Thursday, December 18, 2014

A Simple Plan

As wind and other renewables get cheaper, intermittency will matter more.

I have an idea that I've alluded to here before and which I've been trying to explain on Twitter but which requires -- a bit -- more than 140 characters to explain.

Here it is in a nutshell: fossil fuels could make great grid-scale batteries.

The problem is this: many clean energy sources are either intermittent (solar, wind) or have the opposite problem, being "fixed" (difficult to adjust to demand) like nuclear or geothermal. This is in contrast to, say, a modern natural gas plant, which can easily adjust its output minute by minute to match the demand.

Conventional batteries continue to get better and cheaper, but right now their capacity is orders of magnitude below what would be needed to store, say two or three weeks of energy.

However we do have a large amount of energy storage in the form of fossil fuels: liquid, solid, and gas. This form of storage is stable on geological time scales and extremely energy dense. Unlike many of the alternatives, including chemical batteries, capicators, pumped hydro storage, or molten sodium, the infrastructure to store and release hydrocarbon energy is simple and cheap -- in the case of petroleum, it can be as simple as a barrel or a hole in the ground.

The storage capacity of the German natural gas network is more than 200,000 GW·h which is enough for several months of energy requirement. By comparison, the capacity of all German pumped storage power plants amounts to only about 40 GW·h (Wikipedia). 

These are some of the reasons, of course, why fossil fuels have dominated our energy mix for so long (especially in the transport sector) and threaten to do so for many decades to come. But in using synthetic fossil fuels intended to store power, rather than provide power, we might be able to sidestep the disadvantages of these fuels, whilst retaining some of the crucial benefits.

Start with a conventional gas plant equipped with carbon capture technology (assuming we ever get serious about perfecting and deploying that technology.) Then, rather than put the CO2 in the ground, feed it into a synthetic natural gas plant and use a clean energy source to turn the CO2 back into gas. Burn, capture, and un-burn as needed in a closed cycle that doesn't release CO2 into the atmosphere.

Such a program assumes an abundance of clean energy [1], since carbon capture and synthesizing natural gas both require large amounts of energy relative to the energy stored in the final product. It can easily accommodate intermittancy as well as fixed or semi-fixed outputs. Since you can package and ship fossil fuels, this also means that the generation capacity can exist far from where the power is needed.

Another advantage is that this repurposes infrastructure we already have. We already use natural gas plants to adjust output to demand. We already have literally hundreds of billions of dollars of global infrastructure dedicated to the storage, transport, and burning of fossil fuels. Using hydrocarbons this way would simply mean that we stop pulling them out of the ground and recycle the emissions back into fuel. Much of the same infrastructure could be used.

I still think you would want a smart grid, dynamic pricing of electricity, HVDC networks, and some battery (or battery-like) grid-scale storage. These might function well enough that you wouldn't need this work-around on a regular basis. But it would be available to you if, say, there was a prolonged period of low solar output, or low wind output, or if a nuclear disaster led the government to shut down some or all of the nation's nuclear reactors.

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1. If we estimate that capturing the CO2 require 30% of the energy of burning the gas, and turning CO2 back into gas requires 120% of that energy, you'd need about 1.5MWh of clean energy for every MWh of emissions-free syngas.




Friday, December 5, 2014

A scary graph

Source
Whether or not you think growth in nuclear power is a smart play -- I think, on balance, it is -- nuclear energy production declining in absolute terms is bad, bad, bad news. It's going to eviscerate efforts to cut CO2 emissions via RE. You are going to end up -- as Germany has -- substituting low carbon renewable energy for low carbon nuclear energy. Leaving fossil fuels dominating the energy mix for decades to come. No es bueno.

Tuesday, December 2, 2014

Wind turbines get better

Siemens has just installed a wind turbine with a 154-meter rotor. This is an exciting development because the higher you go, the harder and steadier the wind blows. A report by the US National Renewable Energy Laboratory (h/t The Economist) recently looked at the new generation of giant turbines in terms of the areas they open up for productive wind farms:

They made this calculation by assuming a need for a gross capacity factor of 30%. The larger turbines achieve that over a much larger area than those in common use today.

I'd be interested as to the average capacity factor of these larger turbines in areas with optimal wind conditions. Danish offshore wind farms average a capacity factor of about 40%, compared to a US average (consisting overwhelmingly of onshore turbines) of 29%. However, the wind behaves differently over oceans as opposed to on land. It's probably reasonable, as a back-on-the-envelope calculation, to suppose that onshore installations the size of offshore turbines would achieve a capacity factor that would be intermediate between the two.

Improvements in photovoltaic cells get a lot of press these days, but it is worth noting that wind energy is not a stable technology either. It is rapidly getting cheaper and more productive. Now if we as a country would invest in a grid that can ship power cross-country and manage demand with dynamic pricing, you could really see renewable energy explode.

Tuesday, November 25, 2014

What snow machines can tell us about the 21st century

Studies conducted by University of Colorado snow scientist Mark Williams and his colleagues predict that, if we continue to pollute the way we do now, skiing will be confined to the top quarter of Aspen Mountain in average years by the end of the century. Utah’s Park City Mountain Resort will have no snowpack whatsoever. The Great Melt will hit maritime ski resorts in the Cascades and Sierra even sooner. A study in New England found that only four of the region’s 14 major ski resorts will still be profitable by 2100 — if they even survive that long.
 -- "As the climate warms, skiers can kiss their Aspen goodbye"

Madeleine Thomas over at Grist has an article up with the catchy title "In the ski business, there are no climate deniers." To the optimistic mind, this might seem a herald of good things to come, as climate change's effects impact people and businesses so directly and forcefully that it's no longer practicable not to take into account. And so it may come to pass. But lurking in the latter paragraphs of the piece is a stark warning that the actions taken in response to that reality may not be what climate activists hope:
Many resorts across California, normally a Mecca for powder hounds, are being left with no option but to invest in snow-making equipment in order to stay afloat during the winter months — as much as $8 million worth within the last three years at larger resorts like Squaw Valley and Alpine Meadows. But making snow is not without its costs: At resorts like Big Bear Lake, snowmaking equipment can suck up to 7,000 gallons of water from the lake per minute, at a whopping $3,000 per hour.
Economic analyses of the costs of climate change typically assume rational adaptation -- sacrificing places and aspects of are way of life when sustaining them becomes expensive or impracticable. But the opposite reaction is all too plausible -- expending resources lavishly to sustain one's existing patterns of behavior.

We would like a ski resort owner to hasten to DC a purchase a piece of a Congressperson in the service of fighting climate change. But what they are doing in practice is buying snow machines. Just as the people feeling the heat in New Delhi are buying air conditioning. And not just there, of course, but all over the globe:

China is already sprinting forward and is expected to surpass the United States as the world’s biggest user of electricity for air conditioning by 2020. Consider this: The number of U.S. homes equipped with air conditioning rose from 64 to 100 million between 1993 and 2009, whereas 50 million air-conditioning units were sold in China in 2010 alone. And it is projected that the number of air-conditioned vehicles in China will reach 100 million in 2015, having more than doubled in just five years.
As urban China, Japan, and South Korea approach the air-conditioning saturation point, the greatest demand growth in the post-2020 world is expected to occur elsewhere, most prominently in South and Southeast Asia. India will predominate — already, about 40 percent of all electricity consumption in the city of Mumbai goes for air conditioning. The Middle East is already heavily climate-controlled, but growth is expected to continue there as well. Within 15 years, Saudi Arabia could actually be consuming more oil than it exports, due largely to air conditioning. And with summers warming, the United States and Mexico will continue increasing their heavy consumption of cool.
Beyond air conditioning or snow machines, desalinization of sea water, farmed fish, and vertical farming are all examples of energy-intensive "adaptation" that may make the long-term problem worse. This is something we are going to see a lot of in the come years, so we will need a name for it. You might call it local energy-intensive resistance (LEIR.)

I don't begrudge an Indian family a cool place to sleep or, indeed, a ski resort owner their snow, which is, after all, their livelihood. But from the perspective of the larger civilization, these energy- and carbon-intensive solutions are maladaptive, not adaptive. They exacerbate climate change by increasing greenhouse gas emissions, and in exchange temporarily mitigate the harm caused by those emissions. They solve the problem of over-exploitation of the natural world by exploiting it harder.

Since LEIRs are available only to the comparably well-off, they additionally have the pernicious effect of weakening solidarity in confronting a crisis that threatens both rich and poor. The ski resort owner with his snow machine is not likely to become a climate warrior, even though the cost of climate change is real and immediate to him. He has made a separate peace.




Friday, September 12, 2014

It's official: ENSO is fucking with us

We are now in the longest Nino-less period since NOAA record-keeping started:

Source
The last three-month period classified as El Nino was March-April-May of 2010. 51 months have passed since then (with more likely in the pipeline, given a 0.0 anomaly now.) This chart only goes back to 2002, but the full record shows what an anomaly this is. Fifty month gaps occur in 1959-1963 and again in 1978-1982. The present 51 months is longer than either.

So, how is this significant? Most simply, recent temperature trends are likely to under-estimate the long-term trends, unless a suppressed El Nino is a long-term consequence of AGW. That's possible, but most climate models predict El Nino will become more frequent and strong in a warmer world, rather than the converse.




Monday, June 30, 2014

Hell, yes!

In a Guardian piece on things that annoy climate scientists -- a piece that hit all the usual marks about ignorant politicians, people who don't understand uncertainty, etc. -- was this gem:
The thing that bugs me most about the way climate change is talked about in the media is journalists citing scientific papers without providing a link to the original paper.
Readers often want to get more details or simply check sources, but this is very difficult (or sometimes impossible) if the source is not given. I've raised this a few times, and get lame excuses like 'readers get frustrated when the journals are paywalled' but that's not good enough. Media should provide sources – end of.
-- Professor Richard Betts, chair in Climate Impacts at the College of Life and Environmental Sciences, University of Exeter, UK

 Dear God, that irritates me to no end! Not only no link, but often they don't even give you the name of the paper, or the issue of the journal it's in! (Or is going to be in.) It's 2014, cite your fucking sources! Preach it, Dr Betts, preach it!