LA PORTE, Texas — Just off of Highway 225 past the refineries and coal stacks that line the freeway, one small plant is proving that generators can make electricity without emissions. Nothing that turns into acid rain. Nothing that makes it hard to breathe. Nothing that contributes to climate change.
The Houston Chronicle reports distinguished from the other industrial sites only by a green leaf on its sign, the demonstration plant has been testing operations for just under a year to prove a power technology that, instead of emitting carbon dioxide, heats it to drive the turbines that make electricity. All but 3% of the carbon dioxide is recycled to produce more electricity; the rest can be captured and stored, ready for pipelines to customers in the oil and gas and other industrial industries.
“This is a game changer for the way we make power,” said Ramanan Krishnamoorti, chief energy officer at the University of Houston and a chemical engineer. “It’s a beautiful engineering feat, but it also makes it a clean system that is energy efficient and capital efficient.”
The plant, developed and operated by a company called NET Power, soon will begin selling power into the grid as it completes the final phase of its operational testing over the next few months. The next step, building plants that can produce power on a commercial scale, should get underway in the early 2020s, company officials said.
NET Power’s technology is considered among the most promising for the energy industry searching for ways to reduce carbon emissions as concerns about climate change grow and governments around the world move to increase the regulation and cost of emitted greenhouse gases. The power and transportation sectors are the biggest sources, each accounting for about 28% of the nation’s greenhouse gas emissions, according to the Environmental Protection Agency.
Many analysts and industry officials view carbon capture as critical to the long-term survival of companies that produce fossils fuels — oil, natural gas and coal — but so far developing commercially viable, affordable systems remains elusive. NRG Energy, the power company headquartered in Houston and Princeton, New Jersey, installed a carbon capture system at its W.A. Parrish coal-fired plant in Fort Bend County, but the cost reached $1 billion.
NET Power, backed by a North Carolina investment firm 8 Rivers Capital and other investors, such as the Houston oil company Occidental Petroleum, uses a technology called the Allam power cycle, which heats up carbon dioxide in a combustion chamber to an extremely high temperature — a point known as supercritical carbon dioxide, at which the C02 gas becomes like a liquid. The process uses the heat and mass of supercritical carbon dioxide to turn the turbines. The carbon dioxide, still very hot, then cools and is recycled through the plant.
The excess carbon dioxide generated by the process could be captured at the correct pressure and quality to be easily transported via pipeline. Normally, in air combustion, sequestration of carbon dioxide is difficult because it is expensive to separate the carbon from the air, and then bring it to the correct pipeline pressure. The Allam power cycle removes the need for this separation.
This is potentially a big deal for Texas, where carbon dioxide that can be transported via pipeline is in demand from its energy and chemical industries.