He was short Norway electricity, and long German electricity. Heavy rain in Norway drove down power cost vis-a-vis hydro power. This was entirely foreseeable because unprecedented effects from extreme weather are ordinary--though the average person will equate "unprecedented" with (approx.) impossible. But demographics and inflation alone are enough to necessitate unprecedented effects being ordinary occurrences. Overlay that with climate change making unprecedented weather an ordinary occurrence, and it's flat out negligent to fail to consider that you will be subject to unprecedented effects of weather if you hold a weather-exposed portfolio for very long.
The only thing necessary to tie the above logic into the trader being bad is that he understood seasonal exposure of electricity. I'm going to go out on a limb and say someone who can spin an account up that high temporarily, understood the seasonality.
Basic diversification and risk management, and he'd probably have gone from $30k to $3 million, rather than $30k to -$100 million...and we'd call him "rich" and "successful"--those few who heard of him.
Don't finish the story...you won't like the ending.
It's a neat story, the same way Scarface or Blow are...
