April 7, 2019 - States are ramping up their mandates for clean and renewable energy in the face of federal climate inaction, declining renewable costs and demands from electricity customers, but new policies and yet-to-exist technology will be needed for states to meet ambitious 100% clean energy goals.

In the last year, California, New Mexico, the District of Columbia and Puerto Rico all have joined Hawaii in the ranks of states seeking to get all of their electricity from clean or renewable sources by 2050 or earlier. And individual utilities such as Xcel Energy and Idaho Power have set 100% clean energy targets, too.

Other states are considering making the leap to 100% clean energy, including Minnesota, Wisconsin, Illinois and New York. And in the last four years, New Jersey, New York and Oregon have increased their mandates to 50% by a targeted year, while Vermont boosted its renewable portfolio standard up to 75%.

"What is different now, is that it's not just a matter of having some kind of clean energy standard, but really having a very aggressive, what we are calling a high-volume standard," Sue Gander, energy division director at the National Governor's Association, said recently at the National Hydropower Association's conference.

State Action

States are acting on clean energy because there is a void of climate leadership at the federal level, and because renewables are cheap enough to be competitive in the power markets, Nathanael Greene, a senior renewable energy policy analyst at the Natural Resources Defense Council, said in an interview.

Customer demands are also driving clean-energy commitments, said Emily Fisher, general counsel at the Edison Electric Institute. Renewable energy certificates are no longer enough for the Googles and Amazons of the world; they want clean and carbon-free energy, she said. Utilities are trying to help states and companies meet these goals.

But it is important that the debate seems to be shifting away from 100% renewables and toward 100% clean energy, Fisher said. The latter approach leaves all options on the table, including coal or gas with carbon capture and sequestration, as well as nuclear generation, she noted.

Utility Efforts

Xcel Energy, which operates in eight states, can achieve its 80% carbon reduction by 2030 goal with existing technologies, including wind, solar, natural gas, storage and nuclear, Xcel spokesman Matthew Lindstrom said in an email.

But reaching Xcel's goal to be carbon-free by 2050 will require technologies not yet commercially available, Lindstrom said. All options are on the table, including power to gas, seasonal storage, fossil-fuel generation with CCS, advanced nuclear or small modular reactors and deep-rock geothermal, he said.

Idaho Power has a goal to provide 100% clean energy by 2045 using hydropower -- which meets almost half of its customers' demands -- as well as wind, solar, battery storage and grid upgrades.

Policy Changes

New policies could help ease the shift to clean energy. Creating a national grid, rather than the regional system we have today, would take advantage of the geographic diversity of wind, solar and hydro and get us much closer to 100% with the resources we have today, Greene said.

Meanwhile, EEI's Fisher cited a recent order by the Federal Energy Regulatory Commission to help storage participate in the markets, a measure that the grid operators are currently implementing. And FERC is still weighing how to help distributed energy resources participate in the markets, she noted.

But as more states and utilities move toward 100% clean energy, details are hazy on how to get the last 10%-20% of carbon emissions out of the electric grid.

An NRDC study found that the US could reduce carbon emissions by 80% by 2050 using existing technology. The study found that renewable energy could generate more than 70% of the electricity supply by 2050.

Shifting the Mix

The Energy Information Administration expects 31% of electric generation to come from renewables in 2050, according to the 2019 Annual Energy Outlook. EIA's modeling only incorporates the 100% clean energy mandates in California and Hawaii and Washington, DC.

Getting to 100% clean energy with only wind , solar and short-duration storage can be cost-prohibitive because it requires a massive overbuild of the renewables and storage, said Arne Olson, senior partner with consultancy Energy and Environmental Economics. This is true unless a region has nuclear, CCS, long-duration storage or some form of biofuels, he explained.

"The last mile, so to speak, is going to be the hardest one," but the important thing is to get started, NRDC's Greene said. "If we get to 90% and are worried about that last 10%, that is a good situation to be in," he said. "And at the rate of innovation, something is going to happen."