THE ENERGY INDUSTRY TIMES - APRIL 2017 Technology 15 Chugach puts microgrid to the test An Alaskan utility is demonstrating an innovative solution to help it cope with grid stability issues. Siân Crampsie In 2012, Alaska-based Chugach Electric Association introduced electricity from wind energy to its customers for the first time. Five years on, the utility is about to attain another first in its service territory by installing an innovative microgrid and energy storage system. Chugach Electric serves around 83 000 customers in the Anchorage area and operates some 530 MW of installed capacity. Like many utilities, the company faces the challenge of managing variable output from renewable energy facilities such as wind farms. However Chugach Electric faces the additional challenge of managing high variable loads due to the presence of a port and other industrial facilities in its service area. This combination of variable generation and variable loads has led the firm to seek innovative solutions to help it manage its grid, and it is now implementing a project with ABB to install a microgrid and energy storage system. The Fire Island wind farm, located west of Ted Stevens Anchorage International Airport in Cook Inlet, is Anchorage’s first commercial-scale wind farm. The wind farm is a 17 MW installation that sells all of its output – around 44 000 MWh/year – to Chugach Electric under a power purchase agreement. Although this equates to just three per cent of Chugach Electric’s annual energy sales, the prospect of greater wind energy penetration is growing thanks to a number of local and state-wide initiatives. Chugach Electric itself has formally adopted sustainability into its business management philosophy. In a February 2017 announcement, Chugach said that its board of directors had adopted a new, triple bottom line approach that takes “consideration of sustainability impacts in business decisions, to create greater business value and enhance the Association’s position as a long-term viable organisation for the benefits of its members and the community”. “Making sustainability a focus and priority makes good business sense,” said Chugach CEO Lee Thibert. “Focusing on the fair treatment of employees, members, and stakeholders; reducing environmental impacts; while evaluating financial performance; all equals a better outcome for everyone.” In the state of Alaska, several initiatives are under way to encourage the deployment of renewables – and other innovative technology solutions – to help cut energy bills and promote energy efficiency. The Alaska Energy Authority’s (AEA) Renewable Energy Fund has disbursed $257 million in support of renewable energy projects since 2008. These projects helped the state’s utilities to displace the use of over 21 million gallons of diesel fuel (equivalent) in the first three quarters of 2016, AEA says. AEA has also launched a Wind Working Group to guide the development of wind energy projects in Alaska, as well as an Emerging Technology Fund. “In places like Alaska, fossil fired power generation is being displaced by renewables,” said Massimo Danieli, Managing Director of ABB’s Grid Automation business unit. “When you start pushing the envelope and the penetration of renewables becomes high, i.e., over 50 per cent of electricity, you start getting stability and power quality issues. Utilities such as Chugach Electric are currently investigating and experimenting with the point to which they can push renewables integration.” To demonstrate how renewable energy can be integrated with grids, Chugach Electric devised a project that combines two types of energy storage technologies with a sophisticated control system. It is the first hybrid installation of its kind with both flywheel and battery combined. Other microgrid installations use either battery or flywheel storage. This “microgrid” solution will, hopes Chugach, enable it to manage grid stability issues caused by variable generation and loads and also manage more efficiently the resources in its portfolio. The project site will be next to a power plant owned by Chugach in Anchorage and the storage devices will monitor the actual wind output on Fire Island, which is many miles away, and react to the ups and downs in wind generation to “smooth” output. Chugach intends to explore the ability of this hybrid storage solution to mitigate wind ramp rates, help stabilise system frequency and provide system voltage support. For the project, ABB is providing its PowerStore technology, a containerised microgrid solution combining flywheel and battery storage systems, with software and controls. The firm has installed around 40 PowerStore systems around the world, most of them based on flywheel technology and used in remote or industrial locations to help with the integration and management of renewable energy resources. It launched a battery-based version of PowerStore in 2016, according to Danieli. At the Chugach project, the PowerStore system will comprise two main modules. The first is a flywheel with containerised controls. It has an output of 1 MW and a capacity of 16.5 MW per second. The second is a 500 kWh, 2 MW lithium ion battery, with power conversion and controls. ABB is also providing a Microgrid Plus control solution that will control the two PowerStore modules and integrate their operation with the Fire Island wind farm and the Chugach electric power grid. “The Microgrid Plus control system coordinates actions across the whole system,” said Danieli. In addition to supplying the main components, ABB supported Chugach in the initial design and specification phase and was responsible for the overall design of the microgrid system. It will also undertake commissioning of the microgrid later this year when the project is completed in the second quarter. According to Danieli, combining the flywheel and battery technologies will enable Chugach Electric to achieve a high level of stability and control of its grid. The flywheel acts as a first stage response to grid instability issues, such as frequency regulation and voltage support, while the battery provides other services, such as curtailment avoidance and peak shaving support. “Batteries don’t cope well with very frequent and high peaks and dips of electrical request so they are better used for long term storage,” Danieli noted. “When you have conditions like this in Alaska with high variability of the wind and high variability of loads because of cranes at the ports, for example, you would typically have very frequent requests for the batteries to continuously sync power or release power. This would, over a very limited amount of time, wear and damage the battery. “So the flywheel is basically used to compensate for the high frequency and high variability so that the battery can do its job of accumulating power and releasing power over a longer period of time.” The role of the control system is to correctly dispatch the flywheel over the battery and vice versa. Its functions are complex but ABB’s modular approach makes the design and construction of the control system easier, said Danieli: “ABB’s technology is often used in remote areas where you need to build the system in the shortest possible time. It is therefore highly modularised and highly complex functions are split into smaller modular pieces, which are fully coordinated with each other. The commissioning of the system is therefore simplified and shorter in time.” The microgrid has a load sharing and load shedding capability, said Danieli. “The control system aims to control and stabilise the grid by maintaining the generators, flywheel and battery system in line with the required energy. When this is not possible, for example because there is a lack of wind, or because the battery is discharged, it will implement a load shedding capability.” The microgrid is also enabled for remote monitoring, although Chugach Electric has not yet said whether it will make use of this function in this particular project. “This facility is available in all our microgrid systems,” said Danieli. “There is a gateway that provides access to remote cloud software enabling the operator to view all the variables on the system, for example the status of the batteries, as well as external elements such as the status of PV panels or wind turbines. ABB is therefore able to monitor the condition and performance of the equipment, access diagnostics, and detect the overall performance of the microgrid. “In very remote locations,” he concluded, “this is an obvious advantage, and can help the customer with planning maintenance.” Marble Bar, Australia microgrid solution: Chugach Electric has opted for an ABB microgrid and storage system to manage wind energy from Fire Island The Fire Island wind farm is Anchorage’s first commercial scale wind farm
Energy Industry Times April 2017
To see the actual publication please follow the link above