As Hawaii continues to move toward its clean-energy mandate to generate 100% of electricity sales from renewable resources within the next 25 years, on a smaller scale, Kauai is already catching sight of the finish line.

For stretches of several hours in November and December — 32 hours, in all — electricity on the Garden Island was generated by renewables — a mix of solar, hydropower and biomass. Not a drop of fossil fuel.

Kauai Island Utility Cooperative (KIUC) deserves props for setting aggressive targets for renewable production. Today, more than half of the electricity generated on Kauai is coming from renewables — up from 8% a decade ago.

Collectively, the other electrical utilities in the islands — now operating under a single name, Hawaiian Electric — expect to meet a 2020 deadline for generating 30%. That too is encouraging progress, considering that a decade ago its renewable energy portfolio tallied less than 10%.

However, while the statewide pace to more clean energy has been rapid in recent years, expect the path in coming decades to be increasingly challenging for utilities, which have little or no control over some key matters, such as access to available land for renewable projects, land policies and court decisions.

Further, in the case of Na Pua Makani wind farm in Kahuku, where five of the farm’s eight turbines were recently installed, we’re seeing construction push-back, with some residents arguing that city-approved setbacks situate imposing turbines too close to homes and schools.

Given Hawaii’s land constraints, anticipate some clean energy projects to be located closer to inhabited areas compared with those on the mainland. At the very least, there will be some aesthetic blight. While venturing further into this uncharted green territory, ample caution is in order.

In its most ambitious stride forward to date, Hawaiian Electric is now sorting through some 75 proposals from developers for new projects to provide 900 megawatts of replacement service as coal-fired AES Hawaii on Oahu is slated to close in 2022, and the oil-fired Kahului Power Plant on Maui is set for 2024 retirement.

On the table are projects featuring solar, wind, energy storage and a number of other technologies on Oahu, Maui and Hawaii island. Another set for Molokai and Lanai is expected this year. If a planned timeline holds, the first projects would come online in 2022.

For the sake of a healthier environment and sustainability wherewithal, Hawaii is wise to move toward shedding its rank as the most petroleum- dependent state. Electric power and ground transportation together account for roughly half of the petroleum use here.

In an effort to prod motorists to forgo gas-guzzlers, for several years incentives have been in place for electric vehicles with EV license plates. Among the perks: limited free parking at meters and in state and county government lots, including airports; and lots with at least 100 public spaces are required to have at least one equipped with an EV charging system.

While a call to extend these benefits is expected, they should expire as scheduled in late June. With about 10,000 EVs on Hawaii roads, the switch away from internal combustion engines has momentum.

Also, state lawmakers acted even-handedly last year by approving a bill that charges EV owners an additional annual registration fee of $50, which serves as a contribution to the state highway fund — tapped for roadway repair and maintenance. Other vehicles pitch in by way of fuel tax levied at gas stations.

Aligning with the statewide clean energy finish line in 2045, the mayors from all four counties have pledged to transform ground transportation to 100% renewable in the same timeframe. The push onward must be both cautious and steadfast.