Engerati reviews two island microgrids and one campus project that aim to provide energy security and reliability.
Microgrids and mini-grids offer a key opportunity to electrify rural areas rapidly and cost effectively while at the same time expanding the availability of clean energy.
But rural areas are not the only ones that can benefit. Microgrids are appropriate for islands of all types, from the small remote South Pacific to larger islands in the Caribbean and North Atlantic, where they can support clean energy replacement of costly fossil fuels.
They are also suitable for communities and facilities such as campuses.
For all of these applications, key benefits from the perspective of both providers and users include energy security and reliability, and resilience of supply.
Two examples of such microgrids are as follows.
Tesla and SolarCity are making inroads into the microgrid market, with the first of these on the island of Ta’u in American Samoa.
On Ta’u the approximately 600 residents had relied on imported diesel for power, which was both costly but also when supplies were running low had to be rationed to certain times of the day, with consequent outages.
The microgrid can supply almost all the power needs of the island from solar energy, and from storage could continue to supply power for up to three days if solar generation is not possible.
The second island installation from Tesla and SolarCity has recently come online on Kauaʻi Island in Hawaii.
The project, commissioned by Kauaʻi Island Utility Cooperative (KIUC) and owned by Tesla, is the state’s first dispatchable solar energy plant.
It will feed up to 13MW of electricity into Kauaʻi’s grid to meet peak demand in the evening hours, utilising 52MWh of Tesla’s Powerpack lithium-ion battery storage.
“The importance of this project for the member-owners of KIUC can’t be overstated,” says President and CEO David Bissell.
“By using solar energy stored in the battery after the sun goes down, we will reduce our use of imported fuels and our greenhouse gas emissions significantly.”
From KIUC’s perspective, the project is a good deal. Under the 20-year contract, the cooperative will pay Tesla 13.9c/kWh, which is less than the current cost of oil.
The project also will bring the cooperative to near 44% renewable generation usage.
Hawaii was the first state in the US to set a 100% renewable goal which should be reached in 2045.
Towards this, KIUC has set its own targets including 50% renewables by 2023, which it expects to reach in 2018. In the latest strategic plan adopted in February, KIUC added the goal of 70% renewable energy by 2030.
With Duke Energy Renewables and subsidiary REC Solar, Schneider Electric has constructed an advanced microgrid at its Boston One Campus (BOC), the company's North American headquarters in Andover, Massachusetts.
“The integration of an advanced microgrid at the Schneider Electric campus reduces its energy costs, incorporates more sustainable energy and delivers demand-side efficiency, while also offering resiliency to the facility in the event of a loss of power from the grid,” says Chris Fallon, VP of Duke Energy Renewables and Commercial Portfolio.
The microgrid also will be used by the companies to research and develop new microgrid technologies, solutions and applications in a real-world environment.
The microgrid was funded through Schneider Electric’s Microgrid as a Service (MaaS) business model.
Under this model, Duke Energy Renewables is the project's investor/owner and sells the power to Schneider Electric through a long-term power purchase agreement.
It includes a 354kW solar array with 1,379 modules and additionally uses a natural gas generator as an anchor resource, allowing the solar array to operate during grid outages.
The microgrid also features Schneider Electric's newly released EcoStruxure Microgrid Advisor, a cloud-based, demand-side energy management software platform.
The combination of advanced controls and demand side software is aimed to allow the microgrid to leverage weather forecast data and other operational site data to optimise energy performance across the solar and natural gas generation assets, energy storage, electric vehicle charging and building HVAC.
In addition to the BOC microgrid, Schneider Electric and Duke Energy Renewables are collaborating on a second project of two advanced microgrids to serve the Public Safety Headquarters and Correctional Facility in Montgomery County, Maryland.
These will comprise a 2MW solar project and two combined heat and power units, the latter to use waste heat from on-site power generation to heat and cool the buildings.
These microgrids will help ensure more reliable and efficient power and improve resiliency following major storms and other natural disasters, according to a Schneider Electric statement.