A Texas power plant is rethinking how the world produces – and uses – fossil fuels. For the last several weeks, engineers have been testing a prototype zero-emissions technology, which uses a stream of carbon dioxide rather than air to drive turbines. Developers say it will not only generate power at a lower cost than existing power plants, it will also eliminate all air emissions, including carbon dioxide (CO2).
What sets this facility apart from a standard power plant is how it cycles CO2. Using a patented thermodynamic cycle called the Allam Cycle, start-up firm NET Power successfully fired up its one-of-a-kind Toshiba combustor for the first time at a test facility earlier this week. Altogether, the Allam Cycle eliminates all emissions from natural gas power generation and, in turn, produces energy that could be profitable.
The Allam Cycle utilizes a process called oxy-combustion, where fuel is burned with pure oxygen instead of ambient air, which is nearly 80 percent nitrogen. Oxy-combustion eliminates all air emissions and nitrogen oxide productions, which can ultimately turn into acid rain. Next, CO2 is recycled back into the combustor multiple times where it produces a working fluid that is mostly pure, high-pressure CO2. This CO2 is used in place of steam to drive a turbine, a concept known as “carbon capture” that means that less fuel is needed.
“First fire is a critical milestone for the demonstration plant, as it validates the fundamental operability and technical foundation of NET Power's new power system,” said the company in a statement.
Carbon capture has previously been thought to be uneconomical. Currently, natural gas plants burn natural gas with air (which is a mix of oxygen and nitrogen) and emit CO2 that is difficult and expensive to separate out. Conventionally speaking, power plants burn fossil fuels to generate the steam that drives a turbine, emitting CO2 in the process. NET Power says their technology will produce electricity by burning natural gas with oxygen instead of air, and eliminates the need for water to drive a turbine.
Chemical engineer Rodney Allam told Nature that, if all goes well, the technology will “produce electricity as cheaply and efficiently as a conventional, modern gas-fired power plant – and earn additional revenue by other means.”
Following rigorous testing, the team says they will integrate their technology with an on-site turbine to begin generating electricity.