Solar Already Won?

I forget from where, but I read this article on the Guardian yesterday.  I kept thinking about it, so decided that it would probably be worth posting about.  The article is patently absurd.  Solar has not won yet.  Not at all.  Nor have regulators and customers come fully to grips with the impacts that significant solar deployment on residences and businesses are.

The biggest unaddressed area is that of consistent power delivery.  It's what is known as "reliability" in the industry.  Your house has whatever power it needs (barring storms or some other extraordinary event), whenever you want it.  Solar doesn't work that way.  Despite the positive economics the author cites for per kWh costs, the roof-top solar customers are taking advantage of the fact that whenever the sun isn't shining (or bright enough) to cover the electricity needs, they just draw from the grid.  Reliability is not cheap, but is bundled with your power.

In my opinion, the biggest problem is the way we pay for power (at least in most of the US, I can't speak knowledgeably about Australia).  We should be paying high fixed costs to be customers of the electricity network.  The cost of the wires (distribution and transmission) and transformers and substations is substantial and doesn't vary in the short-run.  Then, we should pay a relatively low variable costs that matches what the cost to produce and deliver the power is (here, delivery would only factor in line losses).  Why don't we pay for electricity this way?

I think that the major reason we don't do it this way is that the current approach tends to incent lower consumption on the part of customers.  That is to say that if people knew they had to pay $100 per month to be connected to the network and then only 4¢/kWh, then they would be less sensitive to leaving the lights on or lowering the AC temperature.  So given that most of us pay a very small fixed component ($10?) and something on the order of 10¢+/kWh, we use less.  Conservation rules! (I guess)

Home Generation Systems

I would really like to have backup power at my house, but I'm not currently willing to pay $10k to install a propane fueled generator that would then require $4/gal propane to run it.  It turns out that gets pretty expensive pretty quickly.  What to do instead?

Alternatives to the Grid

Off the top of my head, I think the following could be alternatives:

• Backup generator
• Large-scale battery storage system
• Solar system
• Wind system
• Combined wind/solar system
• A big hole (Potential energy conversion system)

Let's explore each in turn.

Backup Generator

I'm pretty lazy and would just want my house to work in the event of a short-term grid collapse.  I'd be looking for a whole-house backup generator.  For my 400 amp service, I'm probably looking at $10k in capital costs (based on my initial discussions and research) and then more for on-going maintenance to ensure it actually comes on when I want it to.  It'd be more compelling if it were a combined heat and power (CHP) application, but that is not easily integrated into my house.  Some believe backup generators to be a bad idea.  I tend to agree.  Expensive and might not actually be there when you need it to be.  I'd prefer a simpler solution.

Large-scale Battery Storage System

I'm not an expert here, but it appears that large-ish scale batteries are costing on the order of $600/kWh of storage.  I use around 2,000 kWh during a non-summer month.  I'd be looking for something to last me at least two days.  So for that (on average) we are talking about:

2,000 (kWh/month) / 730 (hours/average month) * 48 hours = 131.5 kWh

So for that size battery, it would cost (just for the battery):

$600/kWh * 131.5 kWh = $78,900

Wowsers.  That's a big hurdle for something that will be used quite infrequently.  No.  Not going to work.  And that is before any of the balance of plant costs (e.g., electrical connections, installation, maintenance).  

Some have suggested that battery costs are going to decline steeply in the coming years down to $200/kWh and there have been sitings of Volt battery packs as low as $144/kWh.  The latter sounds like some dumping and the former sounds optimistic given that Tesla's retail price for their larger battery pack is $517/kWh.  But even at 1/4 the cost, the above battery system is still expensive at almost $20,000.  Maybe some start to see that as reasonable, but I'm not sure that I do.

Solar system / Wind / Combined Wind/Solar

I'm combining all of these because they share the same weaknesses.  You just don't know for sure if they will be there when you need them.  These won't really work unless you combine them with a battery system.  The advantage of the combination would be that you can reduce the size of the battery by the amount of "guaranteed" output from your combined wind/solar system in addition to offsetting your power usage under normal operating conditions.  The downside is that the cost per kWh of residential scale solar and wind is quite high.  Well above the 10¢ or 11¢ that I'm currently paying Dominion.  I think that this would work if I lived in the middle of nowhere and didn't want to pay to connect to the grid in the first place, but I'm already there.

Potential Energy Conversion System

I'm talking about something here that I have no idea about, pretty much just making things up.  Bear with me, they are good ideas :)  First off, I'm not talking about installing a new section of road in front of your house and harvesting energy of the passing cars.  Though, if you could get away with it and have a reasonably busy road in front of your house, it might be a great idea.  I'm thinking about two ideas: car ramp and a suspended (very heavy) weight.

Car Ramps

The idea is reasonably simple.  I think there is a good chance the power could go off tonight, so when I get home, I park my car in a very specific spot in the driveway.  I then raise the vehicle.  In the event that the power goes out, the vehicle starts to descend, its potential energy being converted into electrical energy powering the house.  This is the concept in graphical form:

Let's do the math to see what we've got here:

6,078 lbs * 6 ft = 36,468 ft-lb * 3.76616097 × 10-7 kilowatt hours/ft-lb = 14 Wh

The problem here is that I'm short by a factor of 10,000.  So despite me wanting it to work, its just not going to.  There just isn't much here unless we can dramatically increase the weight or the distance.  My car isn't going to get any heavier (thank goodness - an Expedition is super heavy as it is).

Big Hole - Gravity Power Module

As shown here, I could, with just a six meter diameter hole, have ~ 9 MWh of energy at my house.  Presumably this could scale down measurably, given that I would only need about 1/8 of a MWh (1/72nd the amount of power).  So maybe only a 1 meter whole would do the trick.  But we'd still have to drill down 500 meters.  That is a long ways, but we could double the area of the hole to half the depth.  I'm sure it would work if the concept was developed enough for commercial adoption, but its not going to be cheap in the short-run.

Conclusion

At this point, there really doesn't seem to be any cost-competitive back-up systems to the grid.  This may be a compliment to the engineering that has gone into central station power-based systems, but I think that it is the current reality.  However, how might the environment change, if only on the margin over the coming years?  Might be interesting to think about.

Residential Thermal Solar: This already makes sense and yet people aren't using it (widely) to offset energy usage otherwise.  Natural gas and power are too cheap.  This will be a much bigger deal when (if) gas and power get substantially more expensive.

Residential PV Solar: This will absolutely explode when the unsubsidized cost per kWh of solar is roughly equal (and has the prospective chance of being lower with future fuel cost increases) to the local power company.  Many will jump at the chance.   A few changes will make it even more compelling.  When we cross the threshold of 5% to 10% of residences have solar systems, the real estate community will figure out a way for them to get recognized in the sale price of the house.  Changes to the residential rate structure may make this point in time bleed out 50 years or so (we get charged a variable price for many fixed costs - as people drop off the grid or reduce their variable consumption with no change in the fixed costs - the structure will have to change - see the pain that is predicted in California in the next couple of years).  I'd still rather have a solar stirling engine in the front yard.  Talk about yard art.

Electric Vehicles: If I already have an 85 kWh battery pack in the form of my car, maybe my backup system is my car(s).  Two of them would more than cover my two day costs.  Still doesn't address the (electrical) cost of starting motors, but there are likely capacitor-based solutions to this.

Wide-Spread CHP: If I could have a mini-turbine in my furnace where the exhaust was being used to heat my air as well as my hot water, and do it at a reasonable price, I would.  Freewatt looked like a system that could have fit my needs, if the company hadn't gone away.  Somebody else will do it.  If it costs 50% of the current projected costs ($25k), I might be willing to pay the 200% premium over a normal furnace.  Not a whole-house backup circuit, but it'd run the furnaces and refrigerators and some lights.  That'd (probably) be enough.

Loss of Power

I am not an expert in the analysis of potential blackout conditions as discussed in this WSJ article.  However, I find the conclusion that by taking out only four transformers (probably actually four substations) in the eastern interconnect one could cause an 18 month blackout to be extraordinarily unrealistic.

Yes, we have some issues.  Some of them:

• It takes a long time to build high voltage transformers
• We don't have a lot of transformer building capacity in the U.S.
• We have relatively lax physical security for our substations
• We have an interdependent physical transmission network.  Losing key interconnection points will cause pain.

With respect to the last point, it should be noted that this is a good thing.  The interdependency exists because its more efficient to trade power across systems.  This is due to non-coincident electrical loads and generation outages.  This saves US electrical consumers (literally) billions of dollars a year.

What I find to be unlikely is that we can't respond to a major event like this.  Our response would be a pain, but I think that we could avoid life-altering outcomes.  We have several different ways in which we can respond (in order of escalating severity):

• Run more expensive, but more proximate electrical generation facilities.  We already have market mechanisms to deal with this and a relatively robust reserve margin to cover unexpected system conditions.
• Ask for voluntary reduction in power usage by both residential customers as well by commercial and industrial.  In the summer, this can take the form of raising the temperature in our houses another 5º.  Or not turning on the big screen TV until 7 or 8pm (after the evening peak load usage).
• Pay industrial and commercial customers to reduce their load (off of historical baselines).  There are structures (e.g., demand response) that have been effective at modifying behavior.
• Dramatically increase power rates above a certain monthly kWh usage.  This is already done to a lesser extent in the retail rate structures in many states.
• Mandate a reduction in usage.  For example, outlaw air conditioning usage, perhaps on alternate days of the week.  Impose large fines on people using air conditioning when they should not be.
• Characterize critical and non-critical buildings and usage for power.  Cut power to non-critical ones.

I could be wrong.  It wouldn't be pretty, but this would hardly bring us to our knees.