Pilot Project Aims to Solve Geothermal Power's Biggest Challenge

A trial initiative led by a group of experienced oil professionals has the potential to rescue one of California’s crucial clean energy assets from imminent collapse.

On Thursday, GreenFire Energy based in Oklahoma City revealed that they had brought new vitality to an abandoned well at the Geysers, which stands as the globe's biggest geothermal power plant — a facility that has been experiencing a gradual decline over several decades.

Through technology that harnesses the subterranean heat instead of the quickly diminishing groundwater, the GreenFire team transformed a well with stagnant electrical output into an energy generator.

This provides a possible lifeline for The Geysers, which presently generates about 630 megawatts Of on-demand, zero-carbon electricity to Northern California — a reduction from 2,000 megawatts back in 1987.

"You can observe these disused gray wells," explained Rob Klenner, a former oil and gas engineer currently serving as the CEO of GreenFire. He was referring to an illustration showing where boreholes previously directed steam—warmed by California's tectonic activity—to drive turbine rotation at the facility.

"There's still some warmth in this region, but it's more akin to a depleted well," Klenner explained, drawing an analogy with fossil fuels. "It's like, 'We have a small amount of oil, yet not sufficient to make it economically viable, so they decided to halt all operations,'" Klenner stated.

The cause of the decrease: the rapid rate at which traditional types of geothermal energy can deplete water resources.

Currently, the Geysers facilities utilize approximately 15 million gallons on average — 22 Olympic-sized pools — each day. The facility's 18 power stations, located over a span of 45 miles, utilize steam that drives their turbines as the energy source.

While this largely comes from treated municipal wastewater, it nonetheless represents a significant loss of water in a famously water-stressed region — and a significant brake on the ability of so-called hydrothermal fields to produce power.

GreenFire’s advanced system, positioned above a mostly neglected well due to low pressure, employs a method that generates electricity without depleting water resources.

Instead of using the thermal energy from superheated water to turn a turbine, which subsequently releases heat into the air, GreenFire’s team uses a closed-loop system to recirculate water and enhance productivity.

As the steam billows upwards from the heated rocks beneath, it encounters a distinct type of energy facility known as an Organic Rankine Cycle (ORC) plant. This enclosed system utilizes a 'working fluid' with a significantly lower boiling point compared to water, circulating within a closed loop.

As the working fluid flows through the tubes of the ORC system, it drives a turbine to produce electricity—then releases its heat into a condenser and returns, depleted, to the pump to begin the cycle anew.

Klenner mentioned that inside the well, a comparable process occurs. As the ascending vapor transfers its heat to the ORC system, it subsequently gets reintroduced into the newly established subterranean closed-loop cycle.

It cools back down, and then we reintroduce it," he explained further. "As a result, no more water is surfacing.

He drew parallels between this system and injection wells used to extract additional oil from declining oil wells, noting the key distinction being that ideally, nothing would be extracted from the ground.

As growing interest in geothermal energy shifts towards "enhanced" versions of the technology that employ methods such as hydraulic fracturing to generate artificial subterranean cavities, Klenner believes that these approaches present an easy win for rejuvenating current reserves.

Supporters of enhanced geothermal systems (EGS) aspire to achieve drilling on a scale comparable to the oil and gas surge during the 2010s. However, although GreenFire has several EGS initiatives underway, Klenner pointed out that this sector inherently involves generating power at previously undeveloped locations. These new sites would require planners to determine how best to integrate them with the electrical grid.

At The Geysers, he mentioned, 'The necessary facilities are already set up here. There are existing wells, as well as power lines. Instead of venturing into a location where we aim to initiate such efforts for the very first time, we're operating in an area that’s all prepared—this significantly reduces the financial obstacles.'

Restoring the Geysers to their late 20th-century prime would be akin to adding a gigawatt to the power grid—comparable to erecting numerous new wind farms without facing many of the hurdles associated with constructing them.

"If we manage to achieve this using current wells and potentially doubling our output, there would be significant opportunities," he stated.

Updated at 9:50 A.M. E.D.T.

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