New Zealand's energy landscape is evolving, with renewable energy sources like hydro, wind, and solar contributing significantly to electricity generation. In 2023, the country reached a record high of 88% renewable electricity generation (Energy in New Zealand 2024). However, challenges persist in achieving complete energy self-sufficiency, with the country relying on imported fuels like coal and oil. This article explores the untapped potential of biomass gasification, particularly from wood waste, as a key solution to improve New Zealand's energy resilience.
While renewable electricity generation has made significant strides, New Zealand's overall energy self-sufficiency in 2023 remained at 73% (Energyin New Zealand 2024). The reliance on imported coal and oil has led to fluctuations in energy costs, exacerbated by global market instability and price hikes. Cyclone Gabrielle, which ravaged parts of the North Island in 2023, further emphasized the vulnerability of our energy infrastructure, particularly in the wood processing sector, which saw significant losses.
An estimated* value of 484 PJ of timber was harvested in year 2023. However, much of this resource remains underutilized, with a large proportion of waste from forestry operations often left in-situ, leading to environmental concerns. Based on the flat or steep terrain, the total forestry waste generated during the log harvesting accounts to 20 and 28 % of the harvested log volume respectively (Forest residues for bioenergy). Assuming a base value of 20% of the forestry waste generated, a total volume of 10.8 million cubic meter of forestry residue was generated in 2023, corresponding to an energy equivalent of 96.7 PJ. This represents an immense untapped resource that could be harnessed to improve energy self-sufficiency while addressing environmental concerns associated with waste management.
In 2023, despite disruptions caused by Cyclone Gabrielle, New Zealand generated around 44.4 PJ of solid biofuel from woody biomass (Energy in New Zealand 2024). For putting things in perspective, let’s assume that this solid biofuel consists solely of forestry residue. As a result, New Zealand yielded only 45.9 % of the energy from the total solid biofuel available from forestry waste in 2023. A half of the forestry waste, amounting of 52.3 PJ, is available and could be used to decrease dependence on imported coal and oil and eventually reach energy self-sufficiency in New Zealand.
Biomass gasification is sustainable process for harvesting renewable energy from woody biomass. By converting forestry slash into valuable syngas through gasification, New Zealand could create a cleaner and more resilient energy source. This gas could then be used for Combined Heat and Power (CHP) systems, generating both electricity and heat for industrial and residential use. In addition to syngas production, the gasification process can be optimized to produce hydrogen—a fuel that could play a significant role in decarbonizing New Zealand's transport and industrial sectors.
Typically, gasification process has an efficiency of about 70-80% in converting the energy in wood into syngas (Thermal gasification of biomass). Assuming an average efficiency of 75%, an underutilized solid biofuel of 52.3 PJ could be used to derive 39.2 PJ of energy through biomass gasification in the form of syngas. Syngas could be converted into heat and power by either using an internal combustion engine or gas turbine. The efficiency of converting syngas into electricity through an integrated gasification combined cycle power plant could be taken as 35% (IGCCEfficiency / Performance). As a result, an electrical power output of 3815 GWh could be generated out of underutilized forestry residue alone through biomass gasification process.
By harnessing domestic resources, biomass gasification reduces reliance on imported fuels, improving energy resilience. This enables New Zealand to have more control over its energy supply, enhancing the nation's energy independence. Gasification not only provides a renewable energy source but also reduces methane emissions from decomposing wood waste, contributing to New Zealand’s environmental goals. Investing in biomass gasification infrastructure creates jobs and supports regional economic development, especially in areas affected by the decline of traditional industries. Biomass gasification aligns with New Zealand's renewable energy targets and efforts to reduce greenhouse gas emissions, making it a critical component of the country's clean energy strategy.
At Myst Enterprize, we have the expertise to provide custom gasification solutions tailored to New Zealand’s specific energy needs. From small-scale CHP plants to large hydrogen production facilities, we are committed to helping the country transition to a cleaner and more self-sufficient energy future. Our bespoke solutions are designed to maximize efficiency, minimize waste, and ensure long-term sustainability for New Zealand's energy sector. By focusing on innovation and sustainability, Myst Enterprize is playing a pivotal role in the energy transition, contributing to a greener and more resilient energy landscape.
*Note: A total volume of 34.38 million cubic metres timber was harvested in 2021 (MPI NZ). An forecasted value of mass timber production index for 2023 is reported to be 261 (Wood processing data). Assuming a linear relationship between the timber volume and mass timber production index, the value of timber harvested in NZ in 2023 is estimated to be 53.73 million cubic meters. Assuming an average wood density and lower heating value of 0.5 tons/m³ (dry wood) and 18 GJ/ton respectively, the value of 53.73 million cubic metres timber corresponds to an estimated value of 483.57 PJ of solid biofuel.