Going underground to tame emissions

Most of Colorado’s energy transition has been above ground. Does 100% emissions reduction depend upon geothermal technologies and carbon sequestration?

 

by Allen Best

If you step back to think about Colorado’s big energy pivot, most of the work to reduce emissions in the last 20 years has been above ground, principally with the wind towers and solar panels that have already become commonplace and will become much more so as we approach 2030.

That will take Colorado to significant reduction of greenhouse gas emissions by 2030 although possibly not to the levels specified by state laws.

Beyond that? The subterranean has moved high on the agenda as Colorado and local leaders think about how to stretch from 80% to 85% emissions-free electricity to higher levels yet and how to eradicate emissions from other sectors of the economy.

This attention to the underground has several dimensions, principally:

• Carbon capture and sequestration
• As a source of electricity
• For heating (and cooling) of buildings

The latter — called district geothermal when referring to neighborhood-scale projects — is not new. It will almost certainly be deployed more broadly, as it is now relatively cost effective as compared to infrastructure for delivery of methane when costs are absorbed over a somewhat longer time frame. District heating, particularly in new construction, could make a real dent in emissions by mid-century, maybe earlier.

The other two – stowing carbon emissions underground or using deep wells to produce electricity – pose far greater challenges, especially economic. But both also could draw on the skills of the workforce that has an existing focus on extracting oil and gas.

Some of what is happening was mentioned during the Colorado-Iceland Clean Energy Summit held June 20 in Denver. Gov. Jared Polis spoke, as did various officials in his administration. Iceland, of course, was well represented on the panels, sharing how their country has mined heat not only for outdoor swimming pools that can stay at 92 to 94 degree heat through the long winters but also produce 30% of the island nation’s electricity.

At the conference, Will Toor, director of the Colorado Energy Office, explained that it has become clear that “Colorado can’t get to net-zero just through electrification and renewable energy.”

“Over the last several years, the state has begun to really embrace the potential of carbon capture … and the opportunities it may provide for industrial decarbonization as well as potentially a role in the power sector for providing clean, firm generation to complement a largely renewable grid,” he said.

Legislation signed into law in late May clarifies things like ownership of the subterranean pore space, i.e. the microscopic places between rocks where the CO2 would be stowed.

“We are sort of in the early stages of the adventure of carbon capture in Colorado,” said Toor.

The first Colorado Greenhouse Gas Emissions Roadmap, which was issued in 2022, made no mention of carbon capture and other technologies. The roadmap issued in January 2024 does so, along with clean hydrogen and other technologies that are generally classified as emerging. In other words, at current costs, they’re more difficult to justify.

To be clear, there was a cheerleading aspect to this similar to the pro-nuclear conference I had attended the prior week in Pueblo. In this one, more so than in Pueblo, challenges were discussed. But, like many conferences, the stone was skipped across these ponds.

Now, more on the particulars not only of the conference but what is happening in state government.

 

Rule-making for Deep Geothermal

SB23-285, a law adopted in 2023, changed the name of Colorado’s oil and gas commission to the Energy and Carbon Management Commission. The same law also broadened its regulatory scope to include geothermal resources more than 2,500 feet below the surface.

The idea is that electricity can be generated by circulating water among the hot temperatures of rocks found at deeper levels to produce steam. Draft regulations have now been prepared, and if you have an hour, they can be found here.

Colorado has no electrical production from underground heat, but California generates 4% from what is called enhanced geothermal (as opposed to geothermal for heating and cooling of buildings), Nevada 10%, and Utah 8%, according to state energy profiles for 2023 by the Energy Information Administration.

Why none for Colorado? The simplest answer is that beyond the obvious exception of hot springs such as Mt. Princeton, you have to go far deeper to find the sort of heat needed to produce steam and generate electricity. California has more than 40 geothermal plants, but the most significant production occurs at the Geysers Geothermal Field about 70 miles north of San Francisco. California has had volcanic eruptions as recently as 1914-1917, at Mt. Lassen. Even today, mountain climbers can find steam coming off the top of Mt. Shasta.

Colorado has had no volcanic activity for about 3,500 years, and that last activity at Dotsero was more like Barry Manilow than AC/DC, to use an analogy that I first used when I wrote about Dotsero some 40 years ago.

The Energy and Carbon Management Commission still manages to find cause for optimism. The agency’s website says that Colorado’s “resources are mostly undeveloped and have vast future potential for energy development and direct heat use.”

Rulemaking by the commission for these new regulations is scheduled for Aug. 5-9.

Meetings to inform “stakeholders” what Colorado’s state government is thinking about for carbon management will be held July 15 in Durango, July 16 in Pueblo, and July 17 at Firestone, with an additional online session on July 18. More details here.

Anna Littlefield, of the Colorado School of Mines, considered a key figure in helping Colorado draw up governance, will be giving presentations, as will Quinn Antus, the Colorado Energy Office program manager for emerging markets and carbon management. He will describe work on a carbon management roadmap ordered by legislators in a bill, HB23-1210, “Carbon Management.”

The law also ordered a technical study of the state’s geothermal resources, which was posted on June 30. The same law also ordered a study evaluating the state regulatory structure for geothermal resources. That study was posted on July 1. See here.

It also ordered a study concerning the regulation and permitting of underground hydrogen operations. That study was also posted on June 30.

 

Carbon sequestration regulations

The commission has a second major rulemaking coming up probably later in 2024as it sets out to create the regulatory structure for carbon capture.

Legislators gave key direction in both the 2023 and 2024 sessions. The aforementioned SB23-285 gave the commission regulatory oversight for carbon capture and storage.

Another law, SB23-016, gives the commission authority over Class VI injection wells used for sequestration of greenhouse gas emissions.

The rules, when completed and adopted, will allow the commission to pursue and obtain regulatory authority from the EPA for regulation of the Class VI wells.

Still another law, SB24-1346, “Energy & Carbon Management Regulation,” gave further direction.

Some details can be found on the commission’s website.

Already the commission has approved one test well for potential carbon sequestration injections under the Environmental Protection Agency’s Class VI carbon capture sequestration program.

That 6,500-foot well planned by Project EOS would be on State Land Board property in southeastern El Paso County that is used principally for livestock grazing. This is 36 miles northeast of Pueblo and a comparable distance southeast of Colorado Springs. Drilling is projected to take about 45 days.

Project EOS is a three-year feasibility study being conducted in a partnership of the Colorado School of Mines, Arvada-based Carbon America, and the Los Alamos National Laboratory to explore the potential for developing a carbon storage site for industrial emissions from cement, steel, and power plant operations in the Pueblo area. The project was awarded a $32.7 million grant by the U.S. Department of Energy.

Carbon Storage Solutions has also applied to drill a 9,000-foot stratigraphic test well associated with carbon sequestration under the Class VI program. This would be east of Windsor. A report in June 18 filed by Julie Murphy, director of the state commission, says that this well will monitor the pressures, temperatures, and formation fluid sampling from the injection zone in the Lyons formation as well as the confining zone above (Lykins) and below (Lower Satanka). The drilling is expected to be wrapped up later in 2024.

The commission will take up that proposal on July 10.

Both wells are being processed under the streamlined process for considering and approving such tests wells under an executive order from Julie Murphy, the director of the commission.

 

Carbon sequestration for cement

The Colorado Greenhouse Gas Reduction Roadmap mentions cement only in passing, but it’s a major producer of greenhouse gas emissions, as this 2023 article in Scientific American pointed out: up to 9% across the world. (A speaker at the Iceland-Colorado conference said 8%.)

Lime used to create cement – the substance used to bind together sand and other materials – comes from limestone, which is baked at up to 1,450 degrees C (2,640 degrees F) in kilns that are fired almost exclusively with fossil fuels.

Melissa Carey leads the climate, ESG policy, and government affairs department at Holcim, the largest cement manufacturer in the United States. It has 20% of market share, she said at the meeting with the Iceland officials in Denver. That includes a plant near Florence, located along the Arkansas River in southern Colorado.

The plant tops the company’s list for carbon capture and storage.

“We’re so pleased to have the level of commitment that we’ve had from the state of Colorado for helping companies like ours figure out the many, many technical links in the chain that come between point source, carbon capture, transport, and storage. It really is a team effort that involves a lot of players, and Colorado is just killing it.”

In Colorado, the distance between the Florence plant and one possible sequestration site underneath State Land Board properties is only 40 or 50 or so miles. The company is also looking at transporting, via pipeline, C02 from its lime cement kiln in Ste. Genevieve, Missouri across the Mississippi River but also across much of Illinois to a suitable site.

Pipeline permitting and outreach with local communities will be a huge task, she said, but not insurmountable. “These are operational details. These are not scientific inventions, although they feel sort of like it sometimes. No permitting reform is really easy.”

Might there be easier ways? Carey suggested that there are. She cited other solutions “that we’re not using because, frankly, they’re just not that sexy. We can switch our fuels; we can use different cemetitious materials, we can recycle materials that we currently landfill. I don’t know if you know this, but when we demolish a building, we take all of that demolished concrete and we put it in a landfill.”

One company in Longmont, Prometheus Materials, has been focused on developing building materials to replace conventional concrete by using alternative ingredients.

“We’re not necessarily focused on the near-at-hand solutions as much as we are on over-the-horizon solutions,” said Carey. “If we’re not availing ourselves of all the opportunities to the maximum extent possible, we’re definitely doing it wrong.”

So why would Holcim pursue carbon capture and sequestration at its Colorado plant instead of other solutions. That question wasn’t asked.

But before she left, Carey had this gem of a quote: “We cannot treat climate change as a static problem that will just kind of keep being a problem until we fix it. It’s a problem that gets exponentially worse every year.”

The panel also included perspectives from two other companies. Carbfix, a company founded in 2007 that is using a process that imitates and accelerates the natural process through which dissolved C02 and reactive rock formations interact to form thermodynamically stable carbonate minerals. The company recently launched a second direct-capture project in Iceland. It is also working on five projects with the U.S. Department of Energy in various states.

Carbon Recycling International was founded in Iceland in 2006. The company takes CO2 from biomass, biowaste, and other biogenic sources and combines it with hydrogen to produce a high-quality methanol. It has two large installations in China.

 

Denver’s geothermal district heating

Most buildings in Iceland tap heat from underground. Of course, Iceland has volcanoes. What might be in store for Colorado?

Colorado already has a number of geothermal district heating systems: downtown Pagosa Springs, 70% of the campus of Colorado Mesa University, and at least parts of the Colorado Capitol. Also included is the Geos housing development in Arvada as well as a great many individual homes across the state – with many more added ever month.

Few places in Colorado have such high ambitions for decarbonization as Denver. It aims for 65% decarbonization by 2030 compared to 50% for the state.

Jonathan Rogers, from the city’s Office of Climate Action, explained how his agency hopes to install a district energy system in a way that will be affordable, reliable but also carbon free. In doing so, Denver hopes to provide an example of what can be done on broader scales and replicated elsewhere around the world.

Denver calculates that 40% of its emissions come from the production of electricity, while 30% can be traced to transportation and another 30% to the heat for buildings. Colorado is fast pivoting its electric systems to non-carbon sources, to the high 90%s by 2040, according to modeling commissioned by the Colorado Energy Office.

“That is fantastic, and it makes it very attractive to think, well, how do we shift those thermal loads and those transportation loads to rely on clean electricity.”

Ah, but it’s not as easy as flipping the switch. This requires investment and understanding of various elements of energy infrastructure including transmission and then distribution of electricity.

Denver must think about the worst-case scenarios, as must the utilities and the PUC. Rogers cited the case of a 30 below temperature. It hasn’t happened in many years, but it’s not out of the realm of possible. Every winter the temperature does find its way to about 15 below.

If electricity replaces great amounts of the fossil fuels now used for transportation and buildings gets put into electricity, Denver’s electric grid might be four times what it is today.

“We absolutely expect we’ll more than double the throughput of electricity on an annual basis,” said Rogers. Peak demand could drive costs high.

That said, doing nothing in this energy transition is not an option any more than leaving lead pipes for delivery of water to customers is.

So how does Denver leverage its existing infrastructure in ways that can achieve climate goals without breaking the bank?

Rogers described the use of Xcel Energy’s existing district heating and cooling infrastructure. It delivers electricity and gas through much of the city and, in sections of downtown Denver, chilled water and steam. City officials think some of this infrastructure can be converted to use geothermal heating and cooling. Various alternatives could “help us avoid quadrupling the number of substations, which are also going to be extraordinarily hard to locate.”

Electrical demand will increase, he pointed out, but not as much.

As was advised by prior speakers from Iceland, Denver plans to start small. It hopes to have 14 customers – 12 of them City and County of Denver buildings — on line by 2030 and with enough data to persuade others to participate, too. And this next generation might include 1,000.

“And so, over the next 50 years, we can actually help to make a significant dent in the 225,000 fossil gas customers that we have around Denver – all of which are going to need to transition to something new. I’m not naïve about the individual costs that need to be incurred to retrofit existing properties and existing infrastructure,” said Rogers. He called the task daunting.

The challenge is not just putting pipes in the ground and heat pumps in buildings and moving heat from one place to another.

It’s also the regulatory and business challenge. As one business necessarily is wound down and those profits and revenues decrease, that the revenues increase in a different aspect of the business?

Denver, he added, is fortunate in that Xcel Energy, as a multiple service provider, has the opportunity to think holistically about the services it provides.

“We hope that these first 14 buildings in Denver can create that model (for change). We start small. Someone used the expression the other day: How do you eat an elephant? It’s one bite at a time. That’s how we’re going to start and we’re going to keep taking bites, and we’re going to work our way across the city.”

 

Fraser, Aspen and Vail

Matt Garlick, of Grey Edge Group, a company that specializes in thermal energy networks: “When we say thermal energy networks, most often we’re talking about networked heat pumps, and those can take a few different varieties or flavors.”

But in looking at new systems, they start with understanding the ground and the opportunities at each site.

“I was recently in Fraser, Colorado. Turns out they have a very high water table, which could be a fantastic resource for a thermal energy network. I was in Aspen talking to their sustainability team. Their mountain is Swiss-cheesed full of old mineshafts thar are flooded with water that could be a multi-billion – with a B – water storage tank that we could tap into for a heat pump network system.”

Vail’s wastewater treatment facility is under federal regulation to reduce the temperature of the effluent that’s going back into Gore Creek. That heat can be a resource.

“We are looking for the least-cost path to conditioning a heat-pump loop to provide affordable heating and cooling to the respective town or municipality or campus,” he said.

Grey Edge Group is also working with Colorado Mesa University in expansion of its geothermal system. The university hopes to achieve 100% geothermal heating and cooling.

 

Polis on the underground

Colorado Gov. Jared Polis, in his year as chair of the Western Governors’ Association, shepherded programming about geothermal under the heading of “Heat Beneath Our Feet.” He passed the gubernatorial baton to Wyoming Gov. Mark Gordon, who is wrapping up a year devoted tothe promise of carbon capture and sequestration.

Some think this latter mission is wildly misguided, and that was duly noted here.

In his noon-hour chat with the Iceland ambassador to the United States, Polis said that he believes Colorado by 2040 can get 4% to 6% to even 8% of its electricity from deep geothermal, usually called enhanced geothermal. Currently, it gets none.

He also talked about Global Thermostat, a Brighton company that manufactures carbon sequestration devices.

The problem with carbon sequestration efforts, he said, is that there really isn’t a market, especially in the United States although there is more in Europe. That market would be driven by corporate initiatives that hope to achieve carbon neutrality.

“So many global firms, whether it’s Amazon, Google, Microsoft, have aggressive carbon neutrality goals. And, of course, part of that is choosing places to do business like Colorado, which will be 80% renewable energy by 2030. But that also means that for their remaining emissions, they will likely be purchasing credits. That (would) enable this industry,“ he said, referring to carbon sequestration.

Polis also talked about the potential for “cascading uses for geothermal,” and went on to talk about supersized computers, what are called data centers or quantum computing data. He said Colorado, Iceland, and other places with significant green resources have a competitive advantage for attracting manufacturing, computing, both quantum computing but more notably data centers.

Polis also talked about synergy with the oil-and-gas sector.

“A lot of the expertise around drilling deep wells has been developed,” he said. “We also are very interested in deploying existing wells for potential geothermal energy. Oil and gas wells only produce for a short period of time here, (just) a few years. There’s the opportunity both to use drilling technology or new wells… and I think some federal grants were pulled down by operators in Colorado to explore utilization of existing deep wells. So there is a lot of synergy between those two sectors.”

Polis also mentioned the reform to allow expedited permitting for deep drilling for geothermal.

 

Some departing thoughts

Some skepticism would be in order for a lot of this. Certainly, ground-source district heating is a proven and cost-effective technology. It’s here and now — and has been for a long time.

Many of the 35 geothermal grants recently awarded by Colorado to companies, local jurisdictions and others should go a long way in making this sort of geothermal technology far more commonplace.

But geothermal for electricity? Duane Highley, the chief executive of Tri-State Generation and Transmission, recently put the cost curve on the same path as nuclear energy, which he said won’t be available until 2035 to 2040.

Still others think that the federal government’s expanded Q45 tax credits through the Inflation Reduction Act have incited more optimism than is justified, especially around direct air capture.

Other potential problems were acknowledged by Bryant Jones, who heads the advocacy organization Geothermal Rising..

He was actually making the case for greater advocacy, but first admitted that “all energy technologies have their impacts,” and he later talked about water quality issues and concerns about seismic activity.

Maybe those practical concerns and challenges will be woven into a future conference. This conference certainly presented the bright-eyed future for both geothermal and carbon capture and sequestration.