Sadly, Matt Simmons, peak oil theorist, energy industry investment banker, and author of “Twilight in the Desert” died at his home in Maine yesterday in an accidental drowning. Some news organizations are reporting the cause of death as a heart attack, but, according to this Bloomberg story, “heart disease” was simply noted as a condition on the death certificate.

In recent months, Simmons was best known for a number of rather wild claims about the Gulf oil spill and the future of BP (which may still turn out to be true), however, it is his ground-breaking study of peak oil and more recent work in founding the Ocean Energy Institute (OEI), a group that set out to develop the technology needed to generate energy from the ocean, that he will be remembered for over time.

One of his last interviews was with Jim Puplava at Financial Sense Online a week ago.