I often see posted about how covering a relatively small area in a desert with solar panels could power the world – but transferring that energy is too difficult. Why can’t we just use that to charge batteries and ship them places/ everywhere?
In: Physics
You lose energy when you charge and discharge batteries. It would cost more energy to transport and distribute the batteries. Long distance transmissions are really the least lossy method, and it’s still has significant losses.
It is possible to create jet fuel from ocean water air, and a lot of power. The US Navy has a patent on it. Even then conversions like that are significantly inefficient.
Batteries are much much heavier for the same energy than things like Synthetic fuels, Hydrogen, Methane, Ammonia.
Transporting them would cost a lot of energy by itself.
Suppose you want to power the U.K. from batteries charged in the Sahara. A typical 3″ x 1 foot by 2 foot battery pack for electric cars is 80 kwh and weighs 1000 pounds. The UK daily electricy consumption is around 800 millon killowatt hours. You’d need to ship 10 million of those fully charged battery packs per day. Doesn’t seem even remotely feasible, does it?
Shipping batteries needs a lot of energy. It is much cheaper to transport electricity by cable.
But that also has his price based on the resistance of the cable.
It’s called Ohms Law.
A 100km high voltage line will lose between 3 and 7 % of the energy.
To add to other comments, Some situations are limited on space and/or weight. (Think shipping or air travel) and, while batteries are getting smaller and better all time, we don’t have batteries that can store enough energy that are small and light enough to say power a commercial airplane (a concept known as energy density).
Why use batteries when modern 1+MV HVDC transmission lines can shoot power over 3000km with under 10% loss including conversion losses at both ends.
Batteries that could hold that much energy would be way too big and heavy to transport. There is a ton of research going on to find better, lighter rechargeable batteries, but the tech isn’t there now.
Hi OP.
I think you’ve had a bunch of replies that explain well why storing and transporting solar power in batteries isn’t practical, unless there is a further revolution in battery technology.
However, you may be interested to know that there are other technologies that are being worked on, that seek to address exactly the issue you have been thinking about, but not with batteries.
One of the most significant is using ‘green hydrogen’ – using renewable power to produce hydrogen through the electrolysis of water.
This differs from other potential sources of hydrogen – grey hydrogen (produced from fossil fuels) or blue hydrogen (produced from fossil fuels with carbon capture) or white/gold hydrogen (natural hydrogen deposits underground).
Hydrogen is a useful gas to burn with a pipeline connection. But transport over long distances is still hard. Therefore the most likely technology is to turn that hydrogen into ammonia, which can be shipped and then burnt like a fossil fuel, but without the carbon emissions.
Therefore the ammonia acts a bit like a battery, but with more energy density and easier to ship – combining some of the benefits of renewables and chemical fuels in one.
Now there are still doubts about the economic case for green hydrogen. These steps still struggle to compete with fossil fuels on price and our system is not yet properly oriented to generating energy from ammonia, although it can be added at the margin in many thermal power plants.
(And blue which is probably the main competitor – grey doesn’t address carbon and white is highly unproven). But, the economics are a lot closer to making sense than something like batteries, and there are industrial-scale pilot projects underway right now, notably in Saudi Arabia:
https://acwapower.com/en/projects/neom-green-hydrogen-project/
Lithium Ion batteries have approx 0.25kWh/kg energy density.
1 liter of diesel (which still has to be converted to electricity) has 10kwh/l energy density. At 25% efficiency that’s about 10x more energy in a liter diesel than in a kg of battery.
They’re just not that “size efficient” yet.
We can, it just takes money.
Any major solar panel installation needs a way to time-dhift the energy. The sun shines during the day, but the highest air conditioning loads are when people get home from work and turn on the TV.
People use electricity past the time where the sun is high enough to make useful energy.
Tesla has built several successful time-shifting battery banks (huge). And these will likely be the main use of sodium-based batteries as soon as they re available.
Lithium looks like it will remain rhe best battery for vehicles for at least the next decade.
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