The Promise of a Revolutionary Power Source You Never Heard Of
Not since the War of the Currents during the late 1800s, when Thomas Edison’s electricity faced competition from George Westinghouse has there been a resurgence of major interest in DC energy. Back then, Edison’s low-voltage direct current, or DC current devices, which were able to be powered by batteries and generators, were the status quo. But Westinghouse developed a competing technology, high-voltage alternating (AC) current invented by Nikola Tesla. The high voltage AC current could be generated at centralized power stations, then sent out to customers over long distances through power lines. The AC voltage had to be reduced for customer use in lighting and appliances. As we all know AC eventually won out and it’s still is our main power grid energy source.
Of course once NASA started putting people on the International Space Station for extended periods of time they needed a renewable way to have plenty of energy to run the thing, including experiments with fail-safe reliability and resilience. They designed a DC microgrid with the solar panels to run a 160 volt system, with DC battery backup power during eclipse situations out of sunlight. They have successfully refined the system for all of their power needs and it is complicated. They need to find ways to cool the spacecraft, ground the electricity so it doesn’t arc from a solar panel to the spacecraft or an astronaut. After 20 years NASA engineers have worked out a lot of bugs.
Here on “Spaceship Earth” DC power is making a comeback in the market and it will have several exciting consequences. In fact, some energy leaders believe DC-powered microgrids can have an impact on climate change adaptation and mitigation.
Why would this be a good idea? For several reasons. DC power is produced by solar panels, wind and water turbines and this renewable energy has become cheaper than fossil fuels. And even climate skeptics with go along with decarbonizing the atmosphere if it is for economic reasons.
Second is the fact that many newer electronics, including smartphones, computers, and TV’s, for example, run on DC power. In order to run off our AC power system, each device or applance needs a converter box, called an inverter, to change the incoming AC into DC power. Converting AC to DC results in a five to fifteen percent energy loss in the conversion. Not to mention the expense of installing inverters in all of our devices and appliances that run on DC power.
A third reason DC power is a good idea is that it can easily be decentralized. In other words, it can be produced near the customer so it doesn’t need to be pushed long distances as AC energy does. This saves energy since energy is lost on the way to its destination through wires. And decentralized energy is more resilient and secure. It would be easier for our enemies to knock out or take down a few large power installations than it would with many DC microgrids. This could cripple our infrastructure regionally or nationwide. If we had thousands of microgrids working independently our energy would be more secure and reliable. DC power projects are puttering along in the U.S. and elsewhere.
For example, In Vermont, a small company called Dynapower has been producing DC systems with solar, wind and battery banks for residential and commercial customers for years. There are a few DC microgrid projects in California as well as in Japan.
Elsewhere, back in 2012, Xiamen University in China piloted a renewable energy DC microgrid in a couple of buildings that use 150 Kilowatts of solar power from the roof to power LED lights and electronics. The system is controlled using a handheld device and was a model for commercial buildings running on DC power. China is farther ahead in DC development than we are. Unfortunately the rate of development in the U.S. may not be happening quickly enough to save us from a tipping point scenarios described in the 2018 National Climate Assessment.
In the meantime, massive subsidies still go to fossil fuel companies and very few federal dollars, by comparison, go to renewable energy and microgrid projects. Many funded projects in the past have led to great leaps in innovations and improvements. Large-scale DC microgrids could be a powerful revolution that could help mitigate climate change and ensure American dominance in the energy of the future. Larger-scale DC power grids that will make a difference in our carbon footprint and new energy leadership will depend on incentives and support from the feds. But so far the U.S. Congress has not been eager to do this.
Kerry Emanuel, a conservative and MIT climatologist says there is an energy revolution upon us due to economics and the finite supply of fossil fuels. His question is, “Are we going to be able to lead the world in this new economy?” The more ominous question, Emanuel told me, is this: “In thirty years are we going to be buying clean energy from China and India or selling it to them? That’s our choice now.” Senate Republicans, are you listening?
