Future Fuels 101

California has set an ambitious goal of achieving 100% clean energy by 2045. The state’s current plan for decarbonization includes a Renewable Portfolio Standard that sets a 60% carbon-free target by 2030 before transitioning to 100% clean energy by 2045.

What Will It Take to Decarbonize California’s Electricity Grid?

California relies on four carbon-free energy sources to meet its clean energy targets: solar, wind, nuclear and hydropower. Three of the four are subject to daily and seasonal variability. Grid operators must turn to dispatchable sources, like battery storage and fossil fuel plants, to fill in the gaps when demand outpaces supply.

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 future fuels.

What are Future Fuels?

Future 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 Future Fuels Help California Meet its Clean Power Goals?

Future fuels, such as synthetic methane and hydrogen, have some key advantages when compared to other alternative fuel sources, and can help California meet its clean power goals faster while maintaining reliability.

  • Future fuels can replace carbon emitting fossil fuels
  • Future 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, like heat waves.
  • Future fuels enable a 100% renewable power system

Wärtsilä believes it is possible for California to meet its clean energy goal five years earlier if the state follows “The Optimal Path,” which is outlined in the whitepaper, Path to 100% Renewables for California. To realize the potential of future fuels to power California’s clean energy future, the state needs to formally recognize thermal plants that run on future fuels as renewable generation. This step will provide regulatory certainty and encourage research, development, and deployment of power-to-methane and power-to-hydrogen technologies.


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 →