February 28, 2009

Can bicycling replace 50% of driving?

First, some background. A reader offered this reference and suggested that "they reckon half the trips in america can be done in a 20 minute ride."

So, can bicycling replace 50% of driving?

Not really. First, 50% of US trips may be short enough for a bicycle, but....they're very short trips..and would only account for a relative small% of miles traveled. Second, I don't see a real analysis of how many of those trips could truly be handled by bicycles: many trips involve multiple people, large loads, bad weather, or physically limited drivers for whom bicycles will never be appropriate. I couldn't find how they calculated the 50%, but if we assume that it corresponds to their best-case scenario for bicycling market share, we're talking about 8% of miles driving, of which half (or 4%) is probably realistic. If these are slow urban miles that are more energy intensive than average, maybe 5% of fuel consumption.

Bicycling is A Good Thing, but it's not the main solution. The main (fast) solution is replacement of oil with renewable electrity, mostly in transportation, which in turn is mostly light vehicles, starting with hybrids, moving through plug-in's (for a long time), and ending with EV's.

I'd like to see a real analysis of bicycle safety vs driving; and what it would take to provide real safety; and comparison of various solutions, including lanes, boulevards* and truly separate bike roads. I think we should expand bicycling (and electric bikes, and segways), but it will take a while to do properly.

*“bicycle boulevards,” typically residential streets where traffic volume and speed are reduced to levels at which bicyclists, pedestrians, and motorists can comfortably share the road.

February 26, 2009

Do plug-in hybrids really get good mileage?

14 specially customized plug-in hybrid Toyota Priuses didn't do much better than standard Priuses in fuel efficiency. Google's own fleet of hybrids and plug-in hybrids (Ford Escapes) are only averaging 28.6 mpg while their pluggable versions of the Escape hybrd get 37.7 mpg for a 32% improvement. That doesn't sound great. (hat tip to futurepundit.com)

It looks to me like the main problem is that they're starting with a Prius or Escape. Both of these are parallel hybrids which use both the gasoline engine and the electric motor, even if you stay within the 30 mile range of the batteries. If you drive with a leadfoot or at highway speeds, the battery doesn't get used that much.

A series hybrid plug-in like the Chevy Volt has only an electric motor. It uses only the battery for the first 40 miles. 78% of commuters wouldn't use any gas at all. Combine that with 50 MPG (twice as large as the average US light vehicle) for the 20% of driving after the battery runs low, and overall fuel consumption would be reduced by about 87%* (for a 567% improvement in MPG!).

* A Volt would use about 20% as much fuel as a very efficient (35MPG) conventional car - that's 12.6% as much fuel as the average 22MPG car.

February 25, 2009

Is wind growth stopping, and hurting wind manufacturers - can we see this in the stock market?

Yes, partly.

GE, of course, has seen it's stock fall, but that's because of their finance arm. IOW, they're not a "pure play". Vestas is the other large player: I took a look at them, and they seemed to be doing
pretty well especially for a large, capital stock manufacturer. Such manufacturers are always hit hard by the stock market in a recession like this. They still seem to be profitable - and orders are increasing a bit from last year. It's not clear if world wind installations will be as high as last year (that was also affected by the US's delay in extending the PTC - that killed some early 2009 deals), but they'll still be quite healthy from a longer-term point of view.

Will wind grow in a free market?

Yes, with regulations: CAFE, cap and trade, feed-in tariffs, and utility market share requirements are all compatible with free markets - they just provide guidance to the market.

Can renewables compete with dirt cheap oil and coal ?

Not until recently, when better regulation arrived, and sparked dramatic growth in the market,which produced economies of scale, new engineering, and thus much cheaper prices.

Now, let's be clear on wind's competitiveness. Coal is the big problem: old, dirty plants are dirt cheap. They will be for 50 years, if we continue to build and use them. We don't need wind to deal with PO, we need it to deal with climate change. We may or may not decide to aggressively replace coal with wind, but it's useful to know that it wouldn't be all that expensive: just $2T, less than the cost of a lot of other things: Iraq war, the US finance bailout, etc, etc. Of course, wind has a payback, unlike war, and parts of the finance bailout - in the long run, and counting all costs, it's likely to more than pay for itself.

The main problem with energy isn't technical, it's political: the 20% of the workforce who would be made obsolete will fight it quite hard. But, it's useful to come to consensus that this is the case, and that the technical barriers aren't that big a deal.

What about oil?

The short term problem isn't electricity, at least in the US. It's more moving to PHEV/EV's, and we are, in fact, doing that. The Volt will be in large scale production in 2 years (GM is building it's future around it), and others will be as well.

What if we have a sudden oil shortage?

We have more than enough energy to build new vehicles. For that matter, we can carpool and telecommute during the transition. We really can. I'm often baffled by the lack of awareness of the potential of carpooling: the US could cut it's oil consumption by 25% in 3 months, if it chose to. It would be inconvenient, and require an emergency to do, but everyone would still get to work.

February 24, 2009

Are we running out of coal (part 2)?

Again, for better or worse, the news is that we are not.

A recent report by the US Geological Survey looks at the recoverable reserves of the Gilette field in Wyoming, currently the largest producer in the US.

It found that at current low prices, about $10/ton, that only about 6% of the coal in the field could be economically produced.

On the other hand, if the minemouth cost of coal rose to $30/ton, the retail cost of coal-fired electricity would increase only 10%*, but economically-recoverable coal reserves would increase six times. At $60/ton, 77 billion tons would become economic, enough to singlehandedly maintain US coal consumption for about 75 years. And, that's without Montana coal (Powder River), or the Illinois basin, which I discussed previously.

A spirited discusion of the report can be found here (you'll have to watch out for the tone of pessimism, which is endemic on the site).

Aren't you just taking the USGS at face value?
Not at all - I look at the detail from the USGS, the EWG, Rutledge, industry reports, etc, etc. Ultimately, I find that there really isn't disagreement on the facts, just the interpretation. Those who see coal as peaking are looking at demand for coal, in the context of cheaper and better alternatives. See more discussion of this below.

Will Peak Oil make diesel too expensive to transport coal?


A $100/bbl increase in the cost of oil would increase the cost of transporting a ton of coal by $100/bbl x 1bbl/42 gal x 2.65 gal/ton** = $6.3/ton. That's a 3% increase in the cost of electricity, which means that railroads will be easily be able to out-bid other potential users, like trucks.

Coal transportation by rail can also be converted in a relatively straightforward manner to use electricity instead of diesel, meaning that reduced oil supplies are highly unlikely to have a significant direct impact on the ability of the US to transport coal.
We're going to have to make a conscious decision to eliminate coal - it's not going to run out, and make the decision for us.

What about this report?

"Despite significant uncertainties in existing reserve estimates, it is clear that there is sufficient coal at current rates of production to meet anticipated needs through 2030. Further into the future, there is probably sufficient coal to meet the nation’s needs for more than 100 years at current rates of consumption. However, it is not possible to confirm the often-quoted assertion that there is a sufficient supply of coal for the next 250 years. A combination of increased rates of production with more detailed reserve analyses that take into account location, quality, recoverability, and transportation issues may substantially reduce the number of years of supply." From Coal: Research and Development to Support National Energy Policy

There's no real disagreement here - what disagreement there is, comes from a different frame of reference.

1st, they say "it is clear that there is sufficient coal at current rates of production to meet anticipated needs through 2030". I would argue that's probably all we need, for the transition to renewables.

2nd, they say "there is probably sufficient coal to meet the nation’s needs for more than 100 years at current rates of consumption". I would argue that's certainly all we need, for the transition to renewables (or fusion, for that matter - in 100 years things will be very different).

Finally, they say that there are risks beyond 100 years: the coal is there, but that 1) the US might dramatically increase it's rate of consumption - I think that's highly unlikely, 2) other issues may get in the way. Well, if we really were to face a situation where our economy's collapse could be prevented by digging up our national parks...the national parks wouldn't stop us.

All in all, I'd say that report supports the perspective that in the US, there's no realistic prospect of inadequate electricity caused by real, physical limitations.

*Electricity in the US is about $0.10/kWh, and US coal generates about 2,000kWh/ton. That gives a retail price of electricity of $200 per ton of coal used, so a cost of $10/ton for coal represents only 5% of the overall retail price.

**Rail transportation is about 440 ton-miles/gallon on average, and coal is at minimum 500 tm/gallon. Coal trains are probably even more fuel efficient, because the ratio of load to tare weight is greater than most other rail freight (particularly intermodal). 600 tm/g might be a good estimate. Low-sulfur coal in the US travels roughly 1,000 miles before being used (high sulfur coal travels much less).

Fuel consumption is driven by 1) acceleration and climbing; 2) drive-train friction; 3) wheel friction; 4) wind friction. 1 and 3 will rise (and fall) with weight, but not the others. If coal trains weigh much more, and will be substantially more efficient on average. Conversely, dead-head trains on the return trip from the power plant to the coal mine would consume less fuel, but the decline won't be 100%.

If the industry stat is 440m/g, we can assume that coal gets at least 600 miles/gallon one way (1.52 gallons per 1k miles). The empty train might use 50% as much the industry average for fuel on the dead-head leg (or, in effect, 880m/g, or 1.14 g/kmile). 1.52 + 1.14 = 2.65 gallons for the 2,000 mile roundtrip.

The 440m/g industry stat must include dead-heading: IIRC coal is roughly 1/3 all US train traffic, and it's not the only freight with this problem, so the above calc (which allocates this overhead cost only to coal) is conservative.

February 23, 2009

Could we run out of lithium for EV batteries?

Lithium is reasonably abundant, and reasonably widely distributed: it's mostly produced now in S. America, but China is expanding production, and there are substantial sources elsewhere. It can be recycled efficiently.

It's rather like uranium: in the short run there could be boom-bust cycles of supply expansion and shortfalls, but in the medium-term there aren't really resource limits.

There was a widely read analysis a couple of years ago that raised questions (The Trouble with Lithium: Implications of Future PHEV Production for Lithium Demand, William Tahil, Research Director, Meridian International Research, January 2007 http://www.meridian-int-res.com/Projects/Lithium_Problem_2.pdf ) but those questions have been answered pretty thoroughly. The amount used by each battery isn't that great: one estimate is that most lithium chemistries require around 3+lb/kWh of lithium carbonate, so for a 16KWH Volt type battery we would need about 50 lbs of lithium carbonate (or about 0.3kg of Lithium metal equivalent per kWh, per Tahil). At that level, there's more than enough lithium (see reference below). In the short term, battery producers are very experienced at this sort of thing - for instance GM is assembling the Chevy Volt battery from cells made by LG Chem, the largest li-ion cell producer in the world - I suspect LG is pretty good at getting long-term contracts for their supplies.

At $2.75/lb, that's only $137.50, or 3.4% of the likely Volt battery cost of $4k (wholesale in 2-4 years). A doubling in the price of lithium would only increase the cost of a $30K vehicle (after $7,500 credit) by $137.50.

Here's another good general discusion. If you want a more detailed discussion look here and here, and for some debate go here. A study by the Dept. of Energy's Argonne Lab here said "Known Lithium reserves could meet world demand to 2050".

What about recycling?

Well, according to this, lithium is so cheap currently that it hardly pays, but in a sign of unusual foresightedness, lithium recycling is being put in place. This site indicates that li-ion battery recycling is widely available.

Are lithium-ion batteries, like those in GM's Volt or the Nissan Leaf, unsafe?

No. They're using newer chemistries which are more stable than the the cobalt-based chemistry in laptops or the Tesla. A123systems iron-phosphate chemistry is very stable. Others, like the manganese-spinel LG chemistry is significantly different, and safer.

Toyota has questioned the supply of lithium. Do they know something?

No. The industry as a whole, including GM, Nissan, and Honda are banking on lithium batteries. They also are pretty good at sourcing supplies.

As far as Toyota is concerned - sadly, this is part of a pattern of dishonesty. Several years ago they committed to 1st gen li-ion (cobalt) from a supplier in their Keiretsu, and then Toyota had some Q/A PR problems, and 1st gen li-ion had thermal runaway (fire) problems, and Toyota became nervous. They decided to go w/2nd-gen li-ion, but were caught without a good supplier. They're "dissing" li-ion until they can get their act together, and on the road. This is similar to their dishonest "dissing" of competitors to the Prius, especially GM's Volt (here's an example).

You talked about short-term supply problems. Couldn't these be a problem?

Yes, and they already are. Prius and other hybrid production has been slowed down by NIMH battery shortages, and it looks to me like the same is true for li-ion batteries. OTOH, we shouldn't exaggerate the problem: the supplies are out there, and these large companies are very good at solving these problems over time. On the 3rd hand, in the case of a fuel emergency, it might be difficult to ramp up battery production overnight - we'll need contingency plans for the interim.

Uranium? You mentioned Uranium - is there a question about Uranium supply?

No, my reading doesn't support that. In the short run there certainly could be modest boom-bust cycles of supply expansion and shortfalls, but in the medium-term there aren't really resource limits.

I haven't really seen a definitive resolution of the question, but it looks to me like there are too many alternative sources of uranium, including weapons recycling, reprocessing and expansion of existing mines (including mines in the US, at substantially higher costs, of course), for us to have an absolute shortage.

Here's an example of the kind of change that might happen: "It is also relevant to note there that, as discussed above, enrichment capacity can to some extent be used to produce additional uranium supply, by operating enrichment plants with a lower U-235 assay in the tailings stream. This means that utilities can reduce their uranium demand by 10% or more provided they have access to sufficient enrichment capacity at a price which makes this economic (i.e. provided it is less expensive to buy more enrichment than to buy more uranium). Furthermore. so long as they have surplus capacity, enrichment Plant operators can physically operate their plants at lower tailings assays than that specified in contracts with utilities, effectively producing additional uranium (which they can then sell in the market). This is always likely to be an attractive option for enrichment plant operators. as their marginal costs of production will normally be less than the price paid by utilities for enrichment services." From Nuclear Development Market Competition in the Nuclear Industry: Nuclear DevelopmentBy OECD, Ad Hoc Expert Group on Market Competition in the Nuclear Industry page 60-61

It would be nice to have a really clearcut, definitive answer, but uranium supply looks nothing like oil to me. Oil flows into reservoirs. Where there are no reservoirs it's lost forever, and where there is a reservoir you have a pool with fairly defined edges, the edge of which you can hit relatively abruptly.

That's very different from uranium which is much more abundant relative to consumption, much more widely distributed, with ore-quality distribution that is much more uniform than oil.

There's a spirited discussion here.

When will we see a working Chevy Volt?


At the Chicago Auto Show I asked the woman introducing the Volt if it had a real drive-train, and yes, the Volt on display is a working model! And, there’s another as well! So, there are two completely finished Volt prototypes!

Up until now GM had a working drive-train, but they were only testing it in makeshift car bodies borrowed from other models - "mules". Now, they've assembled the whole thing, with all of the unique, electric accessories that were designed for maximum efficiency.

A milestone.

February 21, 2009

Would eliminating coal be difficult?


We'd need only about $1.6T of wind investment to completely replace coal in the US, and power all light vehicles.

How did I come up with that? Well, we generate about 50% of our electricity from coal, 220 gigawatts. Wind, on average, produces power at 30% of it nameplate rating, so we'd need about 733GW of wind. Wind costs about $2/W, so that would cost about $1,466 billion. Transmission might raise that about 10%, to about 1,613 billion.

That's actually in the ballpark of the cost of the status quo, all told, given how expensive coal plants are to build ($4-$7/W), and the cost of fueling them. It's less than the cost of the Iraq war, all told.

That's only 73GW per year over 10 years. That's quite comparable to the average amount of generation the US installs every year right now. We built about 8.5GW last year in wind alone, IIRC, and expanding that to 73GW wouldn't be that big of a deal.

No big deal at all.

If we were to go to a 100% electric economy wouldn't we need 5 to 10 times as much electrical generation?

Not really. Electrifying all light vehicles, which account for 45% of US oil consumption, would only require an increase in generation of about 17% (220M vehicles x 12K miles/vehicle x .25KWH/mile = 75GW) in overall generation (450GW).

Wind, on average, produces power at 30% of its nameplate rating, so for light vehicles we'd only need 250GW of wind (75GW/30%). Wind costs about $2/W, so that would cost about $500 billion. Transmission might raise that about 10%, to about $550 billion. That's only $50B/yr for 11 years.

PHEV/EV's won't cost any more than existing light vehicles - the average light vehicle in the US costs $28K, and you could certainly add a plug and a much larger battery for $4k.

The same thing applies to air-source heat pumps for space heating.

Electricity is much more efficient than oil and gas.

February 17, 2009

Should we prioritize walking, biking and public transport?

Well, we should encourage all of these things. I wish I had more room for titles, for what I really want to ask is: should these be considered more important than electrification of light vehicles (cars, etc.)?

The answer to that is no.

Walking can't replace light vehicles quickly. In the long run localization will help, but vehicles can be replaced 10x as fast as housing: half of all light vehicle miles driven come from vehicles that are less than 6 years old.

Ask anyone who's bicycled for any sustained distance and time - it's not very safe in most places. To be safe, biking needs large infrastructural investments in the form of dedicated, physically separated and protected lanes. Further, exercise is certainly good for you, but renewably powered electric vehicles are much lower C02, due to the FF-intensivity of our food supply.

Electric bikes are probably the very lowest CO2 transportation. Bicycling purists tend to object to them - I guess it's due to excessive emphasis on exercise, and a lack of awareness of the CO2-related benefits of electricity vs food calories. They're much more accessible for the partially disabled, and people who can't arrive at work all sweaty. The Chinese are moving to electric bicycles as well as electric cars. That's a great thing, but in the US we'll mostly use electric cars.

Bikes have bad aerodynamics: motor bikes have very poor economy given their size and weight. Bicycles are only more efficient because of their low speed. An electric bike might use only 10wh/mile, but that's at 5-15 miles per hour. Bikes have terrible aerodynamics (though not a big cross-section), so an input of 50Wh/mile will be needed to allow you to move close to the normal cruising speed for a Prius (if you're that kind of risk taker).

OTOH, a Prius at 10MPH might well use about 1 HP, or 750W, or 75Wh/mile (and less than 20Wh/pax-mile, with 4 passengers), while a bike would need about 50W. Does that make much difference? An EV would only use about 2,400 KWH's per year. That's the electricity supplied forever by .9 KW of wind capacity, which would cost about $1,800. One-time. That's not much.

But are people buying cars of any kind now?

Construction is down to 500K homes per year, vs 10M light vehicles. We'll replace vehicles 10-20x faster.

Isn't the average turn over time for the whole existing fleet of cars is about 17 years?

Until recently, cars less than 6 years old accounted for 50% of miles driven. New car sales have fallen less (-40%) than new homes (-60%).

Shouldn't we educate folks and pushing for policies that get more and more people out of their cars?

A good idea, but most people don't commute long distances because they're in love with their car: that's the only way they can find affordable housing.

Public transport is important, but slow to build. Buses can be bought quickly, but they use as much oil as the average car per passenger. They use more than a Prius, and 4x as much as a carpooling Prius. Rail is much better, because it can be electrified and because it supports Transit Oriented Development but it's slow to build. We need fast solutions for the majority of the problem.

Aren't we moving to a new paradigm of localization?

We're moving to renewably powered electricity. That will work quite well, and look a fair amount like life today. If we want to move to a different way of life, we'll have to make an explicit and separate decision to do so: PO and CC won't force the decision.

Is a gas tax a good idea? or a higher CAFE?

Yes, but any one of them won't be enough.We need all of them.

We need a tough automotive Corporate Average Fuel Efficiency (CAFE) standard to provide planning certainty.

We need feebates (fees for low efficiency new cars, rebates on high efficiency cars) or fuel taxes to make people want to buy efficient vehicles, and to properly weight operating costs. Otherwise, buyers don't want to buy them, and car companies have to lose money on small cars to sell them - that means car companies fight CAFE tooth and nail. You even have the perverse effect of low prices making small cars seem low-status.

We need taxes to give buyers of used cars an incentive for to look for efficiency: half of all miles driven are driven by vehicles over 6 years old.

Finally, everyone needs an incentive to drive efficiently.

We need a balanced set of regulations and incentives to prevent or mitigate weird results, like the SUV loophole. It's very much like tax policy - minimize any particular tax, broaden the base, and prevent odd side effects.

Here's the story that started this post.

February 16, 2009

Could solar supply all our electricity?

Yes, it could if necessary, but it wouldn't be the cheapest way to do things.

It makes no sense to try to solve our supply problems with just one source. A pure solar US doesn't make much sense for a lot of reasons:

1) The US uses an average of 450GW of electricity. At 20% capacity factor, we'd need 2,250GW of solar to provide that much. 2,250GW of solar would produce a peak of production about 3x as high as noon-time consumption (very roughly 750GW). PV doesn't have built in storage, so that would be a big problem. Demand Side Management could help (see my earlier posts), but at some point there would be diminishing returns. For CSP, even if molten salt storage is pretty cheap that's still a lot of unnecessary infrastructure.

2) Winter is also a big problem. In particular, wind is better at night and during winter. A combination of wind and solar makes much more sense, as they're complementary. We can keep existing fossil fuel plants around for the 5% of the time that we have prolonged, widespread calm periods, or use bio-mass (wood provides 1% of US electricity currently, and is much more sensible as a use for biomass than ethanol).

3) Solar is more expensive than wind (currently at least $15 per average Watt vs $6/W for wind), so we need a higher proportion of wind in the mix. Both wind and nuclear will provide power during the day, and solar would only make sense for the peak component. I can't see a need for more than about 500GW of solar, which would give us a market share of very roughly 30% of KWH's.

Here's an extremely simplified preliminary model: let's assume today's 450GW consumption, plus 75 for PHEV/EV's for a total of 525GW. Current consumption is probably 250GW for 7PM to 7AM, and roughly 650GW for 7AM to 7PM. PHEV/EV charging might raise night time demand to 350GW, and daytime to 700GW. Wind and nuclear might provide the baseload of roughly 350GW and solar could provide the daytime an extra 350GW. That would give an average from solar of 175GW, or 33%.

What about net-metering - doesn't that allow consumers to provide all of their needs through solar power?

Yes, but most net-metering programs are limited by statute to a small % of KWH's, perhaps 1%. Those caps can get lifted, as they did in CA lately, but it won't make sense economically to raise them much above 10% or 15%.

Couldn't ice-storage A/C and electric vehicles time-shift demand?

Sure, but there is a cost to ice-storage A/C, both in terms of capital and efficiency, and night time charging is a bit more natural for PHEV/EV's.

What about a massive PV farm?

Something like that would be on the utility side, and would have to compete with wholesale prices, which are half those of retail. PV is best on the retail side.

It makes more sense for PV to be on I/C rooftops, which is where 80% of CA installations (by KW) are happening, because of economies of scale and flat roofs. New construction is best because of integration with the roof, but these days new I/C construction won't provide a lot of square feet. The ideal size for consumer-side installation is about 90% of the consumer's noon demand - that eliminates the need to deal with selling power back to the utility, and maximizes savings.

Residential is 80% of installations, but they're much, much smaller than I/C on average, and much less economic. Residential only make sense currently because of the non-economic value to the home-owner, which can be substantial. Residential new construction might make sense in the future if the industry achieves very large integrated roof-module manufacturing economies of scale (right now PV roof tiles are surprisingly expensive), and if installation becomes very efficient through integration with the construction process.

How much would the non-module cost of a large PV massive solar farm run us?
The Balance of System includes controls, inverters, mounting structures, and wiring. These are a very fast moving target. Their prices have fallen very quickly in the last few years, and some innovative approaches are in competition. I would hope that overall system prices would fall to $2/W in 10 years, which would give $.10/KWH. That's the average US price currently, so I would think that it would beat peak prices in most of the country at that time.

As I discuss in a previous post, I think that we're now at grid parity without subsidies in ideal locations. That means that PV will continue to grow very, very quickly due to demand. Heck, even now in the worst bank panic since 1929, PV is still growing, albeit slowly enough that supply can finally catch up with demand and prices can begin to fall as quickly as costs.

Is there a problem with solar for peaking in the evening when people come home from work? Won't we still need natural gas for evening peaking?

That's the traditional utility point of view, which is incentivized by a regulatory framework that's based on capital investment ROI. When faced with a peak demand, they think first of new generation, then of expensive central storage.

Demand Side Management is far better, faster, easier and cheaper. Charge based on time of day, and sell cheap timers that lower the thermostat on the A/C (as well as the fridge) at noon, instead of middle evening. Overall KWH consumption rises slightly (due to a larger differential between inside and outside temperatures), but this would be far more efficient than ice storage.
Also, PHEV/EV charging will avoid peak times - GM is working very closely with EPRI and a large array of utilities and DSM companies to make it work.

People will do simple things like reducing lighting in the evening, which will reduce lighting KWH as well as A/C. People will be creative.

Dynamic pricing could cut peak demand, certainly. The regulators just have to allow it. When's that gonna happen?

Actually, it's not only allowed, it's mandated by the energy bill of 2005 - all utilities have to be offering it now. I believe PG&E is aggressively rolling it out over the next several years. The stimulus bill throws some money at this as well.

The utilities aren't all that excited by it, because the capex ROI regulatory model is still in place for most utilities. That means that most are sticking at the pilot program point, where customers can have it on request. Here's an example: http://www.thewattspot.com/ .

Even with dynamic pricing some people are going to turn on the air conditioner.

Sure, but 1) I wasn't talking about less A/C, I was talking about earlier A/C (and refrigeration) and 2) you only have to shift part of demand to move the curve earlier, to where solar shines (pun intended).

"Reduce lighting in the evening: This really undermines the utility of the light bulb. "
Much lighting isn't needed, and that if people pay a little more attention to turning out the lights when it's most expensive, that will make a difference.

I'd also note that if we move to residential PV, the capex needed for energy will become much more transparent to residential customers, and they're likely to realize that there are much higher ROI opportunities than PV, like better lighting, appliances and A/C. A/C in particular could be much more efficient with relatively small marginal investments at routine replacement points.

Won't the big cost cut for installation will come when solar panels replace roof shingles?

That certainly makes sense, but solar shingles exist now, and for some reason they're quite pricey - I'm not sure why.

That would be most true of new construction (after builders perfect the integration), as residential retrofits require a lot of custom work: evaluation of site, angle, and insolation and custom design, sizing, and wiring (including controls and inverter). Installation of wiring is going to be somewhat involved in most multi-story buildings, involving significant pulling of cable, with every installation requiring solving new problems. We only have 500K units/year of residential new construction lately, which would only get us about 2GW per year. Even at more normal construction rates, new residential isn't enough.

Industrial/commercial flat roofs are really the best place for retrofits: you tend to have unobstructed insolation (low-rise I/C districts, and few trees), flat roofs, much simpler wiring (conduit and cable chases designed for easy access and additional wiring) and much larger installations, which give you economy of scale. It's a nice fit with chains, like Walmart, that have access to a lot of buildings of similar design.

February 11, 2009

Do wind & solar need storage?

No. It is often argued that wind and solar intermittency create a need for expensive utility electricity storage facilities. I would argue that there several much more cost-effective alternatives: demand side management; geographical dispersion; and using existing generation as backup.

First, covering demand from storage for any significant time would be very, very expensive. Better to handle as much as possible with almost anything else, and use storage as a much lower priority resource.

Second, I believe there is general agreement that wind can achieve a market share of at least 10%, and probably 20%, with current load-following techniques (including modest levels of the alternatives I'll describe below), so wind can grow quite a bit without anything that might seem exotic. If wind captured only 20% of the market, it could displace 40% of coal, or 20% of coal and 50% of natural gas.

1) The first alternative is Demand Side Management (DSM): short term intermittency is far better handled with DSM than with central storage, especially as the number of plug-ins and EV's grows. DSM is almost free to utilities, and has both effectively instant response times and enormous capacity.

Plug-in/EV charging can be scheduled when it's needed. If your problem is too much wind in the middle of the night, charging can go there, and easily be 1/2 of demand. Heck, for short periods it could be as much as you wanted: visualize 150M plug-in's pulling 6KW each, for a total of 900GW!

Plug-in/EV's could also provide V2G, and provide additional supply in similar numbers.
Does it seem hard to imagine that many plug-in/EV's, or hard to imagine them ramping up quickly enough? Well, the thing to keep in mind is that they can grow as quickly as wind and solar: we could easily produce 10M plug-in/EV's per year in 10 years.

We should note that DSM for PHEV/EV's is more important than V2G. It sidesteps battery cost issues, as well as other complexities that come from using wires in two directions. OTOH, it's highly likely that the 2nd generation Li-ion batteries now being put into production will last longer than the vehicles they power, rendering the cost per cycle question unimportant for V2G.

It's important to maintain clarity about the timeframe and context of our discussion. If we're really talking about a grid that has a very large % of renewables, we're either talking about decades in the future, or a world in which our society makes a much, much larger commitment to dealing with energy issues than it has so far. In such a world, a very large number of PHEV/EV's with relatively large batteries is extremely likely. In that case, it's reasonable to assume that we're talking about over 100 million PHEV/EV's, with batteries that can effectively hold 25KHW or more. Such batteries could power vehicles for days between charges, and provide enormous flexibility for DSM (much more than a 8 hour scenario one might consider).

There is enormous potential from creative use of PHEV/EV's, potential that we are far from understanding. I would note just one: the motors in PHEV's are extremely efficient, on the order of diesels. A fleet of PHEV's would provide backup capacity on the order of 500GW that could be sustained for days, using engines that would be as efficient and far cleaner than most diesel generators. Would we want to use such a capability often? Of course not, but it's availability would be enormously valuable.

3) it's easy to exaggerate the intermittency we need to handle: it wouldn't take much interconnectedness to take advantage of geographical dispersion of negatively correlated wind and sources.

4) solar is negatively correlated with wind, both on a daily basis and seasonally.

5) we also have the option of backup by (hopefully) largely obsolete FF generation plants, so DSM (or storage) wouldn't have to handle very long (but rare) events. The US has slightly less than 1,000GW of nameplate capacity. US average generation is about 450GW, so the overall US capacity utilization is less than 50% - that's useful for people to keep in mind: we have lots of extra generating capacity, which would provide a lot of buffer, especially from Natural Gas, which is the most flexible source. That would help make it possible to dramatically expand wind generation.

I'd love to see a really good simulation of these methods. Unfortunately, no one has seen the need, as 10-20% market penetration seemed distant. There have been analyses of the benefits of combining geographically separated wind sites: they found that variance was dramatically reduced, to the point that it seemed reasonable to describe wind as base-load.

Finally, if we insist on storage, it wouldn't cost that much. A kilowatt (nameplate) of wind costs about $2,000. It might need 4 hours of storage at $120 using lead-acid (1KW x 30% capacity factor x 4 x $100/KWH) - that's not so much.

Here's an article about Google's effort to facilitate such things with in-home power monitoring (hat tip to Bob G).

Cheap solar is here!

First Solar is a very large manufacturer of thin-film PV. Their panels cost $1.08/watt to make, and sell for about $2.50/W.

These numbers are reliable: First Solar provides it's KW sales volume, and revenue $ figures in it's quarterly reports, so the $2.50 figure is pretty easy to calculate. First Solar is a publicly traded company, and those numbers are from their investor communications. If the cost data isn't real, there will be some very big shareholder lawsuits and regulatory consequences.

They're the price leader, so they're under little competitive pressure. Further, they say that costs continue to fall. A sales price of roughly 2x manufacturing cost is pretty common, so I think a sales price of $2/W in the near future is a reasonable expectation. I think that could get us to $3/W for large commercial rooftop installations.

With reasonable assumptions (25 year life, 7% interest, 20% capacity factor) we get $.15/KWH which, for S CA peak retail rates, amounts to grid parity without subsidies. A milestone.

February 6, 2009

Is the Volt's battery too large/expensive?

No. $10,000 for the Volt's battery has been widely reported in the media, but we shouldn't rely on mass media!

Really, no one knows how much the batteries cost. The $10K figure is purely speculation.

Here's an example, in the CS Monitor ( http://features.csmonitor.com/innovation/2009/01/22/worldwide-race-to-make-better-batteries/ ). We see that it doesn't say $10K. Here's what the article says: "the race isn't over making a Chevy Volt battery designed to run 40 miles on a single charge that could (emphasis added) cost as much as $10,000."

That indicates that the reporter doesn't have a firm source for this cost figure.

Elsewhere, the article says: "Still others say that the cost of new battery power for PHEVs may drop faster and already be lower than what has been widely reported at perhaps $500 per kilowatt-hour or even less, says Suba Arunkumar, analyst for market researcher Frost & Sullivan.

"I do expect the price will come down to perhaps as low as $200 per kilowatt-hour when mass production begins in 2010 and 2011," she says."

Tesla's cost is $400/KWH - it's very likely that GM will pay $200-$300 in volume.

The batteries won't be produced in large volumes for several years. They'll use less expensive materials than 1st Gen batteries; the larger format is much less expensive; and they'll have very, very large production volumes relative to most 1st-gen li-ion. Large production volumes reduce costs very quickly.

GM is pricing the Volt high purely to capture the early-adopter premium and the federal rebate - their official justification is that they're pricing in 100% replacement of the battery under warranty, which really isn't credible. We can expect the Volt to cost less than $30K with large volume production.

Is the battery too large?

Yes, they're only using 50% of the battery - a 50% depth of discharge (DOD) is very conservative. That means they have to use a 16 KWH battery to get an effective 8 KWH's. They could be more aggressive (and probably will be in the future), but they're very sensitive to the bad publicity that early battery failures would create.

Could they use a battery that allowed a deeper DOD?

No, there aren't any batteries on the market that are more durable as measured in charge cycles. Tesla's batteries aren't expected to last more than 400 cycles, and the Volt will do 5-10x as many.

In theory, the Volt could have a smaller battery. That would mean a shorter range, which would still accomodate many drivers. That might more perfectly optimize costs, but then it wouldn't feel like a big step forward. It wouldn't feel like a real EV, with generator backup - instead, it would feel like an incremental hybrid. Both GM (for PR) and buyers want a large, step forward, I think.

A plug-in parallel hybrid, like the plug-in Prius, connects to gas engine directly to the wheels, and avoids wasting energy in converting gasoline to electricity. Won't it get better mileage?

No, because there are more variables than RPM. People can get anywhere from 35MPG to 75MPG (or more) depending on how they drive. A big variable is the fact that the Volt can turn the engine off entirely, eliminating the waste that comes from just running when you don't need to.

Even if it were true (and it's not) would it matter? If the Prius can get 60MPG on the highway, properly driven, and the Volt only gets 50MPG, does that matter? A Prius, driven the standard 12k miles, uses 240 gallons/yr. A volt would use 48-60, depending on the MPG: that's only a 12 gallon difference.

Is wind/solar intermittency a fatal problem?


There are many solutions to wind & solar intermittency, each of which is very expensive if taken to an extreme, including pumped storage, CAES, or a planet girdling HVDC system. If you combine the best of each, you're likely to get a much lower cost system.

More importantly, Demand Side Management is very, very cheap, and extremely effective. It's overlooked because it's not "incented" by utility rate regulation.

220M plug-in's and EV's could provide all of the demand buffering that wind could every want. Add V2G (see here for a UK-oriented discussion), which is a bit more expensive but very practical, and you get all of the capacity you need for handling system variance on an hourly or daily basis.

All you'd need is to retain large fossil fuel plants for the 5-10% of the time when wind was calm for a week or more.

The obstacles to a renewable grid aren't technical, they're social: up to 20% of the workforce would be made obsolete. They have an enormous incentive to fight change.

Do you have references for this?

Here's a discussion by Amory Lovins's RMI: http://www.rmi.org/images/PDFs/Transportation/RMIPHEV_decouple_AESP.pdf.

On the other hand, it's very easy to analyze - no experts or peer-reviewed papers are needed.

Take 220M vehicles, with 25KWH effective capacity battery (3x that of the Volt), for a total of 5.5 Terawatt hours. Charging them using 220 volt, 30 amp connections will take about 4 hours, but create peak demand of more than the grid's current capacity, so vehicle charging would be spread out over several days, giving lots of leeway for dynamic scheduling.

If you want, say, 50% of KWH from wind then you need an average of 225 gigawatts from wind. At 30% capacity factor, that's about 750GW of nameplate capacity. An individual wind turbine can hit 100% of capacity, but a windfarm rarely goes above 85%, and a nationwide network would very rarely go above 50%, just based on the laws of large numbers (variance rises more slowly than the mean), and the fact that many windfarms would be negatively correlated to each other (one part of the country is windy, and another is calm).

That means peak wind generation might be 375GW. Night time demand might be 200GW, so we need to soak up 175GW. Our 5.5Twhr plug-in/EV fleet could draw that for 10 hours, using less than 1/3 of it's capacity.

Similar calculations apply for V2G.

Solar appears to have more short-term intermittency, which suggests that PHEV/EV buffering, with it's very fast response time, would be especially valuable for solar.

February 2, 2009

Do we face "peak water"?

Probably not for households, as long as we have plentiful electricity.  It's a very serious problem, especially for farmers, who are accustomed to very cheap water:

"A quick spin through recent headlines reveals just how badly -- and how soon -- we're going to need new supplies of freshwater: Over the past 18 months in the United States alone, the governor of Georgia declared a state of emergency due to water shortages; salmonella contaminated municipal water in Colorado; and eight states ratified the Great Lakes Basin Compact, an agreement designed to ensure that Great Lakes water, nearly 20% of the world's freshwater, won't be shipped beyond those basins -- not even to nearby Minneapolis or Pittsburgh.

Worldwide, the picture is far bleaker. Global water consumption has roughly doubled since World War II, and yet, according to the United Nations, 1.1 billion people still have no access to a clean, reliable supply. Eighty percent of disease and deaths in developing countries -- more than 2.2 million people a year, including 3,900 children each day -- are caused by diseases associated with unsanitary water. The cost of waterborne diseases and associated lost productivity drains 2% of developing countries' GDP each year."

..."In energy-rich, water-desperate countries in the Middle East and Asia, desalination already fills a vital role. Saudi Arabia currently produces about 18% of the world's desal output, and the Middle East is expected to invest $30 billion in the technology by 2015. Places such as Algeria, Dubai, Libya, and Singapore all depend on desal for drinking water. China's desal investments are expected to increase by an order of magnitude, from about $60 million to more than $600 million in the next 10 years. The worldwide market, now about $11 billion, is expected to explode to $126 billion by 2015."

..."What the world really needs is a very low cost to desalinate water. We said 10 cents per meter cubed [an 80% reduction from today's average*]. But you can't think incremental innovation will get us there. You have to think breakthrough. It will take new science, new engineering, breakthrough innovation."

..." ADC has been running a pilot study, funded partly by grants from the state of California that in 2006 produced water for roughly the same price per gallon San Diego residents pay -- and using 1 kilowatt-hour less energy per 1,000 gallons than the State Water Project. The ADC project produced an average household's daily water demands using about as much energy as a PC."


* e.g., the Israeli Ashkelon desalination plant in 2009 was selling water at 52 cents a cubic meter (aka  metric ton of water), or about .2 cents per gallon