Upgrading an Icon

The majority of electric power in the U.S. comes from fossil fuels. Burning coal, oil, and natural gas emits smoke and other toxic substances into the air. It also produces greenhouse gases that trap heat in Earth’s atmosphere, contributing to climate change. That’s why many communities are transitioning to greener energy sources (see Energy in America).

A few years ago, Hawaii passed a law requiring the state to switch to greenhouse-gas-free electricity by 2045. Last year, California passed a law to do the same. Several states are considering similar commitments. But ditching fossil fuel energy is a big step for a state the size of California. It’s the most populous in the nation, with 40 million people, and also has the fifth-largest economy in the world. Compared with Hawaii, California uses about 30 times as much electricity. “It will not be easy,” California governor Jerry Brown said in a statement about the new law, “but it must be done.”

Most electric power in the U.S. comes from fossil fuels. Coal, oil, and natural gas are burned. This releases smoke and other toxic substances into the air. It also produces greenhouse gases. These gases trap heat in Earth’s atmosphere and help cause climate change. That’s why many communities are changing to greener energy sources (see Energy in America).

A few years ago, Hawaii passed a new law. It says the state must switch to greenhouse-gas-free electricity by 2045. Last year, California passed a similar law. Several states are thinking about doing the same. But getting rid of fossil fuel energy is a big step for California. That’s because of the state’s size. It has 40 million people, the most in the nation. It also has the fifth-largest economy in the world. California uses about 30 times as much electricity as Hawaii. “It will not be easy,” California governor Jerry Brown said in a statement about the new law, “but it must be done.”

California has already made some serious strides in clean energy. The state got an impressive 47 percent of its electricity from renewable sources in 2017. And it met its goal of reducing overall greenhouse-gas emissions below 1990 levels back in 2016—four years ahead of schedule. To further the state’s efforts, as of 2020, all newly built homes must get power from solar panels either on their rooftops or in a neighborhood system.

Shifting electricity production to rely more heavily on renewables presents challenges. The amount of energy produced by wind and solar farms can be inconsistent. When the sun is shining brightly and winds are steady, these sources produce more energy than communities can use. But they often fall short on cloudy days, at night, or when winds stop blowing.

The variability of solar and wind “creates a big challenge for the power grid,” says Kelly Sanders, a civil and environmental engineer at the University of Southern California. If California is going to reach its no-fossil-fuel commitment, it must find ways to store excess energy from wind and solar for days when those sources aren’t as productive. That’s where the Hoover Dam comes in.

California has already made big gains in clean energy. The state got 47 percent of its electricity from renewable sources in 2017. It also set a goal to reduce total greenhouse-gas emissions below 1990 levels. The state met the goal in 2016, four years ahead of schedule. Starting in 2020, all new homes in California must get power from solar panels. The panels can be on rooftops or in a neighborhood system.

The switch to more renewable electricity brings challenges. The amount of energy produced by wind and solar farms isn’t always the same. Sometimes the sun shines brightly and winds are steady. Then these sources produce more energy than communities can use. But they often fall short on cloudy days, at night, or when winds stop blowing.

The amount of energy from solar and wind is always changing. That “creates a big challenge for the power grid,” says Kelly Sanders. She’s a civil and environmental engineer at the University of Southern California. To reach its no-fossil-fuel goal, California must find ways to store extra energy from wind and solar. The stored energy can be used when those sources fall short. That’s where the Hoover Dam comes in.

The plan to retrofit the Hoover Dam is still in the early stages. Engineers have examined some possible locations for the massive pump. But more research has to be done.

Ecologists need to study the impact of the redesign on the environment. The federal government must give permission for the renovations to go forward. And the National Park Service needs to review how the project could affect lands downstream of the dam. Researchers must also confirm that the overhaul won’t affect surrounding communities that rely on the Colorado River for their water.

If the plan is approved, building the pump system will be a massive undertaking. It could mean tunneling miles of pipeline underground and could cost about $3 billion. If all goes as planned, the upgrade would be completed by 2028. “This could be a great project for the region,” says Sanders, “allowing much more flexibility in how they produce and store electricity.”

The plan to upgrade the Hoover Dam is still in the early stages. Engineers have looked at some possible locations for the huge pump. But more research must be done.

How will the upgrade affect the environment? Ecologists need to find out. How could the project affect lands downstream of the dam? The National Park Service needs to study that. And the federal government must agree to the project. Also, communities around the dam rely on the Colorado River for their water. So researchers must make sure that the changes won’t affect them.

If the plan is approved, building the pump system will be a huge job. It could mean placing miles of pipeline underground. The cost could be about $3 billion. If all goes as planned, the upgrade would be finished by 2028. “This could be a great project for the region,” says Sanders, “allowing much more flexibility in how they produce and store electricity.”