Sustainable fuels

Power-to-gas provides long-term storage option for 100% goals

As coal, diesel and legacy natural gas plants are retired to achieve ambitious decarbonization goals, the need for new dispatchable capacity is necessary for reliability and resiliency in future power systems.

Short-duration and long-duration energy storage are both necessary in future power systems and they each have different roles. Long-duration storage has been the missing piece of the decarbonization puzzle, however, the use of battery storage in this application is not economical or viable.

The most economical long-duration storage is formed with green hydrogen-based sustainable fuels, such as hydrogen, ammonia, carbon neutral methanol and methane. These fuels can be used to generate electricity in flexible power plants. Such flexible power plants provide carbon neutral firm, dispatchable capacity to the grid at any time.

Power-to-gas (PtG) is a process used to produce sustainable fuels or firm dispatchable capacity, which is less dependent on weather conditions.

What are sustainable fuels?

Sustainable fuels can be produced using a process called Power-to-Gas (PtG), which uses surplus solar and wind energy to produce renewable fuels, like synthetic methane and hydrogen. Hydrogen as a fuel is carbon-free and synthetic methane produced using carbon recycled from the air, is a carbon-neutral fuel.


  1. Excess Renewable Energy – Surplus energy from wind and solar power production of synthetic methane or hydrogen.
  2. Captured CO2 from Air – CO2 is directly captured from the air as a source of carbon for synthetic methane or hydrogen production.
  3. Water Electrolysis – Electrolysis of water as a source of hydrogen.
  4. Methanation – Renewable energy synthesizes carbon and hydrogen into methane.
  5. Stored Gas – Carbon-neutral synthetical methane can be stored in existing natural gas storage infrastructure and used by power plants to produce power. Hydrogen would require new infrastructure.

How can sustainable fuels accelerate decarbonization?

Sustainable fuels, such as synthetic methane and hydrogen, have some key advantages when compared to other alternative fuel sources.

  • Sustainable fuels can replace carbon emitting fossil fuels
  • Sustainable fuels can be stored indefinitely and used on demand for long periods of time (weeks) to produce power and provide balancing services to the grid.
  • Long-term fuel storage can be coupled with shorter-term battery storage to ensure a reliable and secure supply of electricity during periods of extreme weather and stress on the grid, such as heat waves.
  • Sustainable fuels enable a 100% renewable power system

How can sustainable fuels create a flexible power system?

Flexible gas capacity has the role of balancing the system when there is not enough energy available from renewables and battery storage. This means the flexible capacity must be ready to start fast at all times, must be capable of ramping up and down quickly and also be able to go off-line to stop using fuel when it is no longer needed.

Future flexible power systems also require technology that can be converted for sustainable fuels. Flexible engine power plants are already capable of using 100% synthetic and carbon-neutral methane and methanol.

Sustainable Fuels Fact Sheet: California

It is possible to build a 100% renewable power system in California that maintains reliability, and minimizes land use, carbon emissions, and cost. The answer lies in the use of sustainable fuels.

Download the fact sheet


Dig Deeper: More on Methane

Synthetic Methane as a renewable fuel As utility systems attain greater renewable penetrations, seasonal trends or drought impacts on renewable energy throughput have greater impacts on the reliability and affordability of the power system. 100% carbon neutral/free systems must install enough capacity (with the right capabilities) to meet energy needs in worst-case scenarios. At a Read more →