Renewable Energy & Microgrids – Building a Sustainable Future

The power system of the future is unlikely to be 100% grid-based, as solar PV, storage and the potential for micro-grids become widespread.¹

“A grid of the future that relies heavily on renewables will be complex”, says Amandine Denis, Head of Research at ClimateWorks, an independent, research-based, non-profit organisation committed to catalysing reductions in greenhouse gas emissions in Australia. She says the important advances will be in technology we don’t see: energy saving appliances, data mining and IT systems that balance supply and demand in the grid.

Technology types

As the price of generating solar power falls, and more houses and businesses install solar PV and battery storage, users will reduce the amount of power required from the grid, especially at peak demand. Bloomberg New Energy Finance says it’s possible that by 2040 Australia’s installed solar capacity will generate around 2.5 times the electricity generated from coal.²

Other technologies help consumers save money, take control and reduce carbon emissions: they include electric vehicles (EV), energy efficient appliances and LED light bulbs. But solar will be the major technology mover from the mid-2020s onwards, says Bloomberg, as the falling cost of PV puts it on half of Australia’s residential roofs in 2040,³ from a current penetration rate of 15 %.⁴

Large scale generation

Then there are also generation technologies not as well known to most consumers but still important to reducing emissions. Combined-cycle gas turbines are an example. They use natural gas to power one turbine and capture the exhaust heat to create steam and drive a second turbine, generating more power from the same fuel load.

Also important are utility scale solar PV projects, and concentrated solar power (CSP) where the sun is reflected to one point, creating steam; wave and tidal generation technologies which use the ocean’s energy; wind turbines; direct injection carbon engines, which use coal dust to drive low-emission engines; and the ‘supercritical’ technologies in which much higher temperatures and pressures are reached than in typical coal and gas power stations, creating greater efficiencies.

But all technologies have both benefits and drawbacks and the Australian Power Generation Technology Report conducted by the CO2CRC, concludes, “No single technology is optimal across all metrics, so the ideal grid should include a mix of technologies.”⁵

“No single technology is optimal across all metrics, so the ideal grid should include a mix of technologies.”

Smart power

The most subtle future technology is likely to be the ‘smart grid’. When significant numbers of Australian households and businesses are putting power into the grid, real-time data analysis will be crucial in order to balance the system. Grid operators will also read ‘behind the meter’ and understand how much power each household or business generates and its storage/usage pattern.

The key is in combining a number of ‘smart’ technologies, such as smart meters, home energy management systems, and digital communications. Together they enable energy usage (at household and appliance level) to be monitored and controlled remotely. One option enabled by smart meters is ‘time-of-use pricing’, which gives households the option to turn off appliances at times of high demand, thereby saving money on their power bills. This also benefits the broader energy supply system because it drives demand-response outcomes, avoiding the need to add more generation into the grid.

Making more of the way we use power is recognised as a key part of Australia’s productivity. The Council of Australian Governments’ Energy Council believes that productivity gains of up to 40% are possible in Australia’s energy sector if price-use signals and smart meters are integrated. Smart meters have been mandated in Victoria as well as some parts of: the United States and the European Union.

Most micro-grids will have back-up power. To illustrate the concept, the Siemens company has developed a plan⁸ for a 50 MW Australian micro-grid, enough to power around 10,000 homes. In this plan, 40 MW comes from PV panels on house roofs, stored in batteries, while the remainder is generated from a high efficiency/low emissions (HELE) natural gas turbine. HELE gas turbines have a role in many future scenarios because they have the reliability of fossil fuels but can be run at very low emissions.

Technology cost curve

Arif Syed, from the Bureau of Resources and Energy Economics (BREE), says current energy scenarios differ because of the difficulty in predicting technology and its impact.

“Technology changes everything. The current forecasts from the CO2CRC suggest that by 2030 the costs of power from renewables and fossil fuels will be the same.”

Syed authored the Australia Energy Technology Assessments (2012 and 2013) which estimates the change in costs of 40 technologies to 2050.

The assessments show a levelised cost of electricity (LCOE) over the decades, with many currently expensive renewable technologies becoming more affordable relative to some fossil fuel technologies, especially those that are combined with carbon capture and storage.

“We can’t have a 100% renewables grid,” says Syed, who says there are grid systems requirements that can’t be met by wind and solar alone.

“Yes, we have to decarbonise our electricity supply but consumers expect reliability regardless of where the power comes from.”