Liqun "Zoe" Peng

Clean hydrogen has the potential to serve as an energy carrier and feedstock in decarbonizing energy systems, especially in “hard-to-abate” sectors. Although many countries have implemented policies to promote electrolytic hydrogen development, the impact of these measures on costs of production and greenhouse gas emissions remains unclear. Our study conducts an integrated analysis of provincial levelized costs and life cycle greenhouse gas emissions for all hydrogen production types in China. We find that subsidies are critical to accelerate low carbon electrolytic hydrogen development. Subsidies on renewable-based hydrogen provide cost-effective carbon dioxide equivalent (CO2e) emission reductions. However, subsidies on grid-based hydrogen increase CO2e emissions even compared with coal-based hydrogen because grid electricity in China still relies heavily on coal power and likely will beyond 2030. In fact, CO2e emissions from grid-based hydrogen may increase further if China continues to approve new coal power plants. The levelized costs of renewable energy-based electrolytic hydrogen vary among provinces. Transporting renewable-based hydrogen through pipelines from low- to high-cost production regions reduces the national average levelized cost of renewables-based hydrogen but may increase the risk of hydrogen leakage and the resulting indirect warming effects. Our findings emphasize that policy and economic support for nonfossil electrolytic hydrogen is critical to avoid an increase in CO2e emissions as hydrogen use rises during a clean energy transition.

Battery storage is critical for integrating variable renewable generation, yet how the location, scale, and timing of storage deployment affect system costs and carbon dioxide (CO2) emissions is uncertain. We improve a power system model, SWITCH-China, to examine three nationally uniform battery deployment strategies (Renewable-connected, Grid-connected, and Demand-side) and a heterogeneous battery deployment strategy where each province is allowed to utilize any of the three battery strategies. Here, we find that the heterogeneous strategy always provides the lowest system costs among all four strategies, where provinces with abundant renewable resources dominantly adopt Renewable-connected batteries while those with limited renewables dominantly adopt Demand-side batteries. However, which strategy achieves the lowest CO2 emissions depends on carbon prices. The Renewable-connected strategy achieves the lowest CO2 emissions when carbon prices are relatively low, and the heterogeneous strategy results in the lowest CO2 emissions only at extremely high carbon prices.

China is the world’s largest carbon emitter and suffers from severe air pollution, which results in approximately one million premature deaths/year. Alternative energy vehicles (AEVs) (electric, hydrogen fuel cell, and natural gas vehicles) can reduce carbon emissions and improve air quality. However, climate, air quality, and health benefits of AEVs powered with deeply decarbonized power generation are poorly quantified. Here, we quantitatively estimate the air quality, health, carbon emission, and economic benefits of replacing internal combustion engine vehicles with various AEVs. We find co-benefits increase dramatically as the electricity grid decarbonizes and hydrogen is produced from non-fossil fuels. Relative to 2015, a conversion to AEVs using largely non-fossil power can reduce air pollution and associated premature mortalities and years of life lost by ∼329,000 persons/year and ∼1,611,000 life years/year. Thus, maximizing climate, air quality, and health benefits of AEV deployment in China requires rapid decarbonization of the power system.

Accelerating offshore wind power deployment, a critical but underutilized resource for decarbonizing power systems, requires balancing national and local interests. Using China, the global leader in offshore wind, as a case study, here we evaluate how its deployment creates benefits, such as improved energy self-sufficiency, greater resource diversity, enhanced grid reliability, and increased local investment and employment. Our results show that offshore wind can bolster the energy self-sufficiency of coastal provinces, shifting them from net electricity importers to exporters. Furthermore, expanding offshore wind reduces the need for energy storage in a grid with high renewable penetration and drives substantial local investment and job creation. After quantifying uncertainties in policies, technology costs, and electricity demand, we find offshore wind could provide 3-18% of China’s electricity by 2050. Aligning local interests with offshore wind development can facilitate more ambitious targets and accelerate power system decarbonization with limited increases in system costs.

We optimize energy sourcing, electrolysis, storage, and grid use for 548 steel, ammonia, and methanol plants, matching each facility against hourly renewable resources at 25 by 25 km resolution. Two thirds of these plants can be supplied by fully off-grid renewables sited within 200 km, and a small grid connection supplying roughly 8% of electricity raises that share to 79% while reducing average hydrogen cost by 29%.