Renewable energy sources have gained increasing importance for mitigating the negative effects of climate change while meeting the globally rising demands for energy. In reality, however, regions where renewable energy sources can be readily tapped are often far away from industrial or urban centers of energy demand, necessitating long distance energy imports. Transmitting electricity over long distances is impractical and costly. Secondary energy carriers such as hydrogen produced through water electrolysis could be a sustainable means to convert renewably generated electricity, e.g., from wind or photovoltaic power plants, to chemical products that can be readily transported and stored. This work compares the environmental impacts of local hydrogen production to its remote production with the associated transport over various distances. We aim to evaluate, if and under which conditions the import of hydrogen is environmentally more favorable than local hydrogen production. It was found that hydrogen produced by water electrolysis powered by renewable energy sources is more climate-friendly than that generated locally by conventional steam methane reforming. Even so, to minimize the global warming impact related to hydrogen production, there is indeed an environmentally relevant trade-off: Balancing the best available local conditions for hydrogen production via renewable sources with the minimum transport distance to the consumers.

BACKGROUND: Air pollution exposure has been linked to coronary heart disease, although evidence on PM 2:5 and myocardial infarction (MI) incidence is mixed. OBJECTIVES: This prospective cohort study aimed to investigate associations between long-term exposure to air pollution and MI incidence, adjusting for road traffic noise. METHODS: We used data from the nationwide Danish Nurse Cohort on 22,882 female nurses (>44 years of age) who, at recruitment in 1993 or 1999, reported information on cardiovascular disease risk factors. Data on MI incidence was collected from the Danish National Patient Register until the end of 2014. Annual mean concentrations of particulate matter (PM) with a diameter <2:5 lg=m 3 (PM 2:5 ), PM 10 , nitrogen dioxide (NO 2 ), and nitrogen oxides (NO x ) at the nurses' residences since 1990 (PM 10 and PM 2:5 ) or 1970 (NO 2 and NO x ) were estimated using the Danish Eulerian Hemispheric Model/Urban Background Model/AirGIS (DEHM/UBM/AirGIS) dispersion model. We used time-varying Cox regression models to examine the association between 1-and 3-y running means of these pollutants, as well as 23-y running means of NO 2 and NO x , with both overall and fatal incident MI. Associations were explored in three progressively adjusted models: Model 1, adjusted for age and baseline year; Model 2, with further adjustment for potential confounding by lifestyle and cardiovascular disease risk factors; and Model 3, with further adjustment for road traffic noise, modeled as the annual mean of a weighted 24-h average (L den ).

Selection and peer-review under responsibility of the scientific committee of the 11th Int. Conf. on Applied Energy (ICAE2019).

Selection and peer-review under responsibility of the scientific committee of the 13th Int. Conf. on Applied Energy (ICAE2021).

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