We mitigate the cost of energy risk by focusing on reducing specific purchased energy, improving the energy efficiency of our mills, increasing our use of renewable energy and producing and selling surplus green electricity. Focusing on green energy generation aligns with our strategic focus on deriving value from energy opportunities and in light of increasing energy prices.
Globally we have five hydro, two gas and 31 steam turbines which generate around 800 MW of renewable power on 14 sites across seven countries. We also produce biogas from our effluent streams.
We continue to invest in cogeneration and self-sufficiency energy projects, amongst others:
Sappi has a 30% stake in a 25 MW biomass energy unit at Ngodwana Mill which falls under the South African government’s Renewable Energy Independent Power Producer Programme (REIPPP) and which is expected to contribute to the national grid from July 2020. The project will use biomass recovered from surrounding plantations and screened waste material from the mill production process. The power plant will burn up to 35 tons per hour of biomass in a boiler to generate steam and drive a turbine to generate electricity which will be fed into the national grid.
Some 150 years of intensive coal mining in South Africa have produced about a billion tons of discarded thermal-grade coal fines. To utilise this energy source, we constructed and tested a small fuel rod manufacturing plant at Ngodwana Mill. Initial fuel rod test results are positive and could lead to reduced greenhouse gas emissions when compared to low-grade coal. Sappi has entered into a joint venture agreement with the Industrial Development Corporation (IDC) as a strategic equity and debt partner to provide the balance of the capital required for the demonstration plant.
In many of our European mills, we generate renewable energy in the form of biogas. We are reviewing expanded use of anaerobic digestion technology as one of the technologies to treat waste condensate. Rich in organic matter, the condensate could be treated via a process which uses organic acids to produce biogas in the form of methane, which in turn could be used to produce energy, either for internal use or external sales to the national grid.
We are also evaluating the extraction of chemicals from the condensate stream.
Heat from the paper machine dryer hoods used to be vented. Equipment has been installed to recover that thermal energy, which is now being used to generate approximately 4.6 million litres of hot water per day which is used in the papermaking process.
The recovered thermal energy reduces steam demand by approximately 474 GJ/day, resulting in reduced fossil fuel use and enables the mill to generate additional electrical power.