Page 1 - Franzitta_et_alii_2017

sustainability

Article
Energy Saving in Public Transport Using

Renewable Energy

Vincenzo Franzitta *, Domenico Curto, Daniele Milone and Marco Trapanese
Department of Energy, Information engineering and Mathematical models (DEIM),
University of Palermo (UNIPA), 90128 Palermo, Italy; domenico.curto@unipa.it (D.C.);
daniele.milone@unipa.it (D.M.); marco.trapanese@unipa.it (M.T.)
* Correspondence: franzitta@dream.unipa.it; Tel.: +39-091-238-61941
Academic Editors: Francesco Asdrubali and Pietro Buzzini
Received: 24 September 2016; Accepted: 9 January 2017; Published: 13 January 2017
Abstract: Hydrogen produced by renewable sources represents an interesting way to reduce the
energetic dependence on fossil fuels in the transportation sector. This paper shows a feasibility study
for the production, storage and distribution of hydrogen in the western Sicilian context, using three
different renewable sources: wind, biomass and sea wave. The objective of this study is the evaluation
of the hydrogen demand, needed to replace all diesel supplied buses with electrical buses equipped
with fuel cells. An economic analysis is presented with the evaluation of the avoidable greenhouse
gas emissions. Four different scenarios correlate the hydrogen demand for urban transport to the
renewable energy resources present in the territories and to the modern technologies available for
the production of hydrogen. The study focuses on the possibility of tapping into the potential of
renewable energies (wind, biomass and sea wave) for the production of hydrogen by electrolysis.
The use of hydrogen would reduce significantly the emissions of particulate and greenhouse gases in
the urban districts under analysis.

Keywords: hydrogen; wind; biomass; sea wave; mobility

1. Introduction

Among the actions that the Kyoto Protocol indicates in order to reduce CO 2 emissions, innovative
technologies are promoted, in particular based on the exploitation of renewable energy sources (RES).
All RES (expect geothermal) are related to solar radiation: annually the earth’s surface receives about
885 billion GWh of solar energy. This huge amount of energy is equivalent to 6200 times the primary
energy consumed by humankind in 2008 [1]. For this reason, the RES could theoretically satisfy the
entire energy demand of human settlements. Nevertheless, the existing energy systems are dominated
by technologies based on fossil fuels, producing the emissions of greenhouse gases and polluting the
environment [2]. Within this economically managed part of the energy sector, renewable energy sources
currently provide about 25% of the energy supplied [3]. Energy use and resource depletion does not, of
course, constitute the primary goals of any society or individual within a society. For example, average
Europeans or Japanese use about half as much energy as the average North American, but have a
living standard similar to the North American citizens. This underlines the fact that the living standard
and welfare depends on having primary (food, shelter, relations) as well as secondary standards of
individual preference fulfilled and this can be done in different ways with different implications for
energy use [3]. In the last years, the interest of research and policy has been focused on a new system
able to exploit energy from nature or economical sources of energy.
Electricity generation from clean, safe and sustainable energy sources is nowadays a priority
for many industrialized countries to meet increased energy demand and to reduce CO 2 emissions.
The residential and industrial sector modified their fundamental structure, for example with the

Sustainability 2017, 9, 106; doi:10.3390/su9010106 www.mdpi.com/journal/sustainability