Mantle Energy secures $5M seed round led by 17Shoals

What's the deal? Mantle Energy, a subsidiary spun out of Hunt EnergyDealroom has a profile for this one. Try Dealroom →'s incubator, has closed a $5 million seed round led by 17ShoalsDealroom has a profile for this one. Try Dealroom → Inc. The Dallas-based startup aims to repurpose oil and gas formations to generate both enhanced oil recovery and geothermal energy — extracting value from reservoirs that traditional methods leave behind.

James Franks, former director of innovation at Hunt Innovative Technologies, will serve as Mantle's chief executive officer. The company claims it can unlock up to 90% of reservoir energy potential that currently goes untapped.

Why now? The US electric grid faces surging demand from data centres, AI infrastructure, and electrification broadly. That has revived interest in geothermal and other baseload power sources that can run around the clock without the intermittency of wind and solar.

Mantle's pitch — converting existing oil and gas assets into low-carbon thermal energy — sits at the intersection of two powerful tailwinds: energy security concerns and decarbonisation pressure. By keeping most carbon underground while still tapping hydrocarbon reservoirs, it offers a bridge narrative that appeals to both fossil fuel incumbents and climate-conscious investors.

What could go wrong? The technology is unproven at scale. Mantle still needs to formalise its pilot plan and secure partnerships before it can demonstrate commercial viability. Subsurface engineering is notoriously unpredictable, and novel approaches to reservoir management carry technical risk.

There's also the question of whether $5 million is enough runway to reach meaningful milestones before a Series A. Energy hardware startups are capital-intensive, and fundraising conditions remain selective.

The signal: Mantle reflects a growing trend of startups trying to bridge fossil fuels and clean energy rather than treating them as opposites. Investors are increasingly backing companies that can reuse existing oil and gas infrastructure — wells, formations, workforce expertise — for lower-carbon purposes.

If the approach works, it could offer a template for thousands of ageing wells across the US that are otherwise headed for decommissioning. That's a big "if," but it's exactly the kind of bet seed investors are designed to make.

Read more: prnewswire.com