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I wrote earlier that existing technologies aren’t that far from allowing us to produce sustainable energy for as little as a tenth of the cost of conventional electric generation. Solar photovoltaic costs, in particular, are still falling fast.

Solar resources cannot produce energy at their lowest possible cost everywhere, but there are other low-cost renewable energy sources. Wind, hydroelectric power, advanced waste-to-energy technologies and several devices that can convert energy into useful forms from the heat of the ground or water are also advancing. Some of these are commercially available and cost competitive. In most cases, their costs are declining.

Pumped hydroelectric storage systems pump water to a high elevation using energy available when the price is low, for use in producing electricity during times of higher prices. Pumped hydro systems can cost around a third-of-a-cent per kilowatt-hour to operate. They’ve been a well-established, reliable, inexpensive technology for decades.

Other storage technologies are starting to catch up. Lithium-based batteries are the most advanced and lithium batteries for stationary energy storage don’t have to be as lightweight as batteries for cars, so they don’t need materials that might be in short supply. Innovative concepts, including heat storage in water, bricks or molten salt; electrolysis of water to produce hydrogen; and flow batteries are advancing.

The computer controls and weather prediction systems needed to incorporate fast-changing renewable resources and the legislation and utility management systems required to incorporate energy from tens of thousands of small sources, instead of hundreds of big sources, are also improving.

This means that inexpensive renewable energy – say, solar energy on a sunny but cool spring day in southern California – doesn’t have to be curtailed when too much is being produced to be used locally. It can be delivered to other markets, or stored for later use. The long-obvious criticism of renewable energy (that it can’t provide a reliable grid because the sun isn’t always up and the wind isn’t always blowing), becomes less and less true as renewable energy, storage and control capabilities and costs fall.

In La Conner, we might soon find that it isn’t necessary to use fueled electric generation at all.

Suppose, for instance, that we had a water-source heat pump that would move heat into and out of Puget Sound, combined with pipes that would deliver hot or cold water to home radiators. This could conceivably eliminate about half of the fueled or electric energy needed for homes, without changing water temperatures enough to affect wildlife.

Or, suppose we installed small radiators made with well-insulated bricks, to store electricity in the form of heat. We could buy renewable electricity when it’s available at very low costs (e.g., when California solar or eastern Washington wind are overproducing relative to immediate needs) and then release the stored heat into the room where it’s needed the most (e.g., a bedroom overnight, or a living room in the earlier evening). This system isn’t an engineering dream. It’s already in use, in Scotland, to store excess wind power and reduce fueled heating requirements.

Inexpensive batteries, or even batteries in parked electric cars, could similarly store off-peak renewable generation for home electric loads.