The Path to 100% is working to identify the fastest, most cost-effective, most reliable ways to decarbonize electricity — not just city by city, but across entire states and nations. It brings together thought leaders and industry experts to discuss solutions, raise awareness, and discover operationally and financially realistic approaches to building a future that runs on 100% renewable electricity.

This requires addressing economic, scientific, and political challenges that vary around the world. Accordingly, the Path to 100% is not a one-size-fits-all blueprint. Instead, it aims to provide information that can help shorten the time it takes for each nation, state, and community to customize its own Path to 100%.

The Path to 100% is made possible by Wärtsilä, a global leader in smart technologies and complete lifecycle solutions for energy markets.

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The Path to 100% Renewable Energy:

  • Is possible, practical, and financially viable
  • Is rooted in science, data and engineering
  • Develops the most cost-effective and realistic scenarios for nations, states and communities to reach 100% renewable generation
  • Promotes policies that enable rapid reductions in fossil fuel use and rapid increases in renewable generation in the electricity sector
  • Steers electricity-sector decisions about investments, infrastructure and technology toward decisions that quickly reduce greenhouse gas emissions and pave the way for a 100% renewable energy future

The Duck Curve

This duck curve shows variations in the California energy system’s net load, which equals total load minus electricity generated from primarily solar and wind; that is, net load is the amount of power that must by generated from non-renewable sources.

Boosting Renewables is Not Enough

No power system can achieve 100% renewable electricity just by adding more renewable generation. It also needs to slash fossil-fueled generation. That means reducing reliance on traditional gas- and coal-fired plants, whether they’re used for baseload or to back up variable renewable generation. And that can be harder than you might think.

The “duck curve” provides a visual representation of the difficult balancing act facing power systems with substantial renewable energy production. It reflects the fact that, over the course of the day, renewable generation and demand for electricity rise and fall – but not at the same time.

The challenge is that traditional fossil-fuel-powered plants are inflexible: they can’t just switch off when the sun is high and switch back on when the sun sets. Because traditional power stations require many hours to shut down and many hours to start back up, they cannot power up and down quickly enough to handle predictable shifts in demand and generation, let alone unexpected changes in the weather. To ensure a steady flow of electricity, California’s traditional gas-fired power stations have to keep running at 40% to 50% capacity, even on a bright, sunny day. Running at low capacity is inefficient and emits large amounts of climate-warming carbon.

Case in Point: Germany

Germany has ramped up installation of wind and solar generation for two decades, and now renewables could cover more than a third of the country’s annual demand for electricity.

But almost half of that renewable power is pushed to other European countries at peak times. That’s because Germany’s baseload coal-fired and nuclear power plants – which ensure constant power – can’t be quickly turned on and off, and so must stay online, burning coal.

At times when Germany’s wind, solar, coal and nuclear plants together generate more power than the country needs, Germany ends up donating the surplus to neighboring countries. Sometimes, it even has to pay other countries to take its surplus power.

The German power system can’t take the chance of shutting off coal-fired power plants during favorable wind conditions, because if conditions change, it might not be able to restart the power plants fast enough to avoid service problems. Coal-fired plants can only ramp down to minimum load, which is typically about half of full output.

Optimal Path: California

On days when California has too much electricity to handle, it tries to sell some to another state. If it can’t find a buyer, the extra power is wasted. That risk of overproducing electricity and wasting energy is shown in the “belly” of the duck curve.

California is not alone. Other states, cities and nations chart patterns of wind and solar generation and electricity demand that reveal challenges in balancing supply and demand. In every case, simply adding more renewable generation will never be enough to get to a 100% renewable energy future. We must also subtract fossil-fuel generation, and we need to do it quickly, starting now, in a way that continues to ensure a reliable supply of power.

Building a Path to 100%

Every power market is unique, but Path to 100% research shows no matter the market, all transitions to decarbonize power systems require similar actions.

So, what is your pathway to 100% renewable energy?

Download “The Pathway to 100%” today and access information that will help the electricity sector and elected officials make decisions about investments, infrastructure, policy and technology to quickly, cost effectively and reliably pave the way toward a 100% renewable energy future.