As the U.S. undergoes a domestic energy boom, Delaware has switched much of its power generation from coal to natural gas. In 2016, natural gas generated 89 percent of the state's electricity, up 7 percent from two years before, according to the U.S. Energy Information Administration.
Over the same period, coal's share dropped to 5.5 percent, or less than half of what it was two years earlier. But the shift to cheaper natural gas hasn't stopped Delaware from doing its part in a wider effort to move away from fossil fuels towards renewable fuels and energy-efficiency measures.
The state now gets about 10 percent of its energy from renewable sources, according to the Department of Natural Resources & Environmental Control, and it's made annual progress in meeting the goal of its Renewable Portfolio Standards (RPS). The benchmark requires utilities to procure 25 percent of their electricity from renewable sources by 2025.
Delaware is working to cut carbon emissions partly through its membership in the Regional Greenhouse Gas Initiative (RGGI). This nine-state cooperative sells emissions allowances to utilities like Delmarva Power and uses the proceeds to help partnering states make deeper cuts. In Delaware, most of the money is used to fund energy-efficiency programs, said Thomas Noyes, DNREC's principal planner for utility policy.
These initiatives are also helping Delaware hit its target of reducing carbon emissions by 30 percent from 2008 levels by 2030, as part of the 16-state Climate Alliance. The grouping pledged to meet the Paris climate goals for greenhouse gas reductions, even though President Donald Trump withdrew the United States from the accord in June 2017.
So far, the lower emissions have been achieved by the switch from coal to natural gas. Older coal-fired power plants have been retired, and the Indian River plant near Millsboro is now Delaware's only coal plant in operation.
"Most of what we've done so far is from fuel switching from coal to natural gas," said Dr. Jeremy Firestone, director of the University of Delaware's Center for Carbon-Free Power Integration. "That strategy worked well, but it's mostly over."
Unless Indian River switches to natural gas, Delaware will have to look to renewables, such as solar and onshore wind, to make further progress toward its emissions goal, Firestone said.
Delaware's switch to natural gas mirrors a national trend prompted by a boom in production enabled by hydraulic fracturing, or "fracking" technology starting in the mid-2000s. Plentiful natural gas has driven the price down to about $2.50 per million BTUs, near its lowest in a decade, prompting the switch by many coal-fired power plants.
Noyes said renewables are still a part of the reason that the state has made steady progress in cutting emissions of carbon and a range of pollutants in the last five years. "A megawatt-hour of power is cleaner today than it was in 2012," he said.
To hit its RPS target in 2025, Delaware will have to rely mostly on power that's generated by onshore wind in other states that are in the multi-state PJM power grid, Noyes said.
By contrast, the RPS requirement for solar "“ 3.5 percent of the state's total by 2025 "“ will likely be met by facilities inside Delaware, Noyes said.
State officials are also taking another look at offshore wind following the failure of a plan by Bluewater Wind to build a wind farm off southern Delaware about a decade ago.
An offshore wind working group, set up by Gov. John Carney last year, reached its initial deadline in December without saying whether the state should pursue offshore wind as a way of broadening its renewable energy portfolio. Instead, the panel issued a memorandum that contained more questions than answers. It promised to resume talks this year.
Firestone argued that most Delaware citizens appear to be strong supporters of having a fleet of wind turbines offshore, even if they have ocean views from their homes, and more than 80 percent said they would prefer to add an offshore wind farm over new fossil fuel capacity.
Some of the public's support for offshore wind and other renewables comes from a desire to mitigate climate change, Firestone said, but many are concerned about air pollution.
"Every survey that we've done finds that the public in Delaware is incredibly supportive of offshore wind," he said.