Reports on rolling blackouts in California are fueling a debate on the reliability of renewables. The state has been a frontrunner in shifting to renewable electricity, with a 60% target by 2030. But as the lights went out, critics have been quick in framing this as evidence that the state has shuttered fossil fuel and nuclear plants too quickly. According to REN21 experts Duncan Gibb and Mauricio Latapí renewables are not the problem, but the solution: “Decentralisation is the best shot we have at grid stabilization.”
Is variable renewable electricity such as solar and wind only useful to a point?
Duncan: “High shares of renewables do not necessarily increase the risk of blackouts. The potential problem for the electric grid is a shortfall, especially during periods of increased load, if there is not sufficient storage or generation to pick up the load.
Renewable electricity production does not usually just stop at such a scale to cause blackouts. We all know that the sun sets in the evening, so it is something grid operators can forecast and plan for. It also seems that before parts of California plunged into darkness that Friday in August, a gas-fired plant tripped and there wasn’t enough reserve capacity.”
Mauricio: “The events coming together in California were quite extreme, kind of a perfect storm for the system to cope with. The scorching heatwave and soaring consumption for air-conditioning is just one factor. Another factor is the dependency on supplies from neighboring states such as Nevada and limited interconnections. California is by far the biggest electricity importer among the US states.”
Aren’t larger gas-fired and nuclear power plants ultimately more reliable?
Duncan: “Large central power plants are even more vulnerable to extreme weather or other events than renewable electricity plants. Let me give you some examples: In 2018, there was a big summer heatwave in Germany, several nuclear power plants had to reduce their output and a coal-fired plant shut down. Simply, because otherwise, the water temperature in the rivers in which they reject their cooling water would have risen beyond environmentally acceptable limits. At the same time, due to low water levels in the rivers, ships transporting coal to power plants could not be fully loaded. France, disposing of more than 55 reactors, regularly has to decrease its nuclear output during summer. Spain’s nuclear reactor in Santa Maria da Gerona also had to reduce production a number of times for the same reason. Meanwhile, this reactor is not in operation anymore.
Besides, no one is arguing for a system based solely on solar and wind. These should be complemented with other sources, hydropower for example, and flexibility mechanisms. In a transition, it’s important to phase-in sufficient new renewable capacity, create storage possibilities, and make sure there is redundancy in the system.”
Mauricio: “I think the blackouts are a call for California to move even faster to renewables. Let’s assume the share of renewables would be 60%, that almost every house in California had solar panels and an electric car. Then, when the demand for electricity is too high, you could actually draw on electricity stored in your car battery.”
What kind of “flexibility mechanisms” should regulators use?
Duncan: “It’s not only about production technologies, the whole energy system needs to evolve. First, we need to manage demand better. We must improve energy efficiency, whether it is appliances or for example in buildings. If you improve the thermal performance of a building, you don’t have to use much energy to keep it cool. Second, we need market mechanisms to reward demand response. Many industrial, commercial and even residential customers are ready to shed load if there are the right price signals.”
Mauricio: “The United States is among the places with the highest electricity use per capita in the world, because it’s such an electrified society. You have air conditioners in most houses, lots of large electric appliances. So, when the Californian system operator asked the population to lower demand, that was also a good signal to citizens: We are consuming too much electricity, we should turn it down a notch.”
Duncan: “Another way of creating more flexibility is to overbuild renewables. As costs drop, it will just become easier to massively expand solar and wind capacities and to store the surplus. One way to store electricity is batteries, another is to produce renewable hydrogen. More storage means whenever there is a peak in demand, there is enough already in the system.”
Will we see more blackouts in the future?
Duncan: “With climate change, we must expect more extreme and even more unpredictable weather patterns. Grid operators need to adjust their planning and reconsider what kind of redundancy they need in the system.
Luckily, the more decentralized systems become, the more they will become resilient. In Canada too, we have storms and the power lines get knocked out. Sometimes, one power line from a central power plant connects to thousands of people. In a renewable, more decentralized system, such events actually have less impact.”
Mauricio: “A popular proverb says: Never put all your eggs in one basket. If you only depend on three or four companies and a few centralized plants delivering electricity, you have limited possibilities. If an incident forces a single nuclear power plant to shut down, you lose a lot of production. With decentralized renewables and prosumers, you have much more possibilities. You can call upon so many more actors to help stabilize the grid.
Duncan: “Finally, let’s not forget that there are also market risks and manipulations which can threaten the security of supply. With citizens becoming prosumers, electricity becomes less of a centralized commodity, which reduces this risk.”
More on California’s energy mix