Increased attention to geothermal energy’s significant value to California’s clean energy future

Aerial view, Los Angeles, California (source: flickr/ ikewinski, creative commons)
Alexander Richter 2 Feb 2020

With increasing look at complete value of renewables in the future clean energy mix for California, geothermal energy receives increased attention. Providing higher capacity factors, dispatchability it turns out to be a cheaper, more flexible and overall better option as part of California's energy mix.

An interesting article published last week in Utility Dive, describes how cheap renewables could end up keeping (U.S.) states to miss achieving climate goals. Planners – so the article – must think beyond the levelized cost for renewables to the value that each resource brings to the grid.

Describing the realisation that there are tensions between cost and value of renewable energy technologies that provide a cheap source of clean energy to grids across the U.S.

We reported on the awakening of California’s geothermal sector referencing an article in the LA Times last week, see article here.

“We overbuilt natural gas and then we built so much solar that we have solar over-generation, so we have fallen in love with batteries,” Center for Energy Efficiency and Renewable Technologies (CEERT) Executive Director V. John White told Utility Dive. “Batteries are great, but planning is too driven by costs, and not enough by the value in meeting grid needs, and not having a balanced resource portfolio could be the Achilles heel of our climate effort.”

There is an ongoing debate between the system operator and the public utilities commission in California. Here, the focus is on recognising “general values” of renewable energy technologies, such as the ability to meet the needs of the transmission grids. Geothermal there seems to receive new attention.

Elements like dispatch-ability in efforts to balance the energy portfolio in California is being looked in while planning models for the future. The high capacity factors are an important selling point in reconsidering the value put on geothermal in that context.

Of course, the notion of available metals in geothermal brine, such as Lithium in the context of battery production and electric cars, is another element widely discussed.

This analysis shared in the CEER report from 2016 (linked below) compares two renewable energy portfolios.

“The “base portfolio” represents how California might achieve a 50% RPS by continuation of current policies that emphasise development of solar with some out of state wind.

The “geothermal portfolio” replaces 3,800 MW of solar generation with 1,250 MW of new geothermal generation from the Salton Sea.

Total renewable energy production under the two scenarios does not change, despite differences in generation capacity, because geothermal plants have a capacity factor three times that of solar photovoltaic plants.

Relative to the base portfolio, the geothermal portfolio reduces CO2 emissions both in California and the rest of the West, and saves California $662 million per year in energy and ancillary service costs, $44 million per year in system resource adequacy costs, and $29 million per year in flexible resource adequacy costs, reducing overall utility revenue requirements by nearly 2%.

Each megawatt hour (MWh) of additional geothermal production lowers California energy costs by $75 compared to the base portfolio under current operating and procurement practices.

This value difference between geothermal and solar decreases as other measures are taken to increase the flexibility of the grid. However, even after implementing all other potential mitigation measures including investing $4.5 billion in new bulk storage, at the margin, geothermal energy is still over $20/MWhH more valuable than solar energy.”

The study can be found here: “The Value of Salton Sea Geothermal Development in California’s Carbon Constrained Future” (Renewable Energy Transmission Initiative 2.0) comments (2016)

Source: Utility Dive