California will soon be coal-free and its last nuclear plant will be replaced with renewables. It is true that grid imported coal and nuclear power make up a small and declining part of total system power, but the percentage keeps falling with improved demand response, efficiency, and more renewables. Today, the state’s electricity generation capacity is 30 percent renewables and 57 percent natural gas. Solar and wind are California’s largest sources of renewable energy, both growing as hydropower declines.

California law SB 350 will increase building energy efficiency in the state to 50 percent by 2030 and increase the renewable energy utilities use to 50 percent by 2030.

Compared to nations, California is the world’s eighth largest economy, larger than the entire economy of Brazil, Italy, or Russia. Every time California increases renewable goals or taxes carbon, there are dire warnings of economic collapse. Every time the warnings have been wrong including the phase out of coal, requirements for fuel efficient cars, and now requirements for new homes to be zero-net energy starting in 2020.

Wind

Wind is a better match for the peak evening hours of energy demand in California, when people return from work, turn on air conditioning, and charge their electric cars. Wind power provided 24,000 GWh in 2015. At less than 3 cents/kWh, wind is less expensive than other forms of power generation. Massive arrays of wind turbines can be seen in Altamont Pass, Tehachapi and San Gorgonio.

PG&E, the utility that owns California’s last running nuclear reactors, will issue solicitations for greenhouse-free alternatives. Hundreds of bids for solar and wind power are likely. Since these Diablo Canyon nukes are located on the ocean, offshore wind power could be a winner. The Diablo site has the grid transmission infrastructure and 400 MW of pumped hydro so that wind power could be stored until the utility needs dispatchable power.

Offshore wind is popular in the UK, Germany, and Denmark. In California, it could be sited up to 30 miles out to sea, using the floating wind platforms used in the North Sea.

Solar

California’s 10 GW of installed solar is almost half of all solar power in the U.S. Another 32 GW is under development. Solar is running on over 500,000 California homes where people sell excess power to utilities during the day and buy grid electricity at night.

Commercial and industrial corporations are installing as much solar as home owners. Walmart, Walgreens, Kohl’s, Target, and Costco have covered hundreds of their roofs with solar. Technology giants such as Google, Facebook, SAP USA, Salesforce, Oracle, and Apple power data centers and headquarter campuses with renewables plus storage. These corporate leaders also contract for grid-connected solar and wind with utilities, PPA and REC providers.

Two-thirds of solar power in California is from large utility-scale projects. At less than 4 cents/kWh are massive ground-mounted solar. Some use solar arrays with one or two axes, so that the solar panels move to capture maximum sunlight.

For 377 MW, PG&E uses concentrating solar power (CSP), rather than PV, from Ivanpah, a project developed by Google and Brightsource in the California desert and managed by NRG. Future CSP plants could use molten-salt storage, so that solar generation can be delivered during peak evening hours as predictably as electricity from a large natural gas power plant.

Solar is big. For example, when I recently attended the InterSolar conference in San Francisco, over 18,000 attended from 80 countries. Over 550 companies exhibited solar panels, storage, power electronics, utility transmission and distribution technology, software, finance and services.

Zero-Net Energy

California saved $90 billion over a 40 year period with energy efficiency, eliminating the need for 30 large power plants.

California is progressing from its leadership in energy efficiency to being the global leader in zero-net energy (ZNE) homes, buildings, and campuses, over 12 months generating as much with onsite renewable electricity as is used. California building code requires new single-family homes to be ZNE by 2020, government buildings by 2025, and new commercial buildings by 2030.

Two thousand people live in the ZNE community of West Village in Davis. The project includes 662 apartments, 343 single-family homes, and 42,500 square feet of commercial space. These homes are super efficient and use solar power. Energy efficiency is achieved with tight construction, triple pane windows, great insulation, Energy Star appliances and LED lighting. These homes are designed and ventilated to stay cool in the summer and warm in the winter. Heat pump and space cooling is used instead of energy-hungry conventional HVAC.

Delta, a leader in power electronics, has a zero-net energy building in Fremont. The building has 618 kW of solar on the roof and a solar carport may be added. The building also uses a geothermal exchange system to stay cool in the summer and warm in the winter, by using water pipes 15 and 30 feet below ground, where the temperature is constantly in the fifties year round.

The University of California, Irvine, my alma mater, was ranked No. 1 in Sierra magazine’s “Cool Schools” ranking of the nation’s greenest colleges. Buildings are energy-efficient, with over 20 buildings LEED Platinum and Gold. When I visit the campus, everywhere I turn I see solar roofs and parking structures. Sister campus, U.C. San Diego, saves over $10 million annually in utility bills by generating its own electricity with solar, 30 MW of combined heat and power, and fuel cells. The campus has its own substation and microgrid and with multiple thermal and battery storage systems. By 2025, the entire ten-campus University of California system will be carbon neutral, supporting over half a million students, faculty and staff; power-hungry research labs; and hundreds of buildings.

The City of San Diego, the nation’s eighth-largest city, will be 100-percent renewably powered by 2035. That includes powering its buildings and fleet of electric vehicles.

Smart Grid and Intelligent Storage

It is a challenge to match the supply of electricity with demand. As I write this paragraph, only 23 GW of demand is expected at 4 a.m. and 36GW peak is expected at 7 p.m. At different times of the year, highs and lows vary, as can be seen with CAISO hourly demand and generation data.

Utilities need electricity generation that can be ramped up or down in minutes. Old coal and nuclear plants cannot do that. They are designed to burn fuel 24/7, whether power is needed or not. Maintenance costs soar for older plants. Edison spent almost $1 billion on repairs before shuttering the San Onofre nukes.

It is promising to replace these old plants with wind and solar, but the sun does not always shine and the wind does not always blow. The limits of wind and solar are removed when combined with smart grid, time-of-use pricing, energy management software, and storage.

Storage can shift solar’s day time generation until evening and wind’s night time generation to day. With storage and smart grid, wind and solar can be dispatched precisely when needed. GTM Research forecasts that solar-paired-storage will reach 600 MW in California by 2021. GTM Smart Solar White Paper.

Hourly time-of-use pricing is also needed so that everything from smart water heaters to electric car charging to many building operations can run automatically when electricity prices are low because solar and wind generation are high.

Storage, big data and software are taking energy to the next level. Software can manage hundreds of wind and solar farms, making them as manageable as 24/7 power plants. Southern California Edison, the utility that serves 14 million, will use advanced software that makes distributed solar power managed as a virtual power plant and use solar plus storage to replace two shut-down nuclear plants and dozens of methane peaker plants.

The world’s eighth largest economy will be 50 percent powered by renewables in ten to twelve years, ahead of its 2030 goals. There is already enough solar power in development to make California solar 400 percent of today’s capacity. As the lowest-cost fuel, wind power will grow and expand offshore with innovative technology. Energy supply and demand will be smoothly matched using storage, smart grid, software, and demand management that responds to price signals.

In ten to twelve years, several hundred thousand Californians will have permanent jobs in energy efficiency and renewables. Less precious water will be used in fracking, refining, and power plants. Over 40 million people will be energy secure. Peaker methane plants will be replaced with storage. California will be coal and nuclear free, primarily powered with solar and wind.

The story is bigger than 50 percent renewables by 2030. California is accomplishing this as it electrifies cars, buses, and rail. By 2030, many campuses, communities, and cities will be zero-net energy, meeting all of their needs with renewable electricity.