While the interest in microgrid solutions is increasing, it is important to design the right one in order to meet specific needs and overcome certain challenges, says Ullrich Jakobi, Head of Microgrid Solution Design, Energy Automation, Siemens, who conducted a presentation, Design and Control of Microgrids – Typical Applications and Impact on Your Business at European Utility Week.
The need for microgrids in all segments
According to Jakobi, there are key challenges that drive the implementation of microgrids.
Microgrid applications face three technical challenges:
Efficient energy use (power and heat)
Reliability and security of the grid
Customer challenges include:
- Cost per kWh
Energy security (reliable energy infrastructure, energy import dependency especially in remote areas and energy efficiency)
Taxes on fuel and carbon dioxide
Regulations on feed-in tariffs and subsidies
Jakobi explains that there are four main microgrid customer segments and they all have their own needs:
1.Industries with critical processes
For the above segments, there is an increased focus on the optimized use of intermittent generation and increased efficiency by combining heat and electricity generation.
3.Remote locations and islands
4.Critical infrastructures such as hospitals and military operations
The above two segments focus on the increased stability of supply and grid resiliency through on-and-off grid functionality.
Different applications for microgrids
There are many different applications for microgrids that may differ slightly but the solutions may be completely different in order to meet different requirements from various sectors, explains Jakobi. “Individual solutions have to be developed to meet specific customer targets.”
To meet all those different requirements, there is a need to develop a very individual solution to measure different parts of the business.
Some may need a flexible architecture and the use of components to pick up on the change of boundary conditions, both technical and commercial, and to accommodate a change in their own targets or those of the government.
There is also an integrated and consistent solution that will enable more effective energy management of the control centre, substation automation, protection, power generation and storage.
Microgrid case studies
Case study 1:
Jakobi points to the smart polygeneration microgrid Savona campus system overview as a good example of unique solutions. Their challenges were the high cost of electricity and seasonal demand. The solution provided was the Siemens Microgrid Management System in combination with storage systems for electricity and heat, combined heat and power (CHP), concentrated solar power plant (CSP), photovoltaic, eCar charging stations and controllable loads to improve efficiency of traditional generation and better exploit renewable generation. The solution provides the benefits of electricity storage and the optimization of energy production cost. [Engerati - Italy's First Smart Microgrid Demonstrates Benefits.]
Case study 2:
Excess residential photovoltaics in Victoria, Australia poses a number of different challenges and calls for a unique solution.
The challenges include:
The government ‘s aim to increase renewables integration to reduce cost pressures on households and businesses
Degree of deregulation and privatization varies across states and territories
Excess residential photovoltaics
Regulation preference to renewable integration
Bi-directional power flow (requires new grid set up)
Fluctuating loads and generation
Complicated financial planning
The solution is to create a microgrid community and bundle the generation to community storage. Benefits will include the reduction of overloads (and grid collapse), harnessing of renewable energy, better network planning, single point of coupling for the utility, community benefit in case of grid blackout and improvement of power quality.
Case study 3:
In a typical critical infrastructure or city, challenges include huge power quality interruptions due to limited diesel usage because of pollution levels, the integration and use of energy generated locally by CHPs and PV. To overcome these issues, Siemens installed a microgrid controller platform for energy management in islanded mode. They also installed recloser switches at the interface with the local distribution company to isolate the microgrid. They will also have the option to further improve capacity using electrical energy storage. The benefits include long time resiliency in the event of an outage, optimized energy exchange to the main grid in normal operation, and an optimized CAPEX/OPEX, combining renewable and fossil generation.
Jakobi explains that the implementation of microgrids requires a wide range of integrated competencies in terms of knowledge and a proven portfolio of products such as energy management, power generation and storage. “This will help design the right optimal integrated and flexible solution to meet individual requirements in terms of functionality and economics.”