I referenced at the beginning, if you want to look into it, is voltage stability. The key concept to look into is “[dynamic reactive capability curves](https://en.wikipedia.org/wiki/Capability_curve).”
Edit: links
Bad PR. Oil industries have spent billions across decades making people think negatively about solar power and other renewables.
https://www.citizen.org/article/lies-big-oil-told-me/
Because it is much more important to our government to spend billions on the military instead of infrastructure.
Because they don’t produce a stable output(eg clouds,dust,snow, seasons, time of day) and don’t run at night. It’s really important for the grid to have reliable power otherwise you get brownouts and blackouts. Also, energy infrastructure takes time to switch over and affordable solar panels are a recent trend. Lastly their true output per dollar is much lower than reported since we can’t store the excess energy a panel may produce at midday so you are essentially paying for nothing when the supply is higher than demand while with other power plants you can reduce the number of turbines and save that energy for later when it’s needed.
You cannot look at Solar power in a vacuum. You need to compare it to the current market standard, condensed into the following 3 key factors.
1. Space
2. Efficiency
3. Reliability/Consistency
There are (many) more factors at play, but for the purpose of this response I’ll stick to these 3 points.
Solar farms take up a lot of space. The space required can be difficult to obtain & maintain, especially if you’re trying to provide power for a city, let alone a nation. Space is a premium for many nations, and Conventional natural gas/coal/nuclear power take a portion of the space required for significantly higher output.
This ties into the 2nd point – efficiency. Solar energy, with the current technology available to us, is not nearly as efficient as simply burning fossil fuels. What this means is that you will require a lot more infrastructure & land (space) dedicated to solar power to get the same result.
Lastly, Reliability & Consistency. Contrary to what how media tries to portray power storage, we have been unable to efficiently ‘store’ energy. It’s not as simple as building a gigantic battery to store power for later – power today is generated and used as-is, meaning all excess power created is wasted. This bit is slightly too complicated to go into detail, but basically we cannot ‘store’ energy for use later on. Keep in mind we’re talking about at least city-level power consumption here, and not mobile devices.
The previous point is important, because we use power 24/7. As you can tell, solar power simply doesn’t work for around half that time. Now factor in weather considerations (e.g. rain, cloudy weather, haze conditions, etc.) and you see that solar power lacks the reliability of conventional power sources.
Conventional power plants can simply increase the power output in a variety of ways on demand. Unfortunately, we lack the ability to summon the Sun on demand, so if a Solar power plant is not generating enough power, there is quite literally nothing the team can do to increase output.
We do here in South Australia. Today we are producing over 100% of our needs with solar and wind power. We do have a gas power station for back up power when needed. We also have a few large batteries.
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