The rise of renewables has presented a platform for the latest technology in reciprocating gas engines, writes Axel Kettmann

Gas engines have a strong business case says Axel Kettman

Credit: GE

Europe is moving towards basing its energy needs on renewable energy sources.

Already today, 27 per cent of the European Union’s electricity requirements are covered by water, wind, sun and bioenergy. In the next 15 years, the EU wants this percentage to increase beyond 50 per cent.

Most of the renewable sources of energy are non-continuous and unpredictable – such as solar and wind – and have a rather low capacity factor: roughly between 15 and 25 per cent.

When you do the simple math, you see that in some areas, namely Germany, the total demand for electrical energy could already be covered by renewables… when the sun shines and the wind blows.

As we all know, this has brought disruptive change to our energy generation and distribution landscape. To complement shortages from unstable renewable energy sources, three principal solutions exist:

l Energy storage: storing energy in times of high availability of wind and solar power;

l Extending the grid to make reliable energy from distant areas available (e.g., hydropower from Norway or excess capacity from distant production locations);

l Reliable and highly flexible backup power generation with thermal power plants.

As it stands today, we will see a mix of all three options develop over the coming years. What remains is that large thermal power plants which provide baseload power but cannot complement non-continuous power sources due to their inflexibility will lose production share with the rise of non-continuous sources.

As energy storage systems in the size required will not be available at competitive cost for some time and large-scale extensions of the grid will be realized only in the longer term due to investment requirements and political and regulatory difficulties, there is need for highly reliable and flexible back-up power generation with thermal power plants.

This is where we see the benefits and the place of thermal power plants utilizing reciprocating gas engines as prime movers. This list of benefits is long and impressive:

l Gas engines offer single electrical efficiency in excess of 50 per cent in single cycle and up to about 70 per cent in combined cycle;

l Multiple engine applications allow operators to run gas engine plants at maximum efficiency at virtually any load requirement;

l Reciprocating gas engines can respond faster to load changes than any other prime mover;

l Gas engine plants can operate in tri-generation mode, providing electricity and heat/cold, leading to a total energy efficiency of more than 90 per cent;

l LNG has a CO2 footprint that is 80 per cent lower than that of coal (117 vs 200 pounds CO2/MBTU) and does not emit any sulphur;

l The turnkey erection of a 200 MW gas plant with reciprocating engines can be accomplished in less than 12 months;

l Highly competitive initial investment cost and attractive return on investment;

l Proven technology with hundreds of (bio-)gas installations in Europe already existing;

l If fueled by biogas it is a renewable source of energy;

l Dismantling and relocation of gas engine-based thermal power plants in case of changed requirements is technically and financially feasible;

l As it is also possible to achieve high plant efficiency with a small installation, it is possible to generate a distributed power supply system which is safer in case of failure of single units or even of a total single plant;

l Thanks to their low environmental impact, these distributed power plants can be located close to inhabited areas, with the additional benefit of enabling centralized district heating;

l Transmission losses in a gas grid are lower by a factor of 10 compared to those of electricity power lines.

Of course, the present tariff system for electricity in Europe is not conducive to investment in power plants for balancing power.

However, the example of an LNG-fired gas engine plant with a capacity of nearly 200 MW contracted for the utility in Kiel, Germany shows that gas engines have a strong business case, providing electricity to the grid when needed (and therefore attractive in price) and utilizing the heat for centralized heating systems – and even using the electrical energy for heating purposes at times of low electrical demand.

This is a striking real-life answer to why reciprocating gas engines make sense for Europe’s power industry.

Axel Kettmann is Senior Vice President, Global PG Manager Medium Speed, Low Speed and Rail Products at ABB Turbocharging. He is also CIMAC Vice-President for Communication and will chair the CIMAC Circle during POWER-GEN Europe in Milan on Tuesday, 21 June.