Hydrogen can be used efficiently as fuel for thermoelectric power plants. In 2010, Italy’s largest electricity utility (Enel) opened the world’s
first hydrogen power combined cycle plant near Venice (Figure 4.15). Hydrogen is supplied using specially built pipelines from the nearby Polimeri Europa petrochemical plant, where ethylene-cracking is carried out.
The 12 MW power plant comprises a hydrogen-fueled combined cycle plant and burns hydrogen gas in a turbine capable of resisting hydrogen embrittlement, which was developed in partnership with General Electric and generates both electricity and heat. The plant uses 1.3 tonnes of hydrogen per hour, has an overall efficiency of about 42%, and is essentially free of emissions. The efficiency of the process is increased by using the heat from the emissions to generate high-temperature steam, which is sent to the nearby coal-fired plant to generate an additional 4 MW of power capacity. Overall, the electricity generated, equal to
Figure 4.15 The first industrial-size power plant fueled by hydrogen in the world opened in 2010 in Fusina, near Venice, Italy.
(Reproduced from www. demotix. com/photo/388950/enel-first-power- plant-fuelled-hydrogen-world, with kind permission.)
about 60 million kWh per year, will be sufficient to meet the needs of 20 000 households, avoiding more than 17 000 tonnes of CO2 emissions a year.
Hydrogen from the petrochemical plant is transported through a pipeline made of specially coated steel, which resists hydrogen embrittlement (Figure 4.16).
Hydrogen gas piping is routine in large oil refineries, because hydrogen is used to hydrocrack fuels from crude oil. As a result, millions of tonnes of elemental hydrogen are distributed around the world through these pipelines each year. For example, the first long (240 km) hydrogen pipeline was built by Linde Germany, in the Ruhr area, in 1938. The pipeline is still in operation nowadays, connecting some 14 production sites with an estimated capacity of 250 million Nm3 of hydrogen per year.19 The longest hydrogen pipeline in the world is a 250 mile line between Belgium and France. Similarly, about 700 miles of hydrogen pipelines now operate in the USA, generally near oil refineries.
Once built, hydrogen pipelines are the cheapest and most effective way to distribute large volumes of hydrogen. Contrary to common opinion surrounding the so-called ‘‘hydrogen infrastructure’’, hydrogen distribution through pipelines is not problematic, just more expensive than, for example, the distribution of natural gas.
Building the infrastructure in a systematic way is largely affordable. For example, a study20 by researchers from General Motors and Shell
Figure 4.16 The hydrogen pipeline carrying the fuel from the petrochemical station to the power plant in Fusina (Venice), Italy.
Hydrogen clearly showed that an investment of US$10-15 billion, comparable to one-half the cost of the Alaskan pipeline, would be sufficient to establish 12000 hydrogen stations in the USA, putting hydrogen within 2miles of 70% of the US population.
Similar to the Italian Enel, the Germany company Enertrag, together with Total, Vattenfall and Deutsche Bahn, built in 2010, in a lightly populated area east of Berlin, a hydrogen-hybrid power plant that combines wind energy sources to deliver electricity to 2000 homes and heat to 300 households with no carbon emissions (Figure 4.17).21
The Uckermark operation is a hybrid plant that relies on three wind turbines and water electrolysis for energy storage in hydrogen fuel. Hydrogen tanks store the extra power generated by the wind turbines so that the plant’s stored fuel can be used to run hydrogen-powered vehicles or can be combined with biogas to produce electricity during low – wind conditions. In addition, the renewable hydrogen is used in hydrogen refueling stations located in Berlin and Hamburg.
The storage of large quantities of hydrogen functions therefore as grid energy storage, an essential requirement for the forthcoming hydrogen energy infrastructure. As in the case of natural gas, which is currently stored in large amounts in underground caverns, salt domes and depleted oil and gas fields, hydrogen will be stored in underground caverns, as done for many years by ICI with no difficulties; similarly,
ConocoPhillips at its Clemens Terminal in Texas has stored hydrogen since the 1980s in a solution-mined salt cavern.22