Backbone of the energy transition: How gas engine power plants can close the gap

Furthermore, in networks involving high numbers of PV home systems (with and without battery storage), consumers can be self-sufficient and still draw power from the grid during certain hours or in bad weather. Conventional power generation must still cover these events when large-scale storage systems are no longer an alternative due to their restricted capacity.

While combustion technologies were the heart of the power system in the past, they are now becoming a key enabler, filling the gap between demand and renewable energy production. Consequently, they facilitate the increased integration of intermittent RES into the power system, thereby accelerating the energy transition even further.

However, building up new intermittent renewable energy resources presents its own challenges. The great dependency on wind and solar energy leads to capacities being built on a large scale, requiring vast areas to capture as much energy as possible. Point of generation and demand tend to be inherently divergent in these areas.

Large-scale renewable power plants are usually located well away from regions of high demand. Consequently, the power must be delivered to the point of demand, with an ageing transmission and distribution infrastructure struggling to integrate and bear a higher share of renewables. For example, resource availability means that wind power generation facilities are mainly situated in the north of Germany, while most heavy industry lies in the west and south of the country. As a result, the power must be delivered to these locations, resulting in a need to extend the transmission grid, which in turn requires substantial investment to be covered by the final consumer, and also takes years to plan and build. For example, long approval times and resistance from within the population make the process lethargic, with construction and extension of the power grid often lagging behind the change in load and generation patterns.

If the grid is unable to cope with all the power injected, renewable power generation can become subject to redispatching, while conventional power plants in high-load areas ramp up. This means that renewable power plants have to decrease their output in response to grid constraints, while conventional distributed capacities, operating independently of the weather in high-load regions, can be an alternative solution to cover renewable shortcomings and peak loads until the infrastructure has been enhanced and/or local RES generation catches up, thus lowering the need to transport RES energy over great distances.

Turbine power plants are optimized for full-load operation to exhibit high electrical efficiencies. However, since turbine power plants often consist of one or two large turbines, a plant’s efficiency drops significantly for partial load operations/load increments. In the case of engine power plants composed of many small engine modules, partial load operation strategies can differ. To run on load increments, an engine power plant will shut down/not utilize a certain number of superfluous engines. At the same time, the rest will continue to run at maximum load, i.e. maximum efficiency. In conclusion, engine power plants are more suited for frequent partial load operations and demonstrate superior flexibility.

Furthermore, ICEs can respond faster to load changes and do not have significant costs related to start-up, while a CCGT has a minimum up- and downtime, and needs more time to ramp up entailing higher costs. In a world in which conventional power plants primarily provide resilience and security of energy supply, and complement intermittent power generation by PV and wind, fast response times and utmost efficiency, along with versatility, are crucial success factors and enablers of the energy transition.  

The energy transition has come to stay. Hence, flexible solutions with short start-up times and a high degree of modularity, capable of ramping up many times per week, month and year, and providing the greatest efficiency across a wide output range (and at low cost), are becoming a strategic imperative. They are the enablers of a greener energy future and can generate green power themselves by switching to carbon-free combustion gases. The ICE can therefore be regarded as a future-proof technology which is already mature today.

Due to its modularity, an ICE system can run as many engines as needed at full load while keeping the remaining engines shut down, thus achieving greater efficiency than one large turbine running at partial load. High efficiency reduces the need for primary energy, thus reducing cost and greenhouse gas emissions. At the same time, small increments do not limit the handling of large loads, as major customers already operate backup capacity at the higher end without difficulty (e.g. data centers with 100 MW+ capacity run hundreds of backup ICEs).

One might argue that small-scale turbines are also available and offer the same benefits as ICEs. However, ICEs are available on an industrial scale, making their commissioning faster. And short lead time solutions are crucial for an uncompromised energy transition.

Furthermore, containerized solutions can turn a power plant into a mobile asset. Their capacity can be integrated into the grid where needed to alleviate grid constraints. Later, when it is no longer needed, the power plant can be moved, e.g. when long-term carbon-neutral storage systems become more mature. Moving existing assets instead of decommissioning and building new power plants reduces the investment cost in new capacities and in grid infrastructure. It also reduces the risk of a stranded investment.

Looking at the challenges the energy transition now faces and will be facing in the short-, mid- and long-term, ICEs provide a viable option which is becoming more and more worth considering to meet the challenges of the energy transition. ICE technology can provide clean, cost-effective, and reliable energy for today's and tomorrow's energy systems. In addition, ICE power plant projects can be realized quickly and adopting a modular approach, as containerized gas systems are prefabricated on an industrial scale. Lastly, due to the relatively small unit size (optimized for road transportation) of an ICE module in contrast to a large heavy-duty turbine, redundancy can be achieved with minimal additional investment by simply adding individual units to boost plant capacity (cf. Table 2)  

This paper focuses on electricity generation from conventional natural gas. Future publications will shed light on combined heat and power generation and the hydrogen readiness of engines and turbines, respectively.