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Comment by mytailorisrich | Hacker News Reader

Thank you, China.

One question I have with solar is: what is the reasonable maximum it can produce as a proportion of each country's needs? Solar is the most guaranteed to be intermittent electricity source around, and can have high seasonality, too.

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From the article:

  Researchers at the Lappeenranta-Lahti University of Technology in Finland have worked out what a globally cost-effective energy supply could look like. Based on their model, 76% of the world's energy would come from solar. Wind power would make up an additional 20%, with the rest coming from hydro, biomass and geothermal energy.

The heat and electricity energy storage need to grow to 46000 TWh [1]. The current value is about 10 TWh.

[1] https://uk.eragroup.com/wp-content/uploads/2021/09/Global_sy...

Heat storage is quite cheap per kWh and has excellent economy of scale.

Just a note that 46,000 is a 2050 target - which covers current demand AND all the growth in electricity and heat demand over the next 25 years.

That's in line with estimates being bandied about in the Finnish dissertations.

Addendum: please don't downvote @red75prime for bringing a fact to a fact based discussion.

Yes, that does not really answer my question, though. A global average is somewhat interesting but with solar the situation is bound to vary widly by location. Also, does 'solar' then include battery storage?

Australia isn't Norway, there are variations in land area, latitude coverage, existing legacy infrastructure, etc. - I'm not writing a country by country break down for you - the IEA has pages per major countries that show progress and plans.

Solar includes energy storage - be that thermal, battery, hydro, etc.

Areas where solar is much less productive (e.g. Norway, Canada) tend to have lower population density, more abundant hydropower potential (which also means storage capacity) and more wind potential.

So, the ratio of solar, wind and hydro would be different under a 100% green energy scenario for them.

They often have grid interconnects to countries where solar does produce a lot, too.

I live off grid, right on the 45'th parallel, and experience 4 full seasons. The solar array and battery bank I have is built from self sourced miss matched panels, and used batteries, it provides power for my house and a significant portion of my business (welding power is from an engine driven welder). In 10 years it has not just amortised it's costs, it has made me money, and qualifies as a tax right off. My up time is better than the grid. The simple fact is that solar plus batteries is a complete solution for 90% + of the worlds population. One of my side projects was to remove the alternator from the "truckasaurus" and mount solar pv as the only electrical power for starting, lights, etc. It was marginal, but I ran it that way as my only vehicle ,year round, for years. Relevant?, yes! as my experience has shown me where the margin realy is, and there has been a great deal of technological improvements and cost reductions since I built my system.

I have my quite positive experience with solar too. But "90% population" claim is unrealistic.

For starters, solar needs batteries to be truly effective. Batteries need rare-earth metals which is a narrow bottleneck. It's fine to buy 4 batteris for yourself but procuring a million will raise prices and probably break backs of many projects. A trillion, and you probably igniting wars for resources.

Also we can't multiply a homesteader's optimum a million times and expect it to be close to what a million people industrial city really needs.

At a large enough scale everything gets different.

Yet the US government just asked for $200 billion to materialize out of thin air to support a needless conflict. Even if it cost a trillion dollars, that is decades of long term energy independence.

Battery chemistries for grid storage are moving toward commodity elements and rapidly reducing reliance on rare earths. Sodium and Iron/Air batteries can take over fairly easily.

»In 10 years it has not just amortised it's costs, it has made me money, and qualifies as a tax right off.«

Great, so basically the tax payer is subsidizing your energy consumption.

Sounds like a fair system.

> Great, so basically the tax payer is subsidizing your energy consumption.

> Sounds like a fair system.

Yes, people voted for tax credits for solar/renewables. It is a fair system. You know what isn't a fair system? Fossil fuel externalities causing childhood asthma and rising sea levels requiring rebuilding coastal infrastructure globally.

Tax payer is funding a lot of resilience stuff. At least in places where resilience exists at all. GP is where emergency services will charge their radios once their generator fuel runs out. Or whoever the local community improvises as substitute to emergency services, if there aren't any. As a tax payer who doesn't have the opportunity to do anything like that I really don't mind subsidizing.

I think the key is to combine it with a strong, digitalized grid and a lot of BESS—a technology which is now getting progressively cheaper, just like PV.

https://about.bnef.com/insights/clean-transport/new-record-l...

I believe it is realistic to expect that, in combination with other renewable energy sources such as wind (which, for example, generates more energy at night than during the day), biomass, and hydropower—along with the high level of grid integration currently taking place in Europe—the share of renewable energy could reach 100 percent in 10 or 15 years. Provided there is the political will to do so.

ren will not reach 100% in EU because of necessary grid costs and plain data that shows there are continental weather patterns that VRE+bess alone cant solve. Hydro is already mostly tapped and Norway+Sweden dont want interconnect expansion

There must be some kind of calculation generally based on latitude?

A sub-question that I would be curious about is how much climate in that region then affects the total possible solar energy. How much is the variance from a naive calculation just based on latitude?

One other second-order effect is: developed economies are heavily weighted towards places that are cold / farther north than less developed places (as a very general rule). And, a lot of people don't realize how much less energy efficient it is per-capita to make a space human comfortable year round in a "cold" climate vs a warm one.

-That's a new way of comparing economies where the price and stability of energy is better in a warm, more equator proximate location.

You can look at maps of solar insolation[0] - these give you typical levels of solar input. There is of course weather variations, but the long-term trends should be consistent.

One thing that can catch me is how much more north Europe is than basically all of the USA. The general solar insolation is worse, yet they are still doing a healthy business of solar. The panels are so cheap that even if you are in a crummy environment, you can just add more.

[0] https://en.wikipedia.org/wiki/Solar_irradiance

Yes, Europe is very North. Also comparing with China: Beijing is the same latitude as Madrid.

> There must be some kind of calculation generally based on latitude?

I am suspecting the same. Thanks for the reply, not sure why my comment seems to have ruffled some feathers...

It depends on how much generation you expect to 'waste'. Many plans are targetting a lot more generation than demand, with numbers sometimes stated as 300% generation potential for solar plus wind.

Connect enough grids and the sun is always shining.

Yeah, just build a 300 GW transmission line from the US to Europe. It will basically costs nothing.

https://www.earth.org.uk/note-on-EU-US-supergrid-interconnec...

And it absolutely won't be used by MAGA and Putinist crazies as a tool of extortion.

that's delusional if you look at EU generation data unless you suggest US-EU-Russia cable

Edit for downvotes, check https://www.energy-charts.info/charts/energy/chart.htm?l=en&... winter data and navigate through countries and tell me how sun's always shining in EU in winter and what capacity factor it can get in certain timeframes

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