What Is Considered Renewable Energy In California?

Renewable energy refers to energy that comes from natural sources or processes that are constantly replenished. Some examples of renewable energy sources include solar, wind, geothermal, hydropower, and biomass. California has been a leader in developing renewable energy sources and promoting their use.

According to the California Energy Commission, more than 30% of California’s retail electricity sales come from renewable sources, not including behind-the-meter solar generation. The state is aiming to have 60% renewable energy by 2030 and 100% by 2045 under Senate Bill 100.

Expanding renewable energy is important for California to meet its ambitious climate change goals and reduce greenhouse gas emissions. Developing renewable resources can also lead to local economic growth and jobs in the clean energy sector. Overall, transitioning to renewable energy serves environmental, economic and public health objectives in the state.

Table of Contents

Solar Power

Solar power is an important renewable energy source in California. The state has abundant solar resources and leads the nation in installed solar capacity. According to the California Energy Commission, California has over 30 gigawatts (GW) of installed solar photovoltaic (PV) capacity, which can generate over 80,000 gigawatt hours (GWh) per year (California Energy Commission). That’s over 30% of the nation’s installed solar capacity (Wikipedia).

California’s temperate climate, large population centers, and policies supporting renewable energy have made it a leader in solar power adoption. Major utility-scale solar projects like the 550 megawatt (MW) Desert Sunlight plant have come online in recent years. Rooftop solar installations have also expanded rapidly, with over 1 million solar PV systems installed on homes and businesses as of 2021 (Wikipedia).

The state has implemented policies like the California Solar Initiative and Net Energy Metering to incentivize rooftop solar adoption. These programs allow homeowners and businesses to receive credits on their utility bills for excess solar energy exported to the grid. California has also mandated solar installations on new homes through its building energy efficiency standards (California Energy Commission).

Wind Power

California has vast wind energy resources and is a leader in wind power generation in the United States. As of 2019, California had 5,973 megawatts (MW) of wind power capacity installed, the second highest of any state after Texas (Wikipedia). Major wind farms are concentrated in three regions – Tehachapi Pass, San Gorgonio Pass, and the Altamont Pass. Some of the largest wind farms include the Alta Wind Energy Center (1,550 MW), the San Gorgonio Pass wind farm (678 MW), and the Altamont Pass wind farm (580 MW).

Wind power accounted for about 10% of in-state electricity generation in 2019. California has set ambitious goals to further increase renewable energy, targeting 60% renewable electricity by 2030 and 100% zero-carbon energy by 2045. To help meet these targets, experts estimate offshore wind power along the California coast could provide over 100,000 MW of clean electricity. Recently approved federal leasing areas for offshore wind are poised to unlock this massive potential and usher in a new era for wind energy in California (CalMatters).

Geothermal Energy

Geothermal energy comes from harnessing the heat below the earth’s surface. California is the largest producer of geothermal electricity in the United States, with an installed capacity of nearly 3,000 megawatts across 46 geothermal power plants, according to the California Energy Commission (1). The majority of California’s geothermal power plants are located in the Imperial Valley and The Geysers Geothermal Complex in northern California.

Geothermal energy is considered renewable because steam and hot water are continuously produced inside the earth. Key geothermal resources in California include:

The Geysers complex, which spans 45 square miles in Sonoma and Lake Counties. This is the largest complex of geothermal power plants in the world, with 15 power plants generating over 600 megawatts of electricity.

The Salton Sea Geothermal Field in Imperial County, which has 11 power plants generating over 400 megawatts.
Other smaller fields like Coso in Inyo County, Heber in Imperial County, and numerous locations along the Sierra Nevada mountains.

The U.S. Bureau of Land Management estimates the electrical capacity of undiscovered geothermal resources on public lands in California at 3,000 to 4,700 megawatts (2). Expanding geothermal energy production could help California meet its renewable energy goals.

Hydroelectric Power

Hydroelectric power is a major renewable energy source in California, accounting for approximately 14% of in-state generation in 2020 (https://www.energy.ca.gov/data-reports/california-power-generation-and-power-sources/hydroelectric-power). California has one of the largest concentrations of hydroelectric power plants in the United States, with over 200 plants across the state supplying over 14,000 megawatts of capacity (https://californialocal.com/localnews/statewide/ca/article/show/9468-hydroelectric-power-energy-california-climate-change/).

Most of California’s large-scale hydroelectric plants were constructed between 1900 and the 1960s, utilizing dams and reservoirs to store water that is released to turn turbines and generate electricity. While hydro power is clean and renewable, these dams have signifcant environmental impacts, including effects on wildlife habitats and fish migration patterns. In recent decades, smaller run-of-river hydro plants have been constructed that divert a portion of a river’s flow without the need for large dams.

Currently hydroelectric generation is declining in California, as reservoirs shrink due to drought and climate change. Going forward, balancing hydropower, environmental needs and water storage will be an increasing challenge.

Bioenergy

Bioenergy refers to renewable energy derived from organic matter, known as biomass. This includes agricultural residues, forest waste, urban waste streams, and energy crops. Bioenergy can be used to generate electricity, transportation fuels like ethanol and biodiesel, and heat for industrial processes and buildings (Bioenergy Development in California, 2023).

California has significant bioenergy potential thanks to its large agricultural industry and abundant biomass resources. As of 2021, there were 278 bioenergy facilities in California, capable of generating 866 MW of renewable electricity. Over 50% of these facilities use dairy manure as feedstock. California also had 10 commercial-scale biodiesel plants and 4 ethanol plants capable of producing over 200 million gallons per year (CalEPA, 2023).

Biogas production from organic waste like manure, wastewater, landfills, and food waste is a major focus in California. Capturing biogas reduces methane emissions and provides renewable fuel. As of 2022, there were over 140 anaerobic digester projects in California producing biogas. Most digesters are located at wastewater treatment plants, dairies, and landfills (Bioenergy Development in California, 2023).

The state provides funding programs like the California Energy Commission’s Food Production Investment Program to support new bioenergy projects. Key challenges for the bioenergy industry include high project development costs and maintaining reliable feedstock supplies (CalEPA, 2023). Overall, bioenergy is expected to continue playing an important role in California’s renewable energy mix.

Ocean Energy

California has significant potential for generating electricity from ocean waves and tides off its coast. The state has been exploring harnessing wave energy through pilot projects and research initiatives led by the California Energy Commission (https://www.energy.ca.gov/programs-and-topics/topics/renewable-energy/offshore-renewable-energy). There are ideal locations for wave energy converters off the coasts of Humboldt, Mendocino, and San Luis Obispo counties where waves can produce up to 60 kilowatts per meter of coastline.

However, tidal energy is not likely to be a major source of renewable electricity for California. As Jason Busch, executive director of the Pacific Ocean Energy Trust explained, “California does not have high velocities or flow that other parts of the world have” (https://calmatters.org/environment/2023/11/ocean-energy-waves-california/). Still, pilot projects by companies like CalWave Power Technologies are testing new technologies to harness tidal energy.

The potential scale of wave energy off California’s coast remains uncertain. But the Bureau of Ocean Energy Management has leased areas off Humboldt County, and near Morro Bay in Central California, to companies for developing and testing wave energy projects (https://www.boem.gov/renewable-energy/state-activities/california).

Energy Storage

Energy storage plays a critical role in California’s transition to clean energy. With high levels of solar and wind power coming online, energy storage helps manage the variability and intermittency of renewable energy generation. By storing excess renewable energy when supply exceeds demand and discharging it when needed, energy storage facilitates the integration of renewables into the grid.

California has seen massive growth in energy storage deployment over the past few years. According to the California Energy Commission, the state had over 6,600 megawatts of energy storage capacity as of October 2022. This is a thirteen-fold increase from 2020. The growth has been driven by supportive state policies like the energy storage target of 1,000 MW by 2020 under AB 2514 as well as federal investment tax credits.

Most of California’s energy storage capacity comes from lithium-ion batteries. However, the state is also expanding deployment of long-duration storage technologies that can discharge electricity for 10 hours or longer. The California Energy Storage Alliance projects the state will need at least 50,000 MW of storage capacity to achieve 100% clean electricity by 2045.

Challenges

California has set ambitious renewable energy goals, with a target of 60% renewable energy by 2030 and 100% carbon-free electricity by 2045. However, the state faces significant barriers in scaling up renewable energy sources like wind and solar power.

One major challenge is transmission and grid integration. Much of California’s best solar and wind resources are located in remote areas, requiring major investments in transmission lines to deliver power to population centers. However, permitting and siting new transmission lines faces opposition from local communities and takes years to approve (Source). In addition, integrating large amounts of intermittent renewables like solar and wind presents technical challenges for grid reliability and stability.

Local opposition and permitting difficulties also hinder large-scale renewable projects, like desert solar farms. Proposed projects often face lawsuits and yearslong approval processes. Streamlining permitting while addressing local environmental concerns is an ongoing challenge.

The decline of fossil fuel plants combined with the variability of solar and wind generation has made balancing electricity supply and demand more complex. Developing affordable grid-scale energy storage, updating market rules, and leveraging regional partnerships are potential solutions being explored (Source).

Finally, while solar and wind costs have fallen dramatically, they still require subsidies and incentives in California’s energy market. Phasing out natural gas power will likely require new policies and regulations to further encourage renewable adoption.

Future Outlook

California has set some of the most ambitious renewable energy goals in the United States. The state is aiming to generate 100% of its electricity from renewable and zero-carbon energy sources by 2045, as mandated by Senate Bill 100 which passed in 2018. To reach this goal, California will need to rapidly expand its renewable energy capacity, transmission infrastructure, and energy storage capabilities.

According to the California Energy Commission, the state will need to quadruple its current renewable generation capacity and double its energy storage capacity by 2045. Major growth is expected in solar, wind and geothermal energy to replace fossil fuel power plants. The California Independent System Operator estimates that at least 1,600 gigawatts of new renewable capacity along with 15 gigawatts of new battery storage will be required. Transmission lines spanning well over 1,000 miles may also be needed to connect new renewable energy facilities across the state.

Reaching 100% clean electricity will involve overcoming challenges related to reliability, grid integration and cost. However, California has demonstrated strong commitment through legislation, regulatory policy and incentives to continue advancing its renewable energy future.