Techno-economic and environmental assessment of renewable hydrogen import routes from overseas in 2030
Florian Scheffler, Christoph Imdahl, Sabrina Zellmer, Christoph Herrmann
Abstract
Converting renewable electricity via water electrolysis into green hydrogen and hydrogen-based products will shape a global trade in power-to-x (PtX) products. The European Union's renewable hydrogen import target of 10 million tonnes by 2030 reflects the urgent need for PtX imports by sea to early high-demand countries like Germany . This study evaluates the cost efficiency and greenhouse gas (GHG) emissions of four hydrogen carrier ship import options considering a reconversion to H 2 at the import terminal for a final delivery to offtakers via a H 2 pipeline network in 2030. This includes ammonia, a liquid organic hydrogen carrier (LOHC) system based on benzyltoluene (BT) and a novel CO 2 /e-methane and CO 2 /e-methanol cycle, where CO 2 is captured at the reconversion plant and then shipped back to the PtX production site in a nearly closed carbon loop. The GHG emission accounting includes well-to-wake emissions of the marine fuels and direct emissions of the carbon capture plant. Two GW-scale case studies reveal the impact of a short and long-distance route from Tunisia and Australia to Germany, whereas the specific PtX carriers are either fuelled by its PtX cargo as a renewable marine fuel or by conventional heavy fuel oil (HFO). Ammonia outperforms the other PtX routes, as the total hydrogen supply cost range between 5.07 and 7.69 for Australia (low: NH 3 HFO, high: LOHC HFO) and 4.78–6.21 € per kg H 2 for Tunisia (low: NH 3 HFO, high: CH 4 HFO), respectively. The ammonia routes achieve thereby GHG intensities of 31 % and 86 % below the EU threshold of 3.4 kg CO 2 (e) per kg H 2 for renewable hydrogen. LOHC though, unless switching to low-emission fuels, and the CO 2 /e-methanol cycle exceed the GHG threshold at shipping distances of 12,300 and 16,600 km. The hydrogen supply efficiencies vary between 57.9 and 78.8 % LHV (low: CH 4 PtX-fuelled, high: NH 3 HFO) with a PtX marine fuel consumption of up to 15 % LHV for the Australian methanol route, whereas high uncertainties remain for the ammonia and methanol reconversion plant efficiencies. The CO 2 cyle enables a cost-efficient CO 2 supply easing the near-term shortage of climate-neutral CO 2 sources at the cost of high GHG emissions for long-distance routes.