>The best example we have so far is the Orkneys.

Orkneys is a tiny (20k) region, that is connected to the national grid. That's how they solve their intermittency. That they produce excess energy during peak, is fine and dandy, but that's not what we're trying to solve here.

>Add whatever pumped storage and battery the grid might require.

Woah woah woah woah. You just yadda-yadda over the MOST important part. You know, the thing that makes solar/wind unworkable. Pumped storage requires very specific geography and huge land-use. It is not a general purpose answer. And there is no battery technology to power a modern city (much less a nation) for even minutes, much less weeks.

Now what?

>I suspect it's only vested interests stopping us.

No. It's not. It really isn't.

I specifically called out their being tiny. Which is why we need a larger scale example. Nevertheless, despite having the interconnect they are a nett exporter each year, and at the export capacity of that interconnect. Being tiny there is nowhere to put pumped storage, yet they are already using a smart grid managing household, and I think EV batteries. So yeah, they use the grid as storage.

Of course pumped storage, and other storage is a general purpose answer. You don't need 100% capacity to power a nation for weeks. Chances of no sun at all, no rain and empty rivers, and no wind across the whole British Isles, or Europe, including offshore? Nil. So now it needs an appropriate balance of sources, and storage. I don't know what that is in TWh, but I know with certainty it is not "running a nation for weeks".

In reasonable terms, some mix of new projects like Dinorwig, that can run for about 6 hours at max power, battery, managed battery and the more exotic like power to hydrogen - already in use in Orkney, and molten salt that can cover some period far less than weeks will be the right answer.

A house with a solar panel can be a net exporter. So can an island tied to a larger grid.

It is completely orthogonal to the intermittency problem mentioned.

The grid isn't "storage". And yes, Orkney is tiny, but it also needs proportionally less storage.

No, it really isn't. They are inseparable in building a smart grid of intermittent sources.

A house that is an overall exporter still needs coverage for the night time. Maybe household battery, maybe import from the grid. It does not need a battery capable of weeks or even an entire day.

A city needs some TWh capacity when solar is not functioning, some other capacity when wind is not functioning, etc. It's perfectly reasonable to import some of that from other parts of the country or region which aren't currently cloudy or wind-free, and export when there is excess. Storage needs to cover any shortfall, and some excess to cover growth and the unforeseen. It doesn't need to run for weeks assuming zero replacement for a period of dead calm, or assuming country or continent wide dead calm.

If you want every house or city a self contained island without grid interconnect, then your storage requirements ramp up markedly.

Sure, the covariance between solar and wind production at one site isn't 1; and the covariance between all the contributing sites for wind isn't 1. So it does smooth out to some extent. (To some extent-- there are practical limits on grid size).

However, it's inescapable that you need a whole lot of storage. As we conceptualize it now, the grid has to remain available during 1% and 0.1% events.

Again, your point is orthogonal to what was said. If someone grouses about storage, mentioning a net exporter provides zero information. Mentioning that my house is a net exporter does nothing to inform them.

Wind and solar produced electricity. Electricity is a subset of energy (around 20% i think)

Last summer in Denmark was amazing. The best we have had in a long time, the result was that the wind didn't blow wich meant no energy.

So Denmark had to buy their energy from Germany, another country who is all in on trying to use alternatives.

Of course that couldnt' deliver and instead they got energy from coal.

There is so much misinformation going on when it comes to how wonderful solar and wind is.

The reality is that they are less than 1% of the worlds energy production and not projected to be more than around 30% in 2040.

In short. You are as wrong as you can be with regards to your believe in wind and solar.

Hydro is better but only works in some places.

Solar growth projections vs reality: https://steinbuch.wordpress.com/2017/06/12/photovoltaic-grow...

Electricity can be used to replace all uses of energy we have today more or less economically. AFAIK anything but airplanes has replacements that are as good or better than the fossil fuel variant. Problematic are things like concrete and steel production, where we don't have good replacements yet.

Bear in mind that solar capacity and actually fulfilling electricity demand from that capacity are two very different things. The capacity factor of solar is between 20-30% as compared to >50% for fossil fuels and >90% for nuclear [1].

Hydrogen powered aircraft are hypothesized, but require lightweight hydrogen vessels. Maritime vessels can only be feasibly powered by nuclear power. The energy density of batteries is orders of magnitude less than fossil fuels, and sail boats cannot feasibly fulfill demand for shipping. There's a very strong aversion to nuclear energy, so we'll probably be burning fossil fuels in ships for a long time.

1. https://en.wikipedia.org/wiki/Capacity_factor#Capacity_facto...

Ships can probably be run off hydrogen, and if that is impossible for some reason you can always make synthetic fuels. Airplanes could also run off synthetic fuels, but since airplane emissions are actually a lot worse than just their CO2 output, that is not a good solution.

Hydrogen has good energy per kilogram, but bad energy per square meter even in its liquid form [1]. Liquid hydrogen is less than 10 times as dense as water.

Synthetic fuels either require considerably greater arable land and water consumption to grow biofuel, or the use of things like algae cultivation and accelerated decomposition. It's probably more effective on a $ / CO2 mass basis to just sequester carbon and keep using refined fossil fuels. Airplanes account for a single digit fraction of the CO2 emissions from transportation, though, as their mass and drag are both tiny as compared to cargo ships.

1. https://en.wikipedia.org/wiki/Energy_density#/media/File:Ene...

Reply to your post below, HN is not letting me respond:

Those synthetic fuels are effectively the same as biofuels. You're using energy to sequester carbon out of the atmosphere (or a body of water, in the case of algae based biofuels) and using that carbon to power a machine.

You can either do this by using electricity generated from another artificial power source, as in your example. Or you can do this by harnessing natural energy, like setting up transparent pipes to collect solar energy into algae or by farming biomass on land. Since most energy decarbonization plans assume modest energy consumption growth, and sometimes even an overall energy consumption reduction the former plan is less feasible than harnessing naturally occurring energy.

With synthetic fuels I don't mean biofuels, which I think are a terrible idea, but instead something like https://en.wikipedia.org/wiki/E-diesel

Thank you for mentioning nuclear ships, they are a very important and totally ignored piece of the puzzle.

We already have a large nuclear fleet of ships, but they are mostly warships and ice breakers. But as soon as you mention that giant containerships should be nuclear people go ballistic!

They also miss the fact that a nuclear container ship would be 2-3 times faster as fuel economy is a non-issue. That means it would go a long way in replacing air freight and land freight, where you don't need shipment in a day but can't wait a month.

By the looks of it's due to public fear, we will end up using synthetic fuel. You might have a point on offsetting normal fuel by sequestation, but in terms of policing and managing abuse, synthetic fuel might be easier.

No, it can't be used for that and the size of the batteries even for those things it can be used for is a giant issue (and thus cost)

Solars capacity factor is around 20-30 or something like that. It's not even close to being a realistic deliverer and wind doesn't change that either.

I am not joking here. If you can point me to any solution that can economically power ex. the shipping industry using electricity please point me to it so I can invest in it right away.

The reality is that we are decades if not longer away from anything close to the dream scenario you read about everywere around you which becomes very very obvious the second you start looking for investment opportunities and is a good reason why it's primarily driven by politicians, not the market.

Investments in solar and wind are declining too because china is reducing its investments. If it was so great why wouldn't the private market just take over?

My guess is that in 5 years a lot of people are going to get a rude awakening when they finally realize they've been told dreams rather than reality.

But as I said. If you can point to actual solutions to these problems then please let me know so I can invest.

You say "economically" as if there was an alternative to stopping global warming. The shipping industry won't survive catastrophic climate change.

That being said, if you google around a bit you find a number of studies showing how 100% or close to 100% renewable energy can be achieved with today's technology. There is for example

http://energywatchgroup.org/new-study-global-energy-system-b...

or this (just for Germany)

https://www.ise.fraunhofer.de/content/dam/ise/de/documents/p...

I don't need to google around, I know the litterature and I know the difference between what can be speculated and what can be demonstrated :) So don't worry about that.

Fusion is theoretically possible that doesn't mean we are even close to it and neither wind nor solar will be able to deliver anything close to the amount of energy (not just electricity) we need.

Again point me to a concrete solution that is currently being developed and I will invest instantly.

With regards to climate change then, first of all, it's not going to be catastrophic not even IPCC thinks that. Second of all the climate has always been changing and giving us challenges with fossil fuel we've managed to combat most of that.

You live in a rich society BECAUSE of its use of fossil fuels not despite of it.

Nature doesn't give us a safe and friendly environment we make unsafe, it gives us a hostile and dangerous environment we then make safe.

Try and give me a single example of a scientifically demonstrated consequence of the climate changing we can't deal with today.

Phytoplankton is declining: https://www.nature.com/articles/nature09268

Shame they couldn't buy it from France.

That's why a lot of big power lines between European nations are being upgraded so the grid will become more flexible in the future.

Correction 3-4% in 2040!

In other words not even close to being a realistic alternative.