Optimal proportion of renewable energy in energy mix for maximising energy resilience and reducing carbon emissions

Increasing use of renewable energy such as solar and wind power could help reduce carbon emissions and is an approach for helping cities, states and countries to decarbonise their economies. However, renewable energy’s intermittency such as those associated with solar and wind energy meant that its increasing use carries significant risks for energy resilience for cities, states and countries. Specifically, while excess production of wind and solar energy could be stored in large grid level batteries storage facilities, extended periods of extreme weather events such as those associated with rainy weather and wind drought meant that grid level storage of energy might not offer sufficient buffer for coping with the energy needs of cities. In this case, fossil fuel fired power stations would need to ramp up production to help cover the deficit in energy production from renewable sources. Thus, even as we move towards a future where there is an increasing proportion of renewable energy supply in the energy mix of cities and countries, there remains a need to retain fossil fuel fired power stations generating capacity to help cope with low probability but high impact events such as extended periods of extreme weather where renewable energy such as wind and solar power could not be effectively produced. The question that society needs to answer is the level of risk or threshold that they could tolerate in facing the threat of blackouts where insufficient generation capacity from fossil fuel fired power stations meant that deficit from a shortfall in energy generation from renewable sources could not be covered. While grid level batteries storage could help cover some of the shortfall in renewable energy generation, the period in which this could continue remain short and the solution is not applicable in cases where there is prolonged deficit in energy generation from renewables. Hence, there is a need for factoring in fossil fuel fired power generation into the energy mix of cities and countries even as the proportion of renewable energy production is increasing. What is the optimal ratio of renewable energy in the energy mix for maximising energy resilience and reducing carbon emissions lies in society’s acceptance of the risks of blackouts from an energy mix heavily reliant on renewable sources. For societies that choose energy resilience over a greater reduction in carbon emissions, fossil fuel fired power generation would remain a significant contributor to energy generation since every kWh of energy from renewable sources such as wind and solar would need to be covered with an equivalent amount of backup energy production from non-renewable fossil fuel powered sources to prevent blackouts during prolonged extreme weather events. But, in the case of societies that believes in decarbonising the power generation sector, a greater proportion of renewable power in the energy mix would certainly help the society moves towards its goal of reducing the carbon footprint of power generation.