On 24 December 2021, Joulong Energy Technology Co., Ltd., partnered with Zibo Energy Group Chengyi Gas to commission a 300 kW natural gas pressure-differential power generation unit at a city gate station. Throughout start-up, shutdown, and normal operation, outlet header pressure, temperature, and flow rate all stayed within normal ranges — safe, stable, and economically sound. The unit runs in parallel with the existing pressure regulation circuit: if the generator trips or shuts down, the regulation circuit adjusts valve opening automatically, with no impact on gas supply continuity.
300kW Pressure-Differential Generation and Refrigeration System
What sets this system apart is its fixed-expansion-ratio radial turbo-expander. Unlike conventional units, it handles daily fluctuations in gas demand without issue — maintaining near-constant pressure in the customer pipeline regardless of flow rate. Pressure regulation stays within a 1% band, and system efficiency holds at 80% or above.
The turbine and other core equipment are designed for a 30-year service life. With 35 days set aside each year for maintenance, the system runs for 330 days a year, 24 hours a day. There is no consumption of natural gas — the unit simply recovers pressure energy already in the pipeline, so there is no fuel cost. Generated electricity covers the station’s own needs, with any surplus exported to the grid. Both the economic and environmental returns are substantial.
At rated output of 500 kW, the system generates roughly 4 million kWh per year. With a cooling efficiency of 60%, it also delivers approximately 14,400 GJ of cooling annually — equivalent to around 18,000 tonnes of ice production. On the emissions side, the project is expected to save 1,280 tonnes of standard coal per year and reduce CO₂ by 3,987 tonnes, along with 1,088 tonnes of carbon dust, 120 tonnes of SO₂, and 60 tonnes of NOx — a direct contribution to China’s carbon peaking and carbon neutrality goals.
And this may just be the beginning.
Where It Applies
A natural gas pressure-differential power generation and refrigeration system can be deployed whenever these three conditions are met: daily gas throughput exceeds 240,000 Nm³, inlet pressure is at least 1.5 times the outlet pressure, and at least 100 m² of site area is available.
The system suits a wide range of settings: natural gas distribution stations and city gate stations, gas-fired power plants and energy hubs, and large-pressure-reduction stations for industrial users in sectors including metallurgy, glass, ceramics, cement, hardware, and paper manufacturing. It also works for pressure regulation during gas withdrawal from large storage facilities.
So far, Joulong Energy has engaged with PipeChina, CNPC Kunlun Gas, China Resources Gas, and Beijing Gas to explore feasibility studies, and a number of projects are already underway.
There is still a long road ahead. But under the banner of commitment to peak carbon emissions by 2030 and carbon neutrality by 2060, energy companies like Joulong Energy are building something worth watching.
