Answer: Mostly, yes, but there are complications
From The Climate Brink.
Is renewable energy (RE) cheaper than fossil fuels?
To begin to answer this, we need to define what cost we’re talking about. Let’s first talk about the cost of RE energy vs. fossil-fuel energy on a grid that’s dominated by dispatchable power, such as fossil fuels. This is what most electrical grids are like today.
For a grid dominated by dispatchable power (i.e., power sources that can be turned on or off at will), the intermittency of wind and solar imposes no costs. Thus, the relevant cost comparison is between the so-called Levelized Cost of Energy (LCOE) of the various energy sources:
Virtually all credible analyses agree that RE has the lowest LCOE. Therefore, it is the cheapest energy source for grids that contain a lot of dispatchable power.
This explains why, for example, 95% of the power scheduled to be hooked up to the ERCOT (Texas) grid is RE (solar, wind, or batteries). Natural gas is 5%.
For a grid that’s mainly fossil fuels, every kW of renewable power (RE) you add displaces a kW of expensive and dirty fossil fuel power. But, as the grid gets more and more RE, that changes. At high levels of RE deployment, the intermittency of the wind and solar means that you need to add several kW of wind and solar to displace a single kW of fossil fuels. This drives up the marginal cost of RE energy.
In addition, high RE levels mean that RE is competing with the most efficient and cheap fossil-fuel generation, some of which have not yet been paid off. Additionally, the more RE you add, remaining RE sites are higher cost and lower quality.
The net result is that, beyond some point, the price of energy on the grid starts increasing as you add RE. Qualitatively, the price of electricity vs. RE deployment looks like this:
Right now, around 20% of our electricity comes from wind and solar and this is already saving consumers billions of dollars a year. As we increase RE deployment, the price of electricity will continue to decline and consumers save money.
Then we reach the minimum price point. One study from NREL concluded that this occurs when RE penetration reaches 57% (in 2050). At this point, electricity produced on this grid is cheaper than a fossil-fuel heavy grid and, as a bonus, we’re also emitting a lot less CO2.
As we move beyond 57%, the declining value of wind and solar to the grid means the price of energy increases. However, it remains below what we’re paying today for a fossil fuel grid until we get to around 90% RE.
Let me repeat for those in the backrow: we can get to a 90% RE grid and pay about the same as we’d pay with a fossil-fuel heavy grid. And this doesn’t account for the external costs of fossil fuels (see below).
A significant amount of the discourse about RE focuses on the cost of achieving net zero by 2050, which requires completely eliminating fossil fuels. No one knows how much this will cost, but some studies have produced eye-popping numbers:
Many analyses have looked at this goal and they agree that a lot of the costs of reaching net zero are driven by the cost of phasing out the last few percent of fossil fuels. The reason is that the last few percent of emissions are the hardest to abate and the ones for which technology to replace fossil fuels is expensive or undeveloped. For example, decarbonizing long-distance airline flights is one of the last things we’ll decarbonize because it would probably require biofuels, which could have very high costs.
This is quantified in this plot, which shows the incremental abatement cost (orange line) as a function of how much RE is on the grid. For a 95%-RE grid, the abatement cost is $200/tonne, increasing to $930/tonne for 100% RE.
Thus, it’s easy to look at the price tag for getting to net zero and conclude, “Wow, this is too expensive.” But that misses the fact that the cost of getting to a slightly lower value, e.g., a 90% clean-energy grid, is actually quite modest.
These net-zero estimates also hinge heavily on future innovation — a variable notoriously difficult to predict. History has shown us, particularly in the last decade, that technological advancements can drastically outpace predictions, as seen with the enormous drop in the cost of solar panels, which no one predicted.
External costs
All of these discussions focus on the market price of energy. Such a discussion neglects the extensive subsidies that distort the energy market. While RE sources receive financial support, the subsidies for fossil fuels are substantially larger and more ingrained within global economies.
Moreover, the price of fossil fuels seldom reflects their full societal costs — what economists call externalities. Recent estimates of the cost of climate impacts puts it around $185/ton of CO2 emitted. These costs are not included in the cost of fossil fuels.
Air pollution from fossil fuels kills millions of people every year. Like the climate impacts, the costs of this are not included in the price. Fossil fuels have also been linked to significant political and social instability. For instance, the U.S. invaded the Middle East twice in the last 35 years in order to stabilize the oil supply. The Russian invasion of Ukraine is intimately tied to fossil fuels. These costs are also not included in the costs of fossil fuels.
If we added these externalized costs to the cost of fossil fuels, the argument increasingly tilts in favor of RE.
In any complex discussion, you need to carefully define the question you’re asking. Much of the discussion around renewable energy focuses on net zero, because that’s what we ultimately need to aim for. We really don’t know how much achieving net zero by 2050 will cost because it will depend to a large extent on future innovation.
But a large chunk of the cost of net zero is driven by the last few percent of decarbonization. If you talk about, say, a 90% clean grid, the cost of achieving that using today’s technology is approximately zero. And this cost comparison excludes the external costs of fossil fuels: climate impacts, air pollution, geopolitical instability. Taking all factors of those into account, there’s no question that we can largely decarbonize today and end up with a better economy and cleaner environment.
I found this article extremely enlightening. It put into words something which I had only intuitively understood. But it highlights how the cheapest RE now might not be the cheapest RE in 2040 (ignoring of course technological advances). For example, CSP (concentrated solar power) is more expensive than solar panels. However, it can produce dispatchable electricity, which means it will be very valuable for that last 10% of electricity supply. Another example: SMRs (small modular reactors) are prolly 3 or 4 times as expensive as solar, now. But to convert solar into dispatchable power would require at least 12 hours of storage. That's still very expensive, though no doubt battery costs will continue to decline. But so might the costs of SMRs. Again, for that last 10%, SMRs might be the answer. Yet another example: power-to-gas. Using green methane (produced using green electricity to make hydrogen by electrolysis, which is then converted into methane by the Sabatier process) to run peaking gas plants will be expensive, but again, makes sense for the last 10%.
We may have an answer sooner than we thought. The state of South Australia has been steadily increasing the percentage of renewables in its grid for 17 years. So far this year, it has averaged 75%. It could reach 100% within 5 years. Now, this isn't a perfect test for how high renewables can go, because SA (unlike, say, Texas) has high-voltage links with other grids, so it can buy or sell power to the other states. Nevertheless, we will get a clear idea of the issues quite soon.
