As the graphs above (from University of Texas researcher Josh Rhodes) show – the Texas grid operator, ERCOT, which is built insofar as possible to respond to pure market forces, has transitioned over a decade from choosing gas first, to choosing renewables and storage.
Meanwhile, that grid has only become more secure and stable.
As electricity demand grows, alongside wind and solar’s share in the U.S. energy mix, concerns about renewables’ reliability are being raised more frequently — including at the highest levels of the federal government.
“With the electricity grid, you have to match supply and demand in every moment in time,” Energy Secretary Chris Wright said recently on Fox News. “With wind and solar, you don’t know when they’re going to be there, and you don’t know when they’re going to go away.”
Wright went on to say the development of renewables has led to an “extra distribution grid” that has raised energy prices.
But utility planners, grid operators and analysts say wind, solar and batteries are an important part of an evolving power system in which intermittent resources can be reliably scheduled and called upon using sophisticated software and other tools.
They also point to both the levelized cost of electricity for renewables and their competitiveness in automated energy markets that select the least cost units to run in each hour.
“System operators don’t decide whether resources bidding into the market are good or bad,” said Rob Gramlich, president of energy sector consultant Grid Strategies, in an interview.
“There is no central decision maker,” he said. “Markets don’t play favorites.”
With generators retiring, demand rising, and construction, financing, permitting and supply chain challenges growing, operators and analysts acknowledged concerns over the future of the U.S. power system. Many called for diversification of resources, including renewables and storage, to protect electricity reliability and affordability.
“The objective of planning is a portfolio of diverse resources at the least cost possible to avoid outsized impacts from any single one,” said Michael Eugenis, Arizona Public Service’s director of resource planning.
APS is pursuing renewables alongside more natural gas to maintain reliability in its territory, he said.
“That is not the same as a second set or a shadow set of resources,” he added.
One of the major concerns cited by Wright and others is the intermittent nature of renewables and the impact of that on grid reliability.
One of the ways grid operators measure reliability is using a metric called effective load carrying capability, or ELCC.
ELCC is a complex calculation based on comparing what portion of a resource’s nameplate capacity it produces on average in simulations of decades that include factors that cause it to vary, like performance, supply and demand. For fossil resources, variabilities are caused by things like maintenance outages and fuel supply issues. Weather variations impact wind and solar.
ELCCs vary by region and by each system’s portfolio makeup, but nuclear power generally has the highest ELCC, meaning on average over the years, it produces the closest percentage of its nameplate capacity.
Fixed-tilt solar had the lowest at 8%, and tracking solar was 11%. Onshore wind was 41%, offshore was 69%; storage was between 50% and 72%; gas was between 60% and 78%, and coal was 83%.
But despite their relatively low ELCCs, automated markets are consistently choosing renewables over other resources because they are cheaper at the time the grid needs them.
“The automated market mechanisms use all the relevant variables that affect load to pick the cheapest resources,” said Richard Doying, Grid Strategies vice president and a former executive vice president for market and grid strategy for the Midcontinent Independent System Operator.
Those resources are bid out, and “then the next cheapest resources, and so on,” Doying said.
“The markets are selecting wind and solar despite their low ELCCs and low capacity values because the return justifies the investment,” he added.
When they are both generating at the same time, renewables are often cheaper than fossil fuel power.
One reason for this is that the fuel and maintenance costs for fossil-based resources are significant, continuous and volatile. Natural gas prices, for example, have nearly doubled since 2024, but are still lower than they were in 2022 following Russia’s invasion of Ukraine.
The fuels for wind and solar are cost-free, maintenance outage costs are significantly less, and the capital expenditures to build projects are typically amortized over 20 years.
“If natural gas was the cheapest option to meet the peak, the markets would select it,” said Sean Kelly, co-founder and CEO of forecast provider Amperon and a former energy analyst.
Kelly said today’s advanced load and weather forecasting enhances the reliability of a resource portfolio with a high renewables penetration.
While good forecasting can alleviate much of the need for backup generation, he said, rising demand for power will likely require more firm generation to fill the gaps when there is no sun or wind.
The ability to choose the cheapest available power source in real time is why grid operators say renewables are an important part of the same, increasingly flexible power system — not a separate system.
“We don’t have different systems; we have a portfolio of resources and capabilities that meet the needs of the system,” said Mark Rothleder, senior vice president and COO for the California Independent System Operator, in an interview.
Of particular interest to the US, which under the Trump administration has made a major push to expand and lock in fossil fuels as the power of choice for global markets, indications are that the fastest growing economies are moving toward renewables.
As President Donald Trump pressures world leaders to abandon the energy transition in favor of a U.S.-led fossil fuel resurgence, the status of India’s gas-fired power plants helps explain why his pitch isn’t getting much traction.
Half of that fleet in India is sitting idle. Although electricity demand is exploding, and the plants are designed to run for decades into the future, Indian officials have turned away from them. Their calculation: that renewable energy provides a cheaper and more reliable alternative.
“And you don’t have to depend on overseas nations for fuel,” said Sumant Sinha, CEO of ReNew, one of India’s largest renewable energy companies.
From the PBS News Hour a few days ago: “Unlikely alliance builds cleaner geothermal energy network in a Massachusetts community”
Note: In this clip I noticed heat pumps from American manufacturers, WaterFurnace and ClimateMaster
https://youtu.be/sAxelA0iMw0?si=2qc3aBCio6PAYP7w
Other countries’ nukes are lower in capacity factor/ELCC because they’re more flexible, but that’s actually a serious drawback for us reactors. New nukes are already the most expensive source of energy and it would be difficult and even more expensive to make them more flexible with storage (which is relentlessly attacked by fossil and fissile fuel proponents but only when it’s used with renewables. Funny, that.)
Like coal burners, most us nukes are losing money, and to try to minimize that, they tend to run all out all the time—except when refueling, melting down, crashing en masse in safety emergencies a la France, or remaining unbuilt because cost-overrun construction is delayed by years or decades a la Flamingville, Hinkey Point, Olkiluoto, Vogtle, VC Summers, and others. OTOH, the lack of flexibility is also a problem as it makes it difficult and more expensive to build any more than nadir demand demands.
The wind is always blowing; the sun is always shining. Wind and solar in particular but also efficiency and wiser lives are the cheapest sources of energy almost everywhere in the world whether particular W&S facilities are providing energy at any one time or not. And they’re getting cheaper, at roughly 1% a year, or more than 10% per decade.
Efficiency has replaced more fossil fuels than any other source, btw, according to Amory Lovins.
“Outsized impacts from any single [source]”
IOW, sudden massive unexpected shutdowns? They don’t happen with decentralized distributed-generation renewables like onshore, offshore and near-shore wind, solar PV, CSP, geothermal, and tidal.
https://www.yahoo.com/news/articles/researchers-develop-innovative-tool-could-211500633.html
It’s a start. But in the face of the multiple moving targets of climate catastrophe damage, the world needs to vastly diversify the crops it depends on and the varieties it uses.
That doesn’t meet the needs of horizontally, vertically, and internationally integrating corporations, but that’s just one more reason to ditch that model.