Here comes the sun: 100pc renewables by 2050

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This post originally appeared on Sciblogs.co.nz.

Is a fully sustainable global energy system possible by 2050? It's hard to imagine a more important question if we entertain hopes of avoiding the worst effects of climate change. It is the question addressed by a new and substantial report from the World Wide Fund for Nature (WWF) and the sustainable energy research and consultancy company Ecofys.

The answer to the question is a careful yes, with a caveat. The Ecofys team writes:

"We have found that an (almost) fully sustainable energy supply is technically and economically feasible, given ambitious but realistic growth rates of renewable energy sources.

"However, the path to this future world will deviate significantly from 'business as usual' and a few (difficult) choices will need to be made on the way."

The report does not see a future or a need for nuclear generation, and nuclear power does not figure as part of the sustainable energy system envisaged.

The report is divided into two parts. The first is WWF's take on the Ecofys investigation, and a useful presentation of its major points for the general reader. The second contains the more detailed research of the Ecofys team. They provide a scenario, which is not advanced by WWF as the only way forward but as a clear indication that the goal is feasible.

The single most important element in the Ecofys scenario is increased efficiency in the use of energy. They assess global energy demand in 2050 as 15 per cent lower than in 2005, in contrast with 'business-as-usual' projections which predict energy demand will at least double.

The reduction in the scenario is not achieved by reduction in activity but from using energy as efficiently as possible. There are no surprises in the areas in which efficiency can operate to greatly reduce energy demand.

Recycling in manufacture is one. Using recovered aluminium, for example, cuts total energy use by more than two-thirds. Product design is another: cars and appliances offer big opportunities for much improved efficiency. Improvements in small-scale cooking devices in the developing world can add up to significant reduction in energy demand. There is already the architectural expertise to create buildings that require almost no conventional energy for heating or cooling, and the scenario assumes this as the standard by 2030. Retrofitting existing buildings will achieve big reductions if it is undertaken systematically between now and 2050. It would mean retrofitting 2-3 per cent of floor area every year, an ambitious target, but one which Germany has already achieved. More fuel-efficient transport and expanded use of buses, trams, trains and bikes can result in major reductions in energy use.

Energy conservation must be built into every stage of product design, including a 'cradle to cradle' philosophy where all of a product's components can be reused or recycled once it reaches the end of its life.

Better energy efficiency clearly implies appropriate regulatory action from governments. Legally binding minimum efficiency standards worldwide are needed for all products that consume energy, including buildings. Energy conservation must be built into every stage of product design, including a 'cradle to cradle' philosophy where all of a product's components can be reused or recycled once it reaches the end of its life. Strict energy efficiency criteria should result in new buildings which aim at near-zero energy use, and ambitious retrofitting should be planned and provided with incentives. Energy taxation can be used to steer demand towards efficient products. Developing countries must phase out the inefficient use of traditional biomass and pursue the alternatives; industrialised countries can help them in this process. Substantial investment is needed into public transport, particularly rail powered by electricity.

Efficiency is coupled with electrification. As far as possible the scenario uses electrical energy rather than solid and liquid fuels. Electricity from renewable sources, for example, will power our cars and trains. Currently, electricity makes up less than one-fifth of our total final energy demand. Under the Ecofys scenario by 2050 it will account for almost half. Wind, solar, biomass, and hydro power are the main sources of electricity, with solar and geothermal sources providing a large share of heat for buildings and industry.

Solar energy to provide electricity and heat is practically unlimited. To date it is hardly tapped, contributing only about 0.02 per cent of our total energy supply. But the proportion is growing fast and the Ecofys scenario has it providing around half of our total electricity, half of our building heating and 15 per cent of our industrial heat and fuel by 2050. The annual growth rate required to reach this is much lower than the one currently sustained year on year. Solar power can create electricity directly through photovoltaic cells, which have the advantage of being able to be integrated into devices and buildings, or it can be concentrated with the resulting heat used to generate electricity.

Variability is a problem, but energy storage is improving particularly through concentrating solar power systems where design stage systems can now store up to 15 hours for electricity generation. Combining solar electricity with other renewable electricity sources is another way of addressing variability. Apart from electricity direct heat from the sun can also be employed. Solar thermal collectors can be widely used to for hot water. Direct sunshine combined with improved insulation and window architecture can be used to heat buildings.

Wind power currently supplies around 2 per cent of global electricity demand. An additional 1,000,000 onshore and 100,000 offshore wind turbines would meet a quarter of the world's electricity needs by 2050. Geothermal electric capacity is growing and the Ecofys analysis suggests this could reasonably be expected to provide about 4 per cent of our total electricity by 2050. The waves and tides of the ocean provide a potentially vast and reliable source of energy, but because of the challenges in converting it into electricity the scenario assumes only a 1 per cent contribution to global electricity supply by 2050. Hydro power currently provides 15 per cent of our electricity but because of the environmental and social problems associated with large dams Ecofys lowers its contribution by 2050 to 12 per cent.

The scenario is cautious on biomass, preferring other renewable sources wherever possible. However it recognises that there are some applications where bioenergy is currently the only suitable replacement for fossil fuels. Aviation, shipping and long-haul trucking cannot with current technology be electrified or powered by hydrogen. Some industrial fuels and heat will depend on biomass in 2050. While some of this can come from waste products there will need to be bio-energy crops - around 250 million hectares, or the equivalent of one-sixth of total global cropland - and great care will need to be taken to ensure that they do not use land and water required to grow food or sustain biodiversity. The WWF section of the report is exercised by this question of land use for bioenergy, and expresses the hope that the level of demand for liquid fuels the Ecofys scenario caters for can be further reduced. Algae may meet part of the biomass requirement, but the scenario has it appearing on the scene only by 2030 and only a fraction of its potential is included by 2050.

The renewable resources are enormous, far in excess of our needs. But we need to tap them. This means massive expansion of capacity for generating electricity from them, building large-scale renewable energy plants, not a new generation of fossil fuel and nuclear power plants that could set us back decades. Local micro-generation also has a part to play. International electricity networks need to be extended. Urgent investment is required for smart grids which allow for a significantly higher proportion of electricity to come from variable and decentralised sources. Research is needed into storage options and efficient grid management. Legislation, investment and incentives are required to encourage manufacturers and consumers to switch to electric cars.

And the money? We need a lot of it to be spent in coming decades, but the savings will begin to outweigh the costs by 2040. Unfortunately the current financial system is not geared to taking the long view. We will need new financing models such as public-private partnerships with shared risks, to encourage long-term investment. Legislation and stable political frameworks will also help to stimulate investment. Support such as feed-in tariffs is still dwarfed by the value of global fossil fuel subsidies. Since the aim of those subsidies is often to provide affordable fuel and electricity for poorer people they should not be cut outright but reinvested into providing renewable energy and energy efficiency measures.

There's much more that the report addresses. Equity issues are central and the report places the end of energy poverty at the heart of its energy vision. The rich countries have built their economies on cheap plentiful fossil fuels. They are in a position to assist poorer countries who have not had this resource to develop their own renewable energy capacity. Advanced renewable energy technology must be shared with developing countries.

A renewable energy future doesn't mean sacrificing our quality of life. We can maintain rates of economic growth and lead prosperous, healthy lives.

What about the lifestyle implications which worry the well off? The Ecofys scenario does not demand radical changes to the way we live. The report asserts that a renewable energy future doesn't mean sacrificing our quality of life. We can maintain rates of economic growth and lead prosperous, healthy lives. Indeed the quality of life for many will improve greatly with access to electricity and clean energy. There will be some changes. In wealthier countries we will need to eat less meat and waste less food, wean ourselves from large fast cars, use public transport more, walk and cycle more, be more judicious in the frequency of our travel - but these are hardly deep sacrifices, and surely not changes we will refuse to make when the benefits are so apparent.

The shift to renewable energy can be made. Climate change apart it would have to be made as fossil fuels are depleted. But climate change cannot be set apart, which is why WWF has settled on 2050 as the date for the full transition to be realised. Technologically it is clearly possible. Financially it is not beyond our capacity. However, political direction and business and investor engagement are essential. There is much to be cheered by in the report. "Let's get on with it," is the rational response. But rationality still struggles to prevail in the climate change arena. Hopefully the painstaking research and evident good sense of reports such as this will make politicians and business people see clearly that we can achieve what we must achieve if we are to prevent climate disaster.

Bryan Walker is a Hamilton-based science writer and contributor to Hot Topic. View his work and that of 35 other scientists and science writers at Sciblogs, New Zealand's largest science blogging network.