One world: one gas system
One engine that is already expanding this portfolio is a new model in the company's line-up of proven Series 4000 gas engines: the L64FNER. F stands for 'fifty hertz', N for 'natural gas', and ER for 'epsilon reduced', i.e. a lower compression ratio. The engine can be used anywhere – at extremes of temperature and air humidity as well as at high altitudes.
With conventional engines, high humidity means moist air is drawn into the combustion chamber, potentially leading to corrosion. To prevent this, mtu engineers have raised the temperature of the cooling water in the mixture cooler so that the fuel-air mixture is warmer and therefore does not condense. In order to be able to test the engine in real-life conditions, mtu has built a test stand at its Augsburg facility to simulate tropical conditions. Engineers can, say, raise the humidity of the intake air in order to be able to adjust the engine to cope with all possible borderline conditions. The first engine models are presently about to go into full production, with development staff now working to get the others ready.
120-second start-ups: load-balancing power courtesy of gas systems
In parallel, mtu
developers are also working on another variant of the Series 4000 gas engine: an engine with faster start-up capabilities. This one can reach its full output of 130 kilowatts per cylinder within 120 seconds, whereas previous mtu
gas engines took much longer to get there. This quick-start capability opens up a wider range of applications for the gas engine. Increasing use of renewables – such as solar and wind – in power generation may make it greener, but there are also major fluctuations in the power grids that have to be compensated for. For example: When everyone turns on their lights at 7am and switches on the coffee machine, or when big industrial users get going, suddenly a lot of electricity is needed all at once. The trouble is, at this time of the morning there is often little wind blowing, and not much in the way of sunshine, so renewables are not reliable or stable enough to cover all the demand. This is where gas systems come in. They can be relied upon to be available and supply electricity safely and predictably until sufficient wind or solar power comes on stream. Many European countries have special programs for this 'balancing power' used in grid stabilization, setting out how quickly gas-fired power plants must be able to bring their balancing power online.
Hitherto, this was a job mainly undertaken by diesel engines, but that is currently changing. “Gas is cheaper and more CO2-neutral than diesel, which is why more and more customers are opting for it,” explained Andreas Görtz. Moreover, in most cases, the governments' national balancing power programs stipulate that balancing power must be generated using distributed gas engines and associated systems.
Fast start-up of gas engines is also in demand for microgrids. Microgrids team gas engines with renewable energy sources such as wind and solar power plants, adding battery storage systems and an overarching control system. The controller uses parameters specified by the consumer to calculate which power sources are used at which time in order to deliver power either to consumers or to a battery bank such as the mtu 'battery container'.
The dynamics and the resultant dearth of new applications for gas engines initially presented developers with a challenge, since engines had previously been designed for prolonged periods of operation, with start-up time not terribly critical. A new piece of software now ensures, among other things, that the turbocharger can provide the engine with the required fuel-air mixture much more quickly. A special priming pump also supplies the engine with oil at all relevant bearing points within a very short period of time. Together with further improvements in the start-up procedure, the developers have achieved their goal: The engine reaches full power within anywhere up to 120 seconds.
Gas engines for emergency power generation
However, Michael Koliwer, chief engineer for mtu
's power generation systems, knows there is still room for improvement. “We still want to be faster,” he said. Indeed, he also has another vision in mind: combined with a rotating mass and the new mtu
battery containers, gas engines could then also be used to generate emergency power supplies.
So is gas about to beat diesel at its own game? “Certainly not,” said Andreas Görtz. The really important thing to him is that mtu, as a solution provider, is able to offer every customer the ideal engine for each application. “And we're well on our way down that road,” he added.