Elements of Renewable Energy

So this is a question that's been in the back of my mind for awhile while seeing celebrations of dams being removed, no worries if you don't want to be the one to answer it.

I think I understand the extent of the damage caused by the implementation of dams, but I guess my impression had been that that damage was done, and there wasn't much of a timeline on fixing it. Like, after eighty years or so, are there fish still trying to get past it?

At the same time, we're struggling (failing?) globally to get away from fossil fuels quickly enough to avoid the worst of climate collapse. It seems like hydro is one of the more reliable green power sources, and is compatible with old grid infrastructure that counts on fairly consistent power so there's less than has to be overhauled in order to just keep using hydro for awhile longer.

So at first glance, it seems like new solar and wind etc production would be better prioritized in replacing oil, coal, natural gas. Prioritizing replacing hydro feels like letting the perfect be the enemy of the good.

I haven't seen that discussion anywhere, so I genuinely expect I'm wrong about that, but I'm wondering why.

There are forms of hydroelectric generation that aren't damaging to the environment. We just need to actually be aware of the consequences and perform an environmental risk assessment. I think this is a requirement for new installations in the US, but I could be wrong.

As the image above indicates, hydro is not only an energy source, it can be used for energy storage. Run pumps to pump more water over the dam when you have an excess of power and let the water flow through the turbines when you need power.

So it's like a giant battery. Except unlike most batteries there's no toxic chemicals involved.

Given that most renewable energy doesn't generate consistent energy (it's not windy every day, it's not sunny every day, it's never sunny at night) there will be a huge need for energy storage. While we could spend a lot of money of making giant batteries with toxic materials to solve this, we need to also need to consider the environmental impact of that kind of technology. Also consider the time it would take to make these massive banks of batteries. The materials may be better used in replacing gasoline engines, so it may be awhile before we have the materials needed to make the energy storage needed for renewable energy to work, and that's only if we want to make giant chemical batteries someday.

Sorry, but given the importance of hydro in a renewable energy grid, I don't think it's going away for a very long time. Consider the environmental impact of having forests that burn down every year. Gonna have to make some compromises so that doesn't continue to happen forever.

Industrial scale power requires massive destruction of nature. That's the nature of trying to light and heat millions of homes, especially in the winter. The question must become what is the least harmful most effective thing to do. It isn't as simple as "solar farms and wind farms" since you have to heat and light those homes when the sun isn't shining and the wind isn't blowing. "Batteries!" Sure but the environmental devastation from having to build battery banks that large would be overwhelming, not to mention having to size your solar and wind to provide all the province's power while the sun shines and wind blows meaning there'd be way more than you expect, and then after 30 years you'd have to do it all over again because the batteries, windmills, and solar panels would all have to be replaced.

Water looks nice when it's at a scale that can't power anything too. In fact, even small enough scale fossil fuels don't look that bad. The problem is when you make it big enough to actually provide all the energy you need. One big reason why "reduce" is the most important thing we can do.

Creating it from electricity is highly inefficient, so that's why it's made from other fossil fuels (that in theory would have been wasted). If hydrogen was easily compacted and stored long term it would work, but those are the biggest problems it faces, along with having a much lower energy density that fossil fuels. Hard to beat those carbon bonds without going nuclear.

Or you put turbines in your dam and get both, as is common.

There are other types of biomass though. Using waste product from food production or gas from sewage plants is somewhat reasonable.

It is renewable in the sense that given infinite time, you can use it to grow infinite energy (for the nitpickers: assuming an eternal sun).

It is not infinite though and the amount of power you can extract from it is limited but that's true for every renewable sources: you have a limited amount of places where you can put dams, where you can put windmills or even solar panels.

What is important is that it is not power generation that consumes a scarce good (as fossil power does) but that it is increases in power generation that consumes it, in a reversible way.

Poplars and willows are fairly fast growing. Plus there are perennial grass feedstocks

Wood is a material that's made from carbon that has been extracted from the atmosphere using an organic process.

You can make buildings and furniture out of wood and you're sequestering carbon while having a nice place to live and some nice furniture.

You can also burn the wood for heat energy. This releases the carbon into the atmosphere, but the tree that got cut down makes space for a new tree to grow. When that new tree grows it pulls out the carbon that was added by burning the wood. So it's carbon neutral.

Renewable doesn't mean it's instantly replaced. It means there's a well understood process to replace it. It's not popular among those that hate the lumber industry, but it's one of the more environmentally friendly options considering global warming. Consider how trees used for building means using carbon extracted from the air for building things. Even burning wood is carbon neutral, so it's better than most heating options.

@Mihies @gandalf_der_12te Yes it is. The waste from biomass can be used as fertiliser for new plants, so a circle is formed. One tree is not quite the right model, you could think instead about managed forests where older growth is harvested and new growth is always in various stages, from saplings to ‘ready next year’. Carbon from the biomass process is used by the new growth.

Yes, and, once established, a grove of trees can continue providing biomass for literally centuries. Look up coppicing.

The deforestation of the Amazon is largely driven by a desire for more land to grow biofuels (sugarcane) on.

The byproducts of sugar production (the leaves and stalks) are used to produce ethanol from a biological, renewable source, as opposed to fossil fuels.

Oh, and in the Amazon, said sugarcane farming is often done by slaves.

You either need more farmland to grow what will become biofuels on it, or you have to stop growing food on existing farmland, which means food gets more expensive.

Biomass and hydro* aren't storage for intermittent power (*except pumped hydro). Rather they are natural sources of accumulated solar power that can be tapped on demand. In that sense, so is geothermal.

In some senses the whole planet is storing a huge amount of energy underground.

But yeah I think in the context of this kind of discussion it's would be a renewable energy source. While it's probably technically not renewable, but there's so much of it we'd never run out. I mean if you want to be super-pedantic, solar and wind aren't renewable either because we don't have a way to make a new sun when that thing burns out, but it's like come on.

But probably not a storage solution, because why would you put energy into the Earth's core? We worried about hell freezing over or something?

They aren't forms of energy storage on their own. Just like batteries aren't a source of energy on their own.

There's a separate item for batteries on the list.

You can also store energy from wind and solar in a hydro dam by pumping water.

Energy can also be stored as Hydrogen, that should also be included on the list as an energy storage method.

You can't turn other forms of energy into solar or wind and store it in those forms. In contrast, hydroelectricity can store energy in pumped storage systems where excess electricity is used to move water to higher elevation (exchanging electricity for potential energy).