By Jim Harding
The feature in the November 2009 Scientific American shows plenty of renewable energy for future uses. But what are the challenges to conversion and are they manageable? Renewables must be scrutinized with the same criteria used for other energy options. While renewable "fuels" - from wind, sun and water - are inexhaustible and free, what about the availability of other required materials? And how do renewables stack up to non-renewables insofar as reliability? What about the comparative costs? Finally, how will the economy and government policies impact conversion?
REACHING PEAK PRODUCTION
A point is inevitable when nature's non-renewable resources and cost-impediments create "peak production", after which there is steadily declining supplies. An argument rages as to whether we've already passed "peak oil" or "peak gas", and, of course innovation in the technology of extraction plays a role; e.g. natural gas is now being accessed in shale by drilling horizontally. Today's shortfall of uranium supply, shown by the failure to get the high-grade Cigar Lake mine into production and dependency on weapons-grade uranium to meet demand, even without a nuclear renaissance, suggests we've passed "peak uranium". While there are centuries of coal supply, this is the most carbon-intensive non-renewable and the search for "clean coal" dramatically increases costs. Compared to low-cost, low-carbon renewables, spending billions on carbon-storage for high-carbon fuels looks more and more like chasing our tails.
But what about other materials required for renewables? The steel and cement used in wind power is abundant, and in contrast to a nuclear power plant, all of this is recoverable to recycle, which reduces future energy demand. Lower cost neodymium used for wind turbine gearboxes is concentrated in China, but this metal is not in short supply, and research on gearless turbines is quickly advancing. Some photovoltaic (PV) cells presently rely on materials such as tellurium and indium, which have limited supply, but these and alternative materials can be recycled, which could become the most reliable future supply. The lithium used in batteries and platinum used in fuel cells are rare-earth metals, with more than one-half of the lithium in Latin America. Rising prices and shortages are possible, but again, recycling could alter this, showing how an integrated approach to convert to sustainability is required. The throw-away economy, which builds in planned obsolescence for short-term profit, has probably run its course. Regulations to ensure fuel cells and batteries are built for recycling must be part of the sustainable policy package. Compared to unsolved and some think unsolvable carbon or nuclear waste storage problems, these challenges of renewables seem like a cake-walk.
RELIABILITY OF RENEWABLES
Intermittent supply is often mentioned as the Achilles Heel of renewables. It may surprise some readers that the downtime of coal plants runs over 12% per year compared to only 5% for wind turbines at sea and less than 2% for those on land. PV systems are also down less than 2%. And when a coal or nuclear plant goes down a huge source (e.g. 1,000 MW) of energy is removed from the grid. Maintenance of renewable technology makes the public less vulnerable because it involves taking a small amount of overcall capacity out of service at a time (e.g. a 5 MW wind turbine).The shift to renewables requires a change in mind-set; a "smart grid" requires organizing energy production around various sources. Geothermal and tidal energy can provide base power and hydro can provide back-up for wind, which produces more at night, and help meet peak loads. Solar, which produces more in the day, is a great complement to wind. And so on.
Demand-side management (DSM) is already being used by utilities to better match demand with supply and lower peak loads and capital costs. This thinking has to be expanded so that diverse energy sources are coordinated. Wind farms interconnected across wind zones can provide a reliable "base" supply. More available wind at night can be used to "refuel" vehicles to be run off electricity the next day, which shows how renewable energy can be stored cost-effectively.
COMPARATIVE COSTING
Using annualized costs for capital, land, operations, maintenance, storage and transmission, wind, hydro and geothermal are already less than 7 cents kWh, which is cheaper than conventional power. By 2020 wind, wave and hydro are expected to be down to 4 cents kWh. Wind is already equal to or less than new coal and gas plants. Concentrated (thermal) solar and PV are still more costly but are expected to be competitive (8-10 cents kWh) within a decade. Mass produced electric cars will be able to provide transportation that is competitive with gasoline, the price of which will continue to rise after "peak oil". The hybrid vehicle is the coming transition.
But pricing models are still distorted, and can be manipulated to support powerful energy companies and government policies that support them. First, they externalize many actual costs to today's taxpayers, and to future generations who won't benefit at all. If the costs of climate change are added into fossil fuel costs, the industries would quickly collapse. The same is true for the nuclear industry if all future waste costs, including for uranium tailings, are included. When all environmental health costs, including the impact on the quantity and quality of water, are included, renewables consistently come out on top. Second, direct and hidden subsidies must be fully accounted for. Without these we would never have gotten into such over-dependency on unsustainable energy. The tarsands and nuclear power, but not lower-cost wind, got subsidies in Harper's stimulus package. Meanwhile many governments, including our own, still refuse to establish a feed-in tariff to pay a fair price to farmers, small businesses, First Nations, towns and individuals willing to produce electricity for the public grid.
This shows how a more comprehensive and realistic economics comes with the shift to renewables.
Originally published in RTown News, January 15, 2010.