Kinder Morgan Inc.’s (KMI) Will Brown, vice president of business management for the western region gas pipeline business, likes to tell customers his company is focused not just on transporting natural gas, but making sure it’s delivered reliably.

It’s a tall order anywhere in the country, but in the West it can sometimes take days for natural gas traveling over long distances at 25 mph to reach its destination. Places like California and Arizona, where solar and wind power are being added to the grid rapidly, have threatened gas demand, but they’ve also made the fuel that much more important.

“We believe that when pipeline capacity is properly contracted, properly nominated and properly balanced on the day, natural gas is a resilient fuel and a clean fuel with exceptional reliability for power generation,” Brown told an audience on Tuesday at the LDC Gas Forum Rockies & West in Broomfield, CO.

Gas demand in KMI’s western region was about 12.2 Bcf/d last year, of which the company supplied about 55%, Brown said. KMI pipelines are connected to roughly 24 GW of gas-fired power generation in a part of the country that hosts about half of all U.S. installed renewable capacity.

With large solar arrays and wind farms come intermittent drops in power and cycle frequency. Gas-fired turbines can power up faster to meet peak demand or fill the void of variable output renewables.

Wind and solar generating capacity in the West currently stands at 48 GW, Brown said, adding that it’s poised to nearly double in the next decade. Brown and other speakers seemed uneasy about what that means for the gas industry in the Rockies and the Southwest. He echoed ConocoPhillips’ Jim Duncan, director of market research, in estimating that renewable energy growth is on average likely to erode gas demand by roughly 2.5 Bcf/d over the next decade or so.

While that could be made up with growing liquefied natural gas exports, industrial demand, Mexican exports, which are largely been driven by power markets, and other sources, gas is poised to play an important role in the West as more renewables are added.

“As the sun sets and the load continues to grow, we have to have a fast ramp-up of natural gas-fired generation to meet this peak and maintain reliable power,” Brown said. “We call this peak deliverability; it is gas that is stored in the pipeline in line pack or it’s sitting in our storage fields to be able to come on at the required location, at the required time, at the required pressure and in the required quantity.”

KMI delivered about 1.2 Bcf/d of natural gas to power plants in 2016, mostly on its El Paso Natural Gas (EPNG) pipeline system in the Desert Southwest, but also on the Colorado Interstate Gas Pipeline.

As more gas-fired power generation has come online across the country in recent years, it’s put stress on pipeline infrastructure and raised questions about gas-power coordination. Brown said EPNG’s south mainline is currently sold out, partially as a result of power demand. He said “power generation in the area is going to need additional line pack assistance and we believe that natural gas and natural gas storage is the most economic way to go.”

But he added that coordination issues are simpler than people think. “Our delivery point operators must contract for their daily quantities and their peak hour services, schedule their transport, reserve the capacity appropriately and make sure they’re balanced for the day,” he said. “We don’t need hourly scheduling.”

The evolving power grid dynamics could finally necessitate more of the underground gas storage that places like Arizona have called for over the years. Brown said KMI is currently gauging market interest for four storage caverns that would have 1 Bcf/d each of working gas capacity at a location between Phoenix and Tucson.

Duncan said the western states are unequivocally going to continue adding more renewable capacity, if only for the space that exists in the region compared to the more densely populated East Coast. But 100% renewables, whether it’s in California as the state is aiming for by 2045, or across the country, is a long way off.

Consumers, Duncan said, don’t like interruptible power. Barring some kind of renewable energy storage breakthrough or better methods to control the loss of electricity when it’s transmitted over long distances, natural gas is poised to continue providing short-term reliability or even long-term baseload.

Gas-fired power generation is still expected to increase 7.7 Bcf/d over the next decade to match coal and nuclear retirements, even at a time when solar and wind are also forecasted to grow significantly.

Duncan offered a simple example. The average smartphone user consumes about 388 kWh/year. An energy efficient refrigerator uses 322 kWh/year, he said. “What does that say? It says the big growth area is power because the rest of the world has discovered the internet, refrigerators, televisions, and we’ve only just scratched that surface.” He said more than 1,500 gas-fired power projects are in the works globally. “There’s where my signpost should be” for prices and demand.