• Energy Research

The weather-dependent electricity generation from Renewable Energy Sources (RES), such as solar and wind power, entails that systems for energy storage are becoming progressively more important. Among the different solutions that are being explored, hydrogen is currently considered as a key technology allowing future long-term and large-scale storage of renewable power. Today, hydrogen is mainly produced from fossil fuels, and steam methane reforming (SMR) is the most common route for producing it from natural gas. None of the conventional methods used is GHG-free. The Power-to-Gas concept, based on water electrolysis using electricity coming from renewable sources is the most environmentally clean approach. Given its multiple uses, hydrogen is sold both as a fuel, which can produce electricity through fuel cells, and as a feedstock in several industrial processes. Just the feedstock could be, in the short term, the main market of RES-based hydrogen. In this paper, we present the results obtained from a techno-economic-financial evaluation of a system to produce green hydrogen to be sold as a feedstock for industries and research centres. A system which includes a 200 kW photovoltaic plant and a 180 kW electrolyser, to be located in Messina (Italy), is proposed as a case study. According to the analyses carried out, and taking into account the current development of technologies, it has been found that investment to realise a small-scale PV-based hydrogen production plant can be remunerative.

Producing green hydrogen by electrolysis is a goal at European and international level. But hydrogen production by water electrolysis is currently more expensive respect the steam methane reforming. Based on our previous studies, extra revenues in order to reduce the production costs could be obtained by considering the co-produced oxygen. Starting from the point of view of a hypothetical enterprise that needs gaseous oxygen for its activity, in order to meet a variety of requests or applications, a financial evaluation of different sizes of RES-based electrolytic plant (100 kW - 10 MW) is proposed. The most relevant result that emerged from our research is the economic sustainability of the investment if the market price of oxygen is at least 3 EUR/kg. In this case, the self-production of oxygen results to be convenient, whatever the size of the electrolyser. This is valid for both the two scenarios assumed, with the exceptions of the smaller electrolyser sizes (<300 kW), for which the threshold is 4 EUR/kg. This finding is obtained considering a selling price of hydrogen at 10 EUR/kg but, according to our analysis, this condition would not change even with a price of 6 EUR/kg.

The goal that the international community has set itself is to reduce greenhouse gas (GHG) emissions in the short/medium-term, especially in Europe that committed itself to reducing GHG emissions to 80-95% below 1990 levels by 2050. Renewable energies play a fundamental role in achieving this objective. In this context, the policies of the main industrialized countries of the world are being oriented towards increasing the shares of electricity produced from renewable energy sources (RES). In recent years, the production of renewable energy has increased considerably, but given the availability of these sources, there is a mismatch between production and demand. This raises some issues as balancing the electricity grid and, in particular, the use of surplus energy, as well as the need to strengthen the electricity network. Among the various new solutions that are being evaluated, there are: the accumulation in batteries, the use of compressed air energy storage (CAES) and the production of hydrogen that appears to be the most suitable to associate with the water storage (pumped hydro). Concerning hydrogen, a recent study highlights that the efficiencies of hydrogen storage technologies are lower compared to advanced lead acid batteries on a DC-to-DC basis, but "in contrast, [...] the cost of hydrogen storage is competitive with batteries and could be competitive with CAES and pumped hydro in locations that are not favourable for these technologies" (Moliner et al., 2016). This shows that, once the optimal efficiency rate is reached, the technologies concerning the production of hydrogen from renewable sources will be a viable and competitive solution. But, what will be the impact on the energy and fuel markets? The production of hydrogen through electrolysis will certainly have an important economic impact, especially in the transport sector, leading to the creation of a new market and a new supply chain that will change the physiognomy of the entire energy market.

Given the gaps between EU ambitions regarding energy community development and the current reality of clean energy communities in Europe, we explore a research framework enabling viable multi- and interdisciplinary research into new clean energy communities. We offer a definition of new clean energy communities, discuss their potential for wider dissemination and identify four factors that contribute to the current mismatch between ambitions and reality in energy community development. As a broader framework for interdisciplinary research into the field of new clean energy communities, we propose polycentric governance theory, considering the fact that the area of community energy systems is essentially multi-scalar, and that the rules of engagement in such systems are of great significance. This opens up four avenues for research on energy communities, which we outline in terms of enabling institutional contexts, potential for learning and transferability, business models and value propositions, and evaluation of outcomes and processes.

As emphasised by the crisis caused by the COVID-19 pandemic, medical oxygen is an essential health commodity. The purpose of this study is the application of Renewable Energy Sources (RES)-based (photovoltaic-powered) water electrolysis plant for oxygen production in hospitals to self-produce the amount of oxygen they need, and - in particular - to define when this choice could be economically competitive with the current medical gas market. The proposed plant is able to produce oxygen and to store energy in hydrogen form at the same time, proposing a new approach in RES applications. Therefore, we calculated as a function of the hospital size (number of beds, up to 500) what should be the market price of oxygen above which the self-production of oxygen is economically profitable (assuming a break-event point of 15 years). Hydrogen is considered a by-product allowing to increase the system efficiency and supplying extra services. The results demonstrated that, assuming a selling price of 3 EUR/kg for the hydrogen (co)-produced by the plant, the on-site production of medical oxygen could be an interesting alternative compared to purchasing from the local gas resellers, if its market price is higher than 3-4 EUR/kg. Since this value is in line with current prices established for ex-factory oxygen by some national regulatory authorities (e.g., AIFA), we can conclude that the proposed RES-based electrolysis system is a green and economically feasible solution for oxygen production in hospitals, able also to increase hospital resilience against energy and oxygen shortage.