Sammendrag
In the efforts to reduce greenhouse gas emissions and local pollution, hydrogen has the potential of becoming an important energy carrier in the future energy portfolio, for both automotive and stationary use. From an end-user and societal perspective, the viability of the hydrogen energy chain will depend on for instance user-customisation, safety and competitive retail prices. To obtain the latter, the sum of capital and operational costs must be minimised and hence, a crucial element remains keeping the energy efficiency high by reducing the parasitic energy consumption in all parts of the chain: conversion from primary energy sources; conditioning and purification; distribution; storage; and end-use. A significant challenge in the promotion of hydrogen as an energy carrier is hence to demonstrate reduced cost and high energy efficiency throughout the chain. Kramer et al (2006) have performed a comprehensive study on a large-scale hydrogen-based energy supply chain for automotive use. As pipeline infrastructure is deemed to be an unlikely option in the early stages of an infrastructure expansion, bulk transportation of hydrogen by trucks from the production site to filling stations is the likely option. The study concludes that in terms of cost, a chain with central production and distribution of liquefied hydrogen (LH2) is competitive with that of compressed gas (CGH2). Another significant benefit of distribution of hydrogen in liquid form is the flexibility this offers for the retail-side delivery. As LH2 can be pressurised by pumping with very low energy requirements, as opposed to gaseous compression, it can be delivered in various form to end-users according to mobile storage specifications: saturated liquid, sub-cooled pressurised liquid, dense phase or compressed gas. In an envisioned transition of the use of hydrogen to becoming a widely consumed energy commodity transported and stored in liquid form, liquefaction plant sizes are likely to increase c