ALTERNATIVE FUELS CRUCIAL FOR SUSTAINABLE ELECTRICITY GENERATION

By Shane Janse van Vuuren, General Manager: Compressors and Turbines at Howden.

The Government’s move to raise the licensing threshold for privately generated electricity to 100MW has created financially attractive generation opportunities for companies with access to previously wasted yet environmentally sustainable energy sources.

The renewables debate on electricity tends to emphasise the benefits of wind and solar generation, which, while being environmentally friendly, are by nature intermittent owing to their dependence on sunshine and prevailing wind.

It is worth considering that cheap, readilyavailable fuels can be used to generate electricity to supplement solar and wind renewables in peak demand evening and morning periods, especially during the winter season.

Electricity can be generated from biomass, bagasse or biogas, from Combined Heat and Power (CHP) boilers at refineries and industrial plants, or by using waste materials, all used as fuel to drive steam turbines.

Alternative fuels for electricity generation have high dispatchability

Generation plants using these fuels have the advantage of high dispatchability where power output can be quickly increased or decreased, depending on demand during peak times.

Dispatchability is usually the preserve of traditional coal plants, Open Circuit Gas Turbines (OCGT) or Concentrated Solar Plants (CSPs) using thermal storage.

The advantage of using sustainable fuels for dispatchable peaking power is that the fuel is essentially free and environmentally sustainable. Coal and OCGT plants emit harmful gases such as Carbon Dioxide (CO 2), Sulfur Dioxide and nitrous oxides. The fuel is expensive, particularly with OCGTs that burn imported diesel or gas.

The drawback of thermal storage CSP plants is that the technology limits them primarily to evening peak times.

Biomass from sawmills

Biomass waste from sawmills can, for instance, be used as fuel to produce steam that drives a turbine and generator to produce electricity at any time of the day or night.

The generated electricity can be sold to customers during peak power demand times at night or in the morning or used at the sawmill itself during off-peak times.

The sawmill owner benefits from cost savings and additional income while reducing CO 2 emissions and plant waste.

Similarly, biogas, an environmentally friendly, renewable energy source produced from readily available organic matter such as food or animal waste, can be burned to generate electricity in a CHP plant.

CHP boilers can also be incorporated into scrubbers used to control oil refineries and industrial furnaces emissions. Environmental emissions regulations already require gas cleaning plants for these industries.

Instead of flaring the collected harmful gas contaminants at the stack, captured gases such as carbon monoxide and hydrocarbons can be burned in a CHP plant to generate electricity, for use by the owner or for sale to customers.

About Howden

Howden is a leading provider of missioncritical air and gas handling products, providing service and support to customers in highly-diversified end markets and geographies globally.

Howden’s products help customers increase the efficiency and effectiveness of their processes by enabling them to make sustainable improvements in their environmental impact and transition to net-zero carbon emissions goals.