Renewables can power the world

The IPCC report on the potential of renewable energy sources to supply nearly 80 per cent of the world’s energy requirements would not have made comfortable reading for the globe’s fossil fuel industries.

Which is possibly why the representatives from OPEC nations, led by Saudi Arabia, were arguing deep into the night at the end of a four-day session in Abu Dhabi to try and tone down aspects of the report.

The IPCC analysis, like those it has produced on climate change, is a synthesis of member nations views – in this case 194 nations – and the OPEC members were reportedly anxious to insert as many “mights” and “mays” into the 1,000-page document as they could. In the end, they couldn’t take away from the significance of the report’s conclusions.

The analysis canvassed 164 different scenarios that might affect the deployment of renewables out to 2050. Four scenarios were analysed in depth, depending on the world’s response to the challenge of climate change, and in the most ambitious it concluded that renewable energy could supply 77 per cent of the world’s energy needs by 2050.

Notably, it concluded that there are “few, if any, fundamental technological limits to integrating a portfolio of RE technologies” to meet a majority share of total energy demand in locations such resources exist or can be supplied.

The stumbling blocks are elsewhere. “The actual rate of integration and the resulting shares of RE will be influenced by factors such as costs, policies, environmental issues and social aspects.”

The 77 per cent scenario is equivalent to about 314 exajoules (EJ) per year, or broadly equivalent to more than three times the annual energy supply of the United States or continental Europe, in 2005. It compares to just 13 per cent now, much of it is currently produced through traditional biomass and hydro.

The overall cost of this boldest path is expected to be up to $5 trillion to 2020 and a further $7 trillion in the following decade. These are big numbers, but the report says it represents less than 1 per cent of global GDP, and this does not take into account avoided (fossil) fuel and substituted investment costs.

Even under the most ambitious rollout, less than 2.5 per cent of the globally available technical potential for renewables is used – there is no danger of peak wind, peak sun, or peak geothermal. Hydro seems to be the most limited in growth – and not so much because there will be less water, it just may not flow as much where the major dams are currently located.

The report gives its estimates of the current costs of renewable energy in the graph above. But, as it notes – and this is important in the current debate about renewable energy in Australia – “the levelised cost of energy for a technology is not the sole determinant of its value or economic competitiveness. The attractiveness of a specific energy supply option depends also on broader economic as well as environmental and social aspects, and the contribution that the technology provides to meeting specific energy services (eg, peak electricity demands) or imposes in the form of ancillary costs on the energy system (eg, the costs of integration).”

It also noted that renewable energy can decouple the link between economic growth and emissions, can deliver social benefits such as new jobs, create new jobs, help accelerate access to energy – particularly for the 1.4 billion people who don’t have it right now and the 1.3 billion that use traditional biomass, can contribute to a more secure energy supply and, of course, can reduce emissions. Indeed, as the table below suggests, emissions from renewables will likely be below those of fossil fuels even when the latter are fitted with carbon capture and storage technology.

Under the scenarios analysed in-depth, less than 2.5 per cent of the globally available technical potential for renewables is used. In other words, over 97 per cent is untapped, underlining that availability of renewable resources will not be a limiting factor.

The IPCC summarised the key renewable energy technologies and their potential as follows:

Bioenergy technologies can generate electricity, heat and fuels from a range of feedstocks. Some bioenergy systems, including ones that involve converting land into agricultural biomass and energy crops, can generate more greenhouse gas emissions than they save. But others, such as advanced conversion systems – which, for example, convert woody wastes into liquid fuels – can deliver 80-90 per cent emission reductions compared to fossil fuels.

Bioenergy, mainly for traditional cooking and heating in developing countries, currently represents over 10 per cent of global energy supply, or about 50 exajoules per year. While the share of bioenergy in the overall renewables mix is likely to decline over the coming decades, it could supply 100 to 300 exajoules of energy by 2050.

Direct Solar Energy technologies include photovoltaics (PV) and concentrating solar power (CSP). They can produce electricity, heat and light. Currently, direct solar contributes only a fraction of 1 per cent to total global energy supply.

Potential deployment scenarios range from direct solar energy playing a marginal role in 2050, to it being one of the major sources of energy supply. The actual deployment will depend on continued innovation, cost reductions and supportive public policies.

In the most ambitious climate stabilisation scenarios, solar primary energy supply reaches up to 130 exajoules per year by 2050, which can be attributed to a large extent to PV electricity generation. In some scenarios, its share in global electricity generation reaches up to a third by 2050, but in the majority of scenarios it remains below one tenth.

Geothermal energy, utilising heat stored in the earth‘s interior directly or to generate electricity, currently reaches about 0.7 exajoules per year. By 2050, geothermal deployment could meet more than 3 per cent of global electricity demand and about 5 per cent of the global heat demand.

Global geothermal technical potential is comparable to the global primary energy supply in 2008. However, geothermal energy does not reach the technical potential limit in any of the scenarios analysed, with the deployment rate remaining below 5 per cent for both the regional and global level.

With hydropower – including dam projects with reservoirs, run-of-river and in-stream projects, and ranging from small- to large-scale – the installed capacity by the end of 2008 contributed 16 per cent of worldwide electricity supply, making it the largest renewable energy source in the electricity sector.

According to long-term scenarios, hydropower’s share in the global electricity supply may decrease to 10-14 per cent. Despite absolute growth in hydropower supply, the expected energy demand growth and continuing electrification could result in a decreasing share.

Ocean energy technologies are diverse and use the kinetic, thermal, and chemical energy of seawater. Most are at the demonstration and pilot project phases. Due to its nascent stage of development, they are unlikely to significantly contribute to global energy supply before 2020. Ocean energy is currently only represented in very few scenarios. As shown by the review, projected deployments could result in energy delivery of up to 7 exajoules per year by 2050.

Wind energy’s primary application of relevance to climate change mitigation is to produce electricity from large wind turbines located on land or offshore. The wind power capacity installed by the end of 2009 met close to 2 per cent of worldwide electricity demand. The review shows a high expansion rate in Europe, North America and, more recently, in China and India.

A greater geographical distribution of deployment is likely to be needed to achieve the higher deployments indicated by the scenario literature. Under the demand projection of some scenarios global wind power share grows to more than 20 per cent by 2050.

Climate Spectator

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