# Worldwide Solar Grid Hypothetical

1. Jun 27, 2013

### ClarenceCarter

Hi everyone,
I am humbly here to ask a question. I have no EE training or education (as will become apparent) but I couldn't sleep and my head was churning and now I need to know:

Can you operate a city or country on solar power generated on the other side of the globe? i.e. Could solar power generated in Australia be used to light a bulb in London? The upshot of this is that if we had a 'critical mass' of solar generation and an intelligent grid would we be able to always have 'base load' solar?

Please remember I have no technical education. Everybody here is smarter than me. That is why I am here, right?

PS: Please disregard financial/geopolitical complications. I am merely asking if physics will permit the theory.

Sincerely,
ClarenceCarter

2. Jun 27, 2013

### Staff: Mentor

In theory, it is possible, but cables with a length of 20 000 km would waste most of the energy as transmission losses, only a small fraction of the power would reach its destination.
Superconductors would not have those losses, but they need constant cooling.

Those long cables would transmit DC instead of AC, by the way. It can be converted from/to AC at points where electricity is generated/needed.

Power consumption is higher in the daytime - unless you plan to generate all power with photovoltaics, those cables are not interesting. And even then, I think energy storages are cheaper than those really long cables. You need them anyway to cover a variable cloud coverage.

3. Jun 27, 2013

### ClarenceCarter

Power requirements in cities spike around breakfast time and dinner time, i.e. as the sun is rising and setting. So if we generated the power for those times from a small (longitudinal) distance away, might we have a more feasible system?

4. Jun 28, 2013

### Staff: Mentor

Significant power transmission over 1500km exists in China, and systems for up to 5000km (Desertec) are proposed. You lose something like ~5% of power per 1000km, depending on the cable quality and transmitted power.

5. Jun 29, 2013

Solar power includes several other solutions than photovoltaic cells. Some convert solar power into thermal energy, allowing electricity generation after the sun has gone down, reducing the need for a interconnected grid as you propose.

https://en.wikipedia.org/wiki/Solar_power

As for power transmission, the existing grid includes several thousands of km with connected grid. Some are only transmitting (tie-lines) from one region to the other, other have consumers and producers connected along it.

In an idealized way, power production (solar power) and consumption follow time zones (solar production would have a more linear curve, and not discrete as in time zones). So you don't have to transmit power all the way to the other side of the globe. Only a few time zones away, reducing the distance. To some degree this might be provided by the existing grid.

Germany is one of the leading countries in using solar power. Below is a chart of the electricity generation during two days.

Source

At 9 pm the solar production stops. If you would still use solar power in Germany at this instant of time you would have to import it from a location with sun. Below is such a map. At 9 pm on the day in question:

Source

As noticed, your options are limited due to the Atlantic ocean (unless you can have offshore solar plants?) During the morning, your options will be better, allowing import from the eastern countries.