Today, the U.S. electric grid connects more than 9,000 electricity producers to millions of consumers through 6 million miles of transmission lines managed by more than 3,000 different private and public organizations. In the coming years, these numbers are set to expand, while the demand for renewable energy grows.
To meet the surge in demand projected by 2050, innovative engineers, utility operators and grid architects are planning for a future that blurs the distinctions between energy consumers and producers. Homeowners, businesses and other traditional utility customers are beginning to take on a new role as energy producers, through small-scale solar arrays, wind turbines and other new affordable technologies.
To coordinate so many different power sources and demands, the future power grid will depend on artificial intelligence, automated two-way communications and computer control systems to continuously collect and synthesize data from millions of smart sensors.
Cities have signed increasingly large power purchase agreements to buy electricity from renewable energy developers. Over the next 15 years, energy is expected to account for nearly $25 trillion in infrastructure investment, according to the World Resources Institute.
New demands, such as the growing popularity of electric cars, are already altering the national appetite for power. Moreover, sensors linked through the Internet of Things are offering unprecedented amounts of data documenting the moment-to-moment fluctuations in supply and demand.
But that's just the beginning. Here, The Wall Street Journal looks at the elements that will go into the energy grid of the future, based on research by scientists at federal and university laboratories, utility planners and energy analysts. Some technologies, such as wind and solar power, are already on the market but are set to expand vastly in scale in the decades ahead. Others, such as generating power from the movement of ocean tides, are pilot projects. A few possibilities, such as microbe-powered energy cells and orbital solar power, are still experimental.
As electricity needs fluctuate across the globe, utility engineers will have to make the grid smarter, more interactive, resilient and resistant to the threat of cyberattacks.
Beaming Solar Power
Scientists and engineers are working on spacecraft to capture sunlight and transform it into electricity that is wirelessly beamed to Earth. A prototype from the California Institute of Technology transmits power in a steerable beam. Japan's space agency JAXA demonstrated a unit that converted 1.8 kilowatts of electricity into microwaves and then beamed it about 100 yards. China is planning an orbital solar power station.
Living Solar Cells
Researchers are exploring how to exploit the ability of many microorganisms to generate electric current through photosynthesis. Solar cells using microbes would be cleaner and cheaper than those based on conventional semiconductors. So far, the current is only about enough to drive a small fan. By using two kinds of microbes instead of one, scientists in China recently found a way to boost the electrical energy.
The Power of Brine
Scientists in Norway, the Netherlands, Japan and the U.S. are generating electricity by harnessing the difference in salt concentration between seawater and freshwater. In one experiment, a semipermeable membrane allows seawater ions to pass into the fresh water. The movement of the ions generates an electric current.
Harvesting Wind
As wind turbines become bigger, more powerful and cheaper, they're being grouped into ever larger installations, with over 200 new large wind power projects underway in the U.S. All told, about 57,700 wind turbines installed across 41 states generate a total of more than 100 gigawatts, enough to power 32 million American homes. That number will likely grow.
Catching Some Rays
Today's solar power cells can power 13.5 million American homes. The capacity is set to more than double over the next five years.
Stacking Power Bricks
To provide uninterrupted power, grid operators must store extra energy generated when the sun is shining or the wind is blowing, so that power can be distributed when demand is higher or there's no sun or wind. One design uses 35-ton blocks to create a dynamic energy storage system. They are lifted up and down a 400-foot-tall tower, depending on supply and demand.
Home Is Where the Smart Is
At the heart of the future energy grid is the home, where power will be both produced and consumed. To match supply and demand, energy efficient kitchen appliances, water heaters, washer/dryers and other devices will be linked through a household microgrid to share data with new algorithms. Household systems could include basement storage batteries, rooftop solar panels, a backyard wind turbine and a subterranean geothermal heating and cooling system. The ultimate goal is a home that produces as much or more energy as it consumes, feeding any surplus to the local grid.
Burning Biomass
A biomass power plant burns wood, municipal waste and other organic materials in boilers to produce steam. That is fed into a turbine under pressure to generate electricity. Energy researchers say the U.S. could harvest 1 billion tons of biomass a year by 2040--enough to power 7 million households.
Next-Gen Fusion
Fusion, the nuclear reaction that powers the sun and stars, could become a source of safe, virtually limitless energy, though the technology has eluded researchers for decades. Advances in computing, machinery and materials have spawned a new generation of experiments. Read more: Fusion Startups Step in to Realize Clean Power Dream.
Tapping Hot Spots
Geothermal energy, derived from the heat of the earth, can heat and cool homes, as well as generate electricity. The U.S. leads the world for installed geothermal capacity, with more than 3.7 gigawatts. Researchers predict that as technology improves, geothermal could meet more than 10% of U.S. electricity demand.
Go With the Flow
Turbines can be placed on the ocean floor or anchored as buoys to generate power from wave action or tidal flow. One version of a power buoy converts wave energy into electricity through a direct drive generator that continuously charges an onboard battery. More powerful wave generators are in the works. The U.S. Navy is testing a 826-ton turbine buoy that can generate 500 kilowatts in the open ocean. Canada, France, China, Russia and South Korea have pilot tidal projects.
Catch the Currents
A demonstration project on New York's East River converts the kinetic energy of river currents into electricity. Installed underwater, the system operates silently and is invisible from the shore.
Smart Power Substation
Substations are the switching systems of the grid. Electricity from a power plant gets boosted to a high voltage at a substation to travel through transmission lines, then stepped down to a lower voltage for distribution to homes and businesses. The next generation of grid computers, sensors and machine-learning algorithms will allow operators to assess grid stability and recover from faults in the substation automatically by rerouting power around outages. These systems can measure the amplitude and phase of current and voltage up to 50 times a second, generating huge volumes of data daily.