Enhancing Resiliency Through Sustainable Microgrids and Value Creation Using Smart Grid Paradigms
By Krishnakumar R. Vasudevan, Vigna K. Ramachandaramurthy, Thanikanti Sudhakar Babu
Power system resilience has become an important factor with ever-increasing natural calamities and manmade threats. According to the US Department of Energy, about 58% of the power outages are the result of extreme weather conditions. On the other hand, the cyber-attacks on the power system pose an additional threat to the resiliency of the power system. A resilient power system should be able to anticipate, withstand and respond to unprecedented contingencies. The prevailing reliability standards of power system are designed to withstand high-probability, low-impact contingencies. However, resiliency targets to withstand the low-probability, high-impact disturbances. Nevertheless, the power system is deemed as critical infrastructure and any damage to it directly inflicts on the country’s economy, since other critical infrastructure depend on electrical power for its operation. For example, a week-long power outage in a region could incur high losses to the telecom industry, which will directly affect the country’s economy.
Microgrids are inherently resilient due to its ability to operate disconnected from the grid in case of contingencies and reconnect when contingencies clear. After islanding, the backup generators should take over and continue to supply the load. Historically, diesel generators, microturbines and combined heat and power plants have been used for onsite generation at load centers. However, their operation depends on the availability of fuel onsite, which may not be enough to sustain an extended outage. Moreover, the loss of lifelines, such as pipelines and transportation during natural calamity play a critical role in resiliency. In such cases, a sustainable microgrid with a diverse mix of renewables is key to improve resiliency. A sustainable microgrid could ride through an extended outage, with enough storage to meet the nocturnal demand and stability requirements.
In most countries, grid parity is yet to be attained by the renewables, which makes grid supply a cheaper option. So, the willingness to pay for a high-cost generation (cost of resiliency) with renewables and storage is imperative. Moreover, the level of resiliency is subjective and differs across various sectors and consumers. A residential customer might opt to sustain an outage without power, instead of paying for resiliency. Whereas, the services and production sector demand a high level of resiliency since an outage can incur a huge loss. Moreover, the classical cost-benefit analysis yields a higher net present cost (NPC) of the project which deters the investment on sustainable microgrids. So, appropriate valuing of resiliency and estimation of probable revenue generation would attract investments on sustainable microgrids. Furthermore, accurate sizing of sources and storage by considering factors like load profile, critical loads, probable time and duration of the outage, can reduce NPC.
Value creation through smart grid paradigms
Under normal operation of the grid, the conventional fossil fuel-based generators predominantly remain idle throughout its lifetime. Hence, it does not generate any value during the entire lifetime, besides providing back up supply for a few hours. However, a grid-connected sustainable microgrid can take part in various services to generate revenue through smart grid technologies. Firstly, it is possible to minimize the utility bills through efficient management of onsite generation. The microgrid controllers can be programmed to take part in energy arbitrage by optimally dispatching resources considering the time of use tariff signal from the grid. Under such circumstances, the onsite energy storage plays a vital role, since it could deliver power during peak hours. In a de-regulated market regime, it is possible to further maximize the profit by taking part in the market. Besides the capacity market, a sustainable microgrid with fast responding storages can take part in the ancillary services market. Since the bids cleared in the ancillary services market are often high due to the immediate demand for resources.
Demand response is another smart grid paradigm which allows generating extra revenue by controlling the non-critical loads when required by the utility. However, it is also possible to reduce the grid power consumption without losing any loads, thanks to the power onsite generation. As an added bonus, electric vehicles can further increase the resiliency without incurring on any upfront costs. The argument is backed by the purpose (mobility) for which the EVs are bought. A large pool of EVs can connect to the microgrid and provide its service during idle conditions. However, an accurate estimation of the spatial and temporal distribution of EVs (driving pattern) can affect the cost of resiliency.
The critical infrastructures of a country like a telecom, defence base, water utility and hospitals require highly resilient power system since they are responsible for a country’s economy, social well-being and safety of citizens. With the existing diesel generators and a finite amount of onsite fuel storage, it is onerous to increase the resiliency. The operation of diesel generators and microturbines for backup supply is a costly proposition in countries like Iceland, Norway, Sweden etc., where the fuel cost is very high. However, a potential solution is to integrate a diverse mix of renewables and energy storage systems to form a sustainable microgrid. Meanwhile, an effective control technique would improve resiliency and enable the transition to sustainable energy. Nonetheless, the increase in resiliency often comes with a cost to bear. The monetary loss averted through high resiliency pays off for the high financial investment. A cost-benefit analysis with an appropriate estimation of the anticipated revenue generation by the microgrid would attract investment. Hence, a trade-off between the cost and resiliency should be met for a feasible solution.
Krishnakumar R. Vasudevan (S’19) received his Bachelor's and Master’s degree in Electrical Engineering from Anna University, Chennai, India, in 2016 and 2018. He has received Best Outgoing Student of the batch award during his Bachelor’s degree. He has also received Gold Medal for securing University 1st rank in his Master’s degree. Currently, he is working towards his Ph.D. degree in Electrical Power Engineering at Power Quality Research Laboratory, Universiti Tenaga Nasional, Malaysia. He is also working as a Research Engineer at Institute of Power Engineering, Universiti Tenaga Nasional, Malaysia since 2019. His areas of interests include energy storage system, pumped hydro storage, microgrid control, renewable energy and rural electrification.
Vigna K. Ramachandaramurthy (SM’12) received the Ph.D. degree in electrical engineering from the Institute of Science and Technology, The University of Manchester, U.K., in 2001. He is currently a Professor with the Institute of Power Engineering, Universiti Tenaga Nasional, Malaysia. He is also a Chartered Engineer registered with the Engineering Council of U.K., and a Professional Engineer registered with the Board of Engineers, Malaysia. He is also the Principal Consultant for Malaysia’s biggest electrical utility, Tenaga Nasional Berhad, and has completed over 250 projects in renewable energy. He has also developed several technical guidelines for distributed generation, Malaysia. His areas of interests include power systems related studies, renewable energy, energy storage; power quality, electric vehicle and rural electrification.
Thanikanti Sudhakar Babu (M’17) received the B.Tech. degree from Jawaharlal Nehru Technological University, Ananthapur, India, in 2009, the M.Tech. degree in power electronics and industrial drives from Anna University, Chennai, India, in 2011, and the Ph.D. degree from VIT University, Vellore, India, in 2017. He is currently a Postdoctoral Researcher with the Department of Electrical Power Engineering, Institute of Power Engineering, Universiti Tenaga Nasional (UNITEN), Malaysia.
He has published more than 40 research articles in various reputed international journals. He acts as an associate editor for the journals, IET Renewable Power Generation, IEEE Access, International Transactions on Electrical Energy Systems, and as a guest editor for Applied Sciences and Frontiers in Energy Research. He also serves as a reviewer for more than 25 reputed international journals. His areas of interests include design and implementation of solar PV systems, fuel cells, renewable energy resources, power management for hybrid energy systems, fuel cell technologies, electric vehicle, smart grid and optimization algorithms.