Climate Change

How Can We Get to Zero-Carbon Energy?

May 13, 2013

Q-Park 2011 Tata Ace EV Electric Truck. Image credit: kenjonbro/Flickr through a Creative Commons license.

Joe Fargione is director of science for The Nature Conservancy’s North America Region program.

Last week, Earth hit a long-awaited (and much dreaded) climate milestone: the amount of carbon dioxide in the atmosphere (as recorded at Hawaii’s Mauna Loa Observatory) has exceeded 400 parts per million for the first time in the 55 years atmospheric CO2 concentrations have been measured — and perhaps not since the Pliocene Epoch, which was between 2.6 and 5.3 million years ago.

The reading was just for a single day — May 9 — and will fall in the summer if previous annual trends hold. But even with substantial improvements in energy efficiency and conservation, atmospheric CO2 levels will continue to grow over the coming decades unless significant global steps are taking to stabilize them — among them, a large increase in zero-carbon energy production. What will it take to achieve that increase? (I’ll speak on that topic tonight at 7:30 PM as part of The Future of Energy,” a Nature Conservancy/WBUR panel discussion at Boston’s BSA Space that also includes Daniel Kammen of the University of California-Berkeley and Jigar Shah, clean-tech entrepreneur. Learn more about the panel and The Future of Nature discussion series.)

Obviously, political will would help get us to zero-carbon energy. But innovations in several key areas could have a big impact. And innovations that lower costs of zero-carbon solutions, making the switch relatively painless for families and businesses, should help bolster political will.

The future of zero-carbon energy production is a big, complicated topic, but there are three areas that seem particularly worthy of discussion: 1) the importance of energy storage for renewables, 2) the diversity of options for zero-carbon electricity, and 3) zero-carbon transportation.

Energy Storage for Renewables

Wind and solar energy are relatively affordable and widely abundant, making them excellent candidates to meet future energy needs. However, they are intermittent — the sun doesn’t always shine and the wind doesn’t always blow. Most of the time, it is going to be windy somewhere; a well-connected grid will be able to move energy from supply areas to demand areas. But even with a better grid, there will be times when large areas are simply not producing enough energy to meet demand.

Consequently, we’ll need substantial energy storage for intermittent energy to account for more than 20 percent of our energy supply. A surprising number of old and new technologies are designed to address this.

One is pumped hydro: when wind energy production exceeds demand, water is pumped uphill to a reservoir. When the wind dies down, the water is released, producing electricity. Surplus energy can also be used to compress air, which is then decompressed to supply energy. Other methods include liquefied air or nitrogen and batteries, which are getting cheaper. Affordable solutions for energy storage would remove a significant hurdle for integrating large amounts of wind and solar into our electricity grid.

The Diversity of Options for Zero-Carbon Electricity

Although wind and solar will be a key part of the climate change solution, the climate problem is too large to take any technology off the table. There are many technologies that have potential: geothermal, carbon capture and storage, micro-hydro, wave energy, and new nuclear. All of these have their challenges, but all are also just a few technological breakthroughs away from being able to contribute to zero-carbon electricity production.

For example, Bill Gates is putting his money on a new generation of traveling wave nuclear reactors. These reactors will passively self-cool instead of melting down in a natural disaster even without external power or operator intervention; can run for 40 years on one stock of fuel; and can be fueled by stockpiled nuclear waste that poses a proliferation risk while producing waste that does not pose a proliferation risk.

Zero-Carbon Transportation

Transportation provides a unique energy challenge. You can’t capture tailpipe emissions from an internal combustion engine. And it is very difficult to produce biofuels that are truly carbon neutral; they take huge amounts of land to produce and are likely to spur conversion of natural habitat, causing significant carbon emissions.

A more promising solution would be to switch to electric vehicles–and this switch isn’t as far away as you might think. Electric cars already better conventional cars in cost and performance — except for the battery, which is too expensive and can’t drive as far. Once battery prices fall roughly by 50%, electric vehicles will be cheaper than conventional vehicles and all light-duty vehicles could be electric or hybrids.

Even some large vehicles can be electrified using available technology. A new line of buses, delivery trucks and taxis use a small battery that is wirelessly charged with inductive coupling (just like your electric toothbrush) at charging locations that can be buried in the road at bus stops and taxis queues. And developing technology would allow vehicles to charge while moving, which could allow electrification of heavy duty trucks.

Energy production is a technological problem and it will have a technological solution. To move to zero-carbon energy production will require a combination of political will to implement existing solutions and investment in innovations to provide new solutions for meeting our zero-carbon energy needs.

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