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Comment by gregoriol | Hacker News Reader

Renewable energy is quite predictable: there is sun during the day, and no sun during the night. Wind is a bit less but could be too.

Why not organise accordingly?

First, there are batteries: solar roofs should come with batteries, than will power the house during the night. Authorities could enforce that, and could also build larger energy storages with batteries at a region level (see recent examples from Tesla).

Then, this is mostly communication: why not make the grid and the roof "talk" to each other and the roof be turned off from the grid when there is no need for it? Is it because subsidies or some kind of mandatory buy from the grid that this could be an issue? otherwise there could be incentive to have this better integration with the whole system.

Otherwise, use bitcoin miners, during the day!

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> solar roofs should come with batteries

This is a good way to kill new installations by making them needlessly expensive.

Demand is typically higher during the day, because that's when people are working and running their aircon.

You do get a "duck curve" https://en.wikipedia.org/wiki/Duck_curve but that's best dealt with by gas peaker plants. It's just that Australia is in a stupid situation on the gas "markets": https://theconversation.com/gas-crisis-or-glut-why-japan-pay...

This is the part where someone points out why I'm completely wrong:

> solar roofs should come with batteries

The way I understand it, batteries tend to be bad for the environment if/when they need to be replaced, because often they are improperly recycled and/or there are no adequate facilities for that.

If this is correct, do we really want to have more of them around? Wouldn't an environmentally-friendly(ish) central plant be better in the long run?

Lead acid batteries are pretty easy to recycle. We already do this for car batteries. Lithium batteries are currently not as easily recycled, but that seems to be because there is little demand for recycled Lithium and they're not very toxic in landfills.

Stationary batteries have fewer constraints wrt to energy density, because they don't move.

Well, it really depends on the kind of battery.

I don't understand why these utilities are not creating a centralized battery in the form of, for example, pumped water. Use excess energy in the day to pump the water up, and let it down when the current energy demand exceeds standard production rates.

Pumped water is not the only possibility either, there are plenty of alternatives which are not terrible for the environment. See: https://en.wikipedia.org/wiki/Energy_storage

Pumped storage relies on having a suitable natural basin, building one is far too expensive.

Quick googling suggests that Australia is already looking at this: http://www.abc.net.au/news/2018-06-06/tasmanian-pump-hydro-s...

Your question about the grid and the roof "talking" is exactly what was described in the article about "curtailment".

The problems with curtailment are:

1) The management of roof solar output is currently in the hands of solar roof owners, not grid operators, so the grid operators cannot easily "reject" the produced electricity. 2) Solar installations are often financed with expectations of savings and/or revenue, so if the grid operators curtail the solar generation, do the solar roof owners have a right to be compensated for their lost revenue? How is this compensation managed fairly across all solar roof owners?

We're trying to fit square peg into round hole - after 50 years of centralized grid with one type of predictable demand curve now we got all those people that dare to install their own solar.

I'd wish that utilities would stop fighting and accept inevitable.

What's the inevitable?

I would think move to renewables and more decentralization (more choices for individual consumers, as it happened with almost any other industry).

Decentralized is not really the problem here: it's more about the links between each installation and the surplus. It's harder to see it with electricity, but think as if it was water for example: if people were pumping water at home and pushing it into pipes to others, and not that many water was actually needed, where would it go?

By decentralization I mean something different, decentralization of energy production. The fact that, say, a village can decide to install a solar panel array to satisfy some of their energy demands, and they don't have to rely on powerful (and often global) energy companies who mine coal or process oil, is an important game changer in terms of power relations between people.

You just have to buy the solar panels from a global megacorp instead.

Don't get me wrong, this kind of decentralisation can be very effective in small isolated communities such as the Scottish islands, but for most places doing it locally is both more difficult and more expensive.

> You just have to buy the solar panels from a global megacorp instead.

That's still a massive improvement in competition. But I'm pretty sure it's also not true and tons of companies make solar panels.

The service utilities provide changes from energy production to energy storage, distribution, and management.

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