Sustainable Energy Without the Hot Air

Sustainable Energy, without the Hot Air by David MacKay, is a book (available in its entirety online) looking at the sources of energy available, and the ways in which we use it today.  There are lots of options, but any real discussion has to, at the very least, use numbers that add up.

Straight Talk on Climate Progress in California

Andy Revkin talks to Nate Lewis about the scale of the challenge we face in addressing climate change.  Lewis (whom I took Chem 1 from at Caltech) was one of the first people to communicate the scale of the problem effectively to me, in his Powering the Planet talk.  He’s of the opinion that there are big technical gaps to be filled if we’re going to address the issue seriously — we need to learn how to do things we’ve never done before, in a technical sense.  But one of his underlying assumptions is that we will 1. have continuing economic growth globally, and 2. that this will necessarily mean an increase in energy use (even as we continue to decrease our energy intensity).  I think this need not be the case.  High quality lives are available at vastly lower energy usages than we see in the US, or even Japan and Western Europe.  They’re different, sure, but that doesn’t mean they’re inferior.  Compact, walkable/bikeable/livable cities.  Drastically reduced flying and driving, zero energy buildings, petroleum free agriculture, heirloom designed durable goods instead of cheap plastic disposable crap.  These things are huge, and make the remaining energy generation challenge much more manageable.  Yes, we still need to figure out long term storage and reliable renewable portfolio management, but it’s not the same herculean task that Lewis puts forward: of running our society as we do today, but on some other energy source.  Which simply will not work.

A Power Company President Ties His Future to Green Energy

Yale Environment 360 has an interview with the CEO of NRG Energy, a fossil fuel based, nationwide independent power producer (IPP) that sells their 22GW of generation into the wholesale market.  He’s bullish on solar PV, much less so on wind.  No mention of solar thermal.  He believes storage will be vehicle batteries.  Net metering policies and pricing will be key to broad adoption.  Given the lack of forecast energy demand increase, he sees different sources of energy (esp. coal, gas, solar, wind) having to compete for market share for the first time.  It’s important to note that as an IPP his position and incentives are much different from those of regulated utilities like Xcel, who certainly do not want to “keep [their] rates to [their] consumers down and get these electrons onto its grid at a very cheap price”.  And I think regulated utilities still make up a large majority of electrical generation in the US.

Is an Energy Transformation Afoot?


Almost immediately after we empowered Boulder to form a utility, a spate of articles appeared in the national press talking about the relative costs of coal and renewables, and the trends in those costs.  There was Krugman’s Here Comes Solar Energy Op-Ed in the NY Times, making the case that solar PV is already cheaper than coal-fired power once you remove all the subsidies we provide to both of them, and calling for the Feds to fix regulation to make that clear.  Boulder’s own RMI had a bit of commentary on Krugman’s opinion: it’d be nice if Federal regulations were saner, but even without that fix, it makes sense to build this stuff now, and will only make more sense as time goes on and the balance of system costs (which currently make up 50% or more of the cost of a PV installation) are reduced through best practices, standardization and mass production.

From the industry side, GE’s Jeff Immelt also said that federal regulation was a little beside the point now… and that even without government support GE was going all-in, expecting something like 200GW of solar to be built in China and India by the end of the decade.  That’d be a non-trivial amount of generation, on the order of 10 Three Gorges dams, or as much power as the entire US nuclear generation fleet.  Meanwhile NRG Energy, a nationwide and largely traditional fossil-fuel based independent power producer is planning to spend the overwhelming majority of its capital investment funds over the next few years on solar, mostly small utility projects (20-100MW) and distributed rooftop generation.

In the same vein, Xcel Energy’s recently filed 2011 Electric Resource Plan foresees essentially no new generation facilities being built until close to the end of the decade.  Some of this is attributable to the soft economy, but many people are saying it’s just as much a consequence of energy efficiency, demand side management, and increasing distributed (behind-the-meter) generation coming on line.  Unfortunately, Xcel added a gigawatt of coal generation to its grid last year, and this lack of demand for more energy means the company is now walking away from the transmission lines that would have enabled large-scale solar-thermal with storage in the San Luis Valley.  This means that the only way to shift Xcel’s power mix in the near future will be to accelerate the retirement of existing coal-fired generation, making room for more efficiency, wind, and solar.

The optimistic narrative that falls out of the articles above — that our energy systems are undergoing a transformation — seems plausible, and I hope that it’s true.  Certainly it’s the one that the Boulder Light and Power effort is going to be built around.  It’s comforting to see that we’re not alone on the world stage, and less daunting to imagine our job as facilitating an ongoing transformation, rather than starting one from scratch.

Xcel backing away from solar-thermal enabling San Luis Valley transmission

Xcel appears to be backing away from new transmission lines to the San Luis Valley.  This infrastructure is required to implement the several hundred megawatts of solar-thermal generation that they proposed in their 2007 resource plan.  Solar thermal is the only renewable power (other than pumped hydro, which has limited availability) for which energy storage is potentially feasible right now (e.g. using huge tanks of molten salt).  It’s interesting to contrast the utility’s statements on the San Luis Valley project with what they’re saying about the Pawnee retrofit, and what they said about the Comanche 3 plant.

Boulder’s Energy Future Is Bright

Light Pollution

Last night I went to a presentation by the Renewables Yes technical and financial modeling team.  They’ve put up a bunch of information about their modeling efforts on the web site.  I’ve organized nine short videos of a previous iteration of the presentation into a single 90 minute playlist here if you want to see it yourself.  It’s definitely worth watching if you use electricity in Boulder!  This post is my attempt to digest and rephrase their conclusions.

Continue reading Boulder’s Energy Future Is Bright

Energy Efficiency and Economics at Walnut Mews

Our condo HOA had a meeting last fall, and somebody brought up selling the flat plate collectors on the roof that are part of our defunct solar thermal hot water system.  The 750 gallon cylindrical storage tank rusted out in 2003 after 20 years of service.  The outbuilding that houses it was basically built over the tank, so swapping it out for a new one would have meant either chopping the thing up in place with a cutting torch and building a new one on site, or removing the roof, which nobody was keen on.  Some plumbing got re-routed and the tank sits there still, derelict.  It was also mentioned that the main boiler for our hydronic district heating might be nearing the end of its days.  I volunteered to look into whether it would make economic sense to repair the solar thermal system, and what the options were for the boiler.

Given that flat plate solar thermal collectors generate an average of about 1kBTU worth of heat per day per square foot (according to the US EIA), and given that we have about 250 square feet of collecting area (nine 28 square foot panels), the current system ought to collect something like 250kBTU/day.  Our current boiler consumes 520kBTU/hr worth of gas, meaning that the solar thermal system could at best displace a half hour’s worth of operation each day.  Gas costs about $8/million BTUs, so the boiler costs about $4/hr to run.  If we assume optimistically that system losses are negligible, and that the boiler runs at least half an hour a day 250 days a year (it was only hooked up to the baseboard heating, not the domestic hot water) then the solar thermal system is capable of displacing something like $500 worth of gas each year.  This is a best case scenario though, since the hydronic system needs water that’s hotter than the flat plate collectors can make it (so the boiler will have to do some work to boost the temperature) and because the system losses are almost certainly non-negligible.

Still, $500/year might be a significant savings.  To know whether it’s really worthwhile, we need to know how much it will cost up front to get this savings, and how long we ought to expect to be able to collect it (i.e. what’s the system’s expected lifetime).  I got wildly varying estimates of the cost to get the system up and running again.  At the low end it was $5000, to leave the rusty tank where it is and put a collapsible storage bladder in the crawlspace.  At the high end it was $20,000 to remove the old tank and build a new spray-foam insulated stainless steel one in its place.  I used this calculator to sanity check my energy numbers above (which don’t seem crazy), as well as the estimates.  It suggests that all in, the total system cost including installation would be something like $28,000.  I suspect that a plastic bladder in the crawlspace wouldn’t be as efficient or as durable as the new stainless tank.  For the sake of argument, let’s say the cheap option will only last 5 years, and the expensive one will last 30 years.  The original tank lasted about 20 years.  Here’s what it looks like today:

Derelict Solar Thermal Storage Tank

Continue reading Energy Efficiency and Economics at Walnut Mews

Links for the week of October 26th, 2010

If you want to follow my shared links in real time instead of as a weekly digest, head over to Delicious. You can search them there easily too.
Continue reading Links for the week of October 26th, 2010