When widespread power outages swept across Texas in February, residents and infrastructural leaders alike questioned how the blackouts could have been avoided. While some technologists have highlighted the possibilities (and challenges) of renewable energy integration, others point to microgrids as a possible solution.
Microgrids stand in contrast to their large power grid cousins, which provide a network of electricity transmission lines that connect multiple power-generating stations to loads on a national and (occasionally) regional level. Localized microgrids, on the other hand, have long been used in remote areas to power off-grid villages, industrial sites, data centers, university campuses, large residential complexes, or military projects.
The typical structure of a microgrid. Image used courtesy of Binduhewa and the University of Manchester
In case of a grid failure, network faults, or reduced power quality, independently-powered microgrids generate power. Implementing microgrids throughout Texas may not be a long-term solution to the state’s infrastructural power woes, but it may be a helpful safety net—especially given the widespread human effects of the outages, including shutdowns still affecting chip manufacturing facilities.
Microgrid Technology: Harvesting Microsources
Microgrids (MG) use power microsources based on distributed power generation (power generated near the use location). They can be standalone or hybrid systems that use renewable or non-renewable power sources and energy storage systems (ESS). MGs are typically designed with renewable energy sources (RES) as the supply to the average load demand. ESSes, non-renewable generation, and the grid ensure that the loads have a constant power supply.
Load demand with an ESS in a microgrid. Image used courtesy of Faisal et al.
Renewable microgrid systems use wind power, solar power, wave energy, mini-hydro generators, or tidal power, depending on what is available at the microgrid’s geographical location. The energy harnessed from the microsource is converted into electricity and used as a local power supply or part of the EaaS (energy-as-a-service) model.
Is Modular the Way to Go?
The benefits of microgrids go beyond resilience, reliability, and contingency; they include building a critical infrastructure that could reduce fuel use.
One type of microgrid that could be a potential solution is modular microgrids.
Plug-and-play modular microgrids shrink design and deployment costs because they are built on preconfigured components with fewer demands for on-site engineering support. This type of power grid is versatile and especially good for areas that are more difficult to get power to. As such, they are especially beneficial in times of crisis.
One recent example is Scale Microgrid Solution’s Rapid Response Modular Microgrids (R2M2), which contains a solar PV array, a natural gas reciprocating engine, and a lithium battery.
Depiction of how Scale’s microgrid works. Image used courtesy of Scale Microgrid Solution
Seeing the merits of this model, the Engineering and Physical Sciences Research Council has offered a grant to create a plug-and-play microgrid that can utilize an off-the-shelf power converter.
By creating an easy way to integrate a general power converter, this microgrid system has the potential for widespread adoption. The initiative is also designing guidelines and a software tool to be given to DC microgrid engineers, which will help further this concept of universalism and integration.
Though the concept of modular or plug-and-play microgrids is still in its infancy, there could be many benefits toward moving in that direction. Another concept that is being explored is the idea of smart microgrids.
Smart and Smarter Microgrids
One of the most apparent benefits of smart microgrids is to produce RTO (real-time operating) systems. Smart grids show promise in counteracting national power grid failures and managing regional electricity outlook by investing in day-ahead and real-time electricity selling.
For example, Siemens’ diagnostic cloud tool enables quick access to data from complex future power grids without extra engineering configuration effort.
If viewed holistically in the context of the national power grid, microgrids aim to improve energy transmission, distribution, delivery, and consumption. Transforming the current grid into a smart, sustainable grid of the future is not a simple effort.
One proposal to ease adoption is to initially build microgrids on university campuses. This may allow researchers at universities to investigate the variability in weather and load synchronization before microgrid projects hit the market.
Microgrids significantly shrink the complex workings of a traditional power grid system. How might this technology intersect with the expertise of a power engineer? If you have experience with these systems, share your insights in the comments below.