Climate Climate & Energy

If renewables are to work, we need good storage

David's recent post on pumped storage attracted enough angry responses that I guess it is time for a more detailed post on energy storage and renewable sources.

Solar and wind energy are variable sources. If we want them to provide more than 20%-40% of our power, we will need some storage method.

Fortunately, long-distance transmission lines can reduce this need. While the sun and wind have gaps at any one spot, if we use long distance HVDC transmission lines to connect sites thousand of kilometers apart, the sun will be shining or wind blowing somewhere almost all the time. As I pointed out in previous posts, connecting wind farms with such lines could provide a 96% reliable firm commitment with only 12 hours of storage, or a 99%+ reliable firm commitment with 22 hours of storage. With an extensive long-distance grid, most supply gaps shrink to a few hours.

Modular pumped storage (MPS) is not only the lowest cost, but lowest ecological impact electricity storage means available to fill this gap. Separate two artificial reservoirs by a difference in elevation. Pump water uphill when you have extra electricity. Run the water downhill through turbines when you need the power back, recovering from 70-85% of what you put into storage.

Umbra on installing solar power

Dear Umbra, I live on Long Island, N.Y., and am interested in getting solar power for my home. I am not sure, however, if that is viable in this area. Do you have any recommended reliable sources that I can reference? There is just so much confusing information in the marketplace. Thanks, Rick Port Washington, […]

Why the Smart Grid is important

It's the world's largest machine -- the interconnected network of power plants, transmission towers, substations, poles, and wires that make up the power grid. When you flip the switch you expect the juice to flow and don't have much reason to think about it, except during the occasional blackout. Power engineers and energy wonks might get passionate about the grid, but for most people it's just a background fact of life.

It's time to bring the grid into the foreground, because it positions at the exact center of the world's most crucial issue, global climate change. The power grid is the source of one-third of U.S. global warming emissions. Unless we clean it up we cannot avert severe climate change. The grid is also the key to electrifying transportation and making more effective use of heat generated for buildings and industry, source of the vast bulk of remaining emissions. The grid can be the ultimate climate saver.

But today's power grid cannot do it. A system built on central generating stations, little changed from the first power grids deployed in the late 1800s, lacks flexibility and smarts. We need a new grid capable of networking millions of distributed energy devices such as solar panels, wind turbines, electric vehicles, and smart appliances. We need an internet of energy that employs the latest in digital technologies. We need a Smart Grid.

How can renewable energy ‘power up’?

In coming days, we'll be talking about how to "power up" renewable energy.

Everyone's talking renewables. G8 leaders are talking about reducing CO2 emissions and increasing renewables; federal and state officials are talking about tough new renewable portfolio standards; many in the general public seem eager to embrace renewables as the only logical way to address global warming (although whether or not they are aware of the price of renewable energy remains unclear).

There's a fundamental problem, however. The one thing no one is talking about is perhaps the one thing that would make the transition to renewables work, namely energy storage.

Built to scale

Small and medium size wind generators of about 100 KW each are playing an important role in the power supplied by the Alaska Village Electric Cooperative (AVEC) -- a non-profit customer-owned electric co-op serving 52 villages throughout interior and western Alaska.

Wind power on this scale, and in these conditions, is not cheap. Unlike megawatt scale wind turbines which cost around $1,600 per KW of installed capacity, these smaller generators run around $10,000 per installed KW. Part of that cost is simply a matter of buying on a smaller scale. But according to Brent Petrie, Key Accounts Manager for AVEC, the harsh Alaska conditions are responsible for much of this cost. Building in permafrost has always been tough, especially when that permafrost undergoes seasonal melts that turns it to mush and marsh. As an environmentally sensitive utility, AVEC is careful to minimize damage during installation. Overall, electricity costs from such small scale generation are estimated by Petrie to run around 15 cents per kWh -- three to four times the price of larger scale wind farms in milder conditions.

But the same conditions that drive the price of wind electricity for the AVEC customers drive up conventional sources even more. Fuel is shipped by barge to the small isolated communities, or even flows in, meaning that electricity is supplied by diesel generators run on the most expensive of fossil fuels. Since transporting large amount of fuel is an expensive prospect, normally fuel is delivered only once a year.

According to Petrie, AVEC tries to make sure that as a cushion each village has storage capacity for 13 months of fuel. Building a diesel storage facility on permafrost is an expensive prospect too. Combined fuel purchase, shipping, and storage for diesel in these villages runs between 13 cents and 25 cents per kWh -- even before purchase and maintenance of generators is considered. Overall, electricity to these villages averages 45 cents per kWh; so the 15 cents per kWh for wind electricity represents a real savings.

Dirt cheap carbon

Great interview over on Mongabay with Daniel Nepstad, head of the Woods Hole Research Center's Amazon program. When it comes to immediate carbon emissions reductions, the biggest bang for the buck is to stop deforestation of the tropics. This revelation would have much less relevance if there were not also a mechanism envisioned to achieve it called the RED initiative (Reducing Emissions from Deforestation).

As with anything, the concept has its critics. In my unqualified opinion, one of the biggest potential flies in the ointment is fire. How do you keep a carbon sink from going up in smoke? Once the land becomes more valuable for soy, sugarcane or palm oil, how can you stop the local profiteers from setting the forests on fire, nullifying them as carbon sinks?

Hopefully, the authors of this scheme will do a better job than the bozos (again, no offense to you clowns out there) who put the agrofuel consumption mandates in place that are currently consuming carbon sinks, food, and biodiversity all around the world while simultaneously increasing CO2 emissions.

Say the developed countries to OPEC

Biofuels will provide only a small proportion of the world’s demand for fuel in the next decade, the developed countries’ energy watchdog has said in an attempt to reassure OPEC that the need for oil will continue to grow. Well I feel reassured.

Lovins v. Richter

Energy guru Amory Lovins and Nobel Prize-winning physicist Dr. Burton Richter face off, mano a mano, debating the merits of nuclear energy for addressing the climate crisis. MongaBay offers a blow-by-blow account. No one will be shocked to hear that I would call the bout for Lovins, though it was far from a TKO.

Recent report published projecting values of sea-level rise

As anyone who reads my posts knows, I am a big fan of the IPCC reports. They are the best summary of what the scientific community knows about climate change and how confidently we know it.

A recent article (subscription required, sorry) in Science suggests that some scientists view the IPCC as overly cautious:

In the latest report, its fourth since 1990, the IPCC spoke for scientists in a calm, predictably conservative tone (Science, 9 February, p. 754). It is, after all, an exhaustive, many-tiered assessment of the state of climate science based exclusively on the published literature. In IPCC's Working Group I report on the physical science of climate, 600 authors contributed to an 11-chapter report that drew 30,000 comments from reviewers. The report was in turn boiled down to a 21-page "Summary for Policymakers" (SPM). Its central projection of sea-level rise by the century's end -- 0.34 meter -- came within 10% of the 2001 number. And by getting a better handle on some uncertainties, it even brought down the upper limit of its projected range, from 0.89 to 0.59 meter.

The SPM did add that "larger values [of sea-level rise] cannot be excluded." Whatever has accelerated ice-sheet flow to the sea, the report said, might really take off with further warming -- or not. "Understanding of these effects is too limited" to put a number on what might happen at the high end of sea-level rise, it concluded. Lacking such a number, the media tended to go with the comforting 0.34-meter projection or ignore sea level altogether.

I have two conflicting views of this.

A short, powerful video

Greenpeace UK passes along this short, powerful video drawing attention to the dangers of biofuels: