Islands wholly on renewables

The Growth of Renewable Islands

Hawaii plans to transition its electric grid to 100 percent renewables by 2045. The island will be a testbed for bringing large amounts of variable renewables onto the grid.

Some successful examples

Shifting to fuel-free renewables like solar and wind not only saves money, it also means less reliance on imports   and enhancing energy security. But Island grids generally have to pay more attention to backup generation and energy storage than mainland grids, raising the overall costs of renewables. However, as technical problems are resolved several islands are moving quickly to adopt renewables.

Hybrid renewable energy technologies can provide stable power for islands. For example, El Hierro, one of the Spanish Canary Islands off the coast of Africa, operates a stand-alone electric grid to serve its population of 11,000 and run power-hungry desalination plants. Last year the island started a hybrid wind-hydro power plant that combines wind energy when it’s available with pumped hydroelectric storage that runs when the wind drops. This has allowed it to almost completely stop using expensive, shipped-in fuel oil.

Kodiak Island in Alaska has just shifted to fully running its grid with wind and hydro power. With the full system in operation, Kodiak is able to almost completely eliminate imports of close to 3 million gallons of diesel per year.

Many other islands are expanding how much of their electricity can feasibly come from renewables. These islands range from extremely small—such as the tiny Pacific nation of Tokelau, which moved to entirely solar power several years ago—to relatively large—Iceland relies almost entirely on hydropower and geothermal power, although these have so far proved less variable than wind and solar.

Learning from Hawaii

With its new target in place, Hawaii becomes the largest island to aim for a full-renewables grid strategy. The lessons from balancing variable renewable generation on smaller islands will help handling the challenges of large amounts of renewables. And while some of these lessons will remain island-specific, many will be relevant to mainland grids.

One particular example that many utilities around the world are grappling with is the question of how much distributed renewable energy can be safely installed on the grid. In Hawaii one household in eight has rooftop solar which has raised some technical concerns about grid stability. In 2013, the local utility capped the allowed amount of rooftop solar, freezing thousands of permit applications for new installations.

However, after research cap was doubled and new installations were allowed. Now it is charting new territory, including learning how to work with distributed solar companies to better use data from rooftop solar installations to improve awareness of how these systems are performing and their impact on grid stability. As the Hawaiian grid continues to gather real-world experience in incorporating large amounts of renewables, it will serve as both a practical demonstration and a tremendously valuable testbed for how other states could follow a similar path. (WRI)