PG&E’s (PCG) CEO Tony Earley said that the company had already reached a milestone earlier this year of getting 30% of its electricity from clean energy sources. Building on that landmark, PG&E already has clean energy projects lined up that will help it deliver half of its electricity from clean energy, like solar and wind, within less than 15 years, said Earley.

“We can get there,” he confidently predicted.

Earley noted that California’s definition of clean energy is particularly narrow. While some broader definitions of clean energy include big sources of carbon emissions-free power like nuclear power, hydroelectric, rooftop solar energy, and energy efficiency technology, California’s definition of clean energy only includes utility-scale solar and wind energy.

Because that definition is so narrow, by the time PG&E meets that rigid goal the utility will likely “actually hit closer to 70% with non-green house gases,” said Earley. California has many natural clean energy resources—like ample sun and wind—that enables it to meet these targets, Earley explained.

Reaching even 70% clean energy in California could actually be relatively easy, but the challenge will be managing those various new clean energy sources with new technology, noted Danny Kennedy, managing director of the investment group, California Clean Energy Fund. Because solar and wind generate large bursts of power at certain times of day, and can quickly drop off at night (or under a large passing cloud), utilities need to manage large sources of clean energy in new ways.

One of those new ways will be to add more energy storage to California’s power grid, to store solar energy at night or wind power on days when there’s no breeze. California must invest in technology like energy storage to help manage a changing power grid that has so much new renewable energy added to it, explained Kennedy.

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California also needs better ways of helping customers use energy more intelligently, said Alex Laskey, co-founder of energy software provider Opower (OPWR), which was recently bought by Oracle (ORCL). Opower sells software and data analytics to utilities to help utility customers use energy more efficiently.

“We all know nights and weekends [plans] from cell phones,” said Laskey. “We need to make energy efficiency and power grid plans simple enough for consumers to understand them.”