The capacity growth rate in the Asia region excluding China and India is expected to be around 4.0% with an impressive growth rate of 5.5% in low carbon and renewables. (IEA, 2016) Many of those countries have low levels of electricity penetration and lack a nationally interconnected grid infrastructure. This makes it doubly difficult to grow variable renewable energy (RE) faster than the overall electrical capacity growth. In these cases large scale offgrid renewables can be a means to quickly bring power to consumers, although the delivery of stable capacity and the future integration into a national network must be carefully planned.
The microgrid concept will be a natural fit between the reciprocating engines and renewable source of energy, supported by battery storage. Such a pairing increases system efficiency because:
- When e.g. the sun is shining and the solar panels are producing electricity, the fossil fuel generators do not need to run. As well, the batteries can be charged. This reduces fuel costs, emissions and generator maintenance needs.
- When the sun is not shining, the customer has alternative sources of energy to ensure reliability. The reciprocating engines are flexible, can run anytime on fuel and are not limited to daylight hours when the sun shines. Shorter periods can easily be bridged by batteries without starting the reciprocating engines.
The trend towards alternative and sustainable energy sources has led in recent years to the widespread use of photo-voltaic solar farms. Solar energy is eco-friendly and literally inexhaustible but is not continuously and predictably available. Darkness and weather conditions can lead to fluctuations in the energy supply. One answer to this problem is provided by fossil fuel generator sets that produce energy reliably around the clock. Working together with project partners, RRPS and mtu Onsite Energy can offer its clients bespoke solutions that combine the advantages of e.g. photovoltaic solar arrays, battery storage and gas power plants to create a reliable and sustainable system.
Beside little space requirements, reciprocating engine generators are also valued in a microgrid for their ability to ramp up quickly. This speedto- service not only minimizes or negates power outages, but also assists in microgrid optimization. Optimization refers to the ability of an advanced microgrid controller to leverage the microgrid’s various resources for best economics. Sometimes referred to as the “brain” of the microgrid, the advanced microgrid controller is the software that orchestrates all of the microgrid’s resources and enables it to disconnect and re-connect to the central power grid.
The controller constantly calculates the best or optimal mix of resources for the microgrid to use based on energy prices, fuel availability, weather and other factors. Because the reciprocating engine can start and stop quickly — and typically has a ready source of fuel — it’s a flexible tool the controller can leverage. For example, the reciprocating engine generator might be quickly called into action if there is a sudden drop in solar or wind generation. It also may serve as a tool for peak shaving or other forms of demand management. (Microgrid Knowledge, 2016)
Regardless of the pace of increase, it is clear that the scale of variable renewable capacity will increase and it is likely that the share will also increase. A rule of thumb is given that there is an economic and operational ceiling on the maximum capacity share that can be provided by variable renewable energy that is roughly equal to the capacity factor (Jenkins, 2015). While there is much discussion around this suggested maximum economic and technical ceiling, the impact of the variable renewable capacity, at much lower levels of penetration, is already being felt on networks around the world.
The flexibility of gas engine technology is expected to occupy a considerably larger role in maintaining grid stability. Transition from big, centralized peak power stations and gas turbines to smaller units suggesting more engine-based power plants in the future.
The expectation of increased demands for flexibility and efficiency, lower emissions and lower costs is set to increase technical demands on gas engine technology.
Flexibility in the power system to integrate more renewable wind and solar, seems to be the top priority and need of an hour. And also the demand of electricity is less stable than before. It’s getting more and more peaky. And to follow those peaks as precisely as possible, we need fast and flexible generation, and this is what the reciprocating engines are capable of.
Hybrid power plants that combine the advantages of gas generators and photo-voltaic solar arrays are a reliable and efficient answer to the challenges of using renewable energies in regions without power grid access. Natural and renewable energy sources are not always constantly and predictably available. In such cases, gas gensets can quickly and economically ensure power supply availability.
mtu Onsite Energy gensets are ideally suited to such tasks. With their especially good low-load capabilities, their economical fuel consumption and their outstanding load uptake characteristics, they offer customers maximum economic benefit combined with maximum supply reliability.