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Key Considerations for Deploying Microgrids Worldwide
By: Arjun Gupta, NABCEP Certified PV Installation Professional and Senior System Design Engineer at UGE International
Micro-grids powered by renewable energy are fast replacing those powered by fossil fuels. As a global developer, UGE has over 330 MW of renewable energy experience worldwide, including the installation of several solar and wind powered micro-grids. Through our consultative approach, we work to understand how to best design and develop micro-grids across a variety of locations for both grid-tied and off-grid use.
A number of factors are critical to the development of a micro-grid, beginning with the nature of the application for which it will be used. Micro-grids cater to a wide variety of individual applications – often facilitating multiple applications at once – with the three most common being:
- Energy Resiliency – In many places the centralized grid is antiquated and capricious, due to aging infrastructure, supply-demand constraints and external factors like natural disasters, which cause a significant number of grid outages. At the same time, demand for energy security is increasing as facilities like data centers, hospitals and military bases turn to micro-grids to keep power flowing to critical loads during outages.
- Energy Independence – Areas which are off-grid and rely entirely on conventional fuel generators for energy may gain significant advantages by switching to a renewable-powered solution. Considering the volatile cost and pollution associated with conventional fuels, the declining cost of clean technologies like solar photovoltaics and energy storage offer an increasingly attractive alternative for off-grid micro-grids. UGE has helped off-grid sites like remote telecom towers and island resorts achieve energy independence by significantly reducing or eliminating the need for diesel generator sets.
- Maximizing Solar Penetration – In a majority of countries today, the cost of energy generation from solar photovoltaics is more affordable than energy received from the grid. However, solar is an intermittent resource, and in many cases the load profile of a facility does not always synchronize with energy generation. By installing micro-grids that include energy storage, unused solar power produced during the day can be used to run loads when the sun is not shining.
The micro-grid industry is growing rapidly, but no two installations are the same. Developers should be mindful of the following considerations during engineering and construction:
Technology deployed for power generation. Micro-grids are flexible when it comes to power generation technologies, which should be selected based on local solar and wind resource availability. These factors, coupled with local diesel prices and local electricity prices, contribute to how we design the appropriate micro-grid with the best economic value. Often solar is the most economical choice, but when space is a constraint, adding a wind turbine can increase generation capacity over a small area. In a recent installation, UGE was able to develop a hybrid solar and wind solution to offset diesel consumption for our client by 95%, leading to a positive ROI for the project after only 2 years.
Technology deployed for energy storage applications. The choice of storage needs to be based on the nature of the application. When looking at constant long-duration discharge applications like resiliency, lead acid batteries are appropriate. For peak shaving and demand response applications, short spurts of discharge are required, and the ideal choice of storage is usually lithium ion batteries. With the energy storage landscape changing rapidly, an array of new storage solutions are coming to market, like flow and aqueous ion batteries, which will continue to change the way we dispatch these assets.
Optimizing the battery through “stacking” applications is the best way to guarantee greater returns on the customer’s investment, while also benefiting the local utility grid (in grid-tied use). For grid-tied urban areas or community micro-grids, batteries can help with frequency regulation and voltage support in front of the meter, while saving customers on costly demand charges and time of use pricing behind the meter. In New York City, UGE is currently working to deploy 17 micro-grids to Sandy-affected small businesses. As part of the RISE:NYC program, the micro-grids will help customers behind the meter during regular operations and will help keep power flowing to these community resources in the event of another severe weather event or outage.
System design considerations. Sizing a micro-grid appropriately requires determining the optimal mix of different renewable energy sources and included battery bank. System design depends on details of the daily and yearly variation in electrical loads, fluctuations in the weather pattern and specific project requirements. Identifying the facility’s load profile, the critical loads and the existing electrical infrastructure is crucial to prevent undersizing or oversizing the micro-grid. To ensure proper system design, UGE developed an in-house micro-grid modeling software tool, known as UGE SET. Our software accurately identifies the ideal micro-grid solution using statistical weather modeling, a Monte Carlo simulation of system configurations, OPEX forecasting, and LCOE minimization.
Managing unique site-specific challenges. Some sites are in difficult-to-access locations or are subject to temperature extremes that may impact the performance of the equipment. Micro-grids, although robust, are prone to breakdowns like any other technology. UGE and partner Al-Manhal Renewable Energy recently installed 7 micro-grids for the Jordanian army along the Syria-Iraq border in the Jordanian desert, where the monthly average temperature can range from 5°C in the cold winter months to nearly 40°C during the hot summers. During the installation, we deployed temperature control rooms for sensitive equipment to ensure uptime for the Army’s critical telecommunications towers.
Access to sites can be another major issue, especially for off-grid systems. For a telecom tower UGE installed on a remote island in New Caledonia, our team had to transport equipment to the site with a helicopter. For another micro-grid we recently completed for Globo TV, the leading media organization in Brazil, we had to coordinate travel through 50 miles of mountains and hills to reach the installation site. To minimize downtime and operations and maintenance costs, we recommended housing spare components at the site itself to ensure that any equipment matters are quickly resolved. Finally, it is always recommended to install remote monitoring of the micro-grid. Remote monitoring helps track production and cost savings while providing valuable, real-time information to the system owners.
While the renewables micro-grid market is still new and evolving, the major factors to be considered during system design and installation are applicable to most micro-grids. With the potential applications expanding, adoption of micro-grids is rising. Micro-grids represent a major opportunity for developers to bring more affordable, reliable and sustainable energy to the world.