Utilities are working hard towards meeting their renewable energy mandates which have been put into place by governments globally. These goals will be made easier to attain through the deployment of both grid-scale and distributed renewable resources.
Off-grid renewable generation is becoming a necessity in many countries especially when it comes to being faced with an unreliable or lack of central grid power supply. Outlying areas that have no access and need an urgent power supply often turn to off-grid power solutions. This cost-effective solution can be put together within a few months whereas a transmission line costs a great deal more and can take a number of years to build depending on the size of the project.
Overcoming challenges of distributed generation
While renewable energy generation offers a number of benefits for the environment and consumer, there are challenges that must be overcome.
We spoke to Cleverson Takiguchi, S&C Electric Company, Director - Business Development Africa, who gave us more insight into renewable energy generation and how distributed energy storage systems can harness the full potential of clean energy.
The intermittency of natural energy resources such as wind and solar can pose significant integration challenges. This can have a negative effect on grid reliability and stability which will certainly affect the quality of power delivery.
Distributed energy storage systems, particularly when located in close proximity to renewable resources, are well suited to address the key challenges associated with renewable energy supplies.
Variability in output from wind and solar energy generation can create rapid swings in local and feeder-level voltage. But, distributed energy storage provides a fast response to help firm up voltage levels and effectively fill in gaps created by the variation of generation from the renewable sources.
Co-locating storage and renewable energy resources gives utilities a particularly effective way of managing unwanted voltage fluctuations, helping them to maintain grid stability whilst still meeting power quality requirements.
These energy storage systems also provide an easily deployed energy resource for utilities, enabling them to ensure that there is sufficient renewable energy to meet demands. Renewable energy generated when demand is low can be stored to meet demand during peak times.
Energy storage can be deployed in smaller capacity sizes which can help avoid establishing a completely new power plant. It also supports other useful grid functions such as peak shaving which can provide additional savings by reducing the need to maintain conventional generation and maintaining grid capacity to meet peak demand.
Utilities and energy storage
With more distributed generation it is not uncommon to see utilities losing some revenue and at the same time some of these renewable sources at residential levels are part of public-driven incentive programs so it is in their best interest to connect this power to the grid as soon as possible.
But, utilities need to protect the grid from power fluctuations caused by the wind and solar. For instance, cloud effects can create voltage spikes which can damage the grid if the utility does not react fast enough.
To overcome this threat to the grid, utilities use equipment such as voltage regulators and capacitor banks but these devices don’t always respond fast enough to voltage fluctuations. This is where energy storage will provide a fast response as it is able to efficiently compensate for the variations.
Utilities are now beginning to create specifications for the connection of embedded generation. “Utilities are getting smarter. Tight specs are put into place, especially for large scale PV or wind integration.” For instance, for PV systems the utilities are establishing in their specifications a minimum time for ramp up and ramp down of the generation from these sources and in general, to be able to meet these requirements some sort of energy storage can be required.
The mining sector overcoming power challenges
According to Mr. Takiguchi, there is a growing trend amongst Africa’s mines, which are often located in outlying areas with little or no access to grid power, to rely on off-grid installations. Mines are realising that off-grid renewable power can provide them with quicker, reliable and more cost-effective power access for their operations.
However, most mining firms face a major commercial challenge-they are struggling to obtain finance to set up off-grid power systems. A number of these firms have a shorter mining license of around five to seven years so it is difficult for them to obtain finance for larger capital projects. Often, mines require large capital to set up their own generation system but the banks won’t grant 15-20 year finance options for short mining licenses.
In response to this challenge, some Energy Storage vendors are creating commercial solutions. For instance, they are now offering leasing of energy storage systems which accounts for the largest capital outlay.
Choosing the right storage solution
Distributed energy storage technology is new and there are a number of options to choose from. Many of these are not yet mature. However, it is wise to choose the product and solution that suits specific user´s needs, explains Mr. Takiguchi. Distributed energy storage is not an off-the-shelf product. It is a complex system of systems, if you will. Choosing the most appropriate battery does not guarantee the project success because there are other key components such as the Inverters and controls/algorithms. These last ones can impact significantly the overall performance of the whole system which is key to accomplish the projected economic targets of these projects. This is where S&C can help to assess the entire system to find a sustainable or lifetime solution. We only use batteries that have been extensively tried and tested. S&C Electric Company uses a combination of services and products that will improve efficiency and mitigate possible risks. We bring our valuable extensive global experience,of working on innovative projects, such as the first utility scale Li-ion energy storage project in Europe, to every job. Learning from global projects, and adding to the international knowledge base, S&C prides itself on thought leadership in this field”.