Liquid ammonia is easy to transport and a substantial supply chain already exists. “We cannot manage the energy transition with electrification alone. Molecules will play a huge part (…) and we can produce those molecules in an increasingly green way.”
Storing surplus renewable energy as hydrogen or ammonia is more lucrative than curtailing the capacity of offshore wind and solar at times of peak production. Green hydrogen is deemed to become the “backbone of future, largely decarbonized power generation,” a Siemens white paper finds. This is because chemically stored electrical energy is, to date, “the only way to overcome renewable sources or times where there is little or no wind or sunshine.”
Switching from coal to NH3
Japan already retrofits existing coal plants to run with ammonia, a hydrogen liquid, NH3. “You can use carbon capture and storage to produce ammonia, or even use renewable sources to create hydrogen and ammonia,” explained says WEC Secretary General, Christoph Frei.
“It’s important that we go for solutions that are the easiest to implement,” he stressed. Hence, it’s vital to couple the renewable energy sector with the gas infrastructure through Power-to-X.
Half of the world’s capital is invested in energy and related infrastructure. “So rather than kill the molecules, we better see them become green as well,” Mr. Frei said, pointing at electrolysis as a process to generate green hydrogen from excess wind and solar power.
Counting capacity factors and costs
Production costs for renewable energy have fallen drastically as technology advances. Levelized costs of electricity (LCoE) for onshore wind power will soon fall below $20/MWh in the U.S. and Mexico, and similar low prices can be achieved for solar power in northern Australia and the Saharan Africa and Saudi Arabia.
With cheap renewable energy and up to 6,000 full-load hours of wind or solar PV installations for some locations, green hydrogen generated from electrolysis can already compete with grey hydrogen from steam methane reforming (see graph).
Considering today’s prices for hydrogen at fuelling stations, e.g. in Switzerland, green hydrogen would make a positive business case, a Siemens white paper finds.