In a renewable world, baseload generation is redundant

Energy Minister Martin Ferguson revealed the tenuous nature of his understanding of solar technologies in an interview on ABC TV’s 7.30 Report on Tuesday, referring to Solar Flagships projects as “solar baseload power.”

The Solar Flagships may be many things – big is one of them and possibly what Minister Ferguson meant. Or they may not be anything at all, given their problems in financing. But without storage one thing they certainly will not be is baseload. And even with storage, would solar ever work as baseload energy?

It is a common misconception, given that the energy grids for decades have been based on the principal of providing baseload energy, supplemented by peak-load power when demand is high. The question is often put: How could solar – or any other intermittent renewable ever be considered to be a source of baseload energy? According to the latest study produced by experts at the UNSW, it may not need to.

The study by the UNSW team of Ben Elliston, Mark Diesendorf and Ian McGill into how Australia’s National Electricity Market could cope with 100 per cent renewables suggests that the very concept of a baseload power station becomes redundant when fossil fuels are replaced with renewables.

The needs of the grid are met with large penetrations of variable renewable sources such as wind and solar, and topped up with solar storage acting as a form of peaking plant, and gas-turbines running on biofuels that perform a similar function. And, critically, by reducing peak demand through improved energy efficiency and better demand management.

The study, a simulation of 100 per cent renewable scenarios for the year 2010, using actual NEM demand data, weather observations and technologies that are in either mass production (wind, solar PV, hydro and biofuelled gas turbines), or limited production (such as concentrated solar thermal with thermal storage), shows that 100 per cent renewable energy is technically feasible.

It does, however, require a “radical 21st century re-conception” of an electricity supply demand-system. Instead of base-load coal, reliability is maintained with large penetrations of variable renewable sources from as great a diversity as possible, supported by a large array of “dispatchable” generators – be they turbines or storage.

“Nowadays, renewable energy deniers are almost as active in spreading misinformation as the deniers of anthropogenic climate change,” Diesendorf wrote recently. “One of their principal false claims is that renewable energy sources are too unreliable to form the basis of an energy system for an industrial society. In particular, they assert that renewable energy cannot supply base-load (24-hour) power and is only suitable for niche markets.” He says the UNSW research helps to refute these claims.

The study is one of a number that have been and are being conducted around the world to consider how countries wean themselves off fossil fuels. They have been done for the US, northern Europe, the UK, New Zealand, Portugal, Ireland and Japan. Denmark has set a target of going 100 per cent renewable by 2050, Scotland by 2020, Ireland by 2035, Germany – Europe’s biggest industrial nation – wants to have 80 per cent by 2050. (Some say it may come sooner). The common theme of these studies is that it can be done. The challenge in Australia is that unlike most other countries, it doesn’t have access to much hydro, or neighbouring grids to tap in to. But it does have a lot of sun.

The UNSW released their first results at the Solar 2011 conference in Sydney last December. It included a base scenario of 23.2GW of wind (more than 10 times the current capacity), 14.6GW of PV (10 times current capacity), 15.6GW of CST (there is none now), 2.2GW of existing pumped storage hydro, 4.9GW of existing hydro without storage and 24GW of biofuelled gas turbines. They have recently updated their findings to see if reliability could be improved, and if the reliance on gas turbine capacity and use could be reduced.

The biggest changes came through demand reduction – which could be achieved through a variety of measures to get over winter peaks when solar and wind generation may contribute little. Reducing these shortfalls by 10 per cent meant that the gas turbine capacity could be reduced to 18GW from 24GW, while reducing shortfalls by 19 per cent could cut the required capacity to 15GW. (If that sounds like a lot, the Perth Solar City project has recently revealed that air conditioners operated with remote demand management devices – the first such trial in the country – achieved a 20 per cent reduction in peak demand from households, who have been primarily responsible for a 20 per cent increase in peak demand in the state over the past decade).

The other major development in the new study came from changes in the mix of solar PV and CST, given the sharp falls in the cost of PV modules in recent years, and the ability of PV to better cope with cloud cover than CST. The contribution of PV was increased from 10 per cent to 20 per cent, while that of CST was reduced from 40 per cent to 30 per cent.

The increased use of PV allowed generation from CST to be delayed, and use CST energy stored in thermal storage tanks to meet the evening peaks, helping reduce the reliance on gas turbines. (They had considered expanding the capacity of CST to meet the winter peaks, but this appeared more costly and would create excess generation in summer).

The supply and demand plot for a typical week with a 7 hour dispatch delay might look something like this:

The next stage of the UNSW study will be analysing how much this will cost. Broader estimates produced by the International Energy Agency and the European Commission suggest that the final outcome of moving to renewables will be cost-neutral over the long term, and may even save money, but will likely cause a rise in costs over the short term because of new technologies and infrastructure investment. More critically, it will also send shockwaves through the energy industry as economics of fossil fuel generators is undermined, as they are already discovering in Germany and other places where renewable penetration is reaching 20 per cent or more.

The Australian Energy Market Operator has also been commissioned to paint two scenarios of reaching 100 per cent renewables by 2030 and 2050. It is expected to release the scope of that inquiry in coming weeks.