Bioenergy can provide storage, carbon capture, and frequency stability in addition to being a renewable energy source. Due to its unique characteristics, it will be a critical component of the future decarbonized energy mix.
Fremont, CA: Bioenergy will provide a large degree of supply and demand balancing. Wind and solar power are inconsistent. However, bioenergy can supply power when it is needed. Large amounts of energy can be stored for a low cost in simple wood piles, allowing seasonal variations in energy supply and demand to be accommodated. Another important feature of bioenergy is that it allows us to begin absorbing carbon from the atmosphere cheaply and effectively right now by planting trees and then recovering that carbon when the biomass is used to generate electricity in the coming decades. In a decentralized renewables-intensive system, biomass can also supply the inertia needed to maintain frequency stability, which is a serious issue.
Dispatchable bioenergy
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Electricity demand can be met by turning on and off dispatchable generation. During periods of extremely high demand and/or low renewable energy, some dispatchable generation capacity will almost certainly be required in the grid. Daily supply and demand mismatches are expected to be rectified using a mix of smart charging and demand-side response devices, as well as grid energy storage using batteries and pumped-storage hydroelectricity. These methods, on the other hand, are unlikely to withstand a protracted period of low wind during a cold, gloomy winter. This will almost certainly necessitate the use of dispatchable electricity derived from chemically stored energy. There are two main alternatives here — bioenergy and hydrogen.
Frequency stability
The frequency of the AC supply is determined by the rotational speed of the generators. A current is induced as each pole of a generator's rotor bar crosses the stator windings, which then reverses when the opposing pole passes. The magnetic field lessens as electrical demand falls, causing the generator to speed up and the AC frequency to rise. The AC frequency and phase must be synchronized across the whole national grid to guarantee that devices function properly. Biomass has the inertia needed to keep the grid's frequency stable.
Negative emissions without capturing carbon
Trees absorb carbon from the atmosphere as they develop, but breakdown and fires eventually release it back into the atmosphere. Traditionally, mature forests were assumed to reach a point when they released as much carbon as they captured. Even ancient primary forests, it is now recognized, continue to capture more carbon than they release, with some carbon settling in the soil. Biomass can help with land regeneration and afforestation, which the Intergovernmental Panel on Climate Change (IPCC) estimates could absorb between 0.5 and 3.6 Gt of CO2 per year.