Can renewable energy replace coal?

The short answer is yes. Provided that we start scaling up our installation of renewable energy, rely on a broad range of renewable energy technologies, and combine investment in renewable energy with strong programs to save energy. By doing these three things on a large-scale we could start turning off the most polluting coal-fired power stations and replacing them either with megawatts of power produced by renewable energy, or ‘nega-watts’ of power saved by cutting energy waste.

How much energy could be saved through energy savings programs?

Strong energy efficiency programs can shave the demand for base-load power significantly. Australian governments have estimated that 30% of electricity demand could be eliminated with no impact on the energy services delivered and with significant financial, jobs and greenhouse benefits[1]- and that’s a government estimate signed on to by all state governments and the Federal Government! So we could significantly reduce base-load demand and start decommissioning the dirtiest coal-fired power stations in a matter of 4 or 5 years.

What about renewable energy though. Aren’t there limits to how much renewable energy you can have on the grid?

This starts becoming an issue when you have a lot of intermittent renewable energy like wind and solar (e.g. more than 25%) on the grid. Unfortunately we don’t have that issue presently in Australia, where only 8% of our electricity comes from renewable energy[2] and most of that is old hydro power that was built years ago. Having said that in some parts of the world we are now starting to see renewable energy contribute very high proportions of electricity generated, and with some careful planning of the electricity network problems can be avoided. In Australia on a micro level the communities of Denham and King Island are generating 50 to 60% of their electricity from wind power alone, while South Australia sources 11% of its power from wind turbines and Tasmania gets 81% of its electricity from renewable energy (mainly hydro, but also significant wind power). Internationally, Sweden sources over 50% of its electricity from renewable energy, and has a target to increase this to 60% by 2010, while major energy economies like California plan to fast track renewables to provide 20% of electricity by 2010 and 33% by 2020. In parts of Germany and Denmark wind power is providing over 100% of the region’s power needs for months of the year, as well as exporting electricity to other parts of Europe.

But can we really rely on renewable energy? Aren’t renewable energy technologies intermittent, only providing power some of the time? What happens when the sun stops shining or the wind stops blowing?

Some renewable energy technologies like hydro power and bioenergy (burning crop waste) are highly predictable and controllable. Hydro and bioenergy can be deployed when it is most useful, providing either base-load or peak power and they clearly demonstrate that the argument often pushed by the nuclear and coal industries, that renewables cannot deliver base-load power, is flawed. While Australia has seen its last large-scale hydro power stations, there is still plenty of scope for smaller projects like the Bogong 140 MW hydro power station commencing construction in Victoria.

Emerging renewable energy technologies like geothermal and solar thermal are also highly predictable and will be providing large quantities of baseload power in Australia long before either a single nuclear reactor could be built or a commercially feasible carbon capture and storage coal-fired power station has been developed. A solar thermal power plant Liddell power station in New South Wales is already substituting for coal-fired power. Tidal power is in earlier stages of development but some exciting pilot projects are under way in Port Kembla, NSW, and Fremantle, WA.

Wind and solar power are subject to the weather. However, forecasting for both wind and solar power is very reliable. In most cases any lack of sun or wind can be predicted and compensated for (for instance by cranking up hydro and biomass generation). In Germany wind forecasters can tell 48 hours in advance how much electricity will be generated from the country’s 18,000 MW of installed wind capacity with just a 5% margin of error. This contrasts for instance with coal-fired generation where outages and breakdowns are unpredictable and much more likely to plunge the electricity grid into crisis. (see note below)

By deploying wind and solar en masse across the landscape we can also reduce any intermittency of wind and solar generators as it is unlikely that there will be no sun or wind anywhere across the electricity network.

Solar power can be particularly useful for delivering power at times of peak demand. Hot sunny days when air-conditioners are turned on will generally be days when there is a good solar resource. Solar has the added advantage of producing electricity where it is used, thereby minimising transmission losses.

Solar water heating is hugely underutilised in Australia with less than 5% of houses having an installed solar water heater. By contrast countries like Israel, Spain and Ireland are mandating solar water heating, while China has over 60% of the world’s installed solar water heating capacity.

If this is all true, why are so many people saying that renewable energy can only deliver at the margins?

Renewable energy is big business. The solar and wind industries are amongst the fastest-growing businesses in the world. Renewable energy is threatening the market share of the coal and nuclear industries globally. An estimated $38 billion US was invested in renewable energy plant in 2005 alone- up from $30 billion the previous year[3]. It’s because renewable energy can and is replacing fossil fuels that the fossil fuel based industries are fighting back to protect their market share. Their primary line of attack is to belittle renewable energy technologies and attempt to prevent progressive policy which fast-tracks renewable energy. By casting doubts in the public’s mind about whether renewable energy can deliver, the coal industry buys further delays in climate change action, while the nuclear industry attempts to recast itself as a climate change solution. In Australia the coal industry and the nuclear lobby have been very effective in controlling Federal energy policy, although some states are starting to support renewables. While Prime Minister Howard clearly continues to toe the coal industry line, he’s even being left behind by President Bush who recently declared that wind power alone could meet 20% of the US’s massive energy needs.[4]

Renewable energy and energy savings programs can replace coal-fired generation in Australia. They just need a bit of policy support so that they can compete with the coal industry which continues to pollute without cost.

[1] COAG Ministerial Council on Energy “Towards a National Framework for Energy Efficiency- issues and challenges", Discussion paper released by Ministerial Council on Energy p.3, http://www.nfee.gov.au/public/download.jsp?id=183
[2] REGA June 2006, “Renewable Energy - a Contribution to Australia’s Environmental and Economic Sustainability” http://www.rega.com.au/Documents/Publications/J1281%20Final%20Report%20V3%20Exec%20Summary.pdf
[3] REN21, “Renewables global status report: 2006 update”, http://www.ren21.net[4] http://www.awea.org/newsroom/releases/US_Wind_Energy_Installations_Milestone_081006.html

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Eric Rosenbloom commented in email:
About wind forecasting, in Germany that 5% error is an average, and it isn't 5% of the predicted output but 5% of the total installed wind capacity. This is according to grid operator Eon Netz's Wind Reports. They note that the forecasting error ranged up to +/- 50% of total capacity and was more than 10% a third of the time.