I presented a poster at the Anaheim meeting discussing energy backup problems we'd face given a 100% solar & wind energy supply system. With some 27,000 attendees, there were good opportunities to discuss the issue with folks who are wrestling with the problem.
My observation is that many folks who discuss converting the U.S. entirely to green energy (converting all energy use to electricity, including transportation, industry, building heat & A/C, steel production, cement production, etc.) may not have fully evaluated the amount of energy that could be required to handle emergency situations for a grid powered entirely by wind and solar. This poster, below, focuses on just one: a couple of days of extreme electricity demand plus a surprise reduction in supply. The amount of backup energy required to keep a completely green electrical grid alive in such a situation could be enormous. Most commonly proposed storage sources can't come close to handling even this mild scenario:
To ground the discussion, I used recent annual primary energy consumption data from the U.S. Energy Information Agency: roughly 100 quadrillion BTU/year. Divide that by 3412 BTU per kWh: Our annual US energy consumption is 30 trillion kWh. (Note: Assume that by 2050 we’ll have converted all of our energy use to electricity. No more fossil fuel combustion.) We’ll happily lose the inherent inefficiency of steam-based electricity generation but will increase overall demand by 2050, and we’ll need more wind turbines for the cold nights. The total rises to 40 trillion kWh. We’ll need routine backup sources to handle ordinary winter nights in an all solar/wind system. But, the system probably won’t be designed to handle occasional extra-cold and quiet winter nights challenged by an unexpected supply failure crisis. The cost of providing such rarely-used extra storage would be very high and wouldn't provide a good return on investment.
*Crisis-level storage assumptions.
Let’s consider a challenge that increases electricity demand by 10% and decreases production by 20% for a couple of days, overwhelming the grid’s routine reserves. Recall that the poster assumes that we’ve built a national High Voltage Direct Current (HVDC) grid along the Interstate Highway System.
A High Voltage Direct Current Grid powered by wind and solar
We’re imagining a surprise regional failure of electricity production plus a larger-area increase in heat pump demand. Even with incoming support via the new grid, the supply would still be short by an enormous amount. Imagine, for example, a polar vortex event like the one that shut down the Texas supply in February of 2021.
*Hydrogen as the energy source to cover such a crisis.
If enough hydrogen were available, it could store the energy required to cover such a shortage. Why is that a realistic possibility? Assume that hydrogen, rather than batteries, will be our fuel for long-distance highway, rail, sea and air transport. Batteries are great for shorter range travel. Quick refueling, thousand-mile range and light weight are hydrogen’s long-distance advantages. Plus, batteries in highway vehicles create supply bottlenecks: the grid-buckling moments when millions would require quick recharging during peak load periods. If the ten million vehicles on our July 4th highways were battery-powered, peak use would spike drastically. In contrast, hydrogen storage tanks can be refilled gradually and intermittently, electrolyzing water whenever there’s a power excess on the grid. That happens a lot already on grids supplied with wind and solar. Hydrogen-fueled EVs simply draw down stored fuel with no abrupt electricity demands, contrasting with battery-powered EVs that must be quickly recharged at very high rates during long journeys. Bottom line: it seems likely that we’ll need large numbers of hydrogen fueling stations to support long-distance transportation. Those stations would provide a unique opportunity to add relatively low-cost crisis-level storage to a self-supporting vehicle gas station network.
*Is the idea of developing tens of thousands of hydrogen fuel stations by 2050 insane?
Good question 😉. Surprisingly, we already have 100,000+ stations selling gasoline and diesel fuel in the U.S. They’re a curse and a blessing: They sell the fuel that’s burned into CO2. But – those gas stations are at the prime locations, and companies are already specializing in containerized hydrogen electrolysis, storage and delivery equipment to be shipped to replace the gasoline pumps. Storage of extra hydrogen at each gas station could be a secondary benefit of that self-financed system, with the incremental costs covered by local utilities. The other choice, paying for purpose-built, non-self-supporting, rarely-used crisis-energy storage would create enormous cost burdens for those same utilities. And, by encouraging conversion of our gas stations to hydrogen for both vehicle use and crisis storage, we’re co-opting the oil companies toward moving from carbon to clean – they’ll have the real estate and the incentives to support this enormous change.
We don’t have to convert our 100,000 gas stations tomorrow – we can start with 100, updated to H via a cooperative venture. Installing these H-fuel stations U.S.-wide right now could kick-start sales of long-range hydrogen-powered SUVs, pickups and highway transport trucks/trailers, and would initiate real planning for air, sea and rail hydrogen fuel use. Add a few incentives (instant rebates rather than tax credits so that anyone can benefit) and hydrogen-powered personal vehicles should quickly become our long-distance choice, encouraging additional gas station conversions. We’ve seen this pattern before: It’s not clear whether the Model T Ford was the chicken or the egg, but more than 100,000 gas stations were hatched as needed.
*Put the panels where the sun is shining.
Installing solar power on rooftops is an inefficient way to locate the 24 billion panels we’ll need by 2050. Many of the two million dark-tinted square miles on the map below are Federally-owned lands on which solar could instead be installed to operate at peak efficiency. Expanding on the old Tennessee Valley Authority experience, this could be built by adding a citizen participation component.
The sun shines best in the southwest
We could finance the process by encouraging citizens to invest a few thousand dollars each in a new Clean Energy Agency (CEA)3, with their 25 solar panels installed at facilities in the Southwest rather than on a roof in a less-efficient location. The energy would be sold nationally over our new HVDC grid. Each citizen-owner would receive CEA electricity-sales income monthly, with some profit also used to build out the new grid. HVDC trunk line pathway redundancy provides resilience, as would the continuing national buildout of other green energy sources feeding the network. And, the U.S.-wide hydrogen-station system, operated by previously oil-powered corporations, would provide our crisis-response energy when needed.
*What’s the basis for suggesting that extremely safe nuclear power is now possible?
Please see my other articles on this site to appreciate the nuclear safety revolution that’s just happening.