A study published in Nature Communications found that stringent carbon accounting rules requiring hourly electricity matching provide sufficient returns to incentivize investments in Power-to-Gas hydrogen systems. The findings challenge industry concerns that strict temporal matching would limit project profitability by starving electrolyzers during periods of low renewable energy generation.
Regulators tied production tax credits under the United States Inflation Reduction Act directly to the carbon intensity of hydrogen. Clean hydrogen producers receive up to $3.00 per kilogram if life-cycle carbon intensity remains at or below 0.45 kilograms of carbon dioxide equivalents per kilogram of hydrogen. Subsidies step down to $1.00, $0.75, and $0.60 per kilogram as carbon intensity increases up to 4.0 kilograms, above which no credit is awarded.
Hourly matching performance
Calibrating their model to reference plants in Texas and other US states, researchers estimated that hourly electricity matching delivers internal rates of return between 8.0 percent and 15.0 percent for hydrogen priced from $1.00 to $3.50 per kilogram. These return rates align with typical renewable energy infrastructure yields of 8.5 percent to 12.5 percent.
Under hourly accounting, life-cycle carbon intensity ranges between 0.1 and 9.0 kilograms of carbon dioxide equivalents per kilogram of hydrogen. For hydrogen prices above $1.50 per kilogram, this carbon footprint becomes comparable to blue hydrogen produced from natural gas with carbon capture. Higher hydrogen sales prices prompt plant operators to convert more general grid electricity, increasing overall emissions even when forgoing tax credits during specific hours.
Annual matching and existing grid power
Less stringent accounting rules based on annual electricity matching generate higher project profitability, with internal rates of return reaching 10.0 percent to 23.0 percent. However, annual matching significantly increases life-cycle emissions to between 5.0 and 15.0 kilograms of carbon dioxide equivalents per kilogram of hydrogen.
The highest emission levels occur when rules allow producers to purchase energy attribute certificates from existing renewable power sources rather than requiring incremental renewable capacity. In those scenarios, life-cycle carbon footprints approach those of conventional gray hydrogen produced without carbon capture.
On July 4, 2025, the United States Congress voted to shorten the timeline for clean energy support programs, requiring hydrogen projects to begin construction before January 1, 2028, to qualify for tax credits. The underlying carbon accounting criteria remained unchanged under the congressional action.
