Adding renewable, zero-carbon generation to an electricity system helps reduce carbon emissions, just like adding ice to a drink makes it colder.
This may seem like an intuitive point and one not worth arguing about, and yet it’s the subject of a recent column in the New York Times, which claims solar and wind, despite record-breaking expansions in recent years, aren’t reducing carbon pollution. The claim is simply false. The column did get one thing right, though: we are not doing nearly enough in the fight against climate change, and need to do more if we are going to prevent the worst effects of a quickly warming planet.
The column relied on an analysis from an unabashedly pro-nuclear (and anti-renewable energy) group that claimed that increases in wind and solar generation were not correlated with declines in carbon emissions.
Renewables are key to decarbonization
The analysis is fundamentally flawed because it aggregated data to the global level when it is not appropriate to do so. An increase in wind and solar generation in the U.S. has zero impact on emissions in France, and vice versa. Aggregating these data sets together muddies the waters and makes it impossible to determine whether any correlation, or lack thereof, is meaningful. On that note, the study also fails to remember the old statistics truism: correlation does not imply causation; similarly, a lack of correlation does not demonstrate a lack of causation. (The column also shows a chart indicating electricity generation shares from wind, solar and hydro, which only serves as evidence that there has been more historical investment in hydro and nuclear than wind and solar. The chart completely hides that recent growth has been dominated by wind and solar; nor does the chart say anything about the author’s contention that renewable technologies fail to reduce emissions.)
Let’s take the study’s argument at face value, though, that for the most effective emissions reductions technologies, there should always be a correlation between increases in generation and a decline in carbon intensity. Why, then, has the carbon intensity of energy declined in both the United States and Germany since 2010 despite decreases in nuclear generation driven by recent plant shutdowns? Would anyone argue that this is evidence that retiring nuclear generation can help reduce emissions? Of course not—there have been a number of countervailing factors, including the significant increase of renewables generation and energy efficiency savings, that have helped avoid overall emissions increases in spite of those nuclear retirements. (Nuclear generation is carbon-free, but it’s neither clean nor renewable.)
A much different picture arises when you look at more granular data. For example, a detailed analysis conducted by the Department of Energy’s Lawrence Berkeley National Laboratory examined wind and solar growth over the past several years and used a grid emissions model to examine their isolated impacts. Unsurprisingly, that study found that wind and solar generation have played a significant role in decarbonization of the power sector in the United States, and in 2015 alone that resulted in 150 million tons of avoided carbon emissions, or $6.6 billion in avoided climate damages.
States across the U.S. also recognize that renewables have huge climate impacts (and a host of other benefits, like economic gains and public health improvements), which is why many states are choosing to double down on their renewables commitments. In Colorado, the state’s investments in wind are paying off. As the share of wind generation has increased from 11 percent to 18 percent since 2012, the state’s power sector emissions have fallen by 9 percent, all while the state’s economy has grown by 14 percent. In North Carolina, the solar industry has been growing exponentially, jumping from less than 0.2 percent to 3 percent of the state’s generation in just a few years. Since 2012, the state’s emissions have also fallen by 8 percent while the economy has grown by 8 percent, with over 7,000 jobs already supported by the booming solar sector.
Renewables investors are getting more bang for their buck
The Times column also cites flat investment levels in renewables, and we agree that investment levels in clean energy must increase to reduce emissions at the pace we need. However, the column failed to mention that investment levels have remained flat in part because the project costs of wind and solar have fallen so dramatically, allowing investors to finance more and more projects each year without spending more capital. In the U.S., the costs of generating power from wind and solar have fallen by 67 percent and 86 percent, respectively, since 2009, according to the investment firm Lazard.
There is no sign of the declining investor confidence that the column references. Goldman Sachs plans to invest $150 billion in the clean energy sector, and has stated that the world has reached “an inflection point when it comes to the deployment of clean technology and renewables.” Earlier this year, Morgan Stanley declared, “renewable energy hits global tipping point.” China, which experienced a slowdown in clean energy spending in 2016, announced in January that it would be ramping up its investments and plans to spend more than $360 billion on renewables by 2020.
Grid operators reaffirm that wind and solar are part of the modern grid
The column also recycled tired arguments that the integration of variable renewables like wind and solar will be too difficult or overly costly. This runs counter to the strong and growing body of literature as well as the experience of grid operators across the country, who have demonstrated that renewables can be successfully incorporated into the modern grid. For example, in February, the grid operator of the Southwest Power Pool announced that wind penetration had reached 50 percent of generation one morning, setting a new North American record. Multiple studies, including from the National Renewable Energy Laboratory, PJM (the country’s largest grid operator), and others have found that high year-round penetrations (30 percent to 50 percent) of renewables are achievable with moderate transmission upgrades and adoption of innovative grid management practices. More work is needed and there are challenges ahead, but grid planners and operators are already moving toward a more flexible grid that will help enable the integration of zero-carbon resources like wind and solar at low cost.
Don’t forget energy efficiency
Lastly, by primarily focusing on the carbon intensity of energy, the column paints an incomplete picture. Giant strides have been made to reduce the energy intensity of many economies through investments in energy efficiency. The global energy intensity of the economy fell by roughly one-third between 1990 and 2015. In 2015 and 2016, the global economy grew by 3 percent each year while carbon emissions stayed flat thanks in part to smarter energy use and clean energy growth. This was the first time that global carbon emissions were decoupled from economic growth, representing a key milestone in the fight against climate change. Continued productivity gains can and must play a key role in helping to decarbonize the global economy.
While the column’s author is correct that challenges lie ahead and that much more will be needed to avoid the worst impacts of climate change, we already have all the tools we need. We should be focused on strengthening investments in energy efficiency and renewable energy—demonstrated, cost-effective solutions—to stave off the worst impacts of climate change.