As we add more solar to our grid, flattening the duck curve is becoming a bigger challenge. Also, Montana kids win a big lawsuit against their own state in a precedent-setting case.

What is the duck curve and what can you do about it?

For much of America, ducks are seen as cute waterfowl that have inspired some of the most beloved cartoon characters of the past century. But mention the “duck curve” to utility engineers and be prepared for a long conversation.

If you subtract the amount of energy supplied by solar from the total electricity demanded by the grid, you get the amount of energy a utility needs to produce from other sources. If we graph that number over the course of a day, it takes the shape of a duck.

The tail of the duck is a spike in demand in the morning as people get up and get ready for work. The graph curves down like a duck’s back as people are away from home and solar panels are at their most efficient. The curve then spikes again, but higher, forming the head as demand peaks in the evening when people come home just as the sun goes down.

These fluctuations are the source of big headaches for energy providers. Utilities must have enough power plants and generators to reach the top of the duck head, but that expensive infrastructure sits idle most of the rest of the day. The cost of all that unused capacity must get to be passed on to rate payers.

As we add more solar energy, the back gets lower, and the tail and head get higher. Energy storage solutions, like pumped hydro, lithium-ion batteries, or even geothermal, are one key solution for straightening out the duck. These systems store excess solar energy during sunny intervals and release it during peak demand. The storage we have is helpful, but much more is needed, and it is often very expensive.

The duck curve isn’t just about cost, though. Utilities run their most efficient generators throughout the day and use less efficient plants during peak demand hours. These are known as “peaker plants.” Peaker plants emit much more carbon and require much more fuel to run. They often use dirtier fossil fuels, as well.

If a utility charges using a “time-of-use” scheme, it will bill customers at a much higher rate for electricity during these hours. But even if a homeowner is billed at a flat rate, shifting electricity usage away from those peak hours is a great way to reduce your carbon footprint. If you have energy storage such as a backup battery in your home, those hours are a great time to use that stored electricity.

As strange as it sounds, helping to flatten out the duck is one way people can help move toward net zero.

The kids are alright in Montana

This past week, a group of young Montanans achieved a big legal milestone that could have international consequences long into the future. Claiming a constitutional right to a clean and healthy environment they sued their state. They alleged that its promotion of fossil fuel development violated their rights, and they won.

Montana stands as one of three states that recognizes residents’ entitlement to a healthful environment under the state constitution’s bill of rights. Such a law is commonly referred to as a “Green Amendment.” In 2020, 16 youths, now ranging in age from five to 22, filed a suit against their state government, marking a historic moment in legal proceedings. The case finally made its way to a courtroom this past June.

In a ruling delivered on Monday, District Court Judge Kathy Seeley declared that a Montana policy, which barred state agencies from assessing the impact of greenhouse gas emissions when granting permits for energy projects, was unconstitutional. Seeley’s ruling underscored the link between Montana’s emissions, climate change and the resulting adverse effects on the environment and the plaintiffs’ well-being.

Predictably, state officials decried the ruling as “absurd” and indicated that they would appeal. Nevertheless, legal experts anticipate that this judgment, if upheld, could inspire similar lawsuits, strengthening climate-related cases elsewhere, and establishing a new legal standard on governments’ responsibility to shield citizens from the consequences of global warming. (1)

During the two-week trial, legal representatives for the plaintiffs argued that the state’s promotion of fossil fuels worsened climate change, exacerbating health issues for the plaintiffs due to exposure to toxic wildfire smoke and other adverse conditions. Additionally, they contended that these policies deprived the claimants of vital resources and recreational opportunities, intensifying drought conditions and drying up Montana’s rivers.

The state argued that Montana’s carbon emissions were inconsequential in a global context, absolving them of responsibility for the broader impact of climate change. Judge Seeley deemed the state’s argument lacking in persuasiveness, pointing out the absence of a compelling rationale for excluding greenhouse gas emissions from the considerations when permitting energy projects.

Michael Gerrard, of Columbia Law School’s Sabin Center for Climate Change Law, hailed the decision as unparalleled in its significance for climate change jurisprudence. With a 103-page ruling, the court firmly established fossil fuel consumption as the primary driver of climate change, leading to detrimental health and environmental consequences that are poised to worsen over time.

The proliferation of climate change-related lawsuits worldwide has surged, more than doubling since 2017, according to a collaborative report from the United Nations and Columbia’s Sabin Center for Climate Change Law. Gerrard noted that about 150 countries around the world explicitly include the right to a healthy environment in their constitutions. (2)

David Dana of Northwestern Pritzker School of Law regarded the Montana decision as a triumph for young climate activists. He suggested that this ruling could serve as a guiding light for judges inclined to hear such cases, circumventing the tendency to brush them off as too politically charged for legal deliberation.