How will California go Carbon Free by 2045?

In September 2018, Governor Jerry Brown made history by signing the revolutionary Senate Bill 100 (SB 100). The bill creates two major amendments to previous legislature; the first raises California’s renewable energy requirement to 60 per cent by 2030. The truly ground-breaking requirement, however, is the stipulation for California to be 100 per cent carbon free by 2045.

This target specifies that all electricity consumed within California is to be procured from carbon-free sources. Note that this says ‘carbon free’ rather than ‘renewable.’ Earlier iterations of this bill specifically required that the electricity was to be sourced from renewables, however, the last-minute amendment to ‘carbon-free’ allows large hydro,nuclear or even carbon-captured gas to play a part in meeting these goals. This adjustment places less limitations on research and development, thus allowing California’s future electricity sources to remain open to a wider array of future technologies.

SB 100 originates from targets set in 2002 aimed at sourcing 20 per cent of electricity sales from renewables by 2017. This latest amendment, however, might be California’s most demanding ask of its state and, ultimately, its utilities. Nearly a third of California’s current electricity consumption comes from renewable sources (California Energy Commission), with targets of 50 per cent renewables being expected to be achieved by 2020 (Tarantola, 2017). Beyond that, the road becomes less clear as California sails into less charted territory.

California is not the first state to make a push for 100 per cent clean electricity, in 2017 Hawaii mandated the procurement of 100% renewable energy by 2045. Furthermore, Iceland have long since managed its energy demands entirely on a mixture of geothermal and large hydro. California, however, have a population more than 25 times that of Hawaii and is not surrounded by abundant amounts of volcanic rock as Iceland is.

In 2017, a third of California’s electricity came from gas. Although this may become a carbon free source in the future when carbon capture becomes economically viable, the plan is currently to ween off the use of gas as a base load provider and utilise gas primarily to balance the variable generation of solar and wind. Despite the SB 100 allowing nuclear to contribute towards the 2045 goal, California is set on decommissioning the 9 per cent that is today supplied by nuclear power, a major provider of stability for the current electricity grid.

This begs the question of; what will ensure the balance of supply and demand when the major baseload provider – wind and solar –is reliant on weather patterns? For example, solar production peaks at midday when demand is at its lowest and falls drastically with sunset when demand is at its peak. This discrepancy between time of use and peak generation has come to be known as the ‘duck curve.’ The figure below illustrates the most extreme case of spring when temperatures are mild but the sun shines brightly. This two-way effect creates this midday dip seen in the figure, which reverses in the evening as people return home from work as the sun sets.

Source: California ISO, Duck Curve, 2017.

Source: California ISO, Duck Curve, 2017.

A rough forecast using 100 per cent renewables by Wade Schauer, director of Americas research at Wood Mackenzie Power and Renewables estimated that during October through to December there would be 1,439 hours where generation would not meet demand and 745 hours where generation would exceed demand (Spector, 2018c).

Source: Spector, 2018c.

Source: Spector, 2018c.

There have been numerous suggestions on how such a problem could be overcome, the most common answer points to storage – particularly batteries –as playing a major role. Battery technology, however, is currently unable to meet the longer storage durations that the grid requires. The figure above highlights this fact by including hydro-pump storage which although limited by geographic factors, can meet this longer-term demand.

Additionally, the time of use issue is only one of the issues the grid currently faces in the wake of the growth in renewables. Wind and solar by nature are asynchronous and provide no natural inertia for the system’s stability. With traditional generating facilities – that provide spinning reserves, reactive power and voltage control – such as coal or nuclear power plants disappearing, this issue is only becoming more pressing.

One proposed solution is to further integrate the western power market. Currently California imports 29 per cent of its power from neighbouring regions (California Energy Commission). SB 100 legislates that California cannot simply outsource their fossil fuel combustion beyond state borders, however, as other states move towards greater renewables this volatility that arises from variable weather patterns may be reduced with greater dispersion in the locations of generating assets, as the wind is always blowing somewhere. However, not all believe that the integrated market will serve California’s best interests. Moving towards a larger market may mean a more active federal oversight and with a coal and oil enthusiastic Trump policy in place may not be want California wants right now.

A solution which does not hinge on the inter-politics of the state is the innovative new technology developed by Faraday Grid, which offers a viable – technically and economically feasible – way to integrate high proportions of variable renewables safely in the grid. The patented technology known as the Faraday Grid is a fundamental redesign of the historically rigid electricity grid into a resilient distribution platform.

Existing assets can be gradually upgraded into a Faraday Grid by replacing power-flow devices with a new category of device, called Faraday Exchangers. Similarly to the way internet routers enabled entirely new functionalities by integrating into the telecom infrastructure, a network of Exchangers unlocks characteristics that enable unprecedented efficiency in the electricity system. 

Simulations show that Exchangers replacing transformers in an existing grid architecture reduces reactive power injections needed to respond to contingencies by 34%, reduces losses on the network by around 7%, while almost doubles variable renewable hosting capacity. This is in addition to improving the security of the system and significantly increasing the carrying capacity of the grid (Gunda, 2018).

With utilities rapidly approaching the 50 per cent renewables mark – with PG&E at 32.9 per cent, SoCal Edison at 28.2 per cent and San Diego Gas at 43.2 per cent (Tarantola, 2017) – these are no longer issues for a hypothetical future but issues of the present. California the 5th largest economy on the planet and therefore will not be able to brush off these concerns. The rest of the world will be watching, and how California approaches this monumental task may shape how the rest of the world will follow.    



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